EEVblog Electronics Community Forum

Products => Test Equipment => Topic started by: plexus on January 09, 2018, 12:16:53 am

Title: EEVBlog 121GW Discussion thread
Post by: plexus on January 09, 2018, 12:16:53 am
I searched the forum and coulnd't find an appropriate general purpose 121GW thread. So here it is!

Question: what are the various straps in the case to be used for? I can't figure them out.

Here is an unboxing video I made today when mine arrived:

https://www.youtube.com/watch?v=ttpuPpfQqRI&t=14s&ab_channel=plexuss (https://www.youtube.com/watch?v=ttpuPpfQqRI&t=14s&ab_channel=plexuss)

I'll be RTFM now that I have played around with it a bit. It's a very nice meter so far. Feels well built!

Title: Re: EEVBlog 121GW Discussion thread
Post by: Mr.B on January 09, 2018, 01:56:33 am
I don't have mine yet.
I will be in wave 2 of the shipping (March?).

My question:
The manual specifically says: Battery Type: 4 x 1.5 V AA alkaline battery (ANSI/NEDA 15 A or IEC LR6)

Can anyone (Dave) confirm if it is safe to use the slightly higher voltage Energizer L91 Ultimate Lithium
http://data.energizer.com/pdfs/l91.pdf (http://data.energizer.com/pdfs/l91.pdf)

Many thanks
Title: Re: EEVBlog 121GW Discussion thread
Post by: beanflying on January 09, 2018, 02:46:50 am
Quick Capacitance check on mine against my HP box. Does that very close 😎
Title: Re: EEVBlog 121GW Discussion thread
Post by: beanflying on January 09, 2018, 03:48:27 am
Quick resistance check against my 0.02% (1ohm 0.03%) Resistance box. Temp is 25-26 degrees btw.

It does ok below 1 ohm but that territory isn't fair on two wire so just 1 ohm and up was all I have included.

Also tested against some Vishay 0.005% (some pairs) I have 'laying' around  ::)

10k      9.999k
10k      10.000k
500R    0.5000k
500R    0.5000k
100R    100.05
5k        5.000k
Title: Re: EEVBlog 121GW Discussion thread
Post by: knapik on January 09, 2018, 04:43:23 am
I just got mine earlier today. I'm pretty happy with it so far, but I haven't really gave it any purposeful use yet.

In regards to the question about the straps, I'm pretty sure they're for securing the multimeter and leads like this. I also see that there's another strap on the back, Dave must have liked that multimeter strap patent so much, that he wanted one too ;)
Title: Re: EEVBlog 121GW Discussion thread
Post by: beanflying on January 09, 2018, 04:54:29 am
Quick DC low Voltage DC tests against an AD584M (closest Reference to hand) as per my Agilent 34401A % deviation to the 34401A of 0.02% or better.

2.49905   2.4989
5.00021   5.0000
7.49955   7.498
10.00028   9.999

AC Voltage and Frequency Referenced to Agilent 34401a.

Mains Testing
Agilent                 121GW
248.07 49.98       249.90 49.95 Hz

Feeltech Sig Gen (don't mention the war) :horse:
5V P-P (indicated) SINE used (1.7677 V rms)
5V P-P (indicated) Square wave used which is fairly clean and sharp under 1MHz
121GW 'Frequency Range' is shown not the dual scale value!
Rough test on Triangle showed reliable Frequency to 1Mhz and consistent Voltage to 100KhZ.

Indicated    Agilent SINE            121GW SINE            121GW Square
50Hz          1.7992    50.002      1.8040   49.997        2.5513   49.997
100Hz        1.7996   100.004     1.8054   99.995         2.5518   99.995
500Hz        1.7998   500.022     1.8049   499.98         2.5461  499.98
1KHz          1.7994    1.0000      1.8109  999.96         2.5521  999.95
10KHz        1.7953   10.0005     1.8408   9.9996        2.6186   9.9995
50KHz        1.7920   50.0022     1.8394   49.998        2.6634   49.998
100Khz      1.7914   100.005      1.8590   99.996        2.6617   99.995
500Khz       1.7745  500.023      .6801    499.98         0.8457   499.98
1MHz          1.8453  1.00005      0.0000  999.95         0.0000   999.96

These tests are really done for me so I have an idea when to break out the Agilent over the 121GW.

First impressions are good, Auto Range is a little slower than I would like but  :-+ :-+ so far.
Title: Re: EEVBlog 121GW Discussion thread
Post by: beanflying on January 09, 2018, 07:13:52 am
Doing some 'advanced' testing of my reference cabinet. Seems to much 'testing' happening and insufficient drinking the beer is nearly at pommie temp  :-DD

Reference 4 wire RTD against the supplied K thermocouple is within spec at this sort of temp.
Title: Re: EEVBlog 121GW Discussion thread
Post by: fanOfeeDIY on January 09, 2018, 12:07:41 pm
I also made unboxing video. :)

First time to upload a video on youtube.

EEVblog Multimeter Unboxing, Continuity Voltage review
https://youtu.be/tqFaSVsl-R4
Title: Re: EEVBlog 121GW Discussion thread
Post by: lowimpedance on January 10, 2018, 04:13:23 am
Gotta say the weight of it was a bit of a surprise! but it gives that solid built feel  :-+. Nice addition to my already to large a collection of DMMs  :D.

Pic of my 'Blog' related tools
(yes I have taken its blue jacket of for a closer inspection!)
Title: Re: EEVBlog 121GW Discussion thread
Post by: beanflying on January 11, 2018, 12:30:56 am
Temperature logging commenced. 10s intervals. Nearly time to head to the beach or crack a beer while it logs  8)

edit - topped 30 before midday Beach time (sorry Northerners  >:D )
Title: Re: EEVBlog 121GW Discussion thread
Post by: Terry01 on January 11, 2018, 12:59:31 am
I also made unboxing video. :)

First time to upload a video on youtube.

EEVblog Multimeter Unboxing, Continuity Voltage review
https://youtu.be/tqFaSVsl-R4

Nice 1st video buddy.

The EEV meter looked very slow auto ranging? It was quick showing continuity and never missed a beat. You made a very good point too though that not 1 meter does everything the best. Having a couple (3 or 4) is a good idea as you cover all bases.
Look forward to your next video.
I hope you enjoy your new meter and it's all you hope for. Thanks for sharing  :-+
Title: Re: EEVBlog 121GW Discussion thread
Post by: beanflying on January 11, 2018, 04:33:18 am
Dropped onto David's Droid software app while the meter was logging Temperature to the card. Hooked up fine and displayed the data in graph form and mirrored the display  :-+

Hit the save button and it allowed me to save the raw captured data from the start of the sync period till then. Would be nice to have maybe a screen capture option as well.

Raw data captured via bluetooth below. Full log to follow off the SD card which is about 1500 records at 10 seconds.

The Time Stamp I haven't tried to figure out? Perhaps David might chime in?

time (s), Temp (°C)
1.734916, 36
3.002225, 36
5.636383, 36
8.999986, 35.9
9.731009, 36
10.41355, 36
10.6082, 35.9
12.41178, 35.8
13.72841, 35.8
14.41105, 36
Title: Re: EEVBlog 121GW Discussion thread
Post by: beanflying on January 11, 2018, 06:09:00 am
SD card logs follows. Over 1500 records without a glitch (except record 1 being way low?). It is CSV formatted and as the site doesn't allow that format included as Libre Calc and Excel below if anyone is interested.

Couple of observations on the logged data and the format. After the very last record the maximum and the minimum values are stored and will need to be either excluded from the list or moved elsewhere in the data for any post processing. I gather the meter appends them both after each write to the log file? If not can they be moved to the top of the log file with the other headers? If not just something to be aware of.

For a meter that has an internal RTC and Calendar not having an actual time against the recorded data is a PITA.
Basics of it however is it logs data easily and reliably. As you will see from the data there is plenty of other unused columns already.

The sample logs below are a Small log of a VRef last night. Big log of the Temps today (over 36C)  :popcorn:

Title: Re: EEVBlog 121GW Discussion thread
Post by: BravoV on January 11, 2018, 06:12:05 am
It is CSV formatted and as the site doesn't allow that format ....

Compressed file ZIP is allowed, also usually CSV has high compression rate.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Seppy on January 12, 2018, 01:55:07 am
Dropped onto David's Droid software app while the meter was logging Temperature to the card. Hooked up fine and displayed the data in graph form and mirrored the display  :-+

Hit the save button and it allowed me to save the raw captured data from the start of the sync period till then. Would be nice to have maybe a screen capture option as well.

Raw data captured via bluetooth below. Full log to follow off the SD card which is about 1500 records at 10 seconds.

The Time Stamp I haven't tried to figure out? Perhaps David might chime in?

time (s), Temp (°C)
1.734916, 36
3.002225, 36
5.636383, 36
8.999986, 35.9
9.731009, 36
10.41355, 36
10.6082, 35.9
12.41178, 35.8
13.72841, 35.8
14.41105, 36

Yeah, so SD card records the samples in a sort of indexed form.
As Bluetooth LE is sensitive to interference and the packet sent doesn't contain the sample index the app records the time that the packet was received successfully.
Title: Re: EEVBlog 121GW Discussion thread
Post by: flano on January 12, 2018, 08:55:24 am
Is there a link for the firmware download?

I have 1.01, however I see some videos show 1.02?

Thanks Mike
Title: Re: EEVBlog 121GW Discussion thread
Post by: FrankBuss on January 12, 2018, 03:55:10 pm
I thought about buying one, because I really like the low burden voltage, logging, and bluetooth connectivity. But this thread (https://www.eevblog.com/forum/testgear/eevblog-121gw-multimeter-issues/) suggests that it might be better to wait for the next revision, especially the reported contact problems of the rotary switch worries me. Can someone confirm this? The other problems, like unusable 7 seconds for ohms autorange, hopefully can be fixed by firmware updates.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Iagash on January 12, 2018, 08:18:53 pm
I thought about buying one, because I really like the low burden voltage, logging, and bluetooth connectivity. But this thread (https://www.eevblog.com/forum/testgear/eevblog-121gw-multimeter-issues/) suggests that it might be better to wait for the next revision, especially the reported contact problems of the rotary switch worries me. Can someone confirm this? The other problems, like unusable 7 seconds for ohms autorange, hopefully can be fixed by firmware updates.

Well I had two days fun with the meter and tried a lot of things. I think the switch is fine. Over the time I had a lot "malfunctions" of the switch and think it is firmware related.
One time when I switched the meter on from the right side off-position to the mA range it dropped me into LowZ mode, which is on the other side of the switch next to the left off-Position.
This clearly makes it look like firmware problems.

The build quality of the meter is great and I like the size and I don't care about the slow autoranging, it's still faster than me twiddling the range switch on my manual meter.

The 15V diode test is great and the low burden voltage is also very nice.

But the firmware seems to stem from the shadiest corners of the shenzhen market. No matter in which of the "advanced" software features of the meter I look, it's broken or messed up.

So the future will tell if this becomes a good meter or not. The hardware seems great but until there is a firmware that deserves the name it's hard to tell.

If you want something to play with, get one. If you want a "tool" you can trust I'd rather recommend you wait if UEI will either publish enough of the firmware sources that someone who can writes one or they cobble up a firmware that works. Adding up the issues I found, my guess would be that it rather needs to get rewritten than fixed, since some of the bugs point more in the direction of software design errors (look at the bluetooth protocol thread) than just bugs, but I might be totally wrong on that since I have way too little background information.

At the moment it's not an advanced meter but a well built prototype with basic features and hardware working.

That doesn't mean I regretted it one second to get one. It's just to adjust the expectations on a meter that received very limited testing upto now.

If you want something working, you never buy the first revision.
Title: Re: EEVBlog 121GW Discussion thread
Post by: beanflying on January 13, 2018, 09:32:30 am
Without knowing the actual code used for the autoranging I would suspect bloated and lazy code may be part of the issue. It is also possible looking at the bar graph that it is running a loop more than necessary to set a range. I think Dave needs a bit of time to get back from his break and do some to and fro with UEI and nothing really can be gained until that happens.

Apart from the bluetooth data issue above I haven't found an issue but I will set up some more logging tests over the next couple of days as my schedule is a bit lighter.

On the rotary switch I like the general feel of it and it works on the stand with two fingers to turn it. Once again no issues with it.

Very unlikely UEI will publish their firmware and I think that has been made more than clear. The original kickstarter without checking only talked about open source on the bluetooth communications protocol? My meter is still on 1.01 btw but perhaps when future updates are made Dave can put up a changelog along with them?

Title: Re: EEVBlog 121GW Discussion thread
Post by: dcac on January 13, 2018, 03:48:15 pm
Without knowing the actual code used for the autoranging I would suspect bloated and lazy code may be part of the issue. It is also possible looking at the bar graph that it is running a loop more than necessary to set a range. I think Dave needs a bit of time to get back from his break and do some to and fro with UEI and nothing really can be gained until that happens.

Decent speed on Auto-ranging is such a basic function that you’d think Dave made sure of this during the early stages developing the 121GW. And I can’t really see a reason they needed to change anything, and possibly introduce bugs, in those routines. But I agree that the display behaviour during auto-range seems to do some (weird) extra steps or delays, but still I’m not too optimistic an easy fix is going to speed things up enough.

And also the eevblog “VIP" members who had more insight in the early development doesn’t seem a least bit surprised over this issue - even though it’s been established that the 121GW is twice as slow as the U1282A - a DMM Dave even have >warned< about having “Very slow” auto-ranging.

Title: Re: EEVBlog 121GW Discussion thread
Post by: FrankBuss on January 13, 2018, 03:59:17 pm
Decent speed on Auto-ranging is such a basic function that you’d think Dave made sure of this during the early stages developing the 121GW.

Right, that's odd. Usually Dave is not biased and says that some aspect sucks if it sucks, even if he gets money from something. Maybe it is difficult with the high precision? But I guess they could show a few most significant digits fast, then the final result after some seconds if you need it.
Title: Re: EEVBlog 121GW Discussion thread
Post by: 1anX on January 13, 2018, 10:05:59 pm
At the moment it's not an advanced meter but a well built prototype with basic features and hardware working.
If you want something working, you never buy the first revision.

From what I've been reading, Iagash has it summed up with his above quote!

The meter I bought from Dave's kickstarter campaign is in the second production run, so I have my fingers crossed the early firmware bugs are sorted. Buying a version 1.0 is always an act of blind faith but I'm sure Dave will get it sorted out once he is back from his break.

I'm tipping it has not been a relaxing time for Dave with a fake campaign running his product and reading of the teething problems with the nicely made and manufactured EEVBlog 121 GW meter. He could not have picked a worse time to be on "holiday" than with the release of a best selling new product. Hurry home Dave we miss you, and your ability to fix complex electronic things, and to make us smile while you do it!

One of the reasons I waited for this meter to become available was that I believed Dave had some great ideas put into its design. Also Dave's character came into play as he comes across a straight talking no BS engineer. The hardware looks good, lets see if the bugs can be fixed quickly as more owners test the meters and more insights become known. 
Title: Re: EEVBlog 121GW Discussion thread
Post by: mattselectronics on January 14, 2018, 01:02:21 am
I made a short video about it:
https://youtu.be/Ao2Is4LeQIY (https://youtu.be/Ao2Is4LeQIY)

I like it, but the slow auto rangeing is a bit annoying. I hope they can do something about that in software.
Title: Re: EEVBlog 121GW Discussion thread
Post by: 1anX on January 14, 2018, 01:48:12 am
Matt, I liked the video you made!

You commented on the hassle of getting the SD card out from the meter to have access to the csv file for processing. Maybe Seppy, (Dave 2) can comment, but cant you have access to the csv file from the BLE app? I'm assuming the app on android can use dropbox, etc, or maybe the app is also available for your PC?

I would like to know if this is possible with the app?

The accuracy of the meter looks really good from what I have seen so far, just the slow autoranging holding back its full potential.

Title: Re: EEVBlog 121GW Discussion thread
Post by: beanflying on January 14, 2018, 05:12:36 am
Dropping the card out is a bit of a PITA. In general use for me I may only log data with this meter occasionally. Even then being able to check Min/Max figures would do me a lot of the time.

On the other hand my two Victor 86B's are strapped to my coffee roaster and get used 10-30 times a week every week. I also have a couple of Agilent DAQ units I am playing with. Plus a heap of independent Temperature logging gear.

Below is some sample data from the shack on why I have a UPS arriving on Monday. On AC the 121GW logs Voltage and Frequency btw. Approximately 40m cable run from the main switchboard over 1kW of commercial refrigeration, 3.3kW of coffee machine or 3.6kW of Roaster plus the electronics gear.  :o

The Voltage troughs in the graph are the elements of the Coffee machine kicking in and out. 10 Seconds per log point.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on January 14, 2018, 06:53:44 am
Dropping the card out is a bit of a PITA.

It takes me 18 seconds to remove the boot, undo the screws, take off the cover remove the SD card and insert into the PC.
It takes often longer to dick around with a Bluetooth connection.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on January 14, 2018, 06:55:16 am
You commented on the hassle of getting the SD card out from the meter to have access to the csv file for processing. Maybe Seppy, (Dave 2) can comment, but cant you have access to the csv file from the BLE app? I'm assuming the app on android can use dropbox, etc, or maybe the app is also available for your PC?
I would like to know if this is possible with the app?

It is not possible with the app, the meter firmware does not support this.
This was discussed at the time but UEi said it would not be particularly easy, and with all the other stuff on the list it was decided not to add it Because:
a) The bluetooth app does data logging anyway
b) It fairly trivial to remove the SD card if you are doing long term standlone logging. e.g. <20 seconds to remove the card vs all day logging or whatever, it didn't seem like a big deal.
c) If you are doing a lot of serious data logging then you should have a dedicated and more versatile data logger to begin with.
Title: Re: EEVBlog 121GW Discussion thread
Post by: mattselectronics on January 14, 2018, 11:05:08 am
Dropping the card out is a bit of a PITA.

It takes me 18 seconds to remove the boot, undo the screws, take off the cover remove the SD card and insert into the PC.
It takes often longer to dick around with a Bluetooth connection.

That is very true, Bluetooth can also be a big PITA.  8)
As soon as there is PC support, I'll probably use that instead anyway.
Title: Re: EEVBlog 121GW Discussion thread
Post by: dcac on January 14, 2018, 09:43:47 pm
https://www.youtube.com/watch?v=Zele19jm1MQ (https://www.youtube.com/watch?v=Zele19jm1MQ)

Skip to 16:30 - Dave comments on the auto-ranging speed - infinity to zero ohms, for reference i measured it to 1.6 sec.

Title: Re: EEVBlog 121GW Discussion thread
Post by: dcac on January 14, 2018, 09:50:37 pm
https://www.youtube.com/watch?v=9LjWtdgJhkg (https://www.youtube.com/watch?v=9LjWtdgJhkg)

Skip to 12:00 - joe smith comments on the auto-ranging speed - infinity to zero ohms, for reference I measured the Gossen to 4.1 sec and the Brymen to 1.6 sec.

And the 121GW has been measured to 7.4 sec - so in this comparison its really nothing but a toy. Though this was ohms measurements and possibly just an 'annoying' issue - if you instead were measuring potentially dangerous voltages - you really want the meter to show the result as fast as possible so you don‘t have to change focus too long from where/how you’re holding the probes. A good practice is of course to put the meter in its highest manual range if you are expecting high voltages, but if you happen to forget that, or if high voltages happen to be present where they really should not be, then a fast auto-ranging DMM is much safer than a slow one.

The same goes for low voltage measurements - the faster you get the result the less chance it is of slipping with the probes possibly shorting something out causing damage to the circuit.

 
Title: Re: EEVBlog 121GW Discussion thread
Post by: scopeman on January 15, 2018, 01:57:30 am
Hi Dave,

Nice Job on the 121GW. I was wondering why you did not have the DC volt range go to 1kV. I think that is the only think that holds me back on this meter at the moment.

Maybe in GEN II?

Sam
W3OHM
Title: Re: EEVBlog 121GW Discussion thread
Post by: beanflying on January 15, 2018, 02:40:50 am
Dropping the card out is a bit of a PITA.

It takes me 18 seconds to remove the boot, undo the screws, take off the cover remove the SD card and insert into the PC.
It takes often longer to dick around with a Bluetooth connection.


That is very true, Bluetooth can also be a big PITA.  8)
As soon as there is PC support, I'll probably use that instead anyway.

True :) If I was likely to use the SD card for remote logging a lot hacking a slot in the side and putting a remote SD reader. Providing the opening was under the boot somewhere would do the job or even a secondary silicone plug for the opening.

About to set up a very boring bluetooth logging session and video it  :=\
Title: Re: EEVBlog 121GW Discussion thread
Post by: amspire on January 15, 2018, 05:47:26 am
Just noticed that the 1.01 firmware file is on my SD card -

EEVBlog.bin - 117840 bytes - 21st Dec 2017.

i guess the people with firmware 1.02 may have the 1.02 firmware file. Can anyone with 1.02 confirm this? Not sure I actually want to do the update until I get an official update file from Dave. We do not know the difference between the 1.01 and 1.02 firmwares. Could even be a fix for a particular batch of production units that didn't work properly with 1.01.
Title: Re: EEVBlog 121GW Discussion thread
Post by: beanflying on January 15, 2018, 06:08:04 am
Seems most of the Aussie meters might be 1.01? Not in a rush to try and upgrade at this stage.

Boring as Bat Guano video  :=\ Sorry should have had the 121GW backlight on from the beginning. Switched on about 5 minutes in. Bluetooth hiccuped with the first attempt at connecting but hooked up second time around. The Coffee indecently was delicious  ;D

Log below is what I got from the phone app after the entire session. Seems from looking at the video an expected lag but also plenty of either not sent or dropped points? Also the Frequency doesn't seem to have gone into the log but given the stage of the Apps development and data dropping not a big concern.

https://youtu.be/Pm52dcpq2Ac
Title: Re: EEVBlog 121GW Discussion thread
Post by: amspire on January 15, 2018, 06:14:58 am
You will definitely get dropped readings on the Bluetooth. The meter is meant to read at 5 times a second I think, but the Bluetooth sends reading only about once per second. It might then take a second or so for the reading to appear on the 121GW App.
Title: Re: EEVBlog 121GW Discussion thread
Post by: FrankBuss on January 15, 2018, 12:22:38 pm
Skip to 16:30 - Dave comments on the auto-ranging speed - infinity to zero ohms, for reference i measured it to 1.6 sec.

Dave was 8 years younger in this video. When you get older, you are not that impatient anymore  ;D
Title: Re: EEVBlog 121GW Discussion thread
Post by: hyvamiesh on January 15, 2018, 04:11:42 pm
Anyone know what kind of magnetic strap will fit the meter?
Title: Re: EEVBlog 121GW Discussion thread
Post by: iainwhite on January 15, 2018, 04:40:56 pm
The Fluke magnetic hanger that came with my 179 will fit but it has 1/4 inch of play and is not ideal as it is designed for a semi-circular opening (see picture)
However it does hold the 121GW.

Edit:   The Klein tools Model #69190 sold by Home Depot looks like it might fit as it has a square clip.  I will take a closer look next time I visit HD...


Title: Re: EEVBlog 121GW Discussion thread
Post by: dcac on January 15, 2018, 09:20:06 pm
Skip to 16:30 - Dave comments on the auto-ranging speed - infinity to zero ohms, for reference i measured it to 1.6 sec.

Dave was 8 years younger in this video. When you get older, you are not that impatient anymore  ;D

Yes but the DMM Dave is reviewing is then also an 8 year old design. And i.e. MCU performance has increased quite noticeably since then - so 121GW should reasonably be expected to be equal or better in auto-range performance.

To me it’s totally unbelievably Dave would use high quality components - like a good reference and a modern MCU - and then severely limit the 121GW’s practical usability with a ridiculously - possibly even dangerously - slow auto-range speed.

Title: Re: EEVBlog 121GW Discussion thread
Post by: IanB on January 15, 2018, 09:42:04 pm
To me it’s totally unbelievably Dave would use high quality components - like a good reference and a modern MCU - and then severely limit the 121GW’s practical usability with a ridiculously - possibly even dangerously - slow auto-range speed.

It's not like someone would have said, "let's make it slow", and then did it deliberately. One day you have to ship product. You can't hold back forever, fixing every last detail before letting something out the door. If you do that you won't be in business.
Title: Re: EEVBlog 121GW Discussion thread
Post by: FrankBuss on January 15, 2018, 10:11:48 pm
It's not like someone would have said, "let's make it slow", and then did it deliberately. One day you have to ship product. You can't hold back forever, fixing every last detail before letting something out the door. If you do that you won't be in business.

For me 7 seconds autoranging is not a detail, and of course he didn't show this in his Kickstarter video, I guess otherwise it wouldn't have sold that much. But it would be the first thing he would show in one of his EEVblog review videos for other multimeters.

I hope they can fix it in the firmware, then it would be really useful for me. I don't think there are any other meters in this price range and precision, and with all these features, like the VA mode, displaying the burden voltage for current measurement, bluetooth, logging etc.
Title: Re: EEVBlog 121GW Discussion thread
Post by: dcac on January 15, 2018, 10:51:15 pm
To me it’s totally unbelievably Dave would use high quality components - like a good reference and a modern MCU - and then severely limit the 121GW’s practical usability with a ridiculously - possibly even dangerously - slow auto-range speed.

It's not like someone would have said, "let's make it slow", and then did it deliberately.

Thanks for pointing that out - I didn't mean to imply it was a deliberate act to make it slow.

This DMM been 2 years under development and I just can't understand how on earth a basic thing like this issue was missed - or supposed to be good enough - you use auto-ranging most of the time you use a DMM - if it has that feature.

Title: Re: EEVBlog 121GW Discussion thread
Post by: IanB on January 15, 2018, 10:59:11 pm
This DMM been 2 years under development and I just can't understand how on earth a basic thing like this issue was missed - or supposed to be good enough - you use auto-ranging most of the time you use a DMM - if it has that feature.

Sometimes the reality of working with a distant development team is that you cannot always get what you want out of them. For instance, if they don't know how to make auto-ranging faster, you might ask them again and again to make it faster, and it will be to no avail. If they don't know how to do it, they don't know how to do it. And if you don't own the team, what can you do about that?

I'm not saying this is what happened here, but this is the real world of product development, and things like this do happen. Just read all the complaints from Simon about the sub-contractors he works with...
Title: Re: EEVBlog 121GW Discussion thread
Post by: dcac on January 15, 2018, 11:53:04 pm
This DMM been 2 years under development and I just can't understand how on earth a basic thing like this issue was missed - or supposed to be good enough - you use auto-ranging most of the time you use a DMM - if it has that feature.

Sometimes the reality of working with a distant development team is that you cannot always get what you want out of them. For instance, if they don't know how to make auto-ranging faster, you might ask them again and again to make it faster, and it will be to no avail. If they don't know how to do it, they don't know how to do it. And if you don't own the team, what can you do about that?

I'm not saying this is what happened here, but this is the real world of product development, and things like this do happen. Just read all the complaints from Simon about the sub-contractors he works with...

If that was the case - I think it would be very important to provide that information - that the manufacture had failed to meet - what I would call a very basic functionality.

With the secrecy surrounding this project especially in its early stage , perhaps some information might have been missed or messed up i.e. when Dave got somewhat annoyed when he thought joe smith perhaps went too far in his 121GW prototype testing ,several videos was taken down in that event. But what do I know - for sure though I do not think Dave ever was trying to ‘scam’ anyone.

When Dave gets back he can address this the way he feels appropriate. Can the 121GW be speeded up? what auto-range speed would the current HW allow?

Title: Re: EEVBlog 121GW Discussion thread
Post by: beanflying on January 16, 2018, 12:59:11 am


This DMM been 2 years under
....
I'm not saying this is what happened here, but this is the real world of product development, and things like this do happen. Just read all the complaints from Simon about the sub-contractors he works with...

And it is a meter you DON'T have one of and have spent the last 20 of your posts posts beating the drum on one point  :horse:

You have added what to the constructive debate and or knowledge on the product?  ???
Title: Re: EEVBlog 121GW Discussion thread
Post by: dcac on January 16, 2018, 02:50:02 am
I think re-posting them would add little value at this point.

The only value I can see in those prototype videos would be if they somehow showed (significantly) faster auto-ranging than what's now been determined in the production model.

Title: Re: EEVBlog 121GW Discussion thread
Post by: nidlaX on January 16, 2018, 03:53:36 am
Not meaning to beat a dead :horse:, but here's another example of slow autoranging on a high end handheld DMM:

https://www.youtube.com/watch?v=goj8HomoKJY&t=3m11s (https://www.youtube.com/watch?v=goj8HomoKJY&t=3m11s)
Title: Re: EEVBlog 121GW Discussion thread
Post by: dcac on January 16, 2018, 08:44:16 am
@nidlaX - Thanks for your input - and very useful review!

From infinity to zero ohms I measured the Yokogawa to 3.4 sec and the Fluke to 1.9 sec - interesting with the Fluke that the display doesn’t seem to react at first but then it shows the value quickly. Also should be pointed out those DMM only went down to 10milliohms resolution - where the 121GW goes down to milliohms - but I’d give that up anytime for faster speed.

Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on January 16, 2018, 10:45:25 am
When Dave gets back he can address this the way he feels appropriate. Can the 121GW be speeded up?

Almost certainly.
It is being worked on as the first priority, but do not ask for an update, I do not have one.

Quote
what auto-range speed would the current HW allow?

That's a much harder question to answer. Look at the Keysight 1282A perhaps, that uses the exact same front end chipset.
Title: Re: EEVBlog 121GW Discussion thread
Post by: dcac on January 16, 2018, 08:24:32 pm
I think re-posting them would add little value at this point.

The only value I can see in those prototype videos would be if they somehow showed (significantly) faster auto-ranging than what's now been determined in the production model.
So you basically just want to know if anything has changed.  This makes sense.  I setup a very simple test where I placed both the preproduction 121GW and Gossen M248B next to one another with a stop watch.   I then drove the two meters using a common source between there min and max ranges.  So both meters are triggered at the same time for all practical purposes. 

https://youtu.be/Gj9GrW2hi1c

Thanks for showing this!               

And here’s the major WTF moment - infinity to zero ohms - the Gossen is 4.1 sec just like I measured before - but the prototype 121GW is 3.8 sec!! compared to 7.4 sec on the production model I measured in Robert Culver's video - who showed how slow it was compared to his U1253 - a DMM Dave had ridiculed for being slow long time ago.

I wouldn't be surprised if joe got a cleaner more consistent contact is his test and possibly Robert Culver (unknowingly) had a bad probe or lead.
 
Also much of the ‘commotion’ with this issue being people’s different perspective of a fast/slow DMM - and not really prepared for what to expect with the 121GW - which was why I started to measure the time as accurate as possible in the video clips.

The U1282A was 3.5 and about 3.0 sec in 9fps mode - still kinda slooowish but more acceptable and hopefully 121GW can beat that.

Title: Re: EEVBlog 121GW Discussion thread
Post by: kcbrown on January 16, 2018, 08:54:34 pm
I think people are ignoring what is perhaps the most important question about this meter:  can it handle a 1.21GW burst of electricity?    ;D

Sadly, nobody has performed such a test, perhaps because it's difficult to put together.  Even Joe might not be able to do that.  Sounds like it might be a good opportunity for him to expand his pulse test equipment lineup.    :-DD

We're rooting for you, Joe!
Title: Re: EEVBlog 121GW Discussion thread
Post by: 1anX on January 16, 2018, 09:35:13 pm
When Dave gets back he can address this the way he feels appropriate. Can the 121GW be speeded up?

Almost certainly.
It is being worked on as the first priority, but do not ask for an update, I do not have one.

Quote
what auto-range speed would the current HW allow?

That's a much harder question to answer. Look at the Keysight 1282A perhaps, that uses the exact same front end chipset.

Looks to me like Dave has answered the most asked question in all the numerous discussions on this meter on this forum! Maybe just maybe, we can move on for a moment to some other areas of discussion?

Personally I'm annoyed by this issue just like everyone else, but "for the love of god", (quoted ya Dave) can we give them a little time to bring out the new firmware fix!
Title: Re: EEVBlog 121GW Discussion thread
Post by: joeqsmith on January 16, 2018, 11:03:07 pm
I think people are ignoring what is perhaps the most important question about this meter:  can it handle a 1.21GW burst of electricity?    ;D

Sadly, nobody has performed such a test, perhaps because it's difficult to put together.  Even Joe might not be able to do that.  Sounds like it might be a good opportunity for him to expand his pulse test equipment lineup.    :-DD

We're rooting for you, Joe!
Maybe someone will send one to photonicinduction to put across his large cap.   :-DD

Thanks for showing this!               

And here’s the major WTF moment - infinity to zero ohms - the Gossen is 4.1 sec just like I measured before - but the prototype 121GW is 3.8 sec!! compared to 7.4 sec on the production model I measured in Robert Culver's video - who showed how slow it was compared to his U1253 - a DMM Dave had ridiculed for being slow long time ago.

I wouldn't be surprised if joe got a cleaner more consistent contact is his test and possibly Robert Culver (unknowingly) had a bad probe or lead.
 
Also much of the ‘commotion’ with this issue being people’s different perspective of a fast/slow DMM - and not really prepared for what to expect with the 121GW - which was why I started to measure the time as accurate as possible in the video clips.

The U1282A was 3.5 and about 3.0 sec in 9fps mode - still kinda slooowish but more acceptable and hopefully 121GW can beat that.
 

No problem.  Keep in mind both meters change states at the same time.  You can't tell when this happens in the video, only that the meters do eventually start to respond.   You can however tell which meter is faster by which settles first.  There is a fair amount of variance.  Again, I am not mechanically switching the signals for these tests.  As far as the response of the meter, consider the switching errors in the setup negligible.

For those of you that have an obsessive compulsive disorder, I setup another test.  This time using the a frequency counter and Arb to count 1ms events.  Events are sent to the counter at the same time the signals are sent to both the Gossen and prototype UEI meter.    After 10 seconds, I remove reset each meter to their over range state. 

I made four short to open cycles.  Sorry but the high frame rate of the camera limits recording to 4 seconds and the meters are just too slow to capture the entire event.   So I stretched the start and stop of each event to help provide a better estimate.   

For the true OCD people out there, this is not going to be enough.  So I set the camera to manual trigger at 1000fps.  I then captured the last few seconds where the meters settle.  I then repeat this a second time.  Just in these two cycles, we can see the UEI meter change by roughly 40ms and the Gossen by 80ms.   

Again, I can't stress enough that this is NOT the released camera meter.  :-DD  It was an early prototype that Dave provided.  The data shown may not be representative of the released product.

https://youtu.be/13nv-NsQXDs



Title: Re: EEVBlog 121GW Discussion thread
Post by: ez24 on January 17, 2018, 02:08:18 am
I think people are ignoring what is perhaps the most important question about this meter:  can it handle a 1.21GW burst of electricity?    ;D
Since that is enough to power 1,000,000 homes it might require a shunt. 
Title: Re: EEVBlog 121GW Discussion thread
Post by: VK5RC on January 17, 2018, 10:31:20 am
I have done a rough-as-guts comparison of my handheld DMM collection in terms of resistance Auto-ranging time.
The winner ( - chicken dinner) is a 3458 (not fair I know) but then a Gossen. The 121GW is quite close to the Keysight U1282A - as Dave states above -the same chip.

https://www.youtube.com/watch?v=9KY8001f8rk (https://www.youtube.com/watch?v=9KY8001f8rk)

Edit, Grammar
PS If I recall, Dave's criticism of the U1253 was mainly the timing of 'continuity' not the standard resistance range. The U1253B is slow in continuity but does give a reading of ohms - presumably for short finding.
Title: Re: EEVBlog 121GW Discussion thread
Post by: ez24 on January 17, 2018, 06:49:52 pm
I have done a rough-as-guts comparison of my handheld DMM collection ....

If you turned on everything, you would need a 1.21 GW meter to measure the kW used.   :-DD
Title: Re: EEVBlog 121GW Discussion thread
Post by: Terry01 on January 17, 2018, 07:45:02 pm
Holy Smokes!

Is all that equipment for home/hobby use?
Title: Re: EEVBlog 121GW Discussion thread
Post by: VK5RC on January 18, 2018, 01:15:13 am
Don't tell my wife! HiHi
It is about 20yrs of selective purchases.
No,  she knows, I don't look at her shoes / handbags / lululemon running gear!

I wanted to post the big variations in hand dmm autoranging time.
Title: Re: EEVBlog 121GW Discussion thread
Post by: dcac on January 18, 2018, 03:34:46 am
@VK5RC - Thanks for testing your 121GW again and provide even more comparisons with your other DMMs - indeed an impressive collection you have there.

I also thought I mention this as it might help tracking down a possible bug. Even though the probes seems to be closed firmly - the bargraph flicker a couple of times just as if there was intermittent connection. I thought I saw the same flicker in the first video and that’s why I made that comment earlier about the probes possibly being bad. But from what I can tell now - the flicker seems to happen in more or less the same place in the auto-ranging sequence - most noticeably when going from Mohms to Kohms.

The bargraph on Joe’s prototype 121GW did not seem to flicker at all.

Title: Re: EEVBlog 121GW Discussion thread
Post by: dcac on January 18, 2018, 04:12:35 am
The bargraph on Joe’s prototype 121GW did not seem to flicker at all.

No but in that last attempt you can clearly see the fade in vs the half and half, or should I say half + 1 segment.   :-DD   

I could run a side by side of the meters that have survived all my abuse along with the counter to time it.  Seems like an easier way to measure them anyway.  My old analog meter settles pretty fast but does not have auto ranging.  :-DD

Just to clarify - in my previous post I meant the two times Robert Culver tested his 121GW I saw the bargraph flicker in more or less the same place - as if the connection between his probes was intermittent. Compared to your prototype where the bargraph did not seem to flicker at all. Possibly this could be the indication of a bug the auto-ranging routine in Robet’s 121GW that causes bargraph flicker and overall slow auto-ranging speed.

Title: Re: EEVBlog 121GW Discussion thread
Post by: beanflying on January 18, 2018, 04:15:29 am
Seems either the meter and or the reference has drifted 2 LSD.  Decided not to try and figure out which as Yep that is 42+ degrees C on the bench  :phew:
Title: Re: EEVBlog 121GW Discussion thread
Post by: beanflying on January 18, 2018, 04:19:37 am

Just to clarify - in my previous post I meant the two times Robert Culver tested his 121GW I saw the bargraph flicker in more or less the same place - as if the connection between his probes was intermittent. Compared to your prototype where the bargraph did not seem to flicker at all. Possibly this could be the indication of a bug the auto-ranging routine in Robet’s 121GW that causes bargraph flicker and overall slow auto-ranging speed.

Just to clarify you are relying on the videos of others for the content of your last 25 posts to search for any perceived (by you) flaws in a product you haven't used in the flesh?  :palm:
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on January 18, 2018, 11:39:59 am
Seems either the meter and or the reference has drifted 2 LSD.  Decided not to try and figure out which as Yep that is 42+ degrees C on the bench  :phew:

Reminds me of the old garage EEVblog lab. In old videos you can see the sweat running down my forehead.
Title: Re: EEVBlog 121GW Discussion thread
Post by: iainwhite on January 18, 2018, 01:55:52 pm
Has anyone in the USA received theirs?

Joe, I received mine on Jan 8th.   I think there were at least a couple of other US guys that have too.
Title: Re: EEVBlog 121GW Discussion thread
Post by: dcac on January 18, 2018, 02:10:44 pm
Just to clarify you are relying on the videos of others for the content of your last 25 posts to search for any perceived (by you) flaws in a product you haven't used in the flesh?  :palm:

Interesting comment on a Video blog related forum. For me videos are very useful to evaluate a product’s performance or apparent flaws, sorry if you can’t do that, please feel free to ignore my posts.

Title: Re: EEVBlog 121GW Discussion thread
Post by: idpromnut on January 18, 2018, 06:56:22 pm
Probably off topic (a bit), but I am ashamed to say that the significance of this evaded me (as I was busy exploring the meter functionality, and not the serial number on the back):
Title: Re: EEVBlog 121GW Discussion thread
Post by: logictom on January 18, 2018, 09:23:20 pm
Just to clarify you are relying on the videos of others for the content of your last 25 posts to search for any perceived (by you) flaws in a product you haven't used in the flesh?  :palm:

Interesting comment on a Video blog related forum. For me videos are very useful to evaluate a product’s performance or apparent flaws, sorry if you can’t do that, please feel free to ignore my posts.

I don't see the issue with this. I think some people are getting a little bit too fanboy, don't get me wrong, I bought one aswell with the explicit need, it's always good to have more meters and to support Dave. How is critiquing this from video any different to us all saying how dumb apple was to remove the 3.5mm jack on the latest iPhone without most of us owning one.

Banging on the same issue in multiple posts without adding anything to the discussion is another thing, but evaluating a product via video and without owning it - how else would we decide on what to buy from all these online only retailers.
Title: Re: EEVBlog 121GW Discussion thread
Post by: maukka on January 19, 2018, 04:06:21 pm
Did a 10 hour logging of temperature simultaneously with a Uni-T UT181A at 60 second sampling interval. Also another one for voltage for a couple of hours at 1 second interval while discharging a battery. Was very happy to find that they're perfectly in sync. While a Mooshimeter for example drifts compared to them.
Title: Re: EEVBlog 121GW Discussion thread
Post by: 1anX on January 20, 2018, 03:32:10 am
I wrote the following on another thread in this forum after Dave made clear that the wobbly switch issue had been confirmed. I think its more appropriate that its posted on the "Discussion" thread!

It doesn't matter to me about what the details were of the past prototypes!

I'm concerned about the current production models and what I'm going to receive come March 2018. Its not so much about the existence of the problems encountered with the production model, but about how it will be fixed.

There are two items of concern and they are the current meters now delivered may have a hardware issue and how will this be addressed?

The Kickstarter way of buying a new meter is certainly a new experience for me, as it is without certainty or guarantee. I would not have engaged in the campaign if not for finding Dave and his blog to be 100% genuine. I'm certain the existing owners will be looked after and the next batch of meters will be fixed before being shipped.

Dave we need you to communicate a reassurance that hardware and firmware will be fixed. We are all reasonable people and understand this may take some time. Give us one of your EEVBlogs on how the Kickstarter project meters have some issues and whats needed to fix them. Give us some of your trademark sarcasm and humour and include us, (the backers) in how you progress from here. 
Title: Re: EEVBlog 121GW Discussion thread
Post by: tpw_rules on January 20, 2018, 07:40:51 pm
Is the fully open schematic available yet? I'd like to get a peek to answer some questions.

Relatedly, I've cooked up a firmware with a tweak to autoranging that should improve the speed significantly. Trouble is, I've not yet received my meter. Anybody want to PM me and give it a go?
Title: Re: EEVBlog 121GW Discussion thread
Post by: bicycleguy on January 21, 2018, 02:07:39 am
Asked that on the kickstarter page and received this from Dave on January 15th:

They are being neatened up by UEI soon to be released, it will be posted in an update.
Title: Re: EEVBlog 121GW Discussion thread
Post by: mikeselectricstuff on January 21, 2018, 09:34:26 am
Asked that on the kickstarter page and received this from Dave on January 15th:

They are being neatened up by UEI soon to be released, it will be posted in an update.
Any word on publishing the format of the cal data and firmware files - these would be prerequisites for alternative firmware - probably possible to reverse-engineer, though it would be a bit of a pain.
BTW is a full end-user recalibration possible ( this would make reversing the cal data easier if nothing else)?
Title: Re: EEVBlog 121GW Discussion thread
Post by: dcac on January 21, 2018, 12:10:31 pm
BTW is a full end-user recalibration possible ( this would make reversing the cal data easier if nothing else)?

Seems to be, have a look at page 58 in the manual:

http://www.eevblog.com/files/EEVblog-121GW-Manual.pdf (http://www.eevblog.com/files/EEVblog-121GW-Manual.pdf)
Title: Re: EEVBlog 121GW Discussion thread
Post by: mikeselectricstuff on January 21, 2018, 12:18:38 pm
BTW is a full end-user recalibration possible ( this would make reversing the cal data easier if nothing else)?

Seems to be, have a look at page 58 in the manual:

http://www.eevblog.com/files/EEVblog-121GW-Manual.pdf (http://www.eevblog.com/files/EEVblog-121GW-Manual.pdf)
Quote
4. Hold your breath, cross your fingers, and don't make any sudden
movements that could frighten the meter. Beard stroking is allowed.
What, no tongue angle specification ?

Title: Re: EEVBlog 121GW Discussion thread
Post by: tpw_rules on January 21, 2018, 04:08:07 pm
Any word on publishing the format of the cal data and firmware files - these would be prerequisites for alternative firmware - probably possible to reverse-engineer, though it would be a bit of a pain.
BTW is a full end-user recalibration possible ( this would make reversing the cal data easier if nothing else)?

So, IDA and I have been having a bit of fun over the past week and I now have a perhaps 80% complete IDA database of the 1.02 firmware. I'm hesitant to release it because a) it's not done and b) I don't know what UEI would think. I also can't test a lot of theories because my own meter is not here yet.

Anyway, regarding the format of the firmware file. The CPU is an STM32L152 family Cortex-M3 ARMv7-M processor. I don't know what exact chip it is. If anyone could send me a photo of the exact chip in the meter, I would be grateful. The EEVBlog.bin file is burned into ROM starting at 0x08006000. It has a standard Cortex-M3 vector table at the start, where the first 32 bits are the initial SP and the second are the reset vector (+ 1 because the processor always operates in Thumb-2 mode). This is enough to get it disassembling correctly in IDA, or to start your own firmware once the exact chip is known.

Regarding calibration data, it actually seems possible to load and save the calibration area of the EEPROM to the SD card. As before, I can't test it cause I don't have a meter. There is a non-zero chance you could lose all your cal data or start a fire.  If you want to try, here is the procedure:
The cal.bin file is a copy of the first 1200 bytes of EEPROM. The first 48 bytes are used for settings, the rest of the 1200 bytes is calibration factors, and the rest of the EEPROM is involved with logging.

A lot of the ranges share factors and there are some I'm not too sure about. The official manual is pretty light on details, and it seems there are other things such as a bonus 50Mohm range calibration and some frequency calibration factors for the AC ranges which are not mentioned. (And what's with 10% for the AC ranges? Is that 10% of full scale as opposed to a dead short?) Fortunately, for most modes and ranges, it is indeed a simple 0 offset and a full-scale gain and I know which ones use which factors. Sadly, I'm not a metrologist, and these areas are heavy on algorithms I don't understand, so I'm having trouble. But I intend on communicating whatever I learn when I do learn it.

And Dave, could you give me an OK/over my dead body on releasing the work?
Title: Re: EEVBlog 121GW Discussion thread
Post by: fanOfeeDIY on January 21, 2018, 04:38:50 pm
I just uploaded a video reviewing current measurements of 121GW, Fluke 87-V, Keysight U1241B.

I did not spend much time for rendering, and my camera is not good at auto focusing so
at least I tried to have the voice quality reasonable.

Please enjoy. :)

https://youtu.be/EfV_u2MFOPU
 
Title: Re: EEVBlog 121GW Discussion thread
Post by: mikeselectricstuff on January 21, 2018, 04:44:39 pm
Any word on publishing the format of the cal data and firmware files - these would be prerequisites for alternative firmware - probably possible to reverse-engineer, though it would be a bit of a pain.
BTW is a full end-user recalibration possible ( this would make reversing the cal data easier if nothing else)?

So, IDA and I have been having a bit of fun over the past week and I now have a perhaps 80% complete IDA database of the 1.02 firmware. I'm hesitant to release it because a) it's not done and b) I don't know what UEI would think. I also can't test a lot of theories because my own meter is not here yet.

Anyway, regarding the format of the firmware file. The CPU is an STM32L152 family Cortex-M3 ARMv7-M processor. I don't know what exact chip it is. If anyone could send me a photo of the exact chip in the meter, I would be grateful. The EEVBlog.bin file is burned into ROM starting at 0x08006000. It has a standard Cortex-M3 vector table at the start, where the first 32 bits are the initial SP and the second are the reset vector (+ 1 because the processor always operates in Thumb-2 mode). This is enough to get it disassembling correctly in IDA, or to start your own firmware once the exact chip is known.

Regarding calibration data, it actually seems possible to load and save the calibration area of the EEPROM to the SD card. As before, I can't test it cause I don't have a meter. There is a non-zero chance you could lose all your cal data or start a fire.  If you want to try, here is the procedure:
  • Boot holding the MEM key, or maybe boot the meter with no keys and quickly press MEM. (I'm not entirely sure) Screen will show SdCAL if you did it.
  • Press PEAK to load calibration data from SD card (screen shows SdSEt) or REL to save data to card (screen shows SdSAv).
  • Press MODE to do it. If successful, screen shows SAvEd. Else, screen shows -Err-.
  • Turn off the meter. The data is now in cal.bin on the SD card.
The cal.bin file is a copy of the first 1200 bytes of EEPROM. The first 48 bytes are used for settings, the rest of the 1200 bytes is calibration factors, and the rest of the EEPROM is involved with logging.

A lot of the ranges share factors and there are some I'm not too sure about. The official manual is pretty light on details, and it seems there are other things such as a bonus 50Mohm range calibration and some frequency calibration factors for the AC ranges which are not mentioned. (And what's with 10% for the AC ranges? Is that 10% of full scale as opposed to a dead short?) Fortunately, for most modes and ranges, it is indeed a simple 0 offset and a full-scale gain and I know which ones use which factors. Sadly, I'm not a metrologist, and these areas are heavy on algorithms I don't understand, so I'm having trouble. But I intend on communicating whatever I learn when I do learn it.

And Dave, could you give me an OK/over my dead body on releasing the work?
Maybe start a new  hacking thread?
Title: Re: EEVBlog 121GW Discussion thread
Post by: bicycleguy on January 21, 2018, 06:13:36 pm
I just uploaded a video...

Surprised you didn't mention the burden voltage on the 121's secondary display.  I see you didn't hook it up in the video, but would have been nice to compare it's value with the other meters.

thanks
Title: Re: EEVBlog 121GW Discussion thread
Post by: Iagash on January 21, 2018, 07:22:10 pm
Maybe start a new  hacking thread?

There is already one: https://www.eevblog.com/forum/testgear/eevblog-121gw-multimeter-firmware-details/ (https://www.eevblog.com/forum/testgear/eevblog-121gw-multimeter-firmware-details/)
Title: Re: EEVBlog 121GW Discussion thread
Post by: ez24 on January 21, 2018, 09:06:51 pm
Maybe start a new  hacking thread?

There is already one: https://www.eevblog.com/forum/testgear/eevblog-121gw-multimeter-firmware-details/ (https://www.eevblog.com/forum/testgear/eevblog-121gw-multimeter-firmware-details/)

Thanks 

Now that there is talk of firmware hack, I am starting to get interested because I think someone is going to come up with something to make me want to buy one.  I am sure UEI does not understand this.

Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on January 21, 2018, 10:01:03 pm
Any word on publishing the format of the cal data and firmware files - these would be prerequisites for alternative firmware - probably possible to reverse-engineer, though it would be a bit of a pain.
BTW is a full end-user recalibration possible ( this would make reversing the cal data easier if nothing else)?

So, IDA and I have been having a bit of fun over the past week and I now have a perhaps 80% complete IDA database of the 1.02 firmware. I'm hesitant to release it because a) it's not done and b) I don't know what UEI would think. I also can't test a lot of theories because my own meter is not here yet.

Anyway, regarding the format of the firmware file. The CPU is an STM32L152 family Cortex-M3 ARMv7-M processor. I don't know what exact chip it is. If anyone could send me a photo of the exact chip in the meter, I would be grateful. The EEVBlog.bin file is burned into ROM starting at 0x08006000. It has a standard Cortex-M3 vector table at the start, where the first 32 bits are the initial SP and the second are the reset vector (+ 1 because the processor always operates in Thumb-2 mode). This is enough to get it disassembling correctly in IDA, or to start your own firmware once the exact chip is known.

Regarding calibration data, it actually seems possible to load and save the calibration area of the EEPROM to the SD card. As before, I can't test it cause I don't have a meter. There is a non-zero chance you could lose all your cal data or start a fire.  If you want to try, here is the procedure:
  • Boot holding the MEM key, or maybe boot the meter with no keys and quickly press MEM. (I'm not entirely sure) Screen will show SdCAL if you did it.
  • Press PEAK to load calibration data from SD card (screen shows SdSEt) or REL to save data to card (screen shows SdSAv).
  • Press MODE to do it. If successful, screen shows SAvEd. Else, screen shows -Err-.
  • Turn off the meter. The data is now in cal.bin on the SD card.
The cal.bin file is a copy of the first 1200 bytes of EEPROM. The first 48 bytes are used for settings, the rest of the 1200 bytes is calibration factors, and the rest of the EEPROM is involved with logging.

A lot of the ranges share factors and there are some I'm not too sure about. The official manual is pretty light on details, and it seems there are other things such as a bonus 50Mohm range calibration and some frequency calibration factors for the AC ranges which are not mentioned. (And what's with 10% for the AC ranges? Is that 10% of full scale as opposed to a dead short?) Fortunately, for most modes and ranges, it is indeed a simple 0 offset and a full-scale gain and I know which ones use which factors. Sadly, I'm not a metrologist, and these areas are heavy on algorithms I don't understand, so I'm having trouble. But I intend on communicating whatever I learn when I do learn it.

And Dave, could you give me an OK/over my dead body on releasing the work?

No problem.
I'm not going to stop hacking, it is encouraged.
And you are right, there is a boot key press mode that saves the CAL data to SD card. v1.01 firmware has a bug in this routine that was fixed in v1.02 (no other changes). Haven't added this to the manual yet.
Title: Re: EEVBlog 121GW Discussion thread
Post by: dcac on January 21, 2018, 10:17:50 pm
Maybe start a new  hacking thread?

There is already one: https://www.eevblog.com/forum/testgear/eevblog-121gw-multimeter-firmware-details/ (https://www.eevblog.com/forum/testgear/eevblog-121gw-multimeter-firmware-details/)

Perhaps it's best to keep that one for official firmware details. And start a new thread dedicated to firmware Hacking.

Title: Re: EEVBlog 121GW Discussion thread
Post by: benst on January 22, 2018, 12:21:19 am
Is there anything known about when (if?) we can expect the iOS app? Looking forward to that!

Thanks,
Ben
Title: EEVBlog 121GW Discussion thread
Post by: fanOfeeDIY on January 22, 2018, 03:40:05 am

Surprised you didn't mention the burden voltage on the 121's secondary display.  I see you didn't hook it up in the video, but would have been nice to compare it's value with the other meters.

thanks

I thought the same, I spent too much time in the first half of explaining USB-UART converter part and wanted to save time with just swapping the meter.
I would like to included it in the future review.
Title: Re: EEVBlog 121GW Discussion thread
Post by: MatthewEveritt on January 22, 2018, 04:07:16 pm
Anyway, regarding the format of the firmware file. The CPU is an STM32L152 family Cortex-M3 ARMv7-M processor. I don't know what exact chip it is. If anyone could send me a photo of the exact chip in the meter, I would be grateful.
See here https://www.eevblog.com/forum/testgear/eevblog-121gw-multimeter-issues/msg1406994/#msg1406994] [url]https://www.eevblog.com/forum/testgear/eevblog-121gw-multimeter-issues/msg1406994/#msg1406994 (http://[url)[/url]
Title: Re: EEVBlog 121GW Discussion thread
Post by: jordanp123 on January 22, 2018, 08:23:29 pm
Any news on the US meters?
Title: Re: EEVBlog 121GW Discussion thread
Post by: logictom on January 23, 2018, 12:13:31 am
I am having trouble using the Bluetooth, I've got the BT icon on the meter, I have detected the meter on my phone, Google Pixel, and connected, now showing in my paired list, but I see nothing in the app.

Actually just got it to show in the app by forgetting the connection in android settings. But now I've closed the app I cannot get it to reappear.

I've tried the alternative app but that always responds Ble device not found.

Is there a particular sequence on must follow to get it to appear in the app?

When it was connected there appears to be an issue with the fonts in the upper left, auto DC
Title: Re: EEVBlog 121GW Discussion thread
Post by: ez24 on January 23, 2018, 12:21:14 am
I am having ....

Can I ask a stupid question - how did you get that screen shot ?

thanks
Title: Re: EEVBlog 121GW Discussion thread
Post by: Cliff Matthews on January 23, 2018, 12:41:31 am
I am having ....

Can I ask a stupid question - how did you get that screen shot ?

thanks
Roger, this should help. *edit (but you'll have to pull the jpg from the phones DCIM folder and copy or send it to a PC - YMMV)
https://www.greenbot.com/article/2825064/android/how-to-take-a-screenshot-on-your-android-phone.html (https://www.greenbot.com/article/2825064/android/how-to-take-a-screenshot-on-your-android-phone.html)
Title: Re: EEVBlog 121GW Discussion thread
Post by: MagFlux on January 23, 2018, 06:14:32 am
The iOS App has been available in Canada for a week. You may need to search the App Store daily as it could be released where you are very soon.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Halcyon on January 23, 2018, 06:24:18 am
Feature request

Could you include an option in the setup to disable the beeper? It's fine for power-on events and continuity testing etc... but it becomes more of an annoyance every time you turn the knob or press a button. I understand the reasoning behind it, but for me, I'd prefer to have the option to turn it off for key presses/mode changes (or at least select a lower volume).

OFF-LOW-MED-HI options would be fantastic.
Title: Re: EEVBlog 121GW Discussion thread
Post by: mtdoc on January 23, 2018, 06:42:52 am
Feature request

Could you include an option in the setup to disable the beeper? It's fine for power-on events and continuity testing etc... but it becomes more of an annoyance every time you turn the knob or press a button. I understand the reasoning behind it, but for me, I'd prefer to have the option to turn it off for key presses/mode changes (or at least select a lower volume).

OFF-LOW-MED-HI options would be fantastic.

Yes, please.  My wife just asked how often that was going to be beeping. Never had her ask that with another meter.  When I said I wasn't sure, she went in another room and closed the door. ::)

Add - now she just yelled at me through 2 sets of closed doors "make the beeping stop!  :rant:" 
Title: Re: EEVBlog 121GW Discussion thread
Post by: IanB on January 23, 2018, 06:50:12 am
Can probably reprogram the beep with a pair of wire cutters  >:D
Title: Re: EEVBlog 121GW Discussion thread
Post by: mtdoc on January 23, 2018, 06:55:07 am
Can probably reprogram the beep with a pair of wire cutters  >:D

Yes, I may have to resort to that. Otherwise my wife may reprogram it "up the side of my head"....
Title: Re: EEVBlog 121GW Discussion thread
Post by: Halcyon on January 23, 2018, 06:59:20 am
Can probably reprogram the beep with a pair of wire cutters  >:D

Yes, I may have to resort to that. Otherwise my wife may reprogram it "up the side of my head"....

I just want to clarify, I want the beep on power-up and continuity, just no other time.
Title: Re: EEVBlog 121GW Discussion thread
Post by: mtdoc on January 23, 2018, 07:07:09 am
Can probably reprogram the beep with a pair of wire cutters  >:D

Yes, I may have to resort to that. Otherwise my wife may reprogram it "up the side of my head"....

I just want to clarify, I want the beep on power-up and continuity, just no other time.

Yes, loss of continuity beep would be tragic - so the wire cutters will be held at bay for now.  I could tolerate the power on beep but I really don't want any of the other beeps though.   Volume control would also be good as you say.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on January 23, 2018, 07:26:02 am
I have v1.04
Negative VA issue supposed to be fixed (haven't checked)
Beep is now off by default.
Ohms autoranging has been improved down to just under 4.5sec or so. They claim any faster and the meters would require recalibration. I don't know why they can't at least partially use the bargraph ADC for this.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Towger on January 23, 2018, 08:11:19 am
I have v1.04
I don't know why they can't at least partially use the bargraph ADC for this.

Might be worth while getting David to have a good look at the code.  If it can be 'deciphered', with his strong maths background I am sure the algorithm can be improved/rewritten more.

Or just publish the code...

Is there going to be a solution to the wobbly knobs? [For those who already have a meter. ]
Title: Re: EEVBlog 121GW Discussion thread
Post by: hayatepilot on January 23, 2018, 09:34:30 am
Ohms autoranging has been improved down to just under 4.5sec or so. They claim any faster and the meters would require recalibration. I don't know why they can't at least partially use the bargraph ADC for this.
Great news.  8)
Will it be further reduced for the 2nd batch? Calibration will not be a problem since it would be from the factory.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Halcyon on January 23, 2018, 09:53:54 am
I have v1.04
Negative VA issue supposed to be fixed (haven't checked)
Beep is now off by default.
Ohms autoranging has been improved down to just under 4.5sec or so. They claim any faster and the meters would require recalibration. I don't know why they can't at least partially use the bargraph ADC for this.

Thanks Dave, is there an official support page for the 121GW where we can download vetted firmware and manuals etc... (past and latest versions)? I think a lot of us would be keen on updating as I think most (all?) were shipped with v1.01 to-date?
Title: Re: EEVBlog 121GW Discussion thread
Post by: GameProgrammer79 on January 23, 2018, 11:45:19 am
Ohms autoranging has been improved down to just under 4.5sec or so. They claim any faster and the meters would require recalibration. I don't know why they can't at least partially use the bargraph ADC for this.
Great news.  8)
Will it be further reduced for the 2nd batch? Calibration will not be a problem since it would be from the factory.

The speed is basically based on algorithm used, a binary tree search would result in log(n) base2 where as linear (n). For example if linear search was taking 7 sec to reach extreme end (lowest range), then after binary search you can basically reduce time to 2.8 sec (log base 2 of 7 is 2.807355)

Now Dave is saying it is 4.5 sec, with a improved algorithm it can reduce to 2.16 sec. There are many ways to improve firmware speed, essentially they need to profile the code, reduce string copies if any, use all constant time data structures, remove unwanted calls to memory allocator (rather use object pools), check for cache hit analysis .. use simple array structures when possible and so on.

If they can install valgrind under quemu (if thats ported to STM32) you can do a much detailed profiling of the code. That way you can optimize the portions that are slowing down the meter. Not only it will make it run faster, it will also increase battery :)
Title: Re: EEVBlog 121GW Discussion thread
Post by: mikeselectricstuff on January 23, 2018, 11:48:34 am
Ohms autoranging has been improved down to just under 4.5sec or so. They claim any faster and the meters would require recalibration. I don't know why they can't at least partially use the bargraph ADC for this.
Great news.  8)
Will it be further reduced for the 2nd batch? Calibration will not be a problem since it would be from the factory.

The speed is basically based on algorithm used, a binary tree search would result in log(n) base2 where as linear (n). For example if linear search was taking 7 sec to reach extreme end (lowest range), then after binary search you can basically reduce time to 2.8 sec (log base 2 of 7 is 2.807355)

Now Dave is saying it is 4.5 sec, with a improved algorithm it can reduce to 2.16 sec. There are many ways to improve firmware speed, essentially they need to profile the code, reduce string copies if any, use all constant time data structures, remove unwanted calls to memory allocator (rather use object pools), check for cache hit analysis .. use simple array structures when possible and so on.

If they can install valgrind under quemu (if thats ported to STM32) you can do a much detailed profiling of the code. That way you can optimize the portions that are slowing down the meter. Not only it will make it run faster, it will also increase battery :)
I suspect the limiting factor may be the time it takes to settle after re-ranging, rather than actual acquisition rate or any code speed limitations, though it may also be doing stupid things like excessive screen redraws
Title: Re: EEVBlog 121GW Discussion thread
Post by: HKJ on January 23, 2018, 12:15:40 pm
The speed is basically based on algorithm used, a binary tree search would result in log(n) base2 where as linear (n). For example if linear search was taking 7 sec to reach extreme end (lowest range), then after binary search you can basically reduce time to 2.8 sec (log base 2 of 7 is 2.807355)

You do not do a binary search on a multimeter.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Fungus on January 23, 2018, 12:43:51 pm
The speed is basically based on algorithm used, a binary tree search would result in log(n) base2 where as linear (n). For example if linear search was taking 7 sec to reach extreme end (lowest range), then after binary search you can basically reduce time to 2.8 sec (log base 2 of 7 is 2.807355)

It may not be possible to leap around randomly if there's much internal capacitance, etc.

The trick will be to short-circuit the A->D conversions and switch range as soon as possible when you see the range is obviously wrong (eg. look at the initial slope of the ADC charge curve?)

It may never be super-fast no matter what the firmware. It's easy to imagine clever tricks from the comfort of an armchair but the hardware is already built and you have to work with what you've got. eg. Looking at slopes sounds good but there may be too much variation between individual meters to make it reliable, or the ADC might not be suitable.

OTOH 4.5 seconds is a loooong time. I'd bet they're erring on the side of caution in the current firmware.

There are many ways to improve firmware speed, essentially they need to profile the code, reduce string copies if any, use all constant time data structures, remove unwanted calls to memory allocator (rather use object pools), check for cache hit analysis .. use simple array structures when possible and so on.

If they can install valgrind under quemu (if thats ported to STM32) you can do a much detailed profiling of the code. That way you can optimize the portions that are slowing down the meter. Not only it will make it run faster, it will also increase battery :)

None of that will be applicable here. It will be down to the hardware design, knowledge of the hardware, etc.
Title: Re: EEVBlog 121GW Discussion thread
Post by: glarsson on January 23, 2018, 01:02:00 pm
The front end chip has a slow and a fast ADC. No need to figure out how to trick the slow if the fast is available. Is the fast ADC used for the bargraph?
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on January 23, 2018, 01:05:04 pm
I suspect the limiting factor may be the time it takes to settle after re-ranging, rather than actual acquisition rate or any code speed limitations, though it may also be doing stupid things like excessive screen redraws

Yes, there will be some sort of chipset limit based on range switching and settling time. I don't know what that is.
I do know that Hycon recommended switching between constant voltage and constant current modes at the 500k range, so that may impact things.
I'm hoping that further tweaks are possible, and I've asked them to try some more, but it's almost certain we won't be able to magically get it to down to say 1 second.
There is likely a good reason why the Keysight U1282A isn't hugely faster using the same chipset.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on January 23, 2018, 01:06:44 pm
The front end chip has a slow and a fast ADC. No need to figure out how to trick the slow if the fast is available. Is the fast ADC used for the bargraph?

Yes, and I have asked them to consider that.
Title: Re: EEVBlog 121GW Discussion thread
Post by: mikeselectricstuff on January 23, 2018, 01:09:32 pm
Another data point : I have a meter here using the same chip that ranges from open to 0R in 2 seconds.
Title: Re: EEVBlog 121GW Discussion thread
Post by: HKJ on January 23, 2018, 01:12:50 pm
The trick will be to short-circuit the A->D conversions and switch range as soon as possible when you see the range is obviously wrong (eg. look at the initial slope of the ADC charge curve?)

In ohm mode I can see two strategies:
1) Du a full measurement and select range depending on the result, this allows you to go down 3-4 decades at once.
2) Use the bargraph converter to change range, that is only on decade at a time.

Each range shift requires some settling time and I have no idea if 1) or 2) would be fastest.
Title: Re: EEVBlog 121GW Discussion thread
Post by: dr.diesel on January 23, 2018, 01:36:36 pm
I'd like the option of recal to even further reduce the auto ranging time.   :-+
Title: Re: EEVBlog 121GW Discussion thread
Post by: dcac on January 23, 2018, 02:13:04 pm
Another data point : I have a meter here using the same chip that ranges from open to 0R in 2 seconds.

Very interesting!

http://www.hycontek.com/wp-content/uploads/DS-HY3131_EN.pdf (http://www.hycontek.com/wp-content/uploads/DS-HY3131_EN.pdf)

I wonder what clock rate the HY3131 in 121GW is running? - typical is 4.9152MHz but max is 8.0MHz according to the datasheet. If higher clock rate would mean faster auto-ranging (my guess is that it would) but then also less battery life - I would really go for faster auto-range as long as the 121GW has a auto-power off function.

Title: Re: EEVBlog 121GW Discussion thread
Post by: glarsson on January 23, 2018, 03:18:26 pm
One aspect of autoranging with a faster but lower precision ADC is that the meter might select a range that is not optimal. If for example the fast ADC measures 4.9999 as 5.04 it will select a range to high. More problematic is if the difference is the other way, then a low range is selected with overflow. The fast ADC could be tweaked to always read slightly too high.

This could be a user selected feature. Reasonable fast autoranging with precise range selection or very fast autoranging with imprecise range selection?
Title: Re: EEVBlog 121GW Discussion thread
Post by: Fungus on January 23, 2018, 03:34:39 pm
One aspect of autoranging with a faster but lower precision ADC is that the meter might select a range that is not optimal.

You could always detect that and change range...  :popcorn:
Title: Re: EEVBlog 121GW Discussion thread
Post by: glarsson on January 23, 2018, 06:34:38 pm
You could always detect that and change range...  :popcorn:
Yes, there are several options.
1. SLOW: Use the slow high precision ADC for ranging.
2. FAST: Use the fast low precision ADC for ranging, then switch to the high precision ADC and eventually make an additional step up or down.
3. EXTRA FAST: Use the fast low precision ADC for ranging. Use a slight offset to avoid over range.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on January 23, 2018, 10:41:55 pm
I wonder what clock rate the HY3131 in 121GW is running? - typical is 4.9152MHz but max is 8.0MHz according to the datasheet. If higher clock rate would mean faster auto-ranging (my guess is that it would) but then also less battery life - I would really go for faster auto-range as long as the 121GW has a auto-power off function.

It's 4.9152MHz
And I don't think that's how it work, it doubt it would magically make the autoranging faster. The micro controls the autoranging, not the HY3131.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on January 23, 2018, 10:43:56 pm
I'd like the option of recal to even further reduce the auto ranging time.   :-+

There are production meters in the field now, so we can't release firmware that would break the calibration, that would be very foolish.
Title: Re: EEVBlog 121GW Discussion thread
Post by: nidlaX on January 23, 2018, 10:44:55 pm
How is the range switch modification going to be implemented? Who is doing the replacement for the US meters, and will you send replacement parts to customers who've already received theirs?
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on January 23, 2018, 10:51:16 pm
Any news on the US meters?

Yes, sorry but the US meters will be delayed, they want to make some small tolerance changes to the range switch. We'd rather have them delayed a bit than to have any more potential range switch issues.
Title: Re: EEVBlog 121GW Discussion thread
Post by: dr.diesel on January 23, 2018, 11:02:39 pm
I'd like the option of recal to even further reduce the auto ranging time.   :-+

There are production meters in the field now, so we can't release firmware that would break the calibration, that would be very foolish.

One would of-course put this FW behind a warning of such.  If the improvement is negligible then who cares, but if significant it would be a shame to censor it for those of us capable of a full cal, which could be quite a few as we now pass cal standards around.

All depends on how much improvement is hiding behind the recal FW, which might be ~2sec as Mike suggested, making it very worthwhile.
Title: Re: EEVBlog 121GW Discussion thread
Post by: mikeselectricstuff on January 23, 2018, 11:23:53 pm
Any news on the US meters?

Yes, sorry but the US meters will be delayed, they want to make some small tolerance changes to the range switch. We'd rather have them delayed a bit than to have any more potential range switch issues.
Does the US batch include the EU ones that didn't pre-pay VAT? - ISTR you said some other countries were being fulfilled via US.
Title: Re: EEVBlog 121GW Discussion thread
Post by: dcac on January 23, 2018, 11:26:49 pm
I wonder what clock rate the HY3131 in 121GW is running? - typical is 4.9152MHz but max is 8.0MHz according to the datasheet. If higher clock rate would mean faster auto-ranging (my guess is that it would) but then also less battery life - I would really go for faster auto-range as long as the 121GW has a auto-power off function.

It's 4.9152MHz
And I don't think that's how it work, it doubt it would magically make the autoranging faster. The micro controls the autoranging, not the HY3131.

Yeah you’re probably right, I notice now from the datasheet that range selection seems to be fully under software control by the MCU. So possibly only the actual ADC conversion would speed up with higher clock rate.

Great to see UEi responded so quickly and if  FW ver 1.04 achieved auto-ranging in 4.5 sec it’s a significant improvement over the 7.4 sec we saw before. More useful now for sure but still annoyingly slow. The prototype 121GW was 3.8 sec and U1282A about 3.0 sec in its fastmode, so there’s still room for improvement with a tweaked/hacked FW which I'm sure the programming wizards here at EEVblog eventually will provide.


Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on January 24, 2018, 12:02:05 am
Does the US batch include the EU ones that didn't pre-pay VAT? - ISTR you said some other countries were being fulfilled via US.

No, we shipped those from here.
Title: Re: EEVBlog 121GW Discussion thread
Post by: benst on January 24, 2018, 12:03:12 am
I see an app in the iOS App store called "EEVBlog 121GW" by Cheon Myoung-kun. That doesn't sound legit, does it?

And it looks bloody awfull.  :wtf:

Ben
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on January 24, 2018, 12:04:12 am
I'd like the option of recal to even further reduce the auto ranging time.   :-+

There are production meters in the field now, so we can't release firmware that would break the calibration, that would be very foolish.
One would of-course put this FW behind a warning of such.  If the improvement is negligible then who cares, but if significant it would be a shame to censor it for those of us capable of a full cal, which could be quite a few as we now pass cal standards around.

Almost all users do not have the ability to calibrate the meter themselves, and you would be effectively forcing those users to do that if they wanted to upgrade their firmware in the future. That would be very poor form.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on January 24, 2018, 12:05:13 am
I see an app in the iOS App store called "EEVBlog 121GW" by Cheon Myoung-kun. That doesn't sound legit, does it?
And it looks bloody awfull.  :wtf:

It is bloody awful which is why we wrote our own. But yes it is "legit". UEi got that person to write it.
Title: Re: EEVBlog 121GW Discussion thread
Post by: dr.diesel on January 24, 2018, 12:08:35 am
Almost all users do not have the ability to calibrate the meter themselves, and you would be effectively forcing those users to do that if they wanted to upgrade their firmware in the future. That would be very poor form.

I'm apparently communicating poorly, no worries.
Title: Re: EEVBlog 121GW Discussion thread
Post by: benst on January 24, 2018, 12:12:59 am
I see an app in the iOS App store called "EEVBlog 121GW" by Cheon Myoung-kun. That doesn't sound legit, does it?
And it looks bloody awfull.  :wtf:

It is bloody awful which is why we wrote our own. But yes it is "legit". UEi got that person to write it.

Ok, good to know, thanks! Any idea when your app will be ready for iOS?

Thanks,
Ben
Title: Re: EEVBlog 121GW Discussion thread
Post by: Kohanbash on January 24, 2018, 12:18:11 am
Any news on the US meters?

Yes, sorry but the US meters will be delayed, they want to make some small tolerance changes to the range switch. We'd rather have them delayed a bit than to have any more potential range switch issues.

Just to verify the Great Scott meters for the USA are getting the updated switch. Were they already manufactured (I thought they were sitting in a dock somewhere)?

(I am not rushing this, I am just curious)
Title: Re: EEVBlog 121GW Discussion thread
Post by: Scottjd on January 24, 2018, 12:21:30 am
Any news on the US meters?

Yes, sorry but the US meters will be delayed, they want to make some small tolerance changes to the range switch. We'd rather have them delayed a bit than to have any more potential range switch issues.

Ok, so your saying the meters are now in the US, and UEI is taking them to fix the range switches. Will UEI be shipping them, or will they get shipped again to the reshipper in the US and then make it to the customers. Or did you can the reshipper and UEI will be shipping the US meter now?

I have an idea, it’s not uncommon to have 2 different firmwares for different hardware releases.
As a “Thank you for being patient” can the US customers request maybe UEI can update the auto range speed on the US meters and mark them hardware version 1.1. Since it will be at the manufacturer I’m sure they can calibrate for the faster update ranging. Going forward for new batches can also all be marked as HW1.1 with the faster range update.
It will only make it a better product with future sales of the meters. And I’m sure someone will review it with the faster update range showing the meter with all the bugs fixed as well. And this way you get some of the faster update meters in people’s hands to work out any bug that might inadvertently happen from the faster update range improvements for hands on testing.

And for those that have the ability to calibrate the meter they can also load hardware version 1.1 firmware and do the calibration themselves.

If an open source firmware does happen, then who ever is working on the firmware will need to be aware of the different hardware versions.  This is a common thing when hardware changes happen anyway.


Title: Re: EEVBlog 121GW Discussion thread
Post by: mikeselectricstuff on January 24, 2018, 12:47:03 am
Presumably the cal issue is that they need to do measurement differently, so different cal data is needed.

This could be handled by the firmware looking to see if the new format data is present, and only using the newer ranging method if so. A user could choose to recal to enable this if they have the facility.

Another approach for a user to recal would be simply to use old FW to set a multiturn trimmer to the required cal value, update the FW, then use the trimmer to recal.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Halcyon on January 24, 2018, 12:47:20 am
How is the range switch modification going to be implemented? Who is doing the replacement for the US meters, and will you send replacement parts to customers who've already received theirs?

Dave has answered this in the "Issues" thread, see below...

The switch on my meter (#000499) is also wobbly and has the problem described here.
I took it apart, and contacts and pcb looked ok. After I put it back together it worked allright for a while, but now it's back and I have to fiddle with the switch again to get it to display correct readings. :-BROKE
Dave, once UEi figures out a fix, will you send out a replacement part?

Yes we'll have to do that for those existing shipments who have problems.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Scottjd on January 24, 2018, 01:22:01 am
Presumably the cal issue is that they need to do measurement differently, so different cal data is needed.

This could be handled by the firmware looking to see if the new format data is present, and only using the newer ranging method if so. A user could choose to recal to enable this if they have the facility.

Another approach for a user to recal would be simply to use old FW to set a multiturn trimmer to the required cal value, update the FW, then use the trimmer to recal.

True, but just because a meter is calibrated again doesn’t mean the format of the cal data stored in the eeprom is going to be in a different format. Assuming it will be the same formate, just different numbers to the firmware to read I not sure the firmware could determine what is an old cal data vs re-cal for the faster  update rate. And then theirs the issue of space, adding extra code if timcoild determine the difference between new and old cal data woild take up more space. And we don’t know how much is available as it currently is.
Besides, my thought behind it was technical the updated switch is a hardware change also. They would need someway to mark what meters have the updated switch bs the older one. This way if the issue comes up again they will know if it was an older meter first batch, or a fixed one that the problem re-surfaced on.
I guess when others get the parts to fix it themselves thenpart bag might want to include a self repair sticker unless UEI plans to stamp the under side of the switch with s different code or add a code to the mold?
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on January 24, 2018, 01:24:28 am
Ok, so your saying the meters are now in the US, and UEI is taking them to fix the range switches. Will UEI be shipping them, or will they get shipped again to the reshipper in the US and then make it to the customers. Or did you can the reshipper and UEI will be shipping the US meter now?

They will now ship direct from Kane Test (UEi) in the US.

Quote
I have an idea, it’s not uncommon to have 2 different firmwares for different hardware releases.
As a “Thank you for being patient” can the US customers request maybe UEI can update the auto range speed on the US meters and mark them hardware version 1.1. Since it will be at the manufacturer I’m sure they can calibrate for the faster update ranging. Going forward for new batches can also all be marked as HW1.1 with the faster range update.

There is no change in actual PCB hardware, it's a small mod to the tolerance range switch parts.

Quote
And for those that have the ability to calibrate the meter they can also load hardware version 1.1 firmware and do the calibration themselves.

I've said this before, we will not release firmware that requires a recal. Most people are NOT  in a position to calibrate their own meters.
To do so would require screwing existing customers, or maintaining two version of the firmware. Either solution is not acceptable.
Title: Re: EEVBlog 121GW Discussion thread
Post by: dcac on January 24, 2018, 01:44:28 am
Another approach for a user to recal would be simply to use old FW to set a multiturn trimmer to the required cal value, update the FW, then use the trimmer to recal.

That would also make a great video for Dave to show this procedure.

But I can see Dave’s problem - from the manual: “Factory calibration will be VOID if this function is used”

So that warranty will be lost on the already delivered units. So I guess then the only way is to issue a recall and who's going to cover that cost? If spread out over all backers (who bought a 121GW) what money are we talking about?

Title: Re: EEVBlog 121GW Discussion thread
Post by: hwti on January 24, 2018, 01:49:57 am
Dave posted the schematic in the firmware thread, but I reply here since my questions would be off-topic there :
Here is the schematic which may help
David2 is working on seeing what we can provide in terms of documentation to help people who want to write their own firmware.
http://www.eevblog.com/files/121GW%20EEVBlog%20Circuit%20diagram.pdf (http://www.eevblog.com/files/121GW%20EEVBlog%20Circuit%20diagram.pdf)
Why are Q13/Q16 (and Q14/Q15 if they were populated) used ?
To set the power-on (floating GPIO ?) state, a pull-up resistor would be enough.
The invert could have been done in software.

What would the B/Y channel of U14 would do if it was connected ?
It would connect TP11 to TP13 if DCmV_CTL (not used elsewhere) is high :-//

Is it safe to let 4053 logic input pins floating (C pin of U11, A pin of U14 if it was populated) ?
Usually it's not recommended, so unless the 4053 is special it's strange.
Title: Re: EEVBlog 121GW Discussion thread
Post by: logictom on January 24, 2018, 02:21:24 am
Regarding the specs of the meter, in the manual it lists the ranges:

(https://www.eevblog.com/forum/testgear/eevblog-121gw-discussion-thread/?action=dlattach;attach=389136)

So what is the resolution and accuracy for 501uA to 4999uA?
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on January 24, 2018, 02:40:00 am
Regarding the specs of the meter, in the manual it lists the ranges:

(https://www.eevblog.com/forum/testgear/eevblog-121gw-discussion-thread/?action=dlattach;attach=389136)

So what is the resolution and accuracy for 501uA to 4999uA?

They use the 5mA range.
Title: Re: EEVBlog 121GW Discussion thread
Post by: IanB on January 24, 2018, 03:06:13 am
In other words, the table is like this: (?)

Range    Resolution, Accuracy  Burden Voltage
50 µA    1 nA, ±1.5%+15  100 µV/µA
500 µA    10 nA, ±1.5%+15  100 µV/µA
5 mA    0.1 µA, ±0.25%+5  2 mV/mA
50 mA    1 µA, ±0.25%+5  2 mV/mA
0.5 A    10 µA, ±0.75%+15  0.03 V/A
10 A    1 mA, ±0.75%+15  0.03 V/A
Title: Re: EEVBlog 121GW Discussion thread
Post by: hwti on January 24, 2018, 03:36:49 am
Dave, http://www.eevblog.com/files/121GW%20EEVBlog%20Circuit%20diagram.pdf (http://www.eevblog.com/files/121GW%20EEVBlog%20Circuit%20diagram.pdf) is rev 1752, and my actual meter is rev 1745 on the PCB.
Are there any différences ?

The rev 1705 and 1720 from your "121GW Final Test Unit Inspection" video had U14 for example.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Scottjd on January 24, 2018, 05:10:54 am
The rev 1705 and 1720 from your "121GW Final Test Unit Inspection" video had U14 for example.
Are you referring to the video with them all on the table, and the close up shots? I saw that one as 1745 with u14 missing also. Or are you referring to another video?
Title: Re: EEVBlog 121GW Discussion thread
Post by: logictom on January 24, 2018, 05:45:00 am
Regarding the specs of the meter, in the manual it lists the ranges:

(https://www.eevblog.com/forum/testgear/eevblog-121gw-discussion-thread/?action=dlattach;attach=389136)

So what is the resolution and accuracy for 501uA to 4999uA?

They use the 5mA range.

If that is the case, why is it listed as 5 to 50 mA instead of that actual range of 0.5 to 50mA? Am I missing something simple here? ???
Title: Re: EEVBlog 121GW Discussion thread
Post by: amspire on January 24, 2018, 05:55:01 am
Regarding the specs of the meter, in the manual it lists the ranges:

(https://www.eevblog.com/forum/testgear/eevblog-121gw-discussion-thread/?action=dlattach;attach=389136)

So what is the resolution and accuracy for 501uA to 4999uA?

They use the 5mA range.

If that is the case, why is it listed as 5 to 50 mA instead of that actual range of 0.5 to 50mA? Am I missing something simple here? ???
You are missing something. Multimeter specifications always refer to the ranges - not to currents or voltages you are measuring. So this table is talking about the 50uA to 10A ranges.

If you want to measure 500uA, you can use the 500uA range, the 5mA range, the 50mA range, the 0.5A range, or the 5A range. The 10A is just a bit too far to see the 500uA. Each of these ranges will have its own accuracy that you can read from the table.

Why would you want to measure 500uA on the 0.5A range? The reason would be the burden voltage. For that range, the voltage drop across the multimeter (ignoring the 10A fuse) is 0.03V/A or at 500uA, that is only 15uV! The accuracy of the 500uV measurement would only be about 30%, but that can often be good enough.
Title: Re: EEVBlog 121GW Discussion thread
Post by: hwti on January 24, 2018, 06:28:42 am
The rev 1705 and 1720 from your "121GW Final Test Unit Inspection" video had U14 for example.
Are you referring to the video with them all on the table, and the close up shots? I saw that one as 1745 with u14 missing also. Or are you referring to another video?
The video I'm referring to is unlisted, but easy to find by its title.
But those older revision don't really matter, it's just to show there are differences, and not limited to the changes needed to pass certification.

What matters is we have rev 1745 meters, so perhaps we need rev 1745 schematic, and not rev 1752 which might be different.
Title: Re: EEVBlog 121GW Discussion thread
Post by: amspire on January 24, 2018, 06:34:22 am
The rev 1705 and 1720 from your "121GW Final Test Unit Inspection" video had U14 for example.
Are you referring to the video with them all on the table, and the close up shots? I saw that one as 1745 with u14 missing also. Or are you referring to another video?
The video I'm referring to is unlisted, but easy to find by its title.
But those older revision don't really matter, it's just to show there are differences, and not limited to the changes needed to pass certification.

What matters is we have rev 1745 meters, so perhaps we need rev 1745 schematic, and not rev 1752 which might be different.
Dave did say that they had to tidy up the schematic before they could release it. When you tidy up a document, that is a change and so the revision must increase. We do not know why the tidy up was needed - it might be just removing confidential information like employees names.

The circuit will be either accurate, or pretty close to accurate.

Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on January 24, 2018, 06:36:04 am
The circuit will be either accurate, or pretty close to accurate.

I am told that schematic is accurate to the shipped hardware.
Title: Re: EEVBlog 121GW Discussion thread
Post by: firewalker on January 24, 2018, 07:06:49 am
The meters of "Johnie be good" for Europe via the Germany company, will include the switch tweak?

Alexander.
Title: Re: EEVBlog 121GW Discussion thread
Post by: JacquesBBB on January 24, 2018, 07:09:12 am
How does the 121GW meter compare to the micro current ?

Is the micro current still useful for those who have the meter ?
Title: Re: EEVBlog 121GW Discussion thread
Post by: ChrisG on January 24, 2018, 07:12:34 am
Thank you for the diagram! Some of the parts are not specified or listed in a separate table. Is this on purpose?
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on January 24, 2018, 07:15:34 am
The meters of "Johnie be good" for Europe via the Germany company, will include the switch tweak?

Yes, all future meters shipped will have the revised switch
Title: Re: EEVBlog 121GW Discussion thread
Post by: FrankBuss on January 24, 2018, 07:15:57 am
Presumably the cal issue is that they need to do measurement differently, so different cal data is needed.

This could be handled by the firmware looking to see if the new format data is present, and only using the newer ranging method if so. A user could choose to recal to enable this if they have the facility.

Another approach for a user to recal would be simply to use old FW to set a multiturn trimmer to the required cal value, update the FW, then use the trimmer to recal.

Right, no need to maintain two different firmware versions, just a small portion of the firmware has to handle the old and new format. I hope they are experienced firmware developers who versioned the calibration data, because such things always change. But even if they didn't, it shouldn't be a problem: just use something impossible for the old format as the first byte for the new calibration data, to mark it as the new format. Fortunately it doesn't have to be compatible in the other direction, like there is nobody who would use a new set of calibration data with the old firmware. Could be programmed in like an hour.
Title: Re: EEVBlog 121GW Discussion thread
Post by: ChrisG on January 24, 2018, 07:19:00 am
@DaveJ: will you publish a list at a certain moment which lists the confirmed issues? And which ones can be solved by firmware updates? The issues thread does not seem to have many more new issues coming in so I assume we've captured 90-95% of them by now.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on January 24, 2018, 07:22:36 am
Right, no need to maintain two different firmware versions, just a small portion of the firmware has to handle the old and new format. I hope they are experienced firmware developers who versioned the calibration data, because such things always change. But even if they didn't, it shouldn't be a problem: just use something impossible for the old format as the first byte for the new calibration data, to mark it as the new format. Fortunately it doesn't have to be compatible in the other direction, like there is nobody who would use a new set of calibration data with the old firmware. Could be programmed in like an hour.

It might not be that easy.
It might affect calibration of other ranges, because (guessing) it might use a common ADC read averaging routine or something. What if you have to recalibrate the whole meter.
I really think this is bad idea and I am loath to recommend such a thing.

Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on January 24, 2018, 07:23:04 am
@DaveJ: will you publish a list at a certain moment which lists the confirmed issues?

Yes.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Towger on January 24, 2018, 07:40:59 am


To do so would require screwing existing customers, or maintaining two version of the firmware. Either solution is not acceptable.

At worse they just don't update beyond the version of firmware their meter supports.  If the the calibration data structure was well designed it should contain the initial firmware/hardware version it is for.  Newer firmware should be able to check it and decide it is is going to display a meaningful error or use the old method etc.  If they don't currently embed a version number it can be added to the new firmware etc.

At the end of the day if the meter is slow it will greatly impact future sales.
Title: Re: EEVBlog 121GW Discussion thread
Post by: hwti on January 24, 2018, 07:59:54 am
Thank you for the diagram! Some of the parts are not specified or listed in a separate table. Is this on purpose?
AFAIK, the components with an "x" value aren't populated on the PCB.
Some were probably added to allow to change the circuit in case of issues, or to be able to do some tests.
Others like U14 have been used in previous revisions and were removed (even if they didn't plan to reuse it, it's perhaps easier to avoid rerouting the PCB).
For example :
 - adding R142/C108 (and all the others) would do hardware debouncing on the keys (it's probably done in the firmware instead)
 - removing R101/R102 and adding R133 would switch to the AD8436 OUT without the OUTBUF follower
 - many 0 ohm resistor could be removed if someone wanted to test individual components for any reason
Title: Re: EEVBlog 121GW Discussion thread
Post by: exe on January 24, 2018, 12:28:25 pm
Does hardware let simultaneous measurement of AC and DC voltage? (I want to measure AC and DC bias at the same time)

Is it possible to do faster sampling at the expense of accuracy/resolution?
Title: Re: EEVBlog 121GW Discussion thread
Post by: imidis on January 24, 2018, 12:42:19 pm
At the end of the day if the meter is slow it will greatly impact future sales.
I think this is a very good point. To hinder performance for all future meters doesn't seem the best decision either.

Title: Re: EEVBlog 121GW Discussion thread
Post by: Iagash on January 24, 2018, 01:14:49 pm
So the Bluetooth Module is not used in the released meter.   :-DD

Well, yes if you look at the bluetooth protocol and the transmission, this feels true. ;-)
Title: Re: EEVBlog 121GW Discussion thread
Post by: Iagash on January 24, 2018, 01:28:31 pm
At the end of the day if the meter is slow it will greatly impact future sales.
I think this is a very good point. To hinder performance for all future meters doesn't seem the best decision either.

I would also think about this a little longer. We are talking about 500 meters now. Is it worth to settle for a second choice solution for the rest of the product live or even maybe fix it now before the Jonny be Good batch is shipped and only have to deal with the small amount that is in the wild? Maybe even fix it for the US meters and you reduce the number even further? What would be the cost for an recalibration offer for the existing meters and what would be the sales impact in the future on the product? What would be the cost of maintaining two firmware versions? I don't know the answers but it's something to think about at this point of the live cycle of the meter.
Title: Re: EEVBlog 121GW Discussion thread
Post by: mikeselectricstuff on January 24, 2018, 01:40:33 pm
Right, no need to maintain two different firmware versions, just a small portion of the firmware has to handle the old and new format. I hope they are experienced firmware developers who versioned the calibration data, because such things always change. But even if they didn't, it shouldn't be a problem: just use something impossible for the old format as the first byte for the new calibration data, to mark it as the new format. Fortunately it doesn't have to be compatible in the other direction, like there is nobody who would use a new set of calibration data with the old firmware. Could be programmed in like an hour.

It might not be that easy.
It might affect calibration of other ranges, because (guessing) it might use a common ADC read averaging routine or something. What if you have to recalibrate the whole meter.
I really think this is bad idea and I am loath to recommend such a thing.
I think you need to find out more details of the exact reason - maybe "require recal" just means "requires rewriting code we can't be arsed to do"
Title: Re: EEVBlog 121GW Discussion thread
Post by: exe on January 24, 2018, 02:00:10 pm
Concerning calibration, may be just implement import of it in, say, json or csv?
Title: Re: EEVBlog 121GW Discussion thread
Post by: fboehle on January 24, 2018, 02:06:11 pm
How does it actually function with so many different grounds. From what I can tell, most of the grounds are not directly connected to each other, but at the same time a large potential difference would certainly blow up some ICs. So how is their potential brought close together?

(I couldn't find a connection between AGND, GND, VSS)
Title: Re: EEVBlog 121GW Discussion thread
Post by: Fungus on January 24, 2018, 02:31:49 pm
a large potential difference would certainly blow up some ICs.

The meter is battery powered and the only connection to the outside world is the input jacks. Where would a large potential difference come from?

Title: Re: EEVBlog 121GW Discussion thread
Post by: Kean on January 24, 2018, 02:54:01 pm
I wonder if someone could check the meter in the LowZ mode.   In the early unit, if I applied a 1VRMS 60Hz signal, the meter would read zero as expected.   However, when I would increase the frequency to 389KHz, the meter was displaying 181.3 volts even though there was still only a volt being supplied.   There was something strange going on with it that I never looked into.  I reported the problem when I discovered it but with as many problems that the meter still has, I wonder if this was addressed in the released version.

Joe, I can confirm this issue is still present in FW1.01.
I generated a 2.8Vpp 60Hz (& 1kHz) sine wave with my MSO1104Z-S and it read 0V in LowZ mode.
When I upped the freq to 389kHZ and I got a reading of 189.2Vac.  See photo...

Edit: and it correctly read ~1V AC without LowZ up to maybe 100kHz, but that dropped to 0.773V AC at 389kHz
Title: Re: EEVBlog 121GW Discussion thread
Post by: maukka on January 24, 2018, 02:54:55 pm
I wonder if someone could check the meter in the LowZ mode.   In the early unit, if I applied a 1VRMS 60Hz signal, the meter would read zero as expected.   However, when I would increase the frequency to 389KHz, the meter was displaying 181.3 volts even though there was still only a volt being supplied.

With a 1Vrms signal the LowZ mode stays at 0V until 28kHz where it jumps to 10.4V. At 389kHz it shows 195.7V. This on v1.01.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Towger on January 24, 2018, 03:26:02 pm
I think you need to find out more details of the exact reason - maybe "require recal" just means "requires rewriting code we can't be arsed to do"

Probably true 'can't be arsed' programmers are very common   :-\
Title: Re: EEVBlog 121GW Discussion thread
Post by: tpw_rules on January 24, 2018, 04:29:11 pm
I don't buy the 'requiring recal' excuse either.

The meter has three sources of autocalibration delay. The first is an enforced delay on changing mode or range, which depends on the switch that was performed. When this delay is active, the display is blanked and the autocalibration routine does not run. The second is a sample averager, which is 8 samples for OHMS range and 16 for every other. This average value controls the screen display, and the current sample controls the bargraph. The same calibration factors are applied to both numbers. The third is a rolling average applied to the screen display, which depends on the mode and range as well. This should not be a factor, as the average resets on overrange or a large measurement delta.

The autorange is performed on the final displayed screen number that you see, after all three sources have been factored in. There is little to no software or calibration reason they couldn't shorten the delay during autoranging (which is what I think the v1.04 firmware does) or use the bargraph value initially. The calibration factor applied is the same for both measurements.

I've made a patch which removes that mode/range change delay while autoranging, but I can't test it without a meter. I'm now wondering if anybody would be willing to sell me their meter for testing purposes?
Title: Re: EEVBlog 121GW Discussion thread
Post by: dcac on January 24, 2018, 04:43:36 pm
Dave posted the schematic in the firmware thread, but I reply here since my questions would be off-topic there :
Here is the schematic which may help
http://www.eevblog.com/files/121GW%20EEVBlog%20Circuit%20diagram.pdf (http://www.eevblog.com/files/121GW%20EEVBlog%20Circuit%20diagram.pdf)
Is it safe to let 4053 logic input pins floating (C pin of U11, A pin of U14 if it was populated) ?
Usually it's not recommended, so unless the 4053 is special it's strange.

Yes that seems strange - C is pin9 on U11 and is a digital cmos input and really shouldn't be left floating. Schematics error? should it be connected to A and B which already are connected together.

Title: Re: EEVBlog 121GW Discussion thread
Post by: exe on January 24, 2018, 09:02:44 pm
I've made a patch which removes that mode/range change delay while autoranging, but I can't test it without a meter. I'm now wondering if anybody would be willing to sell me their meter for testing purposes?

Well, I have two, I can sell one. It cost me ~194 euros each delivered (I had to pay VAT and "processing" fee), I ask 180euro+delivery. The one I can sell was never used except a few power ups just to check. Please let me know (here or PM) if you are interested.

PS did other guys from EU also paid VAT? I though it supposed to be delivered from Germany via a distributor...

EDIT: I calculated price wrong first time.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Smokey on January 24, 2018, 09:32:53 pm
Oh man... can't wait for firmware version ...

v1.21

I hope it includes some serious shit!
Title: Re: EEVBlog 121GW Discussion thread
Post by: hwti on January 24, 2018, 09:35:46 pm
Yes that seems strange - C is pin9 on U11 and is a digital cmos input and really shouldn't be left floating. Schematics error? should it be connected to A and B which already are connected together.
I don't see any obvious trace connected to the pin.
I didn't want to reopen the whole meter, but by just removing the backcover the pin is accessible : I measured 13MOhm to ground, so it really seems to be floating (so no connection to ground under the chip, which could have been another option).
Title: Re: EEVBlog 121GW Discussion thread
Post by: dr.diesel on January 24, 2018, 09:44:37 pm
Oh man... can't wait for firmware version ...

v1.21

I hope it includes some serious shit!

I just about spilled my Beer, well done Sir. 
Title: Re: EEVBlog 121GW Discussion thread
Post by: logictom on January 24, 2018, 11:24:37 pm
You are missing something. Multimeter specifications always refer to the ranges - not to currents or voltages you are measuring. So this table is talking about the 50uA to 10A ranges.

Thanks amspire, that makes sense and it is what I see in the manual for my fluke, but what I still don't get is, why is the range specified with the lower value, so the 5mA value, when it can measure down to 500uA?
Title: Re: EEVBlog 121GW Discussion thread
Post by: Kal on January 24, 2018, 11:26:45 pm
Just want to add that rotary switch wobble issue exists also with my meter (EU shipped). https://youtu.be/pjaWWMoPMsE
Is this same for everyone or only part of the already shipped meters?
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on January 24, 2018, 11:45:18 pm
I've made a patch which removes that mode/range change delay while autoranging, but I can't test it without a meter. I'm now wondering if anybody would be willing to sell me their meter for testing purposes?

If you upload the firmware file then we can test it.
I'd get you a meter, but we only have two production units left here.
Title: Re: EEVBlog 121GW Discussion thread
Post by: fboehle on January 24, 2018, 11:45:26 pm
You are missing something. Multimeter specifications always refer to the ranges - not to currents or voltages you are measuring. So this table is talking about the 50uA to 10A ranges.

Thanks amspire, that makes sense and it is what I see in the manual for my fluke, but what I still don't get is, why is the range specified with the lower value, so the 5mA value, when it can measure down to 500uA?
Ranges on multimeters are always specified with the upper limit. The lower limit is always 0. So with the 5V range you can measure from 0V to +-5V. But to get a meaningful measurement, you need to have enough resolution to discern values at the lower end. A 50000 count DMM, like this one, will have a resolution of 0.0001V or 100 uV on the 5V range. So you can measure only discrete values from 0 to +-5V in 100uV steps.
Title: Re: EEVBlog 121GW Discussion thread
Post by: IanB on January 24, 2018, 11:57:56 pm
Thanks amspire, that makes sense and it is what I see in the manual for my fluke, but what I still don't get is, why is the range specified with the lower value, so the 5mA value, when it can measure down to 500uA?

Please see my reply from above, reproduced below.

The table is really listing each of the independent ranges and their attributes, like this:

Range    Resolution, Accuracy  Burden Voltage
50 µA    1 nA, ±1.5%+15  100 µV/µA
500 µA    10 nA, ±1.5%+15  100 µV/µA
5 mA    0.1 µA, ±0.25%+5  2 mV/mA
50 mA    1 µA, ±0.25%+5  2 mV/mA
0.5 A    10 µA, ±0.75%+15  0.03 V/A
10 A    1 mA, ±0.75%+15  0.03 V/A

As per usual, you would pick the lowest range suitable for the value you wish to measure.

Title: Re: EEVBlog 121GW Discussion thread
Post by: tpw_rules on January 25, 2018, 04:27:11 am
I've made a patch which removes that mode/range change delay while autoranging, but I can't test it without a meter. I'm now wondering if anybody would be willing to sell me their meter for testing purposes?

If you upload the firmware file then we can test it.
I'd get you a meter, but we only have two production units left here.

Sure, as long as I'm not responsible for any possible bodily harm as a result :) And thanks for the note, I do understand you need to keep those. But I leave the country in a month and I'm worried I won't get a meter before then as I'm in the US group. I'd really like one to continue hacking on, it's been fun so far.

For the patch, I just made the autorange routine ignore the mode/range change delay if the last mode/range change was caused by autoranging. It might just oscillate wildly, who knows! If it does work, it could more than halve autorange time.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on January 25, 2018, 08:15:31 am
I've made a patch which removes that mode/range change delay while autoranging, but I can't test it without a meter. I'm now wondering if anybody would be willing to sell me their meter for testing purposes?

If you upload the firmware file then we can test it.
I'd get you a meter, but we only have two production units left here.

Sure, as long as I'm not responsible for any possible bodily harm as a result :) And thanks for the note, I do understand you need to keep those. But I leave the country in a month and I'm worried I won't get a meter before then as I'm in the US group. I'd really like one to continue hacking on, it's been fun so far.

For the patch, I just made the autorange routine ignore the mode/range change delay if the last mode/range change was caused by autoranging. It might just oscillate wildly, who knows! If it does work, it could more than halve autorange time.

Works!  :clap:
I compared UEi's v1.04 and it's only a smidgen slower, not even half a second.

https://www.youtube.com/watch?v=3MD88EYLdQQ (https://www.youtube.com/watch?v=3MD88EYLdQQ)
Title: Re: EEVBlog 121GW Discussion thread
Post by: ChrisG on January 25, 2018, 08:27:45 am
I've made a patch which removes that mode/range change delay while autoranging, but I can't test it without a meter. I'm now wondering if anybody would be willing to sell me their meter for testing purposes?

If you upload the firmware file then we can test it.
I'd get you a meter, but we only have two production units left here.

Sure, as long as I'm not responsible for any possible bodily harm as a result :) And thanks for the note, I do understand you need to keep those. But I leave the country in a month and I'm worried I won't get a meter before then as I'm in the US group. I'd really like one to continue hacking on, it's been fun so far.

For the patch, I just made the autorange routine ignore the mode/range change delay if the last mode/range change was caused by autoranging. It might just oscillate wildly, who knows! If it does work, it could more than halve autorange time.

Works!  :clap:
I compared UEi's v1.04 and it's only a smidgen slower, not even half a second.

https://www.youtube.com/watch?v=3MD88EYLdQQ (https://www.youtube.com/watch?v=3MD88EYLdQQ)


NICE!!!!  :-+ :-+ :-+ :-+
Title: Re: EEVBlog 121GW Discussion thread
Post by: FrankBuss on January 25, 2018, 08:29:17 am
The company should hire tpw_rules. Pretty amazing to hack the binary without the source code and not even a meter for testing. Imagine what he could do if he would have the hardware and the source code :)
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on January 25, 2018, 08:42:42 am
The company should hire tpw_rules. Pretty amazing to hack the binary without the source code and not even a meter for testing. Imagine what he could do if he would have the hardware and the source code :)

Indeed, thoroughly impressed!  :-+
Title: Re: EEVBlog 121GW Discussion thread
Post by: AgiRigSig on January 25, 2018, 08:47:57 am
Wow, I am deeply impressed. As Frank already wrote,  UEI should hire tpw_rules  :-+ :-+ :-+
Title: Re: EEVBlog 121GW Discussion thread
Post by: mikeselectricstuff on January 25, 2018, 09:58:19 am
I've made a patch which removes that mode/range change delay while autoranging, but I can't test it without a meter. I'm now wondering if anybody would be willing to sell me their meter for testing purposes?

If you upload the firmware file then we can test it.
I'd get you a meter, but we only have two production units left here.

Sure, as long as I'm not responsible for any possible bodily harm as a result :) And thanks for the note, I do understand you need to keep those. But I leave the country in a month and I'm worried I won't get a meter before then as I'm in the US group. I'd really like one to continue hacking on, it's been fun so far.

For the patch, I just made the autorange routine ignore the mode/range change delay if the last mode/range change was caused by autoranging. It might just oscillate wildly, who knows! If it does work, it could more than halve autorange time.

Works!  :clap:
I compared UEi's v1.04 and it's only a smidgen slower, not even half a second.

https://www.youtube.com/watch?v=3MD88EYLdQQ (https://www.youtube.com/watch?v=3MD88EYLdQQ)
It's clearly doing some stuff it doesn't need to though - you see some intermediate displays during ranging
Title: Re: EEVBlog 121GW Discussion thread
Post by: ChrisG on January 25, 2018, 10:18:21 am
I've made a patch which removes that mode/range change delay while autoranging, but I can't test it without a meter. I'm now wondering if anybody would be willing to sell me their meter for testing purposes?

If you upload the firmware file then we can test it.
I'd get you a meter, but we only have two production units left here.

Sure, as long as I'm not responsible for any possible bodily harm as a result :) And thanks for the note, I do understand you need to keep those. But I leave the country in a month and I'm worried I won't get a meter before then as I'm in the US group. I'd really like one to continue hacking on, it's been fun so far.

For the patch, I just made the autorange routine ignore the mode/range change delay if the last mode/range change was caused by autoranging. It might just oscillate wildly, who knows! If it does work, it could more than halve autorange time.

Works!  :clap:
I compared UEi's v1.04 and it's only a smidgen slower, not even half a second.

https://www.youtube.com/watch?v=3MD88EYLdQQ (https://www.youtube.com/watch?v=3MD88EYLdQQ)
It's clearly doing some stuff it doesn't need to though - you see some intermediate displays during ranging

Indeed Mike next to that I'm wondering if the v1.04 version can not be released to this group to try, test and give feedback.
Title: Re: EEVBlog 121GW Discussion thread
Post by: bicycleguy on January 26, 2018, 06:04:38 pm
The company should hire tpw_rules. Pretty amazing to hack the binary without the source code and not even a meter for testing. Imagine what he could do if he would have the hardware and the source code :)
NO !   NO !  NO !     Don't let UEI steel him.  tow_rules should stay on the open source side and help us to not only get a more awesome meter but understand how it works!  I am really impressed :)
Title: Re: EEVBlog 121GW Discussion thread
Post by: Candid on January 26, 2018, 08:40:05 pm
I am having problems with connecting the 121GW app from dave2. I did no get any data shown in the app up to now. Most time it even does not connect.

I first run bluetooth and connect to the 121GW then I start the app. Sometimes when I click on refresh I can see the 121GW. Only one time it was able to connect (but no data shown, only white screen). Most time it says "connecting..." but never does.

The other app "EEVBlog 121GW" sometimes connects successfully and shows some values but sorry, it's so ugly.

/EDIT:
Now I got it running for one time but I think I am missing some data on the screen?
Title: Re: EEVBlog 121GW Discussion thread
Post by: plexus on January 27, 2018, 07:39:30 pm
Unforunately I immersed myself in the Apple eco-sh*thole starting in 1981. So I have macOS and iOS crap now. Eventually I will migrate away from all that.

But for now, where can I find updates on iOS/macOS software for the 121GW? I found the UEI iOS app and it works ok.

Is there somewhere where Dave is keeping us updated on software status? Or do I have to follow a thread?

Thanks!
Title: Re: EEVBlog 121GW Discussion thread
Post by: gnavigator1007 on January 27, 2018, 08:22:38 pm
 Acts like everything is fine set on volts with both leads plugged in A/mA
Title: Re: EEVBlog 121GW Discussion thread
Post by: tpw_rules on January 27, 2018, 08:37:24 pm
Acts like everything is fine set on volts with both leads plugged in A/mA

Strange.  Maybe someone missed an OR statement.  Just an added bit of info, both the Fluke 189 and Brymen BM869s will fault out under this condition.

Yup, they missed it. Code is here (https://github.com/tpwrules/121gw-re/blob/e0a0d88c952e8e1e61eedb4d6fb0b3b62a58be6a/database/EEVBlog-102.c#L14754). v0 is 0 if nothing's plugged in, 1 if mA is, 2 if A is, and 3 if both. They assume everything is OK if 0, or if 3. Maybe the hardware won't do the correct thing in case both are plugged in so they didn't check. I don't really understand how it's sensing a plug.
Title: Re: EEVBlog 121GW Discussion thread
Post by: bicycleguy on January 28, 2018, 01:10:05 am
...
Yup, they missed it. Code is here (https://github.com/tpwrules/121gw-re/blob/e0a0d88c952e8e1e61eedb4d6fb0b3b62a58be6a/database/EEVBlog-102.c#L14754). v0 is 0 if nothing's plugged in, 1 if mA is, 2 if A is, and 3 if both. They assume everything is OK if 0, or if 3. Maybe the hardware won't do the correct thing in case both are plugged in so they didn't check. I don't really understand how it's sensing a plug.

From the schematic it looks like the mA and A input terminals are physically split with part pulled up to Vdd through ~30M res.  Inserting a lead shorts the split to the respective amps shunt to ground and op-amps sense and condition signal to the STM.  Just my speculation though, my meter arrives in March :'(
Title: Re: EEVBlog 121GW Discussion thread
Post by: Candid on January 28, 2018, 11:48:09 am
Just tested it. AUTO DC+AC mode and I supplied about 25Vdc and it hunts. Raised voltage to about 44Vdc and it reads correctly. Lowering the DC voltage and it hunts again.

It looks like all pre-production errors are still present in the first batch of production meters of the 121GW. Even my crappy UNI-T UT71E is doing a better job in all of the discussed bugs.

I like to hear something soon from Dave how they will go on with the production meters of the early adopters...  :-\
Title: Re: EEVBlog 121GW Discussion thread
Post by: ChrisG on January 28, 2018, 12:10:25 pm
I use the AC+DC mode.  On the pre-production meter, this never worked very well.  If you wanted to try something very simple, switch the meter to AC+DC.  Attache the two leads normally (volts and common).   Now attach a DC supply and set it between 5 and 30 volts.  Does the meter just continue to hunt?   If it does, take the supply to 40-50 volts.  Does it now read correctly?    If it does, try lowering the voltage is see if it again starts to hunt.     Surely the released meters AC+DC mode works.

Hi Joe, not sure if what I did was right but I put it in AUTO DC+AC. Connected to my  EEZ H24005 power supply dialed in 25V (2mA current limit) and it displays it at 24.992 volt. on 5V it displays 5.000 volt at 40V it displays 39.989 on the meter. Apart from the still slow update rate it does not hunt in my opinion. Assuming the hunting is going back and forth and not getting a fix?
Title: Re: EEVBlog 121GW Discussion thread
Post by: Candid on January 28, 2018, 04:31:30 pm
Are you both using the same firmware? 
I have the 1.02 with the auto range patch installed and I can reproduce the exact same behavior as you showed in the video with the pre-production meter.

I made some quick pictures without tripod. Hope they are ok to see the details:
http://www.abload.de/gallery.php?key=so5gQFPZ (http://www.abload.de/gallery.php?key=so5gQFPZ)
Title: Re: EEVBlog 121GW Discussion thread
Post by: ChrisG on January 28, 2018, 07:21:09 pm
Well it was not a cheap power supply at 500€ but will try with a 9V battery then later. I’ve so far not se3n what you show in your viceo. Anyone else?
Title: Re: EEVBlog 121GW Discussion thread
Post by: ChrisG on January 28, 2018, 07:32:36 pm
Are you both using the same firmware? 

The pre-production meter would lock in depending on the AC and DC components.  If you have a cheap power supply with a lot of ripple for example, the meter may actually read correctly.   

V1.02 original (no autoranging patch)
Title: Re: EEVBlog 121GW Discussion thread
Post by: prof on January 28, 2018, 08:25:50 pm
Just want to add that rotary switch wobble issue exists also with my meter (EU shipped). https://youtu.be/pjaWWMoPMsE
Is this same for everyone or only part of the already shipped meters?

Mine's the same. Not worried about that though.
Title: Re: EEVBlog 121GW Discussion thread
Post by: ez24 on January 28, 2018, 08:40:39 pm
Regarding the switch.  It seems like "you can't have your cake and eat it to" issue.

Isn't one of the selling points is that it can be turned with one hand?

My AN8008 switch is tight as it can be but it cannot be turned with one hand unless it is tied down.  Personally I like the one hand use and I am experimenting tying down the AN8008 (zip ties work the best so far).

So far no one has said that if there was no wobble, if it could or not be used with one hand.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Candid on January 28, 2018, 09:08:58 pm
First, thank you for taking these pictures!  Don't tell me that's a section of solder stuck to the bottom of the spring??
No it's part of the spring. I already re-soldered it.

Did you notice what appears to be metallic contamination around your pads?  It would be nice to get a better shot of this area with a microscope or macro lens.
Maybe next week or someone else can have a closer look on his meter.

I don't like that you are already seeing what appears metallic dust this early.  Maybe it's something in the lighting.
I did not use any flash, only room light (very strong cold LED at the ceiling and warm LED on the bench) what is not the best for taking neutral pictures. I was surprised myself to see that much dust after only some turns. I may have a second nearer view if I find some time the next days. Hopefully someone else can make some pictures to compare.
Title: Re: EEVBlog 121GW Discussion thread
Post by: KNSSoftware on January 28, 2018, 09:29:26 pm

Isn't one of the selling points is that it can be turned with one hand?

So far no one has said that if there was no wobble, if it could or not be used with one hand.

If so, probably only after Dave realised early on that is was never going to be as stiff as the BM235 (which was a selling point about how stiff it was, and any shootout would get extra point for stiffness), and quickly turned a negative into a positive.  I think we underestimate how good he is at the marketing, and his own down playing of this skill, is a key part.  I would bet, if he could have got them to make it as stiff, he would have.
Title: Re: EEVBlog 121GW Discussion thread
Post by: 1anX on January 28, 2018, 09:58:21 pm
Just tested it. AUTO DC+AC mode and I supplied about 25Vdc and it hunts. Raised voltage to about 44Vdc and it reads correctly. Lowering the DC voltage and it hunts again.

It looks like all pre-production errors are still present in the first batch of production meters of the 121GW. Even my crappy UNI-T UT71E is doing a better job in all of the discussed bugs.

I like to hear something soon from Dave how they will go on with the production meters of the early adopters...  :-\

A fair and candid, (pun intended) comment !

I cant see us hearing from Dave anytime soon as he is keeping a very low profile and with good reason. He cant comment until he has a defined course of action to rectify the bugs and switch issue. Its up to UEi at this stage to pull their finger out and and turn this first "production" run meter into what it should be.

Dave needs to be extremely diplomatic with both his backers/buyers and with UEi. Nothing to be gained by pounding a fist on a table! As much as I dislike the situation with this meter, I am following Dave's lead with patience and high expectations for speedy fix.

The meter's potential with its unique specification is high and so is its potential for high worldwide sales. It will be interesting to see if Dave can turn the V1.0 bugs around and turn it into a best seller. It will also be interesting to see if UEi has the technology and ability to respond quickly to this meter's faults and apply thorough testing before releasing V1.01.

The EEVBlog forum has proved its worth once again by providing insights into this meter's teething problems and also presenting some impressive solutions. The firmware hacking and Joe's testing of the prototype, and informing us all of the carryover bugs, stand out for me!
Title: Re: EEVBlog 121GW Discussion thread
Post by: tpw_rules on January 28, 2018, 10:14:52 pm
Are you both using the same firmware? 

The pre-production meter would lock in depending on the AC and DC components.  If you have a cheap power supply with a lot of ripple for example, the meter may actually read correctly.   

V1.02 original (no autoranging patch)
Strange.  You would think it would do it or it wouldn't.  I am not sure what sort of regression testing is being ran on the patched code.  Maybe the patch has something to do with it.   

Yeah, it was a regression.

The original problem was that AC/DC mode operates by switching the meter mode every measurement and caching the result, to mix in when measuring the other mode. So you'd get:
1. read 5.5000V DC, store as 55000 counts. Autorange decides to range up.
2. switch to reading AC, read 00.000V, add previous DC counts to show 55.000V. Autorange decides to range up.
3. switch to reading DC, read 005.50V, add previous AC counts to show 005.50V. Autorange decides to range down.
4. switch to reading AC, read 00.000V, add previous DC counts to show 00.550V. Autorange decides to range down.
5. and so on and so on, literally forever.

The obvious way to bring the meter back is to input a DC value that's > 4000 and < 55000 counts, which explains in Joe's video why it hunts starting around 5.0000V and comes back at nearly exactly 40.00V. Or, input an AC value that results in a value within that range after both a bogus addition and a correct addition (by the way, it's not addition, it's sqrt(AC^2+DC^2) which I don't entirely understand why), so autorange settles down. So yeah, it definitely can depend on the AC and DC content.

Anyway, they fixed this by adding a delay so it would show two measurements before autorange decided to act again, thus flushing the bogus cached counts. But my patch mashes that delay to 0 whenever autorange acts (vs. the user), giving the same situation. My apologies for the confusion, but I can't test anything due to the delay in the US meters. I'll look into either applying that only to the resistance range, or perhaps just not to AC+DC mode.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on January 28, 2018, 10:43:34 pm

Isn't one of the selling points is that it can be turned with one hand?

So far no one has said that if there was no wobble, if it could or not be used with one hand.

If so, probably only after Dave realised early on that is was never going to be as stiff as the BM235 (which was a selling point about how stiff it was, and any shootout would get extra point for stiffness), and quickly turned a negative into a positive.  I think we underestimate how good he is at the marketing, and his own down playing of this skill, is a key part.  I would bet, if he could have got them to make it as stiff, he would have.

Actually, I think the BM235 range switch is a bit too stiff, I find i have to apply some downward pressure in order to switch it one handed on a smooth surface, worse if it's up on the tilt stand
Whilst the 121GW technically has the same pressure issue, the action is less "violent" than the BM235 and requires less force. Sometimes I think that's better, sometimes not, depending upon my mood and usage scenario, it's entirely personal preference. The 121GW range switch was simply UEi's standard method used in their other meters and I didn't see any reason to mess with it.
Title: Re: EEVBlog 121GW Discussion thread
Post by: nuclearcat on January 28, 2018, 11:09:23 pm
A bit fun with 121GW bluetooth data stream + USB microscope + (C++/wxwidgets/OpenCV to add OSD layer)
https://www.youtube.com/watch?v=nIbdnlQJ1fA&feature=youtu.be (https://www.youtube.com/watch?v=nIbdnlQJ1fA&feature=youtu.be)
Still PoC, not sure if such will be useful, or maybe such apps already exist.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Seppy on January 29, 2018, 05:08:11 am
I am having problems with connecting the 121GW app from dave2. I did no get any data shown in the app up to now. Most time it even does not connect.

I first run bluetooth and connect to the 121GW then I start the app. Sometimes when I click on refresh I can see the 121GW. Only one time it was able to connect (but no data shown, only white screen). Most time it says "connecting..." but never does.

The other app "EEVBlog 121GW" sometimes connects successfully and shows some values but sorry, it's so ugly.

/EDIT:
Now I got it running for one time but I think I am missing some data on the screen?

There are a couple things to note when using the app and its easy to prevent it from working.
1. Make sure only one instance is running at a time.
2. You shouldn't need to pair the app at all on android to give that a try before you go and pair the device.

It seems people tend to open the app to see what they installed then pair or enable bluetooth, then open a second instance of the app. That is known to cause issues.
Title: Re: EEVBlog 121GW Discussion thread
Post by: ChrisG on January 29, 2018, 05:49:35 pm
Hi Joe, I just tried it and can not replay your issue in the video. 10Vpp sine-wave from the Siglent SDG 2042X into the 121GW and the BM869s connected too. This 121GW on any ms range indicates correctly at frequencies from 10Hz to 200Hz (10, 50, 100, 200). I can not get a wrong reading on the meter. Still on V1.02 not patched for slow update rate.
Title: Re: EEVBlog 121GW Discussion thread
Post by: ChrisG on January 29, 2018, 05:55:20 pm
Well it was not a cheap power supply at 500€ but will try with a 9V battery then later. I’ve so far not se3n what you show in your viceo. Anyone else?

Hi Joe, tried a 9v (actually bit dated and went to 8v) battery. Apart from slow auto-ranging no issue on locking in. So if slow auto-ranging is hunting then yes but I assume not.
Title: Re: EEVBlog 121GW Discussion thread
Post by: benst on January 29, 2018, 11:39:29 pm
Just want to add that rotary switch wobble issue exists also with my meter (EU shipped). https://youtu.be/pjaWWMoPMsE
Is this same for everyone or only part of the already shipped meters?
Mine (#000499) is similar, maybe a bit less.

Edit: and I have the funky display sometimes. Wiggling the switch a few times fixes it.

Ben
Title: Re: EEVBlog 121GW Discussion thread
Post by: dcac on January 30, 2018, 01:43:18 am
Yet another auto ranging benchmark - Keysight U1461A which also uses hy3131 but has a 6600 counts mode - goes from infidelity infinity to zero ohms in just 2.2-2.4 sec. Though it only goes down to 0.1 ohms resolution so to be fair 121gw has two more range steps to complete. Still seems promising if a low resolution mode can be added to 121gw.

Perhaps sniffing the bus on how U1461A controls the hy3131 could give an idea how it achieves this speed. But if we're unlucky there are other HW differences that makes the 121gw so dreadfully slow.

Title: Re: EEVBlog 121GW Discussion thread
Post by: ANTALIFE on January 30, 2018, 11:56:56 am
Quick question/problem, I am trying to measure power (VA) of a device plugged into an AUS AC socket.
I have everything connected as per diagram on pg46 of manual (11 December 2017 rev), when I switch to mVA/VA mode (in AC too) I get Vac too large to read.
Interestingly enough I can measure Vac & Iac individually which come out as ~245Vrms & ~16mA (rms?)

So my question is, am I doing something wrong or is the meter not designed to measure stuff plugged into an AC socket
Title: Re: EEVBlog 121GW Discussion thread
Post by: ChrisG on January 30, 2018, 12:06:55 pm
Hi Joe, I just tried it and can not replay your issue in the video. 10Vpp sine-wave from the Siglent SDG 2042X into the 121GW and the BM869s connected too. This 121GW on any ms range indicates correctly at frequencies from 10Hz to 200Hz (10, 50, 100, 200). I can not get a wrong reading on the meter. Still on V1.02 not patched for slow update rate.
Well it was not a cheap power supply at 500€ but will try with a 9V battery then later. I’ve so far not se3n what you show in your viceo. Anyone else?

Hi Joe, tried a 9v (actually bit dated and went to 8v) battery. Apart from slow auto-ranging no issue on locking in. So if slow auto-ranging is hunting then yes but I assume not.
9V I assume was for the AC+DC mode.  If you read the previous posts, looks like the reason for the difference was indeed the patch.   It appears they did address a few of the problems.   I think the big one is what appears to be a metallic dust in those previous pictures.  If you have been putting a few cycles on yours (even a few hundred total) and a camera that you can take some close ups of the pad area, it would be interesting to see a few more pictures.   

Hi Joe, I'll give that a go the coming days. Too much normal work going on for me at the moment. I'm not sure I'm looking forward to this to be honest. If the tracks are or seem to deteriorate quickly I would be appalled. Are you getting an official, non pre-production, 121GW soon perhaps?
Title: Re: EEVBlog 121GW Discussion thread
Post by: ChrisG on January 30, 2018, 12:54:11 pm
Hi Joe, I just tried it and can not replay your issue in the video. 10Vpp sine-wave from the Siglent SDG 2042X into the 121GW and the BM869s connected too. This 121GW on any ms range indicates correctly at frequencies from 10Hz to 200Hz (10, 50, 100, 200). I can not get a wrong reading on the meter. Still on V1.02 not patched for slow update rate.
Well it was not a cheap power supply at 500€ but will try with a 9V battery then later. I’ve so far not se3n what you show in your viceo. Anyone else?

Hi Joe, tried a 9v (actually bit dated and went to 8v) battery. Apart from slow auto-ranging no issue on locking in. So if slow auto-ranging is hunting then yes but I assume not.
9V I assume was for the AC+DC mode.  If you read the previous posts, looks like the reason for the difference was indeed the patch.   It appears they did address a few of the problems.   I think the big one is what appears to be a metallic dust in those previous pictures.  If you have been putting a few cycles on yours (even a few hundred total) and a camera that you can take some close ups of the pad area, it would be interesting to see a few more pictures.   

Hi Joe, I'll give that a go the coming days. Too much normal work going on for me at the moment. I'm not sure I'm looking forward to this to be honest. If the tracks are or seem to deteriorate quickly I would be appalled. Are you getting an official, non pre-production, 121GW soon perhaps?
Personally, I would rather know if there was a problem early on.   If there is, maybe it could be corrected before any major damage happens to the PCB.  What sort of warranty did you get?   If you put a few thousand cycles on the switch over the next few weeks and the parts are damaged, is the meter covered? 

From what I understand, very few meters made it to people in the USA so even if I had joined, I doubt I would have it.  Strange as I would have thought they would have been the largest consumer.   Anyway, I was concerned that there had not been a full review of the meter that disclosed what the problems were and how they would be mitigated.  Obviously, there were problems that have been known for some time.  I had asked a question in the kickstarter that went unanswered.   Also, looking at the closeup video, it appeared the meter's weak front end was still in play.  Again, it's not a lot of money but if I bought one it would be to run it to failure and I did not want to invest this amount of time if the design was still not stable or if it was not going to be an improvement over the earlier version.  If and when it looks like the meter is stable and it becomes available through normal channels, I may run one.   For now, it seems it is way too early.   

Agree with you Joe and at the same time I'm happy I did join the campaign very much so. It's a joint effort in the end of this community to come up with a solid product and I would not have expected it to be perfect during the first production version. However traces on the PCB which are not up to spec would a, as said already, disappoint me.
BTW: I thought the front end was pretty okay and not weak. Did I miss it in your pre-production test video?
Title: Re: EEVBlog 121GW Discussion thread
Post by: Smokey on January 30, 2018, 10:54:31 pm
....Keysight U1461A .... goes from infidelity to zero ohms in just 2.2-2.4 sec

HA!  I thought infidelity was already due to low resistance
Title: Re: EEVBlog 121GW Discussion thread
Post by: dcac on January 31, 2018, 12:04:24 am
....Keysight U1461A .... goes from infidelity to zero ohms in just 2.2-2.4 sec

HA!  I thought infidelity was already due to low resistance

lol, yeah autocomplete at its best - should of course have been - infinity to zero ohms in 2.2-2.4 sec.

Title: Re: EEVBlog 121GW Discussion thread
Post by: dcac on January 31, 2018, 12:27:28 am
From what I understand, very few meters made it to people in the USA so even if I had joined, I doubt I would have it.  Strange as I would have thought they would have been the largest consumer.

Probably the large time difference between USA and Australia caused potential consumers to be too late in the game - at least for the first batch anyway.

Title: Re: EEVBlog 121GW Discussion thread
Post by: nidlaX on January 31, 2018, 03:13:54 am
From what I understand, very few meters made it to people in the USA so even if I had joined, I doubt I would have it.  Strange as I would have thought they would have been the largest consumer.

Probably the large time difference between USA and Australia caused potential consumers to be too late in the game - at least for the first batch anyway.
No... The US meters were simply stuck in customs all the way up to when the switch tolerance issue was reported. Now they won't ship until that issue is fixed.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on January 31, 2018, 05:51:28 am
Look at the data.  There are several meters that have done very well in these tests.  2KV is lower than the average and not something I would be impressed with.  I was just as surprised by the Fluke 87V result.  Received a lot of negative posts over that one from the fans.  Not much I can say about how the meter's do in the tests.   I can say that the Fluke 87V is not what I consider the goal post.

I guess this goes to show how important this stuff actually is in the real world, as much as we all like to fuss over these sorts of details because, you know, we are nerds.
I have never heard a single person complain that the Fluke 87 series isn't a robust industrial meter, and not surprising because it's been an industry standard for like 30 years now.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on January 31, 2018, 05:53:49 am
Perhaps sniffing the bus on how U1461A controls the hy3131 could give an idea how it achieves this speed. But if we're unlucky there are other HW differences that makes the 121gw so dreadfully slow.

FYI, the 121GW is now on par with the U1282A.
Title: Re: EEVBlog 121GW Discussion thread
Post by: 1anX on January 31, 2018, 06:08:29 am
Perhaps sniffing the bus on how U1461A controls the hy3131 could give an idea how it achieves this speed. But if we're unlucky there are other HW differences that makes the 121gw so dreadfully slow.

FYI, the 121GW is now on par with the U1282A.

So whats that in Seconds?
How are UEi progressing on the bug fixes?
Any timeline on when they expect to have a fully functional and thoroughly tested meter to ship?
Sounds like progress is being made, so thats good news  :-+
Title: Re: EEVBlog 121GW Discussion thread
Post by: exe on January 31, 2018, 12:32:01 pm
Dave, a week or two ago you mentioned Dave2 was working on making some instructions how to make own firmware for the meter (or was it only about how to flash it?). Is there any progress on this? I understand you are busy guys, but I'd appreciate any information on how to roll own firmware so I could start developing it (or other duded smarted than me). I know it's possible to reverse-engineer the current firmware, but I think it's a waste of time this is inefficient. Also, I think it is already proven community can fix problems much faster than any manufacturer.

I also would like to get more updates on the meter. Any rumors, estimations, etc. So, we could see it's not abandoned. If possible. Or, better, a UEI representative here in the thread. Like other manufacturers do on this forum (e.g., MicSig, R&S, Siglent (tautech), Rigol, etc).
Title: Re: EEVBlog 121GW Discussion thread
Post by: joeqsmith on January 31, 2018, 12:35:34 pm
Look at the data.  There are several meters that have done very well in these tests.  2KV is lower than the average and not something I would be impressed with.  I was just as surprised by the Fluke 87V result.  Received a lot of negative posts over that one from the fans.  Not much I can say about how the meter's do in the tests.   I can say that the Fluke 87V is not what I consider the goal post.

I guess this goes to show how important this stuff actually is in the real world, as much as we all like to fuss over these sorts of details because, you know, we are nerds.
I have never heard a single person complain that the Fluke 87 series isn't a robust industrial meter, and not surprising because it's been an industry standard for like 30 years now.
As I have mentioned before, I  really don't know what the failure rate is for the 87V.  I've seen posts where they have failed which is not too surprising.  Enough hype and marketing can easily cover up any short comings.   You are right that there are people that that care less about the marketing and more about the results.  I certainly classify myself in that category and offer these test results as proof of that. 

Another data point we have is the age of the 87V and how it compares with Fluke's newer designs.  I've also looked at the 101,107,115 and 17B+.  All newer, all from China.   The worst of them was the Fluke 17B+ that was damaged at 10KV 50us.   Sure, it could be by accident that their newer meters are so much more robust but I doubt it.  I suspect it has more to do with reducing the number of field failures and warranty returns.  But again, I really don't know and can only present the data.   It's up to the people that view it to interpret it.     
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on January 31, 2018, 01:20:00 pm
Look at the data.  There are several meters that have done very well in these tests.  2KV is lower than the average and not something I would be impressed with.  I was just as surprised by the Fluke 87V result.  Received a lot of negative posts over that one from the fans.  Not much I can say about how the meter's do in the tests.   I can say that the Fluke 87V is not what I consider the goal post.

I guess this goes to show how important this stuff actually is in the real world, as much as we all like to fuss over these sorts of details because, you know, we are nerds.
I have never heard a single person complain that the Fluke 87 series isn't a robust industrial meter, and not surprising because it's been an industry standard for like 30 years now.
As I have mentioned before, I  really don't know what the failure rate is for the 87V.  I've seen posts where they have failed which is not too surprising.  Enough hype and marketing can easily cover up any short comings.

Or maybe the "short comings" aren't really short comings in a practical world? And the 87V's reputation as one of the most reliable and robust meters on the market is actually well earned?
Maybe the 61010 CAT IV 600V rating as tested by UL is more than enough for almost everyone?
For instance, the now infamous 87V GSM bug wasn't found for a decade, and countless units sold of the biggest selling meter on the market.
Or the very popular Keysight U1272A's EMC problem taking how long before someone found it?

Title: Re: EEVBlog 121GW Discussion thread
Post by: dcac on January 31, 2018, 04:11:58 pm
Perhaps sniffing the bus on how U1461A controls the hy3131 could give an idea how it achieves this speed. But if we're unlucky there are other HW differences that makes the 121gw so dreadfully slow.

FYI, the 121GW is now on par with the U1282A.

FYI, that still makes it dreadfully slow - I’m sorry, but I guess I miss the old clonk-clonk-clonk Dave who’d facepalme and hammer his failbutton through the desk if confronted with an auto-ranging this slow on a DMM in this class. But still I really do appreciate what you’re trying to provide with the 121gw and my main point was that the U1461 was so much faster in a 6000 count mode.

Am I expecting UEi to provide a fast 5000 count mode for 121gw? - no not really - but they’re in a much better position having the FW source code to make an addition like that - compared to hacking/patching the binaries. But I’m starting to wonder if UEi them self is limited in what they can achieve with the development tools they’re using. Else I can’t really understand why 121gw ever was released with an auto-raging that was so slow that backers would go seriously WTF!
Title: Re: EEVBlog 121GW Discussion thread
Post by: ChrisG on January 31, 2018, 04:26:45 pm
Perhaps sniffing the bus on how U1461A controls the hy3131 could give an idea how it achieves this speed. But if we're unlucky there are other HW differences that makes the 121gw so dreadfully slow.

FYI, the 121GW is now on par with the U1282A.

FYI, that still makes it dreadfully slow - I’m sorry, but I guess I miss the old clonk-clonk-clonk Dave who’d facepalme and hammer his failbutton through the desk if confronted with an auto-ranging this slow on a DMM in this class. But still I really do appreciate what you’re trying to provide with the 121gw and my main point was that the U1461 was so much faster in a 6000 count mode.

Am I expecting UEi to provide a fast 5000 count mode for 121gw? - no not really - but they’re in a much better position having the FW source code to make an addition like that - compared to hacking/patching the binaries. But I’m starting to wonder if UEi them self is limited in what they can achieve with the development tools they’re using. Else I can’t really understand why 121gw ever was released with an auto-raging that was so slow that backers would go seriously WTF!


That would not be good at all and with all the issues piling up till now and the fact that some if not most are really HW related it starts to be a real problem for me. This morning I had to cycle the knob 3-4 times before it wanted to switch on?   :-//  how can that be?
Title: Re: EEVBlog 121GW Discussion thread
Post by: ChrisG on January 31, 2018, 05:38:53 pm
POSTING again since the other one got lost?

Herewith the pictures of the PCB selector tracks.
Title: Re: EEVBlog 121GW Discussion thread
Post by: ChrisG on January 31, 2018, 05:42:23 pm
Another set.
Title: Re: EEVBlog 121GW Discussion thread
Post by: ChrisG on January 31, 2018, 05:47:45 pm
3rd set. Comments to follow.
Title: Re: EEVBlog 121GW Discussion thread
Post by: The Soulman on January 31, 2018, 05:59:53 pm
ChrisG, can you post pictures of the wiper contacts as well? Just curious.
Title: Re: EEVBlog 121GW Discussion thread
Post by: ChrisG on January 31, 2018, 06:22:01 pm
They are spotless.  And I just put the whole thing together again... :-)
Title: Re: EEVBlog 121GW Discussion thread
Post by: ChrisG on January 31, 2018, 06:38:15 pm
Appears to have less contamination but we have no idea how many cycles were on the two meters posted so far.   Can you tell with your eyes if any of that is metallic?   

I wonder how the people with the intermittent switches would compare with the ones the work as expected.  It would seem that the intermittent meters make have less contact force and would be less prone to wear but we really don't know.   

Does not seem to be metallic but I'm not an expert. On purpose I did not clean the contacts though. Btw I just noticed that on the wiper side there also one track very close to the hole of the selector pivot. As already said the wiper dots where pretty clean and shiny. Let's keep this conversation going please. Perhaps other people dare to open up their 121GW and see, check or take pictures. BTW Dave and Dave could also open up their 121GW's right?
Title: Re: EEVBlog 121GW Discussion thread
Post by: Candid on January 31, 2018, 06:43:14 pm
Appears to have less contamination but we have no idea how many cycles were on the two meters posted so far.   Can you tell with your eyes if any of that is metallic?
I posted the first pictures and checked today. I think it's not metallic at least not magnetic. I checked with a strong neodyn magnet and it doesn't feel metallic.

I cleaned it and will check in some weeks.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on January 31, 2018, 10:10:40 pm
Practical world sounds like a marketing term.  I really have no idea idea about the 87Vs reputation, if it has one or how it came to be.

After almost 30 years in the industry I can assure you it has that reputation. But I guess you have to be in the industry and closely follow this stuff to know.
How did it get that rep? - With a great deal of time giving dependable and trustworthy service.
But this is a 121GW thread so I'll stop talking about this now.
Title: Re: EEVBlog 121GW Discussion thread
Post by: 1anX on January 31, 2018, 10:18:55 pm
I also would like to get more updates on the meter. Any rumors, estimations, etc. So, we could see it's not abandoned. If possible. Or, better, a UEI representative here in the thread. Like other manufacturers do on this forum (e.g., MicSig, R&S, Siglent (tautech), Rigol, etc).

Dave, I think it is time that you found your voice and provide an update of the current situation!

What progress, (if any) has been made by you and UEi in rectifying the faults?

I am becoming concerned by the lack of communication and wondering if the root cause of the "bugs" is hardware related and only you can provide details on the meter to make clear the situation.

Considerable time has passed without you providing meaningful info on the rectification of the meter's abundant faults.

The meter comes with a warranty and is covered under ACCC laws, but I'm hoping you will be proposing a meter replacement/fix program for the shipped meters and a thorough revision for the meters awaiting manufacture/shipping.

With great respect, what is the current state of play Dave?
Title: Re: EEVBlog 121GW Discussion thread
Post by: amspire on January 31, 2018, 11:01:41 pm
I also would like to get more updates on the meter. Any rumors, estimations, etc. So, we could see it's not abandoned. If possible. Or, better, a UEI representative here in the thread. Like other manufacturers do on this forum (e.g., MicSig, R&S, Siglent (tautech), Rigol, etc).

Dave, I think it is time that you found your voice and provide an update of the current situation!

What progress, (if any) has been made by you and UEi in rectifying the faults?

I am becoming concerned by the lack of communication and wondering if the root cause of the "bugs" is hardware related and only you can provide details on the meter to make clear the situation.

Considerable time has passed without you providing meaningful info on the rectification of the meter's abundant faults.

The meter comes with a warranty and is covered under ACCC laws, but I'm hoping you will be proposing a meter replacement/fix program for the shipped meters and a thorough revision for the meters awaiting manufacture/shipping.

With great respect, what is the current state of play Dave?
IanX,

If you have a meter that is so faulty that you are talking about invoking ACCC laws, then I hope you have contacted Dave directly - as the ACCC would expect you to do first.

Dave has actually given a lot of communication - far more then any other manufacturer I have seen and he does not even design or make the meters. Just be patient.

I am puzzled by your mention of the "abundant faults". My meter is pretty functional. The biggest issue that people seem to raise is the slow autoranging that is not a fault, but it is being improved.

I am prepared to wait for issues and improvements to be fully tested before release. I have a 121GW meter that seems to be safe and measures volts, amps, resistance, temperature, capacitance, frequency and duty factor all within specifications. I am very happy that Dave has already seen updates that will improve the meter.

What sort of meter did you get?
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on January 31, 2018, 11:20:47 pm
I also would like to get more updates on the meter. Any rumors, estimations, etc. So, we could see it's not abandoned. If possible. Or, better, a UEI representative here in the thread. Like other manufacturers do on this forum (e.g., MicSig, R&S, Siglent (tautech), Rigol, etc).

Dave, I think it is time that you found your voice and provide an update of the current situation!
What progress, (if any) has been made by you and UEi in rectifying the faults?

The issues are being investigated, stuff just takes time, especially when you have more than one issue. There is no point in me speculating daily.
There is essentially very little I can do personally to speed this up or really even help them out from a technical perspective.
They are still waiting on the range switch parts, due in a few days I believe, and then there is testing etc.
On top of that of course are several software issues, some like slow autoranging for example has been solved (to match that of the U1282A), others are still being worked on (presumably one by one).
Please be patient, when I know for certain, you'll know.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Brumby on January 31, 2018, 11:39:11 pm
1anX - you seem to be running hot and cold....

I cant see us hearing from Dave anytime soon as he is keeping a very low profile and with good reason. He cant comment until he has a defined course of action to rectify the bugs and switch issue. Its up to UEi at this stage to pull their finger out and and turn this first "production" run meter into what it should be.

Dave needs to be extremely diplomatic with both his backers/buyers and with UEi. Nothing to be gained by pounding a fist on a table! As much as I dislike the situation with this meter, I am following Dave's lead with patience and high expectations for speedy fix.

and now this...

Dave, I think it is time that you found your voice and provide an update of the current situation!

What progress, (if any) has been made by you and UEi in rectifying the faults?

I am becoming concerned by the lack of communication and wondering if the root cause of the "bugs" is hardware related and only you can provide details on the meter to make clear the situation.

Considerable time has passed without you providing meaningful info on the rectification of the meter's abundant faults.

The meter comes with a warranty and is covered under ACCC laws, but I'm hoping you will be proposing a meter replacement/fix program for the shipped meters and a thorough revision for the meters awaiting manufacture/shipping.

With great respect, what is the current state of play Dave?

My definition of "patience" in this scenario is a little more than a couple of days.  It's taken over 2 years of development to get the 121GW to where it is today - and the first run of units were bound to encounter some issues when released to the sort of people who frequent here.

In my limited experience, Dave has been pretty candid with his comments - and usually only says something when there is something worth saying.  If you want comforting on a daily basis, then that's not going to happen here.

This stuff takes time.

Oh, and even mentioning the ACCC at this point is really unfair.  Not only that - but it comes across as a threat.

Besides, the ACCC won't give a flying fig about getting the meter fixed to your satisfaction.  They would look at these threads and immediately understand what the situation is and they will tell you to talk to Dave.  They will simply ensure that you haven't been swindled.  An issue which would be immediately resolved by returning the meter and getting a full refund.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Brumby on January 31, 2018, 11:42:23 pm
My post above was written as Dave made his reply - but I posted it on principle.

I also would like to get more updates on the meter. Any rumors, estimations, etc. So, we could see it's not abandoned. If possible. Or, better, a UEI representative here in the thread. Like other manufacturers do on this forum (e.g., MicSig, R&S, Siglent (tautech), Rigol, etc).

Dave, I think it is time that you found your voice and provide an update of the current situation!
What progress, (if any) has been made by you and UEi in rectifying the faults?

The issues are being investigated, stuff just takes time, especially when you have more than one issue. There is no point in me speculating daily.
There is essentially very little I can do personally to speed this up or really even help them out from a technical perspective.
They are still waiting on the range switch parts, due in a few days I believe, and then there is testing etc.
On top of that of course are several software issues, some like slow autoranging for example has been solved (to match that of the U1282A), others are still being worked on (presumably one by one).
Please be patient, when I know for certain, you'll know.

This shows exactly what I expected.

... and you can't say he isn't responsive!!
Title: Re: EEVBlog 121GW Discussion thread
Post by: rstofer on February 01, 2018, 01:27:41 am
This certainly won't be my first or only meter.  Whether I get it today, next month or even a few months from now really makes no difference.  Sure, I'm looking forward to receiving it because, among other things, it is already paid for.  But I would rather have the upgraded switch and firmware rather than try to figure out what to do next. It takes what it takes and getting these issues resolved before it ships to me makes all the sense in the world (to me).

Title: Re: EEVBlog 121GW Discussion thread
Post by: lowimpedance on February 01, 2018, 02:24:33 am
About a week ago I reported the mechanical issue I had on my 121 with the switch and input terminals here ;
https://www.eevblog.com/forum/testgear/eevblog-121gw-multimeter-issues/msg1403241/#msg1403241 (https://www.eevblog.com/forum/testgear/eevblog-121gw-multimeter-issues/msg1403241/#msg1403241)

So after returning from holiday I thought I would have a look inside at what may be happening with my meter.
What I can see happening with mine to cause my issue was the small flexing of the PCB by the input plugs movement
was causing referred movement at the switch area and since my switch was rather 'sloppy' in its location hole this had caused
either contact or contact location issues on their relevant PCB tracks and thus the mode failures.

Further investigation of the switch rotor showed quite a lot of lateral movement in the PCB locating hole.
So next step was what to do to reduce this lateral 'slop'!.
After removing the PCB from the switch knob I could test fit various rod diameters, (rear ends of twist drills in 0.1mm inc.), to lightly expand
the switch plate plastic fingers that go through the main PCB to remove the slop but still have easy rotational movement.
The best size for my meter was 6.1mm OD. To help alignment further I made the ID be a good sliding fit to the hex shaft of the knob at 5.6mm.
 The resulting sleeve I machined up can be seen in the photo below in its final position (I left it longer so its easily removed.). The material used was PEEK which is
reasonably stiff and has good insulation properties, (I also had it anyway  :P). Did not want to use PTFE which would have been too soft at the cross section used.

As an additional exercise I also cut up some 0.3mm PTFE sheet as spacers under the knob circlip, see photo below. Two pieces provided a good take up
of the space between the housing and the circlip. This reduced the knob free play up and down but allowed some compliance in the well in the top housing and the circlip too
due to the soft flexible nature of the PTFE.

So the end result of this exercise was a considerably less 'wobbly' feel to the knob and more importantly all the issues I had reported have now gone
completely and any movement of the input plugs have no effect on the switch nor does wiggling the knob itself set off any failures of the mode its in.
Title: Re: EEVBlog 121GW Discussion thread
Post by: 1anX on February 01, 2018, 04:33:31 am
This certainly won't be my first or only meter.  Whether I get it today, next month or even a few months from now really makes no difference.  Sure, I'm looking forward to receiving it because, among other things, it is already paid for.  But I would rather have the upgraded switch and firmware rather than try to figure out what to do next. It takes what it takes and getting these issues resolved before it ships to me makes all the sense in the world (to me).

Agreed!

I have a collection of meters and was going to by a second Fluke, but then Dave came along with his integration of a few good ideas to make a "unique" meter. I put the Fluke on hold as I watched his ideas develop into a best bang for buck meter. Hackable and with BLE and the low burden voltage won me over, as I was seriously considering a uCurrentGold.

So Dave has my money and I'm looking forward to a best bang for buck meter turning up in March or whenever. I'm concerned that UEi have stumbled at the first production run and the switch is an issue. Look forward to seeing if Dave's good ideas get the build quality they deserve!
Title: Re: EEVBlog 121GW Discussion thread
Post by: 1anX on February 01, 2018, 04:38:10 am
I'm hoping to use this meter for measuring ucurrent on my ESP32 projects. Has anyone used the meter for ucurrent measurement by placing a zero ohm shunt in place of the fuses? If you have tried it what burden voltage was present and how does it compare to the uCurrentGold?
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on February 01, 2018, 05:11:57 am
I'm hoping to use this meter for measuring ucurrent on my ESP32 projects. Has anyone used the meter for ucurrent measurement by placing a zero ohm shunt in place of the fuses? If you have tried it what burden voltage was present and how does it compare to the uCurrentGold?

You can calculate that from the schematic value for the shunt resistors.
http://www.eevblog.com/files/121GW%20EEVBlog%20Circuit%20diagram.pdf (http://www.eevblog.com/files/121GW%20EEVBlog%20Circuit%20diagram.pdf)
10mohm, 1.01ohm, and 100.1ohms.
x1 or x10 amp depending on range using that shunt.
Title: Re: EEVBlog 121GW Discussion thread
Post by: JonM on February 01, 2018, 05:31:01 am
For anyone interested in Dave candidly discussing the 121GW issues:

 https://theamphour.com/377-debugger-vs-printeffer/

Spoilers: Dave chuckles over the irony of the slow resistance settling time and what he has said about other meters.  He also noted that the slowness was introduced in a late firmware update and he noted that they should have had a formal list of tests to be done for each release.

I'm standing by for the US deliveries....
Title: Re: EEVBlog 121GW Discussion thread
Post by: lowimpedance on February 01, 2018, 05:34:20 am
About a week ago I reported the mechanical issue I had on my 121 with the switch and input terminals here ;
https://www.eevblog.com/forum/testgear/eevblog-121gw-multimeter-issues/msg1403241/#msg1403241 (https://www.eevblog.com/forum/testgear/eevblog-121gw-multimeter-issues/msg1403241/#msg1403241)
....
The best size for my meter was 6.1mm OD. To help alignment further I made the ID be a good sliding fit to the hex shaft of the knob at 5.6mm.
 The resulting sleeve I machined up can be seen in the photo below in its final position (I left it longer so its easily removed.). The material used was PEEK which is
reasonably stiff and has good insulation properties, (I also had it anyway  :P). Did not want to use PTFE which would have been too soft at the cross section used.
....
So the end result of this exercise was a considerably less 'wobbly' feel to the knob and more importantly all the issues I had reported have now gone
completely and any movement of the input plugs have no effect on the switch nor does wiggling the knob itself set off any failures of the mode its in.

By adding the sleeve, I wonder if the PCB will wear away at shaft where it rotates in the hole.  Time will tell.
I did apply a small amount of contact type grease in that area but I also made sure the pressure from the sleeve was just enough to mitigate the lateral movement without grossly effecting the rotary movement of the switch.
Title: Re: EEVBlog 121GW Discussion thread
Post by: JonM on February 01, 2018, 05:34:31 am
I forgot to mention that a couple of days ago I dumped the batteries out of a set top box remote control I need to return and was surprised to see that they were made by UEI. I wonder if the 121GW comes with a UEI battery?

Title: Re: EEVBlog 121GW Discussion thread
Post by: lowimpedance on February 01, 2018, 05:39:30 am
I forgot to mention that a couple of days ago I dumped the batteries out of a set top box remote control I need to return and was surprised to see that they were made by UEI. I wonder if the 121GW comes with a UEI battery?
For us in Oz it was duracell.
Title: Re: EEVBlog 121GW Discussion thread
Post by: amspire on February 01, 2018, 05:57:45 am

So after returning from holiday I thought I would have a look inside at what may be happening with my meter.
What I can see happening with mine to cause my issue was the small flexing of the PCB by the input plugs movement
was causing referred movement at the switch area and since my switch was rather 'sloppy' in its location hole this had caused
either contact or contact location issues on their relevant PCB tracks and thus the mode failures.

Further investigation of the switch rotor showed quite a lot of lateral movement in the PCB locating hole.
So next step was what to do to reduce this lateral 'slop'!.
After removing the PCB from the switch knob I could test fit various rod diameters, (rear ends of twist drills in 0.1mm inc.), to lightly expand
the switch plate plastic fingers that go through the main PCB to remove the slop but still have easy rotational movement.
The best size for my meter was 6.1mm OD. To help alignment further I made the ID be a good sliding fit to the hex shaft of the knob at 5.6mm.
 The resulting sleeve I machined up can be seen in the photo below in its final position (I left it longer so its easily removed.). The material used was PEEK which is
reasonably stiff and has good insulation properties, (I also had it anyway  :P). Did not want to use PTFE which would have been too soft at the cross section used.

As an additional exercise I also cut up some 0.3mm PTFE sheet as spacers under the knob circlip, see photo below. Two pieces provided a good take up
of the space between the housing and the circlip. This reduced the knob free play up and down but allowed some compliance in the well in the top housing and the circlip too
due to the soft flexible nature of the PTFE.

In the following, when I refer to just the "switch", I meant all the parts attached to the circuit board.

I decided to fix my 121GW wobbly switch up a while ago, but after looking at the mechanism, I took a very different approach. I did look at your method but I think it was making the situation even worse rather then better mechanically.

First, instead of putting a spacer under the circlip, I put a spacer between the knob and the the nylon detent spring so that the circlip was in contact with the case plastic. This lifts the knob upwards. I didn't make it tight. I just wanted to stop any signifigant vertical movement. The reason for this method was so that the circlip does not press on the switch at all. If you put spacers under the circlip, the circlip is pressing on the switch which I think is wrong. The spacer was actually just many layers of duct tape. I had a punch to make a nice hole in the middle.

But now the knob was even looser. So I added a few strips of Kapton tape around the knob sides to widen it till it stopped wobbling much. You want to change a cone shape that is narrowest at the top to one widest at the top, so start off with a thin strip of tape just near the top side of the knob . Then a thicker one that goes to 2/3 down the knob  sides. Then some that goes around the whole sides. The idea is to increase the knob diameter to the point it can hardly wobble, but still have a tiny clearance to the case. Correctly done and the knob is no stiffer then before.

A bit of heat (I just used some hot water) to set the Kapton adhesive and it stays in place really well.

The way you have fixed the switch is you are trying to use the switch to stop the knob from moving which is putting more stress on the switch. It should be the knob that correctly locates the switch. The switch should be free to float a bit.

After this fix, I don't think anyone would notice an issue. I didn't take the tape right to the top and you cannot actually see it at all.

Richard
Title: Re: EEVBlog 121GW Discussion thread
Post by: ChrisG on February 01, 2018, 08:47:20 am
Appears to have less contamination but we have no idea how many cycles were on the two meters posted so far.   Can you tell with your eyes if any of that is metallic?
I posted the first pictures and checked today. I think it's not metallic at least not magnetic. I checked with a strong neodyn magnet and it doesn't feel metallic.

I cleaned it and will check in some weeks.
I wouldn't have expected it to be magnetic but it's good to know.

Copper, aluminum, gold etc are non-ferro and this test will not work IMHO.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Towger on February 01, 2018, 09:30:51 am
I have reattached one of ChrisG's photos with a couple of questions:

(https://www.eevblog.com/forum/testgear/eevblog-121gw-discussion-thread/?action=dlattach;attach=391571)

1) What is the point of the two notches in the outside track?
    Are these to give slightly more resistance when moving the switch from the Off position, however there appears to be an slightly worn segment with no track, so this maybe the 'Off' position.

2) A number of the vias too close to the rubbing line/area of the track for my liking.   Joe's testing has clearly shown the wear caused by vias in the track is a major contributor to early failure of the switch.  There appears to be plenty of space in the other side so this only costs initial design time to be done right.
Title: Re: EEVBlog 121GW Discussion thread
Post by: lowimpedance on February 01, 2018, 11:33:04 am

So after returning from holiday I thought I would have a look inside at what may be happening with my meter.
What I can see happening with mine to cause my issue was the small flexing of the PCB by the input plugs movement
was causing referred movement at the switch area and since my switch was rather 'sloppy' in its location hole this had caused
either contact or contact location issues on their relevant PCB tracks and thus the mode failures.

Further investigation of the switch rotor showed quite a lot of lateral movement in the PCB locating hole.
So next step was what to do to reduce this lateral 'slop'!.
After removing the PCB from the switch knob I could test fit various rod diameters, (rear ends of twist drills in 0.1mm inc.), to lightly expand
the switch plate plastic fingers that go through the main PCB to remove the slop but still have easy rotational movement.
The best size for my meter was 6.1mm OD. To help alignment further I made the ID be a good sliding fit to the hex shaft of the knob at 5.6mm.
 The resulting sleeve I machined up can be seen in the photo below in its final position (I left it longer so its easily removed.). The material used was PEEK which is
reasonably stiff and has good insulation properties, (I also had it anyway  :P). Did not want to use PTFE which would have been too soft at the cross section used.

As an additional exercise I also cut up some 0.3mm PTFE sheet as spacers under the knob circlip, see photo below. Two pieces provided a good take up
of the space between the housing and the circlip. This reduced the knob free play up and down but allowed some compliance in the well in the top housing and the circlip too
due to the soft flexible nature of the PTFE.

In the following, when I refer to just the "switch", I meant all the parts attached to the circuit board. The "switch rotor" is the knob part attached to the case.

I decided to fix my 121GW wobbly switch up a while ago, but after looking at the mechanism, I took a very different approach. I did look at your method but I think it was making the situation even worse rather then better mechanically.

First, instead of putting a spacer under the circlip, I put a spacer between the switch rotor and the the nylon detent spring so that the circlip was in contact with the case plastic. This lifts the rotor upwards. I didn't make it tight. I just wanted to stop any signifigant vertical movement. The reason for this method was so that the circlip does not press on the switch at all. If you put spacers under the circlip, the circlip is pressing on the switch which I think is wrong. The spacer was actually just many layers of duct tape. I had a punch to make a nice hole in the middle.

But now the switch rotor was even looser. So I added a few strips of Kapton tape around the switch rotor sides to widen it till it stopped wobbling much. You want to change a cone shape that is narrowest at the top to one widest at the top, so start off with a thin strip of tape just near the top side of the switch rotor. Then a thicker one that goes to 2/3 down the rotor sides. Then some that goes around the whole sides. The idea is to increase the switch rotor diameter to the point it can hardly wobble, but still have a tiny clearance to the case. Correctly done and the switch rotor is no stiffer then before.

A bit of heat (I just used some hot water) to set the Kapton adhesive and it stays in place really well.

The way you have fixed the switch is you are trying to use the switch to stop the rotor from moving which is putting more stress on the switch. It should be the switch rotor that correctly locates the switch. The switch should be free to float a bit.

After this fix, I don't think anyone would notice an issue. I didn't take the tape right to the top and you cannot actually see it at all.

Richard

For reference when referring to the rotor, that is the plastic carrier for the contact fingers, the PCB is the Stator and the knob would be the 'clicker plate' just like any rotary wafer switch assembly.
 Okay when making it worse are you referring to the small sleeve or the PTFE under the circlip ?.
For the sleeve i disagree that any additional stress is being applied to the contacts or the PCB. The dimensions of it are carefully chosen by measurement to only
apply enough pressure to the plastic fingers of the rotor body to the PCB hole reducing only lateral free play ,(which in my opinion is excessive ), to a minimum without
adversely effecting the effort required to rotate. This mechanical change guarantees alignment of the switch contacts on the rotor with the PCB stator and how will this
introduce ant further stress on the contacts.
 Now for the PTFE under the circlip, has anyone measured the distance from the top of the rotor body to the underside of the circlip to determine how much distance
there actually is ?. I will admit it has crossed my mind and yet I did not actually do it myself , so as soon as I can I will take the meter apart again I will attempt to get some
measurement done there and post back, as well as try the knob without the PTFE spacers to see if only the sleeve cured my issue or it is indeed needed to apply light pressure to the rotor.
If even that is actually happening with the spacers installed.
Title: Re: EEVBlog 121GW Discussion thread
Post by: amspire on February 01, 2018, 12:05:06 pm

For reference when referring to the rotor, that is the plastic carrier for the contact fingers, the PCB is the Stator and the knob would be the 'clicker plate' just like any rotary wafer switch assembly.
You are right. I used the words switch rotor when I meant knob. I have corrected it.
Quote
Okay when making it worse are you referring to the small sleeve or the PTFE under the circlip ?.
For the sleeve i disagree that any additional stress is being applied to the contacts or the PCB. The dimensions of it are carefully chosen by measurement to only
apply enough pressure to the plastic fingers of the rotor body to the PCB hole reducing only lateral free play ,(which in my opinion is excessive ), to a minimum without
adversely effecting the effort required to rotate. This mechanical change guarantees alignment of the switch contacts on the rotor with the PCB stator and how will this
introduce ant further stress on the contacts.
I believe that when you put the PTFE under the circlip, then the circlip does push downwards on the switch rotor slightly. Not much deflection, but I don't think anything you do on the knob should be pushing the rotor up and down.

The way I have fixed my meter, there is a clear gap between the circlip and the rotor.

As far as the sleeve goes, I do not think you need any reduction in play of the rotor since the hex shaft from the knob locates the position of the rotor. You should have a knob that is centred and doesn't wobble.

If you need the sleeve to help stop the knob from wobbling, then I think you are making the switch rotor do something it shouldn't be doing. Any rotating pressure on the knob is transferred directly to the rotor and the PCB. There is no need for this to be so.
Quote

 Now for the PTFE under the circlip, has anyone measured the distance from the top of the rotor body to the underside of the circlip to determine how much distance
there actually is ?. I will admit it has crossed my mind and yet I did not actually do it myself , so as soon as I can I will take the meter apart again I will attempt to get some
measurement done there and post back, as well as try the knob without the PTFE spacers to see if only the sleeve cured my issue or it is indeed needed to apply light pressure to the rotor.
If even that is actually happening with the spacers installed.
I just observed some deflection, but I didn't measure the amount. I had already decided to go a different way. The best way to measure this deflection may be to measure the height of the rotor clip above the PCB on the component side.

What struck me is that when the front case was away from the switch, the knob was really loose - much worse then when attached to the switch.

The problem is threefold - the circlip allows a big vertical movement, the knob sides have too much clearance and the knob moulding taper is all wrong. The knob hole in the case gets wider at the top, and so the knob should also get wider and not narrower at the top. I wanted a knob that on its own wasn't wobbling and that didn't rely on the tightness of the circlip to stop the wobbling.

Now both our "fixes" are definitely not approved by Dave or the manufacturer, so they are both just our own opinion of a solution. Given that it seems that a new knob is coming, it is probably best to wait if you have no problem right now - just be careful with the knob.
Title: Re: EEVBlog 121GW Discussion thread
Post by: lowimpedance on February 01, 2018, 12:44:41 pm
Indeed the fixes we have done for our own are for a bit of tinkering and not 'approved'. And of course I will use the redesigned assembly when it arrives.
But as I have clearly found on my meter the was a direct link to PCB flexure from only small movement of the probe inputs that caused major issues
on the ohm/diode modes of that switch position that it was completely unusable until I did my version of a fix and now in the interim the functions work.
(note that my 121 meters knob was quite 'wobbly' to start with! so I am not convinced its just the knob and not also the rotor slop at play here too.).
Now purely for my own edification I will see what effect the sleeve has without the PTFE packing. Is most surely not going to damage my meter to have a play
while I wait for the 'approved ' replacement part.
Title: Re: EEVBlog 121GW Discussion thread
Post by: ChrisG on February 01, 2018, 01:58:45 pm
Indeed the fixes we have done for our own are for a bit of tinkering and not 'approved'. And of course I will use the redesigned assembly when it arrives.
But as I have clearly found on my meter the was a direct link to PCB flexure from only small movement of the probe inputs that caused major issues
on the ohm/diode modes of that switch position that it was completely unusable until I did my version of a fix and now in the interim the functions work.
(note that my 121 meters knob was quite 'wobbly' to start with! so I am not convinced its just the knob and not also the rotor slop at play here too.).
Now purely for my own edification I will see what effect the sleeve has without the PTFE packing. Is most surely not going to damage my meter to have a play
while I wait for the 'approved ' replacement part.


Gents, all of this is fine for the wobbly knob and rotor action. However it does not address the wear of the knob axis within the PCB. The gunk which was on my PCB tracks (or does it?).
Title: Re: EEVBlog 121GW Discussion thread
Post by: videobruce on February 01, 2018, 03:48:29 pm
I hate to ask, but what is so special about this DMM???  ???
One would think by all the posts in now THREE sticky threads that it was the 3rd coming, especially considering these threads are only 3 weeks old.   ::)

Who is the manufacture?  I don't see it listed in that DMM thread thou that hasn't been updated in 8 months.
Title: Re: EEVBlog 121GW Discussion thread
Post by: nidlaX on February 01, 2018, 04:03:02 pm
I hate to ask, but what is so special about this DMM???  ???
One would think by all the posts in now THREE sticky threads that it was the 3rd coming, especially considering these threads are only 3 weeks old.   ::)

Who is the manufacture?  I don't see it listed in that DMM thread thou that hasn't been updated in 8 months.
There are three stickies and a ton of posts because it's Dave's multimeter, so this is the primary place to discuss it.

If you haven't learned by now that the multimeter is made by UEi, then you aren't trying hard enough.
Title: Re: EEVBlog 121GW Discussion thread
Post by: videobruce on February 01, 2018, 05:14:15 pm
Now I have learned.
Of course if there was specific info, other than some U-Boob video as to whom was making/selling this and a link where to buy it, it would of been apparent. This should of been in the OP, without the ASSUMPTION that EVERYONE here already knows about another multimeter of which there are a hundred already in existence and hundreds more discontinued.

That's almost as bad as using acronyms & abbreviations (that aren't COMMON and often used) in documents without at least stating once what they stand for.  :--

"EEVBlog" doesn't ring a bell as a importer or manufacture.   ::)
Title: Re: EEVBlog 121GW Discussion thread
Post by: nidlaX on February 01, 2018, 05:26:32 pm


Now I have learned. O
Of course if there was specific info, other than some U-Boob video as to whom was making/selling this and a link where to buy it, it would of been apparent.
There was an announcement thread. There is a Kickstarter page. There is Google.

I recommend learning how to use the Internet.
Title: Re: EEVBlog 121GW Discussion thread
Post by: mikeselectricstuff on February 01, 2018, 06:41:34 pm
"EEVBlog" doesn't ring a bell as a importer or manufacture.   ::)
The clues are out there...
Title: Re: EEVBlog 121GW Discussion thread
Post by: lowimpedance on February 01, 2018, 11:18:37 pm
Indeed the fixes we have done for our own are for a bit of tinkering and not 'approved'. And of course I will use the redesigned assembly when it arrives.
But as I have clearly found on my meter the was a direct link to PCB flexure from only small movement of the probe inputs that caused major issues
on the ohm/diode modes of that switch position that it was completely unusable until I did my version of a fix and now in the interim the functions work.
(note that my 121 meters knob was quite 'wobbly' to start with! so I am not convinced its just the knob and not also the rotor slop at play here too.).
Now purely for my own edification I will see what effect the sleeve has without the PTFE packing. Is most surely not going to damage my meter to have a play
while I wait for the 'approved ' replacement part.



Gents, all of this is fine for the wobbly knob and rotor action. However it does not address the wear of the knob axis within the PCB. The gunk which was on my PCB tracks (or does it?).

Are you sure the ''gunk' on the PCB is related to the rotor fit/action in the hole of the PCB ?. Looks more like its related to the contacts wiping action on the gold plated traces, unless I'm
looking at the wrong picture!.
If its related to the abrasion of the rotor plastic there should be noticeable scrape marks on the plastic fingers of the rotor that pass through the PCB hole. One would think this type of multimeter
switch rotor construction would be a problem no matter who's brand it is.
Title: Re: EEVBlog 121GW Discussion thread
Post by: lowimpedance on February 02, 2018, 12:29:19 am
Followup to the above where I said ;
Now purely for my own edification I will see what effect the sleeve has without the PTFE packing.
I have removed the packing and left off the circlip too.  So testing of the diode mode, (which failed to work on my meter when received), it still works with no issues at all from any probe movement or
any lateral or wiggling movement of the knob. So it appears at least for my meter the sleeve HAS fixed the issue I had and the PTFE packers are in fact not needed.
Thus too much lateral free play of the rotor is the problem and not contact pressure on the PCB. (and I'll bet its the same with all others meters doing odd things on other ranges that are not firmware related.).


Using a piece of 0.85mm thick PTFE sheet cut in a thin strip and bent to go into the space between the rotor top and top housing I can see the distance (tested by inserting the 'shim' where the knob would have been) to be close to 0.9mm.
The circlip is 0.6mm thick. So in the stock production meters there is no contact between rotor and circlip.
Picture showing the knob removed from the assembled meter and using a teflon shim to measure the gap between the rotor and hosing.

Edit: To note also the knob is much less 'wobbly or free' in its movement when seated with the sleeve in place and no packing under the circlip. (or even the circlip ! :P)
Title: Re: EEVBlog 121GW Discussion thread
Post by: Kean on February 03, 2018, 09:45:35 am
I forgot to mention that a couple of days ago I dumped the batteries out of a set top box remote control I need to return and was surprised to see that they were made by UEI. I wonder if the 121GW comes with a UEI battery?

UEI batteries in a remote control would be from a different UEI: Universal Electronics (https://www.uei.com/) vs UEi Test Instruments (http://www.ueitest.com/)
Title: Re: EEVBlog 121GW Discussion thread
Post by: 1anX on February 04, 2018, 10:33:31 pm
For anyone interested in Dave candidly discussing the 121GW issues:

 https://theamphour.com/377-debugger-vs-printeffer/

Spoilers: Dave chuckles over the irony of the slow resistance settling time and what he has said about other meters.  He also noted that the slowness was introduced in a late firmware update and he noted that they should have had a formal list of tests to be done for each release.

I'm standing by for the US deliveries....

I had a listen to it myself today, as still no word from Dave or UEi on the current state of the meter's repair and updated firmware!

Seems on the theamphour.com interview, Dave says that UEi have a fix for the hardware switch issues. All the suggestions on this forum thread seem to indicate that a fix is necessary and probably straightforward to implement.

Can anyone provide info on what UEi have come up with to fix the wobbly switch and intermittent contact issue?
Title: Re: EEVBlog 121GW Discussion thread
Post by: amspire on February 04, 2018, 11:22:45 pm
Can anyone provide info on what UEi have come up with to fix the wobbly switch and intermittent contact issue?
When UEi release fully tested fixes and upgrades, Dave will announce it.

Like it or not, it does not help anyone if companies release updates and fixes in a bit of a panic. It doesn't help if companies promise solutions before they actually have the complete solution. This is a Kickstarter meter - it is close to a prototype unit. They have made the initial 500 or so meters and found a few problems. If you want a great meter, give UEi time to resolve the issues in a proper manner. This is a normal process. A fix for the knob probably means a new moulding and then it should be properly tested to decide if the mark II knob is right or not. It might be too tight for a good feel. They might have to try a third or fourth knob to get it right. Software updates can actually mean major rewrites that then need to go through a full quality audit and testing.

Do you actually have intermittent contact issues yourself? If not, just use the meter, and when the updates come in a week or a few months, you will have a better meter.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on February 04, 2018, 11:27:00 pm
For anyone interested in Dave candidly discussing the 121GW issues:

 https://theamphour.com/377-debugger-vs-printeffer/

Spoilers: Dave chuckles over the irony of the slow resistance settling time and what he has said about other meters.  He also noted that the slowness was introduced in a late firmware update and he noted that they should have had a formal list of tests to be done for each release.

I'm standing by for the US deliveries....

I had a listen to it myself today, as still no word from Dave or UEi on the current state of the meter's repair and updated firmware!

For the third or fourth time now, when I know it's all done and dusted, you'll know.
This stuff doesn't take days to do, it can take weeks.
I have just got a new version that fixes the Low-Z high frequency issue, but I have not tried it yet.
So I think that's most of the software issues now fixed, but we will not be dribbling out updates every few days and they solve an issue, there will be one big update that includes all the software bug fixes.
The hardware switch issue is still waiting on parts delivery.

Quote
Can anyone provide info on what UEi have come up with to fix the wobbly switch and intermittent contact issue?

They have tweaked the dimensions of the white plastic spring assembly and switch assembly I believe.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Brumby on February 05, 2018, 01:14:29 am
For those who might miss it ... I will highlight a couple of points...

For the third or fourth time now, when I know it's all done and dusted, you'll know.
This stuff doesn't take days to do, it can take weeks.
If you seriously look at what is involved in the manufacture of an even moderately complex product, this should be no surprise at all.

Quote
So I think that's most of the software issues now fixed, but we will not be dribbling out updates every few days and they solve an issue, there will be one big update that includes all the software bug fixes.
Getting people to re-flash the firmware 20 times in a month is NOT conducive to a high standard of testing - nor is it an appealing prospect to owners.  It is also bad form.
Title: Re: EEVBlog 121GW Discussion thread
Post by: BravoV on February 05, 2018, 01:28:36 am
Getting people to re-flash the firmware 20 times in a month is NOT conducive to a high standard of testing - nor is it an appealing prospect to owners.  It is also bad form.

Kids these days tend to love frequent updates, no matter how shitty the update, as long the manufacturer keep pumping out updates every week, they will be happy, just don't know why.  :-//

Just look at popular PC forums on motherboards when these tons of whiners cried/cursed/begged etc for frequent BIOS update just for minuscule non critical bug.  :palm:

Prolly they already used to live with their gadgets that do frequent updates like in smartphone apps ? or worst Win 10 syndrome ?  :-DD

Title: Re: EEVBlog 121GW Discussion thread
Post by: nidlaX on February 05, 2018, 01:52:12 am
Getting people to re-flash the firmware 20 times in a month is NOT conducive to a high standard of testing - nor is it an appealing prospect to owners.  It is also bad form.
Just look at popular PC forums on motherboards when these tons of whiners cried/cursed/begged etc for frequent BIOS update just for minuscule non critical bug.  :palm:
While I generally agree with you, I disagree that firmware updates for this meter in its current state should be aggregated for months before being released.

1. The meter is essentially in a beta phase of release right now, so frequent updates and testing will help the manufacturer find and fix issues more quickly. Issues are expected to be the norm at this stage.
2. The people who wanted first dibs on this meter are also probably the ones who will tolerate more frequent updates. Better to do rapid revisions with 500 willing guinea pigs now than later on when customers expect a mature product.
3. You can always let people opt-in to a faster firmware release channel. If there's a significant new issue or regression, you can always roll back.
Title: Re: EEVBlog 121GW Discussion thread
Post by: amspire on February 05, 2018, 02:02:50 am
While I generally agree with you, I disagree that firmware updates for this meter in its current state should be aggregated for months before being released.

1. The meter is essentially in a beta phase of release right now, so frequent updates and testing will help the manufacturer find and fix issues more quickly. Issues are expected to be the norm at this stage.
But the manufacturer also has to provide warranty on these meters and they do not want to have to support 100 different versions of updates.

They haven't released any firmware update officially yet. Until they do, they can still change things. It could be that today, there is a meeting at UEi right now where someone is saying "Our autoranging code is not really capable of managing the needs of this meter, particularly in VA mode. There is no way to fix it. We really have to rewrite the autoranging from scratch."

The last thing they would want is a flood of public complaints, Youtube videos, posts and emails about problems with previous updates that will become absolutely irrelevant when the new code is in place.
Title: Re: EEVBlog 121GW Discussion thread
Post by: IanB on February 05, 2018, 02:50:35 am
This stuff doesn't take days to do, it can take weeks.

While I generally agree with you, I disagree that firmware updates for this meter in its current state should be aggregated for months before being released.

The suggestion was weeks, not months. Let's not exaggerate.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Brumby on February 05, 2018, 03:07:55 am
For some of the "Now" generation, even saying "tomorrow" will get you howls of disapproval...
Title: Re: EEVBlog 121GW Discussion thread
Post by: Brumby on February 05, 2018, 03:19:49 am
... so frequent updates and testing will help the manufacturer find and fix issues more quickly.
Except ... that it won't - necessarily.

Each time a revision of any software is made - especially firmware in a device like this - it should undergo full regression testing to make sure that some little tweak in one place didn't break something somewhere else.

Also, an interim solution may demand a particular behaviour in some aspect of operation - but it is later found that this interim solution to one problem caused other issues.  These other issues could then dictate a different solution, with a different behaviour.

No.  As a software developer, I would NOT be happy about releasing something half-baked, especially when there is pressure to get the whole thing sorted.  The rigmarole in just getting a release out would be a waste of resources.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on February 05, 2018, 03:23:41 am
https://www.youtube.com/watch?v=uUCQuIp_hzU (https://www.youtube.com/watch?v=uUCQuIp_hzU)
Title: Re: EEVBlog 121GW Discussion thread
Post by: amspire on February 05, 2018, 03:25:16 am
If a rushed update corrupted the calibration data in the meter, then UEi or Dave would have to organise the recalibration of hundreds of meters located around the world under warranty. Releasing firmware is definitely not to be taken lightly.
Title: Re: EEVBlog 121GW Discussion thread
Post by: 1anX on February 05, 2018, 04:24:49 am
https://www.youtube.com/watch?v=uUCQuIp_hzU (https://www.youtube.com/watch?v=uUCQuIp_hzU)

Hey, many thanks Dave!

That's the Dave I know and love watching. I for one enjoy watching the meter development process and it getting tested by you along the way. No need for a media blackout and a code of silence being enforced. We members on these forums are mostly technical people and supporters of yours and appreciate being kept in the loop.

Bring us along for the ride as it develops, so we can all learn from the experience.

IMO your selling this meter's attributes short by not showing the features off as they are fixed. I say more videos highlighting what goes on technically to rectify the bugs. Don't discount the tremendous interest in this product. Make these early shortcomings its strengths by highlighting the fixes. I would have thought this is a video bloggers dream opportunity!

Those who seem to want to know nothing about the meters progress, and are more than happy to wait weeks without an update, well they can just view the thread once a month or so. That way all forum members/backers and supporters of the kickstarter project are catered for. 

Food for thought, Dave?
Title: Re: EEVBlog 121GW Discussion thread
Post by: amspire on February 05, 2018, 04:39:39 am

Bring us along for the ride as it develops, so we can all learn from the experience.

IMO your selling this meter's attributes short by not showing the features off as they are fixed. I say more videos highlighting what goes on technically to rectify the bugs. Don't discount the tremendous interest in this product. Make these early shortcomings its strengths by highlighting the fixes. I would have thought this is a video bloggers dream opportunity!

Those who seem to want to know nothing about the meters progress and are more than happy to wait weeks without an update can just view the thread once a month or so. That way all forum members/backers and supporters of the kickstarter project are all catered for. 

Food for thought, Dave?
Would you like to see daily posts saying "There is no update today" ?

Quite often, there is not much more to say until there is an update released. Dave does actually say a fair bit about the multimeter, but it is spread across many threads. It almost sounds like you want to see a live video feed of Dave discussing problems with UEi. Just don't hold your breath waiting for it.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Brumby on February 05, 2018, 04:40:10 am
That's the Dave I know and love watching. I for one enjoy watching the meter development process and it getting tested by you along the way. No need for a media blackout and a code of silence being enforced. We members on these forums are mostly technical people and supporters of yours and appreciate being kept in the loop.

Bring us along for the ride as it develops, so we can all learn from the experience.

I'm sure Dave will be on top of that ... just remember, he does have other things to do.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on February 05, 2018, 06:48:40 am
That's the Dave I know and love watching. I for one enjoy watching the meter development process and it getting tested by you along the way. No need for a media blackout and a code of silence being enforced. We members on these forums are mostly technical people and supporters of yours and appreciate being kept in the loop.
Bring us along for the ride as it develops, so we can all learn from the experience.

It's not that easy, I have little visibility in what's going on at UEi, and I am not in a position to demand hourly updates from them.
And whilst it may sound great to have every little thing blogged, that does invariably lead to people trying to micromanage what's happening. That's bad enough when it's my own project and I'm in control of everything and can work on things instantly myself, but when you are dealing with a design team in another country on the other side of the planet, invariably with of priorities, it's even worse.

Quote
IMO your selling this meter's attributes short by not showing the features off as they are fixed. I say more videos highlighting what goes on technically to rectify the bugs. Don't discount the tremendous interest in this product. Make these early shortcomings its strengths by highlighting the fixes. I would have thought this is a video bloggers dream opportunity!

Those who seem to want to know nothing about the meters progress and are more than happy to wait weeks without an update can just view the thread once a month or so. That way all forum members/backers and supporters of the kickstarter project are all catered for. 

Food for thought, Dave?

This is not my first trip down the "publish as it happens" route, why do you think I essentially lost interest in the uSupply? Hint,  hundreds of people telling me to do this and do that doesn't help...
So no, it's not necessarily the "dream opportunity" you might think it is.
Title: Re: EEVBlog 121GW Discussion thread
Post by: exe on February 05, 2018, 12:16:37 pm
Kids these days tend to love frequent updates, no matter how shitty the update, as long the manufacturer keep pumping out updates every week, they will be happy, just don't know why.  :-//

Talking bullshit with confidence and calling other names doesn't add you credibility. Modern software development is not based on waterfall model anymore.

A good process development process starts with automated tests. But even if you do (semi-)manual testing I don't think it takes much time to test it. Besides that, let the user decide if s/she wants a hotfix that wasn't fully tested.

BTW, I guess you completely missed Dave saying that FW is a mess. I believe this is the main reason it's taking so much time to fix trivial problem, nothing else.
Title: Re: EEVBlog 121GW Discussion thread
Post by: FrankBuss on February 05, 2018, 12:22:36 pm
They have tweaked the dimensions of the white plastic spring assembly and switch assembly I believe.

Does it get a new version number, or some minor revision I can see when I want to buy one for the mechanic changes? The bluetooth feature and integrated uCurrent etc. are really something I could use, but non-wobbly dial would be nice.

The autorange of the BM235 looks incredible. My BM257s is only as fast as the 121GW now. But no problem, if I need fast autorange, I can use my Fluke 8842A, which is at least as fast as the BM235. Sometimes fast autorange is important for me, e.g. when I sort a bunch of resistors after some breadboarding.
Title: Re: EEVBlog 121GW Discussion thread
Post by: BravoV on February 05, 2018, 12:33:34 pm
Kids these days tend to love frequent updates, no matter how shitty the update, as long the manufacturer keep pumping out updates every week, they will be happy, just don't know why.  :-//

Talking bullshit with confidence and calling other names doesn't add you credibility. Modern software development is not based on waterfall model anymore.

A good process development process starts with automated tests. But even if you do (semi-)manual testing I don't think it takes much time to test it. Besides that, let the user decide if s/she wants a hotfix that wasn't fully tested.

BTW, I guess you completely missed Dave saying that FW is a mess. I believe this is the main reason it's taking so much time to fix trivial problem, nothing else.

Thanks, point taken ... kiddo.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Brumby on February 05, 2018, 02:06:34 pm
But even if you do (semi-)manual testing I don't think it takes much time to test it.
Typical armchair expert.  "I don't think" indicates you have no practical knowledge.

Quote
Besides that, let the user decide if s/she wants a hotfix that wasn't fully tested.
This really shows how out of touch you are with practicality, let alone commercial reality.
Title: Re: EEVBlog 121GW Discussion thread
Post by: IanJ on February 05, 2018, 06:10:19 pm
All I can say is kudos to Dave for the meter in the first place. It takes balls to go commercial with a product worldwide and there is a lot, lot more work across multiple areas that most folks don't see. Net result it consumes your life for a while.

I agree whilst it's tempting to rush out firmware updates fast it invariably ends up needing a follow-up, then another..........IMHO Dave/UEi's approach is deffo the way to go.......Fairly fast but more importantly gotta be thorough and well tested.

I think Dave and UEi have done a great job so far, the issues being fairly light and easily fixed. No show stoppers.
Can't wait to receive mine.

Ian.
Title: Re: EEVBlog 121GW Discussion thread
Post by: dcac on February 05, 2018, 10:16:36 pm
https://www.youtube.com/watch?v=uUCQuIp_hzU (https://www.youtube.com/watch?v=uUCQuIp_hzU)

Thanks for the video Dave, yes the 1.05 FW is noticeably faster than 1.04 and at least as fast as the U1282A. And as expected the Brymen 869 is quite faster but then it also only goes down to 10 milliohms resolution where the 121GW goes down to 1 milliohms.

It would be great if you could do two additional auto-ranging comparisons between 121GW, U1282A and U1272A (and perhaps the Gossen) it would be:

1. AC Volt position, all meters connected in parallel, measuring mains 240volt.       

2. DC Amp position, all meters in series, measuring roughly 4.5A DC current load.

This could be good tests to see if any other slowness quirks is lurking in the 121GW FW.

Title: Re: EEVBlog 121GW Discussion thread
Post by: GameProgrammer79 on February 05, 2018, 11:57:53 pm
totally agree, good to taste volts and amps as well.  :-/O

https://www.youtube.com/watch?v=uUCQuIp_hzU (https://www.youtube.com/watch?v=uUCQuIp_hzU)

Thanks for the video Dave, yes the 1.05 FW is noticeably faster than 1.04 and at least as fast as the U1282A. And as expected the Brymen 869 is quite faster but then it also only goes down to 10 milliohms resolution where the 121GW goes down to 1 milliohms.

It would be great if you could do two additional auto-ranging comparisons between 121GW, U1282A and U1272A (and perhaps the Gossen) it would be:

1. AC Volt position, all meters connected in parallel, measuring mains 240volt.       

2. DC Amp position, all meters in series, measuring roughly 4.5A DC current load.

This could be good tests to see if any other slowness quirks is lurking in the 121GW FW.


Title: Re: EEVBlog 121GW Discussion thread
Post by: beanflying on February 06, 2018, 01:54:02 am
Please no more SOOKING about slow auto ranging it is until a release of official new firmware fairly pointless and the issue more than well known. Design of firmware by committee with no code in front of you and zero direct contact to the manufacturer even more pointless. Please look up the term of WOFTAM, which is exactly what it would be called in business this behavior would additionally earn you an ass kicking. Let Dave/UEI sort it and then let us know.

More importantly is my meter is reading 0.1 mV low in 29.4 degrees and took less than 5 seconds to stabilise unlike the 50+ year old 740B that took 30 minutes+ . Reference against the Agilent measures 5.00021 at 25C :popcorn:

Title: Re: EEVBlog 121GW Discussion thread
Post by: dcac on February 06, 2018, 09:39:14 am
I’m very convinced it’s up to Dave if he wants to make any further auto-raging comparisons. By his own admission - he just didn’t notice how slow the production model was, possibly his focus was on other problems like ie. the bluetooth interface. But if he now feels confident the 121GW really is on par with comparable DMM’s,  well then - that’s great!

Title: Re: EEVBlog 121GW Discussion thread
Post by: GameProgrammer79 on February 06, 2018, 02:35:11 pm
I’m very convinced it’s up to Dave if he wants to make any further auto-raging comparisons. By his own admission - he just didn’t notice how slow the production model was, possibly his focus was on other problems like ie. the bluetooth interface. But if he now feels confident the 121GW really is on par with comparable DMM’s,  well then - that’s great!

Really appreciate the amount of attention it has received and number of issues reported so far. It will definitely get better with each iteration of the firmware. We should not get fussy about bugs, it is every where including large firms like Intel (spectre and meltdown) are not immune to it. There are some 3 billion dollar exploding projects as well (http://www.techradar.com/news/this-is-how-much-samsung-says-itll-lose-on-the-galaxy-note-7-recall (http://www.techradar.com/news/this-is-how-much-samsung-says-itll-lose-on-the-galaxy-note-7-recall))

121GW is future proof, simply because one can change the firmware with ease, firmware bugs are technically fixable. I am not sure if it runs a kernel or simple RTOS, probably community with catch up with alternative firmware before long.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Towger on February 08, 2018, 11:22:34 am
Dave,

The natives on Kickstarter are starting to get restless.  It would not go a miss to post an update, with links to the video etc.  It should be the primary source of updates, but as they are spread over the forum, Amp Hour, Twitter and YouTube are being missed.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Diosol on February 08, 2018, 11:17:53 pm
https://www.youtube.com/watch?v=gtov0o8VTW8 (https://www.youtube.com/watch?v=gtov0o8VTW8)

I also made a quickie of 121GW. Dave's second video got me interested inspecting what happens while measuring resistance with multiple meters.
Fluke 322 clamp meter works a little bit differently and other meters went haywire. Switching lead polarity solved that issue.
Some day I'll do inspection of the voltages while measuring resistance and take a look does the Fluke 322 have reverse polarity.

Insulation tester had the highest current of 1,00 mA and maybe that's why it showed 1,4 MOhms in baseline setup.
Title: Re: EEVBlog 121GW Discussion thread
Post by: joeqsmith on February 13, 2018, 11:20:39 pm
I saw your test fixture and it looks pretty good.   I assume printed.  If you wanted to replicate the tests I have been running,  the switch is fully rotated both directions to complete one cycle.  I cycle them 50,000 times in 60 hours while measuring the contact resistance.  If the resistance gets about 1K for 1000 cycles in a row, I abort the test.  Other than that, I just let the run.   Pictures before and after and document if the use any sort of lubrication on the contacts.  That's about it. 

If you don't plan to record the contact resistance, you may want to consider inspecting the contacts every 10,000 cycles like Brymen.

Looking forward to seeing what you decide to do and the end results. 
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on February 13, 2018, 11:51:58 pm
https://www.youtube.com/watch?v=QSmiMlWEpy0 (https://www.youtube.com/watch?v=QSmiMlWEpy0)
Title: Re: EEVBlog 121GW Discussion thread
Post by: joeqsmith on February 14, 2018, 12:18:01 am
First, thanks for taking the time to run this test.  Second, thanks for posting how you are running it and the results.  I have been curious if the pads had changed at all.   

Five minutes in, I switched to 1080.   Your 50K cycles would be a half for Brymen and what I am doing but still, what is up with this meter?   There is no way I would have expected to see these results after sending you those original pictures.    Impressive indeed. 

I could try and repeat it assuming the contacts are the same but it's not really going to prove anything.   Thanks again and looking forward to seeing the production parts ran.   
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on February 14, 2018, 12:29:08 am
Five minutes in, I switched to 1080.   Your 50K cycles would be a half for Brymen and what I am doing but still, what is up with this meter?   There is no way I would have expected to see these results after sending you those original pictures.    Impressive indeed. 

I expected worse too, but that's what we got.
I don't know what serial number I sent you, but it would have been around a similar date, so likely exactly the same switch and contacts.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Scottjd on February 14, 2018, 03:55:39 am
Five minutes in, I switched to 1080.   Your 50K cycles would be a half for Brymen and what I am doing but still, what is up with this meter?   There is no way I would have expected to see these results after sending you those original pictures.    Impressive indeed. 

I expected worse too, but that's what we got.
I don't know what serial number I sent you, but it would have been around a similar date, so likely exactly the same switch and contacts.
If these were the production parts, I would like to try and understand why such a dramatic difference.  I wouldn't have guessed it had more than a thousand cycles on it but for all I know, UEI may have cycle tested it.   Looking back over the pictures, it appears the contacts are what was wearing.  Even looking at the last few that they sent, it looks like something was still going on.  Strange.   

Looking at the video and the large gap in the fingers that rotate the knob, are you sure you are getting the full stroke of the switch?  It looks like it may only rotate 90 degrees.  Still even it that was the case, I would have still expected that area to have a fair amount of wear.   

Just scratching my head.

I’ll add to the head scratching. Or let’s just say thinking out loud.
I agree with Joes counting as this is only a half cycles since a user will turn on, then off and that’s a full cycle. Just like they charging cycles on a battery, charge and discharge for a full cycle.

My questions thinking out loud would be around the way the PLA adapter is mounted to the stepper motor. Seems to me and knowing PLA (it looks like PLA) the part will wear some and if a set screw was used the adapter on the motor will start to slip. I’m not a big fan of PLA for mechanical use from personal experience when I first started doing 3D printing.

Maybe something a little stronger on the adapter with something that also has a little flex like a nylon mix filament. The nylon will allow a little flex without breaking the part, and you can over turn the switch just a little past the off positions. My thinking is most people always turn past the off point, they only let go of the switch because the switch stopped them. I’m not talking crazy over shoot on the switch with massive torque, just a little to replicate real human usage. If you set the controller to over shoot with a PLA part even if it’s made with 100% fill, it will start to stress crack, break, or give away on the tolerances of the whole for the set screw and slip.

But I guess that’s why I’m wondering how the part is held into the stepper motor?
It’s a nice rig, but just might benefit from a few little tweaks?
Scott
Title: Re: EEVBlog 121GW Discussion thread
Post by: 1anX on February 14, 2018, 04:16:51 am

I agree with Joes counting as this is only a half cycles since a user will turn on, then off and that’s a full cycle. Just like they cling cycles on a battery, charge and discharge for a full cycle.

Hmmm, I disagree with your observation in regards to the operation of this meter!

There is an OFF position at each end of the selector, so in effect a user could easily select a range and then switch OFF by continuing in the same direction. Hence one cycle of the switch is achieved by rotating in one direction.

Regardless of how you view the definition of one cycle, at the very least we now have a measured number of cycles to interpret contact wear!

Its interesting, but of course it needs to be repeated with a production unit which I'm sure will happen just as soon as UEi provide one.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on February 14, 2018, 05:12:39 am
My questions thinking out loud would be around the way the PLA adapter is mounted to the stepper motor. Seems to me and knowing PLA (it looks like PLA) the part will wear some and if a set screw was used the adapter on the motor will start to slip.

It's not slipping.
That meter did 50,000 genuine rotations.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Scottjd on February 14, 2018, 06:15:22 am

I agree with Joes counting as this is only a half cycles since a user will turn on, then off and that’s a full cycle. Just like they cling cycles on a battery, charge and discharge for a full cycle.

Hmmm, I disagree with your observation in regards to the operation of this meter!
There is an OFF position at each end of the selector, so in effect a user could easily select a range and then switch OFF by continuing in the same direction. Hence one cycle of the switch is achieved by rotating in one direction.
I see your point. But at the same time I think most users will always go for the same “off” position. Maybe based on if they use the meter mostly for current readings, or voltage readings. With mode selected aside I’m still thinking most people will always go to the left off position if they own more then one meter just based on muscle memory and the fact the most other meters they own also go off to the left.

For me personally I will always turn it off to the left because I’m used to turning my meters off to this direction. I do own one meter that has a dual off just like the 121GW (Digitek DT-4000ZC) and it always goes off to the left. Even if I use a mode on the right side of the range switch it still gets turned off to the left. If I had bought a meter that only turned off to the right and didn’t have a left off option, this would probably annoy me to the point of returning it.

But as you said, either way 25K, or 50K is still a lot of switching, and at least it’s getting tested now before being put back into manufacturing and sold to more people.
So what is that saying, “Better late then never”.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Brumby on February 14, 2018, 07:09:21 am
For me personally I will always turn it off to the left because I’m used to turning my meters off to this direction. I do own one meter that has a dual off just like the 121GW (Digitek DT-4000ZC) and it always goes off to the left. Even if I use a mode on the right side of the range switch it still gets turned off to the left. If I had bought a meter that only turned off to the right and didn’t have a left off option, this would probably annoy me to the point of returning it.

Same.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on February 14, 2018, 07:50:22 am
Now I need to know if there is or has ever been such a meter?

Near enough

(https://pbs.twimg.com/media/DV-3ZN0WsAAKnOl.jpg:large)
Title: Re: EEVBlog 121GW Discussion thread
Post by: HKJ on February 14, 2018, 08:06:47 am
For me personally I will always turn it off to the left because I’m used to turning my meters off to this direction. I do own one meter that has a dual off just like the 121GW (Digitek DT-4000ZC) and it always goes off to the left. Even if I use a mode on the right side of the range switch it still gets turned off to the left. If I had bought a meter that only turned off to the right and didn’t have a left off option, this would probably annoy me to the point of returning it.
Same.

Now I need to know if there is or has ever been such a meter?


I have not seen that, but some meters has off at the center.
(http://lygte-info.dk/pic/Southwire/16040T/DSC_3023.jpg)
Title: Re: EEVBlog 121GW Discussion thread
Post by: Hydron on February 14, 2018, 09:03:16 am
Megger annoyingly do the middle-OFF thing too, but ugh, I think that meter above would win a prize in several "worst meter" categories.
Title: Re: EEVBlog 121GW Discussion thread
Post by: 1anX on February 14, 2018, 09:20:14 am
Here's one that turns off on the right hand side  :)

http://www.dx.com/p/bside-acm03-auto-range-digital-clamp-meter-multimeter-blue-black-302517#.WoP-K-eYNPY (http://www.dx.com/p/bside-acm03-auto-range-digital-clamp-meter-multimeter-blue-black-302517#.WoP-K-eYNPY)
Title: Re: EEVBlog 121GW Discussion thread
Post by: Brumby on February 14, 2018, 09:52:14 am
For me personally I will always turn it off to the left because I’m used to turning my meters off to this direction. I do own one meter that has a dual off just like the 121GW (Digitek DT-4000ZC) and it always goes off to the left. Even if I use a mode on the right side of the range switch it still gets turned off to the left. If I had bought a meter that only turned off to the right and didn’t have a left off option, this would probably annoy me to the point of returning it.
Same.

Now I need to know if there is or has ever been such a meter?

I picked up two of these from the "crap bin" at Jaycar many years ago.  They had problems with the rotary switch.  One I was able to sort out and it has been pretty reliable.  The other was not so inclined - and is buried somewhere.

(https://www.eevblog.com/forum/testgear/eevblog-121gw-discussion-thread/?action=dlattach;attach=394979;image)


(Sorry about the transistor tester)
Title: Re: EEVBlog 121GW Discussion thread
Post by: Scottjd on February 14, 2018, 10:41:55 am
I have not seen that, but some meters has off at the center.
Do clamp meters count?  Well I have both (left and right), left, top (up), bottom (down), and push button. I can’t find my greenlee meter and I used to have a southwire, but I gave it away. I had to check my old BM235 review video to see what that one was. Now I also wish I never gave away my first RadioShack meter I bought when I was a kid.
But I still didn’t realize until tonight I had this many, and I left out the other 3 harbor freight free meters that are just basically battery testers.
Most of them were given to me, one was found, one was $1 yard sale buy, and the others I bought. One more still on the way that I’m waiting on. I think I have a multimeter problem. But surprisingly no right off switch meters. Even the bottom meters have the power button on the left side.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on February 14, 2018, 10:50:32 am
Have you checked to make sure you were getting a full cycle with that coupler?

Yes.
Title: Re: EEVBlog 121GW Discussion thread
Post by: ChrisG on February 14, 2018, 06:56:45 pm
I'm puzzled now that with my 121GW which I use 2-3 times a week for let's say 20-25 cycles I had gunk, abrasion or wear after a couple of weeks already. Perhaps I should clean it now and then take picture and re-take after a month or so. Btw when switching to Ohms range I have to depress the selector switch in order for the meter to switch on otherwise it beeps and then goes dark.
Title: Re: EEVBlog 121GW Discussion thread
Post by: 1anX on February 14, 2018, 08:59:24 pm
I'm puzzled now that with my 121GW which I use 2-3 times a week for let's say 20-25 cycles I had gunk, abrasion or wear after a couple of weeks already. Perhaps I should clean it now and then take picture and re-take after a month or so. Btw when switching to Ohms range I have to depress the selector switch in order for the meter to switch on otherwise it beeps and then goes dark.
Sounds like a good idea to me, take pictures now with cleaned contacts and again later to compare.
Probably a waste of time though, if you consider that you will be receiving new contacts and selector switch in the near future?
Title: Re: EEVBlog 121GW Discussion thread
Post by: ChrisG on February 20, 2018, 10:26:11 am
I'm puzzled now that with my 121GW which I use 2-3 times a week for let's say 20-25 cycles I had gunk, abrasion or wear after a couple of weeks already. Perhaps I should clean it now and then take picture and re-take after a month or so. Btw when switching to Ohms range I have to depress the selector switch in order for the meter to switch on otherwise it beeps and then goes dark.

Please don't clean it or even take it apart.  Just keep using it until you get your replacement parts.  Then take some new pictures so we can get some feel for how the wear was progressing, if at all. 
 

I will not take it apart anymore althought the selector switch is behaving less well every time I use it. Selecting from left to rigth to the Ohms/Diode range it just dies and have to fiddle the switch to make it work. From right (off) to left it tends to work nearly perfect every time.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Insatman on February 20, 2018, 10:54:08 am
Here is a post from left field....is the name of this meter the 121GW, some reference to Back to the Future...as in 1.21 Gigawatts?    Just thinking...
Title: Re: EEVBlog 121GW Discussion thread
Post by: Fungus on February 20, 2018, 11:13:59 am
Here is a post from left field....is the name of this meter the 121GW, some reference to Back to the Future...as in 1.21 Gigawatts?    Just thinking...

There's also a flux capacitor inside...

Title: Re: EEVBlog 121GW Discussion thread
Post by: tautech on February 20, 2018, 11:49:22 am
Here is a post from left field....is the name of this meter the 121GW, some reference to Back to the Future...as in 1.21 Gigawatts?    Just thinking...
Yes, be very careful not to take it past 88 mph !
Title: Re: EEVBlog 121GW Discussion thread
Post by: Brumby on February 20, 2018, 11:55:10 am
Here is a post from left field....is the name of this meter the 121GW, some reference to Back to the Future...as in 1.21 Gigawatts?    Just thinking...

There's no mystery about that.  It absolutely is.  The naming of this meter was discussed in the Supporters Lounge - two years ago.  That's when the name was first put forward .... and Dave jumped at it.

Dave is a BTTF fan boy.  (Not sure if I would call him a tragic.)
Title: Re: EEVBlog 121GW Discussion thread
Post by: Insatman on February 20, 2018, 11:40:14 pm
Here is a post from left field....is the name of this meter the 121GW, some reference to Back to the Future...as in 1.21 Gigawatts?    Just thinking...

There's no mystery about that.  It absolutely is.  The naming of this meter was discussed in the Supporters Lounge - two years ago.  That's when the name was first put forward .... and Dave jumped at it.

Dave is a BTTF fan boy.  (Not sure if I would call him a tragic.)

I knew he was a fanboy from his video about the BTTF clock.   Thanks for the verification
Title: Re: EEVBlog 121GW Discussion thread
Post by: 1anX on February 21, 2018, 03:37:33 am
Heeeeeey Joe...

Ok so theres not much happening with the 121GW! UEi are taking a new years holiday or something?

Lets really go BTTF and I'll provide an insight into what too much time on my hands can do.

I love joeqsmith's meter torture tests, he goes all out and in-depth to provide insights into how accurate and durable a multimeter can be made.

Every time I see a post from Joe I start singing "Hey Joe" in my head but change the words to, "heeeeey joe, where ya gunna go with that meter in your hand, where ya gunna go". Maybe I'm showing my age as probably no one on this forum has ever heard of Jimi Hendrix or his band the Jimi Hendrix Experience.

Jimi was also famous for another song, Purple Haze, and it seems to me a direct connection with joeqsmith. Its obvious why, when Joe hits a meter with his HV spike test the meter explodes into a purple plasma haze.

Its a slow afternoon for me, so just thought I'd share a BTTF memory moment that the 121GW triggered.

Lets hope that UEi and Dave have some good news for us soon on how this meter is coming along!

When the production unit finally ships, I'm really looking forward to it being given the JoeQSmith Experience and singing along while I watch him destroy it, just like Jimi used to do to his guitars  :D
Title: Re: EEVBlog 121GW Discussion thread
Post by: Brumby on February 21, 2018, 04:24:32 am
Maybe I'm showing my age as probably no one on this forum has ever heard of Jimi Hendrix.....

Just how old do you think people are here?

I'm sure a lot of us - if not the majority - will have heard of Jimi Hendrix, many will know his music and some will no doubt have been fans.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Insatman on February 21, 2018, 05:08:05 am
Maybe I'm showing my age as probably no one on this forum has ever heard of Jimi Hendrix.....

Just how old do you think people are here?

I'm sure a lot of us - if not the majority - will have heard of Jimi Hendrix, many will know his music and some will no doubt have been fans.

LOL...I was/am a Jimi fan.   I had the opportunity to visit his grave a number of years ago in the Seattle area.  Still one of the best guitar players ever lived
Title: Re: EEVBlog 121GW Discussion thread
Post by: joeqsmith on February 21, 2018, 12:47:53 pm
Heeeeeey Joe...

Ok so theres not much happening with the 121GW! UEi are taking a new years holiday or something?

Lets really go BTTF and I'll provide an insight into what too much time on my hands can do.

I love joeqsmith's meter torture tests, he goes all out and in-depth to provide insights into how accurate and durable a multimeter can be made.

Every time I see a post from Joe I start singing "Hey Joe" in my head but change the words to, "heeeeey joe, where ya gunna go with that meter in your hand, where ya gunna go". Maybe I'm showing my age as probably no one on this forum has ever heard of Jimi Hendrix or his band the Jimi Hendrix Experience.

Jimi was also famous for another song, Purple Haze, and it seems to me a direct connection with joeqsmith. Its obvious why, when Joe hits a meter with his HV spike test the meter explodes into a purple plasma haze.

Its a slow afternoon for me, so just thought I'd share a BTTF memory moment that the 121GW triggered.

Lets hope that UEi and Dave have some good news for us soon on how this meter is coming along!

When the production unit finally ships, I'm really looking forward to it being given the JoeQSmith Experience and singing along while I watch him destroy it, just like Jimi used to do to his guitars  :D

Heeeeey joe, where ya gunna go with that meter in your hand, where ya gunna go
I'm gunna stuff that old meter
Stuff that old meter into a garbage can
Cause that's where it belongs
Hey joe, I heard you fried your best meter to a crisp
You fried it to a blackened crisp
Yeah
Yes I did, I fried it to a crisp
You know that meter was such a peace of shit
and I gave it the zap
and I fried it
Alright
Zap it one more time again, baby
Yeah!

Hey Joe,
what meter you gonna run now?
Hey Joe,
what meter you gonna run now?
Which one?

Gonna zap that old Fluke
gonna zap that old Fluke with my ESD gun

Ain't no fan boy gonna
put a stop to me
Title: Re: EEVBlog 121GW Discussion thread
Post by: geekGee on February 21, 2018, 08:03:42 pm
"Ode to an 87V"    ;D
Title: Re: EEVBlog 121GW Discussion thread
Post by: ChrisG on February 22, 2018, 07:26:07 am
Gentlemen, as much fun and smiles this all gives it does digress from the topic for me. I would really like to see things from Dave: 1. an overall issue list of all the hardware and software related issues, 2. an update, with tentative dates, on when which issue will be addressed (e.g. I could imagine all to be resolved or some to drop and then re-certification is needed?). 3. how to continue with new issues people will start to find (like say the range-switch PCB tracks wearing down or gunk build-up or .... ). Agree?
Title: Re: EEVBlog 121GW Discussion thread
Post by: Brumby on February 22, 2018, 08:29:05 am
Sorry.  As much as I might like an update - there's little point in pushing.

If anything, I'd rather effort be put into addressing the issues than taking time out to give progress reports.  Reporting is one way to waste time - and pressing for it, when it isn't going to change the timetable, is somewhat counterproductive.
Title: Re: EEVBlog 121GW Discussion thread
Post by: ChrisG on February 22, 2018, 09:24:20 am
Sorry.  As much as I might like an update - there's little point in pushing.

If anything, I'd rather effort be put into addressing the issues than taking time out to give progress reports.  Reporting is one way to waste time - and pressing for it, when it isn't going to change the timetable, is somewhat counterproductive.

Don't think I'm pushing here (a lot). I've not even indicated that my request was a request to change the timetable at all. Taking your suggestion, or perhaps even guidance, it would be great to have a simple list on the issues which are there. If I missed it somewhere here please let me know.
Title: Re: EEVBlog 121GW Discussion thread
Post by: 1anX on February 22, 2018, 09:28:11 am
Gentlemen, as much fun and smiles this all gives it does digress from the topic for me. I would really like to see things from Dave: 1. an overall issue list of all the hardware and software related issues, 2. an update, with tentative dates, on when which issue will be addressed (e.g. I could imagine all to be resolved or some to drop and then re-certification is needed?). 3. how to continue with new issues people will start to find (like say the range-switch PCB tracks wearing down or gunk build-up or .... ). Agree?

My understanding is that this is the discussion thread, so the little diversion of "Hey Joe" is really just passing time till we get an update. There is another thread, (Issues) for reporting the issues arising from the production meter.

It is also my understanding that the issues raised on the Issues thread are being addressed by UEi. Dave has said that UEi are/were in discussion with the meter chipset's makers for support in rectifying some issues. He also stated that South Korea were affected by the Chinese new years holiday which has only just finished.

I'm guessing Dave will be in a position very soon to provide the release date for the Johnny B Good backers and to update us on all the fixes. From what Dave has said about the first release of meters with faulty switches, the backers will be contacted and arrangements made to replace the meters or the switches.

We are all waiting for Dave to inform us of the situation and he is waiting on UEi to fix and thoroughly test the meter.

Have I missed anything?
Title: Re: EEVBlog 121GW Discussion thread
Post by: Brumby on February 22, 2018, 10:05:03 am
2. an update, with tentative dates, on when which issue will be addressed

Sorry, this is just not practical.  Dave is one step closer to the problem solvers - but he is not project manager of them.  To get the information you have mentioned would mean bugging the manufacturer - and that would wreck a working relationship.

Don't think for a nanosecond that Dave is not keen to get these issues resolved as soon as possible - but that doesn't mean he is going to shove stuff out just to appease the noisemakers.  That is a suicidal path.


Be patient.  Dave will give us updates when there is something to report.

It takes as long as it takes.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Brumby on February 22, 2018, 10:10:53 am
PS.  As soon as you put a date on something that has one or more an unknown time components, you might as well stick your head in a noose.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on February 22, 2018, 11:05:30 pm
It has been found that the switch contact issues were ultimately caused by a slight PCB thickness difference between the pre-production and production boards.
Pre-production boards were on the high side of the tolerance allowance, and production boards on the low side. Actually, the production board thickness was actually slightly outside of UEi's board spec.
A 0.95mm shim (as has been found by others) is the fix for existing units and current stock boards (i.e. all Kickstarter ones and for sometime afterwards). Future volume production boards shouldn't need a shim however.
Shims are on the way to me now for cycle testing.
Title: Re: EEVBlog 121GW Discussion thread
Post by: amspire on February 22, 2018, 11:27:15 pm
It has been found that the switch contact issues were ultimately caused by a slight PCB thickness difference between the pre-production and production boards.
Pre-production boards were on the high side of the tolerance allowance, and production boards on the low side. Actually, the production board thickness was actually slightly outside of UEi's board spec.
A 0.95mm shim (as has been found by others) is the fix for existing units and current stock boards (i.e. all Kickstarter ones and for sometime afterwards). Future volume production boards shouldn't need a shim however.
Shims are on the way to me now for cycle testing.
Does "the low side" mean that the board is too thin? Is the 0.95mm shim meant to be attached to the circuit board? Just confused a bit.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on February 22, 2018, 11:30:35 pm
It has been found that the switch contact issues were ultimately caused by a slight PCB thickness difference between the pre-production and production boards.
Pre-production boards were on the high side of the tolerance allowance, and production boards on the low side. Actually, the production board thickness was actually slightly outside of UEi's board spec.
A 0.95mm shim (as has been found by others) is the fix for existing units and current stock boards (i.e. all Kickstarter ones and for sometime afterwards). Future volume production boards shouldn't need a shim however.
Shims are on the way to me now for cycle testing.
Does "the low side" mean that the board is too thin? Is the 0.95mm shim meant to be attached to the circuit board? Just confused a bit.

Yes, on the thin side.
The shim goes between the plastic range switch and the case, as per how others have done their own DIY solution.
For those that want to do it themselves, the shim thickness is 0.95mm.
Title: Re: EEVBlog 121GW Discussion thread
Post by: amspire on February 22, 2018, 11:45:50 pm
Does "the low side" mean that the board is too thin? Is the 0.95mm shim meant to be attached to the circuit board? Just confused a bit.

Yes, on the thin side.
The shim goes between the plastic range switch and the case, as per how others have done their own DIY solution.
For those that want to do it themselves, the shim thickness is 0.95mm.
So that means that the fact the board is too thin is not being addressed unless the shim is causing the shaft clip to press down on the switch rotor. It just seems to me that if the board it too thin, there should be a shim under the rotor clip.
Title: Re: EEVBlog 121GW Discussion thread
Post by: 1anX on February 23, 2018, 01:58:24 am
Does "the low side" mean that the board is too thin? Is the 0.95mm shim meant to be attached to the circuit board? Just confused a bit.

Yes, on the thin side.
The shim goes between the plastic range switch and the case, as per how others have done their own DIY solution.
For those that want to do it themselves, the shim thickness is 0.95mm.
So that means that the fact the board is too thin is not being addressed unless the shim is causing the shaft clip to press down on the switch rotor. It just seems to me that if the board it too thin, there should be a shim under the rotor clip.

Like this picture from forum member lowimpedance previous post?

Title: Re: EEVBlog 121GW Discussion thread
Post by: amspire on February 23, 2018, 02:11:58 am
Like this picture from forum member lowimpedance previous post?
I think that is the fix Dave is talking about. I am just asking if there should be a shim on the plastic clip on the actual switch rotor on the PCB and not just one on the shaft.

That shim in the photo is certain a way to reduce the wobble in the switch knob which is a second problem.
Title: Re: EEVBlog 121GW Discussion thread
Post by: ChrisG on February 23, 2018, 07:31:29 am
Like this picture from forum member lowimpedance previous post?
I think that is the fix Dave is talking about. I am just asking if there should be a shim on the plastic clip on the actual switch rotor on the PCB and not just one on the shaft.

That shim in the photo is certain a way to reduce the wobble in the switch knob which is a second problem.

Agree with you. I think the range switch, the plastic knob, could be redesgined a bit so that a wobble is less likely to occur. Let's wait for final testing by Dave and team for a prolonged period 50.000 cycles or more if this is the solution. Nonetheless happy to read that a difference and potential root cause has been identified.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on February 23, 2018, 11:09:49 am
Like this picture from forum member lowimpedance previous post?
I think that is the fix Dave is talking about. I am just asking if there should be a shim on the plastic clip on the actual switch rotor on the PCB and not just one on the shaft.

That shim in the photo is certain a way to reduce the wobble in the switch knob which is a second problem.

Agree with you. I think the range switch, the plastic knob, could be redesgined a bit so that a wobble is less likely to occur. Let's wait for final testing by Dave and team for a prolonged period 50.000 cycles or more if this is the solution. Nonetheless happy to read that a difference and potential root cause has been identified.

The switch wobble is separate problem that is fixed with a slightly redesigned white plastic indent ring. Backers with existing meters will be shipped a new knob, plastic indent ring, and a shim.
Title: Re: EEVBlog 121GW Discussion thread
Post by: amspire on February 27, 2018, 12:01:37 am
Can someone please measure the input impedance when the mVDC is selected.
It is about 9.9M.
Title: Re: EEVBlog 121GW Discussion thread
Post by: 1anX on February 28, 2018, 07:58:51 am
Dave commented much earlier on the probability of Murphy playing a role in this meter's fate. The comment that comes to mind ran along the lines of delivery dates could be impacted by such things as the USA coming into conflict with North Korea.

Hopefully UEi can deliver before this comes into operation and hopefully diplomacy will find a way. https://www.washingtonpost.com/opinions/trumps-team-is-floating-an-attack-on-north-korea-americans-would-die/2018/02/27/8e6cdf66-1826-11e8-92c9-376b4fe57ff7_story.html?utm_term=.5808f5ad42ac (https://www.washingtonpost.com/opinions/trumps-team-is-floating-an-attack-on-north-korea-americans-would-die/2018/02/27/8e6cdf66-1826-11e8-92c9-376b4fe57ff7_story.html?utm_term=.5808f5ad42ac)
Title: Re: EEVBlog 121GW Discussion thread
Post by: Bud on February 28, 2018, 08:13:20 am
Stay away from politics.
Title: Re: EEVBlog 121GW Discussion thread
Post by: JonM on March 02, 2018, 05:58:16 pm
I was away and missed the live stream. Upon returning last night I saw the pop-up notification which took me to a recording of the live stream. David2's "plot" was there, shortly before Dave has to leave he holds a tablet up to the camera. First was pass/fail data, then a bit later "raw" data. I think that there was some good explanation of why some data are bad. In the reproducible research world (if making a document), it is best to show two plots with one including the "bad" data and the explanation of why it is bad. You don't want the scale set so that "real" variation cannot be seen. Of course, I don't think that they are planning a document on the testing.
Title: Re: EEVBlog 121GW Discussion thread
Post by: bitwelder on March 03, 2018, 01:36:35 pm
Any plans regarding sigrok support for this meter?
Title: Re: EEVBlog 121GW Discussion thread
Post by: Tinkerlad on March 03, 2018, 11:40:57 pm
Any plans regarding sigrok support for this meter?

Once I get my hands on one I will be looking at adding sigrok support if someone hasnt already. Im also very interested in seeing what sort of data throughput the BT module can get and if I can get a low data rate stream over Bluetooth into sigrok lol.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on March 03, 2018, 11:55:19 pm
If you go back now and look, it appears the data was removed.  I watched it after it was live and assume it would have had to been cut and reloaded.

No, that's not how Youtube live streams work. It records the whole thing and makes it available afterwards. I did not edit it or even upload it.

Quote
Strange as I don't remember it being anything that I considered that out of the ordinary.  They were messing with the jig a fair amount and maybe just want to show a clean data set.  It sounded like they may run a few other meters as well.

No, we only ran the one meter.
Title: Re: EEVBlog 121GW Discussion thread
Post by: 1anX on March 04, 2018, 07:11:53 am
That's odd.  I know I saw the plots the first time I watched the videos. Maybe I am just not able to find it.

Hey Joe, are you going to be getting a production run meter from the next batch?

The first release meters even to backers were really prototypes, so the next batch will really be the first production run released having undergone substantial testing.

I'm hoping to see you test the new updated meter and look forward to your unbiased results!
Title: Re: EEVBlog 121GW Discussion thread
Post by: IanB on March 04, 2018, 05:03:45 pm
I really have not seen a lot of testing going of of these first meters, not like I had hoped for anyway.   It's premature to think about it.

I think the timing of the Kickstarter announcement made it most accessible to people in the USA (it was in the middle of the night in Europe), so many (even most?) orders came from here. And as you know, the USA batch has not been delivered yet. I think you can expect to see much more discussion and testing once the USA meters get into people's hands.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on March 05, 2018, 12:50:19 am
Results from the 50,000 cycles with the shim solution

https://www.youtube.com/watch?v=u2-ot2vWLxI (https://www.youtube.com/watch?v=u2-ot2vWLxI)

Title: Re: EEVBlog 121GW Discussion thread
Post by: TheSteve on March 05, 2018, 01:20:37 am
Very cool! The results are pretty darn good for 50K cycles.

Going to have a giveaway for the highest use 121GW in existence?
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on March 05, 2018, 01:30:47 am
Going to have a giveaway for the highest use 121GW in existence?

Fraid not, we only have two beat up meters in the lab.
Title: Re: EEVBlog 121GW Discussion thread
Post by: amspire on March 05, 2018, 01:59:28 am
If you put some thin Kapton tape on both sides of the spacer and heat it to set the glue, it would probably stop the abrasion.

The normal tape is HN Kapton. There are non-Dupont FEP coated (teflon) polyimide tapes available. I just do not know if the Kapton FN (FEP coated) film is available as a tape.

Two layers of Kapton tape varies in total thickness between 0.13 mm for the 1mil tape to 0.23mm for the 3mil tape. Not sure if 0.13mm is too much or not - may have to thin the spacer a little. If you only add the tape between the spacer and the case, the thickness can drop to 0.065mm.

I have also mentioned before the method I used with polyimide tape around the outside of the knob to reduce clearance between the knob and the case so it cannot wobble much. Seems to work great. You can reverse the camber of the knob edges to match the case.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on March 05, 2018, 02:11:22 am
UPDATE: We completely screwed the pooch! We installed the shim upside down!
There was supposed to be no contact friction between the shim and the plastic case (which created all the dust). Apparently we were too dumb to read UEI's instructions precisely. Doh.?  :palm:
Title: Re: EEVBlog 121GW Discussion thread
Post by: amspire on March 05, 2018, 02:14:45 am
UPDATE: We completely screwed the pooch! We installed the shim upside down!
There was supposed to be no contact friction between the shim and the plastic case (which created all the dust). Apparently we were too dumb to read UEI's instructions precisely. Doh.?  :palm:
Why have they routed the recess then? It isn't meant to fit between the case and the clip, is it? Otherwise it seems they have thinned the part of the spacer taking all the force.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Brumby on March 05, 2018, 04:12:06 am
Why have they routed the recess then?
That's the question that came to my mind as well.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on March 05, 2018, 07:24:19 am
UPDATE: We completely screwed the pooch! We installed the shim upside down!
There was supposed to be no contact friction between the shim and the plastic case (which created all the dust). Apparently we were too dumb to read UEI's instructions precisely. Doh.?  :palm:
Why have they routed the recess then? It isn't meant to fit between the case and the clip, is it? Otherwise it seems they have thinned the part of the spacer taking all the force.

The recess fits over the protruded tab on the actual top of the range switch, I showed this on the latest live feed.
The circlip actually resides flush with the case as it's in a concave part of the case molding.
Title: Re: EEVBlog 121GW Discussion thread
Post by: 1anX on March 05, 2018, 09:12:37 am
The recess fits over the protruded tab on the actual top of the range switch, I showed this on the latest live feed.
The circlip actually resides flush with the case as it's in a concave part of the case molding.

How about a link Dave!
I couldn't find the live feed where you show the correct position of the spacer.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on March 05, 2018, 10:11:52 am
The recess fits over the protruded tab on the actual top of the range switch, I showed this on the latest live feed.
The circlip actually resides flush with the case as it's in a concave part of the case molding.

How about a link Dave!
I couldn't find the live feed where you show the correct position of the spacer.

You'll see it eventually in a saved live feed. live streams only go back 2 hours.
Title: Re: EEVBlog 121GW Discussion thread
Post by: amspire on March 05, 2018, 01:42:48 pm
If you want to compare it with the Fluke 17B+, SC4.   I have no answer why this meter is so stable. The contacts are a whole different setup. 
I wonder if the resistance connections going through the switch are 4 wire in the Fluke. It is one possible explanation for the dramatic improvement in performance over all the other meters.

It is also possible that they have put in the engineering work needed to make fabulous switches.
Title: Re: EEVBlog 121GW Discussion thread
Post by: 1anX on March 06, 2018, 05:14:54 am
Watching Dave's switch testing live video earlier on today. Had the spacer on the right way round this time  :D
Looks like the switch is fixed and thoroughly tested!
All we need to find out now is have the firmware fixes been applied and tested?
Must be getting close to shipping out to the Johnny Be Goode backers  :-+
Title: Re: EEVBlog 121GW Discussion thread
Post by: Brumby on March 06, 2018, 05:35:44 am
You're keen.

I can understand that to a point - but if we take it to an automotive equivalent ... adding a packing piece that helps keep the steering wheel from wobbling around and properly connected to the steering rack doesn't mean the rewrite of the engine management system is nearly finished.

You are not the only one anxious for the updates to go out.

Also, just remember those who did get the meters, got them at a reduced price.  That came with a risk, one that was pretty much expected by many.  When I'm able to get one of these for myself, I will be paying more in dollar terms, but less in time.
Title: Re: EEVBlog 121GW Discussion thread
Post by: 1anX on March 06, 2018, 08:29:52 am
Also, just remember those who did get the meters, got them at a reduced price.  That came with a risk, one that was pretty much expected by many.  When I'm able to get one of these for myself, I will be paying more in dollar terms, but less in time.
Well I dunno about that Brumby! I think you have invested plenty of time on this thread already :D

Your comments are plentiful and you usually dont spare us the depth of your insights into how this meter should or shouldn't be developed and what should or shouldn't take place before its released as a production unit.

I personally decided to place an order, (become a backer) because of its novelty value and because of it coming from Dave and EEVBlog. I paid whatever for the meter and ended up in the Johnny Be Goode group. I make no pretense of being privy to the design and release of this meter just my own thoughts and observations. If the meter works out to be great value for money I will be well pleased.

As this forum is for Discussion I will continue to discuss and share my thoughts with those who care to read them. I dont pretend to be an expert in meter design and testing, I'm simply interested in this meter and Dave's kick starter venture. For me its about a meter and its development and having fun while discovering whats involved.

In a discussion, its not only "expert" opinion that makes for interest, drawing a cross section of personalities and opinions makes it more diverse and complete.
Title: Re: EEVBlog 121GW Discussion thread
Post by: joeqsmith on March 06, 2018, 10:40:17 am
Dave, I mentioned I had uploaded  a few clips of  Brymen's test jig in operation.  The attached link starts at those clips.  It is followed by showing how my setup works.

Also, the formulas on the yellow sticky notes were r=v/2300 and R=2740/((1/r)-1) . The second note stated the first column was V.    So for v=128,  R=2740/((2300/128)-1) = 152.5.  But this is way too high.  Even if it were 1.525  ohms, this is not close.   With all that computer power, I am a bit surprised that the software just did not display the value in ohms rather than use bits of paper.   Your programmer needs to step up their game.   :-DD

 
https://youtu.be/bs5n3a__Yq0?t=400
Title: Re: EEVBlog 121GW Discussion thread
Post by: Brumby on March 06, 2018, 01:48:25 pm
Your comments are plentiful and you usually dont spare us the depth of your insights into how this meter should or shouldn't be developed and what should or shouldn't take place before its released as a production unit.
Sorry.

I just made comments about the development process as I see it, based on what little I know, what Dave has said and what logic suggests.

I take any comment that infers the process should be in such-and-such a state as something a little more aggressive than "a hope".  It will take as long as it takes.
Title: Re: EEVBlog 121GW Discussion thread
Post by: 1anX on March 06, 2018, 09:06:52 pm
Dave, I mentioned I had uploaded  a few clips of  Brymen's test jig in operation.  The attached link shows starts at those clips.  It is followed by showing how my setup works.
https://youtu.be/bs5n3a__Yq0?t=400

Joe, watching the video of your test jig in action, it becomes apparent just how brutal Dave's jig is compared to yours. Your switch actuating "fingers" and timed sequencing approximates real world usage. At least it appears that way to me.

It suggests to me that Dave's jig would inflict more wear and damage than may be found in other manufacturers testing of their meter's switches?

It also shows the relevance of having someone like you running uniform consistent tests on a range of meters and brands so that a true indication of robustness, precision and accuracy can be conveyed to the prospective buyer.

Definitely looking forward to seeing how the blue meter performs once you get hold of a "production" unit.

Watching the video also presented me with the same dilemma that confronted Neo. Choose the Red meter or the Blue meter, as I considered the Brymen a worthy competitor for my money!
Title: Re: EEVBlog 121GW Discussion thread
Post by: joeqsmith on March 07, 2018, 01:17:03 am
Dave, I mentioned I had uploaded  a few clips of  Brymen's test jig in operation.  The attached link shows starts at those clips.  It is followed by showing how my setup works.
https://youtu.be/bs5n3a__Yq0?t=400

Joe, watching the video of your test jig in action, it becomes apparent just how brutal Dave's jig is compared to yours. Your switch actuating "fingers" and timed sequencing approximates real world usage. At least it appears that way to me.

It suggests to me that Dave's jig would inflict more wear and damage than may be found in other manufacturers testing of their meter's switches?

It also shows the relevance of having someone like you running uniform consistent tests on a range of meters and brands so that a true indication of robustness, precision and accuracy can be conveyed to the prospective buyer.

Definitely looking forward to seeing how the blue meter performs once you get hold of a "production" unit.

Watching the video also presented me with the same dilemma that confronted Neo. Choose the Red meter or the Blue meter, as I considered the Brymen a worthy competitor for my money!

I am not really sure which setup would be harder on the meter or closer simulate real world use or even if it matters.   I can only show what I am doing, present the data and let the viewers draw their own conclusions.  Similar to the transient tests.  As you suggest, I do try and keep the tests consistent and there does seem to be some trends even with the limited data I have collected.   One benefit is because I really don't care about hand held meters and have no vested interest in any brand and draw no income from running them, coupled with a somewhat consistent set of tests, things are fairly unbiased.   You get data rather than feelings. 

blah blah blah....

Now about those yellow sticky notes.   I saw they were no longer shown in the edited video so I have attached a screen shot.  Granted, I am not sure why they use r=V/3300 only to invert it below but the numbers don't seem to work out even close to what their meter was reading and everything is well above the 10 ohm limit.  Is this that new math I keep hearing about? 
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on March 07, 2018, 02:56:28 am
Now about those yellow sticky notes.   I saw they were no longer shown in the edited video so I have attached a screen shot.  Granted, I am not sure why they use r=V/3300 only to invert it below but the numbers don't seem to work out even close to what their meter was reading and everything is well above the 10 ohm limit.  Is this that new math I keep hearing about?

a) Nothing was "removed in editing". The entire original 23 hour video is still being processed by youtube and will eventually be available online. It seems that only the final 2 hours is currently available.

b) By the "edited video" I presume you mean the one "How to do Lifecycle Testing". I simply extracted some content from the stream to create a new video were I talked about general range switch testing as I thought it might be interesting to people as separate video.

c) There is a uCurrent x100 amplifier used in the jig across the switch contacts, that is not shown in the equations.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on March 07, 2018, 03:11:29 am
UPDATE:

Hardware:
- We are now confident in the shim and revised indent spring solution for the range switch. This fixes both the intermittent contact issue and the switch wobble issue.
- Existing backers with meters will get shipped a replacement switch and shim and instructions.
- All future backer meters shipped will come with these installed.

Firmware
- We will now release version 1.07 it can be downloaded here:
https://www.eevblog.com/product/121gw/ (https://www.eevblog.com/product/121gw/)
Just rename it to EEVblog.bin on the SD card and update as per the manual instructions.
This fixes several major issues including:
- Improved ohms autoranging speed, now on par with the Keysight U1282A
- Negative VA value issue
- Beeper now defaults to off and can be switched on in the setup menu.
- High frequency Low-Z measurement issue fixed.
- VA over reading issue fixed.

Software
- Windows app software is now available on the Microsoft store.

Barring any more issues we will be proceeding with fulfillment again shortly. Sorry, no ETA actual dates will be promised at this stage.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Average Meatsack on March 07, 2018, 05:41:26 am
UPDATE:

Software
- Windows app software is now available on the Microsoft store.

I have downloaded the software onto my Windows 10 laptop. I am waiting for my meter but I thought I would have a quick poke around the software beforehand. I would have though that it would be similar to the Android version that actually has a display but no such luck. All I get when I start the software is a window with <Settings> and a refresh button at the bottom of the screen. Clicking on <> or Settings does nothing. Mousing over the Reset button causes a change colour but it is impossible to know if it is doing anything.

I am using Windows 10 Build 1629.248, 8Gb RAM, Core i5-4200U CPU and with plenty of space on the Windows OS install partition. Bluetooth is enabled. I tried disabling Avast to see it that was causing the seeming issue but there was no change. I believe I am having an issue with the software unless it behaves completely different to the Android version, not displaying anything if it cannot see the meter.

I have attached a screenshot of what I am seeing.
Title: Re: EEVBlog 121GW Discussion thread
Post by: imidis on March 07, 2018, 06:16:42 am
That looks like a typical windows 10 app to me.  >:D :-//
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on March 07, 2018, 06:40:32 am
I have downloaded the software onto my Windows 10 laptop. I am waiting for my meter but I thought I would have a quick poke around the software beforehand. I would have though that it would be similar to the Android version that actually has a display but no such luck. All I get when I start the software is a window with <Settings> and a refresh button at the bottom of the screen. Clicking on <> or Settings does nothing.

It shouldn't display anything unless you have a meter to talk to, sorry.
Title: Re: EEVBlog 121GW Discussion thread
Post by: bitwelder on March 07, 2018, 06:47:53 am
F/w 1.07: the Sound of Silence  :-+
Title: Re: EEVBlog 121GW Discussion thread
Post by: amspire on March 07, 2018, 06:55:47 am
F/w 1.07: the Sound of Silence  :-+
I was going to post earlier but hit a stumbling block.

After loading 1.07, I found my current ranges no longer work. Put it back to 1.01 and they still do not work - reads overflow on many ranges. I am debugging the meter to see if I just got a switch problem at the same time as the upgrade. The meter has not been near high voltages and currents and the fuses and shunts are fine. The current ranges did work perfectly. It is not a lost calibration issue - it looks more like a floating connection that should be going to the shunt resistors.

The resistance  now goes from open to a short in under 5 seconds - much more respectable.  :-+

Looks like VA is still restricted to 55V maximum and they haven't fixed the issues with the capacitance manual range yet:
https://www.eevblog.com/forum/testgear/eevblog-121gw-multimeter-issues/150/ (https://www.eevblog.com/forum/testgear/eevblog-121gw-multimeter-issues/150/)
Title: Re: EEVBlog 121GW Discussion thread
Post by: 1anX on March 07, 2018, 07:57:24 am
F/w 1.07: the Sound of Silence  :-+
I was going to post earlier but hit a stumbling block.

After loading 1.07, I found my current ranges no longer work. Put it back to 1.01 and they still do not work - reads overflow on many ranges. I am debugging the meter to see if I just got a switch problem at the same time as the upgrade. The meter has not been near high voltages and currents and the fuses and shunts are fine. The current ranges did work perfectly. It is not a lost calibration issue - it looks more like a floating connection that should be going to the shunt resistors.

The resistance  now goes from open to a short in under 5 seconds - much more respectable.  :-+

Looks like VA is still restricted to 55V maximum and they haven't fixed the issues with the capacitance manual range yet:
https://www.eevblog.com/forum/testgear/eevblog-121gw-multimeter-issues/150/ (https://www.eevblog.com/forum/testgear/eevblog-121gw-multimeter-issues/150/)

Bugger!

Interested to see what you find the problem is with your current ranges.

Thanks for reporting the capacitance reading problem. Looking at your previous post you think this is associated with the oscillator not having a time out function and more specifically a time out function suited to the range selected.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on March 07, 2018, 12:12:51 pm
After loading 1.07, I found my current ranges no longer work. Put it back to 1.01 and they still do not work - reads overflow on many ranges. I am debugging the meter to see if I just got a switch problem at the same time as the upgrade. The meter has not been near high voltages and currents and the fuses and shunts are fine. The current ranges did work perfectly. It is not a lost calibration issue - it looks more like a floating connection that should be going to the shunt resistors.

I would presume that has to a coincidental intermittent switch issue. No other reason would make sense.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Iagash on March 07, 2018, 12:23:09 pm
The bluetooth data corruption is not fixed in 1.07.

Some can be detected, but others can't, see the random "LowZ" signaling in the 6th column.

Quote
1520424876.136 2017-08 00042    Power DC (VA)     0.0 mVA       DCA    0.01
1520424876.406 2017-08 00042    Power DC (VA)     0.0 mVA       DCA    0.01
1520424876.676 read STDIN: invalid byte: 6 of 34
1520424876.676 read STDIN: invalid byte: 13 of 20
1520424876.676 read STDIN: invalid byte: 10 of 19
1520424876.811 read STDIN: invalid byte: 10 of 14
1520424877.081 2017-08 00042    Power DC (VA)     0.3 mVA       DCA    0.01
1520424877.352 2017-08 00042    Power DC (VA)     0.3 mVA       DCA    0.01
1520424877.621 read STDIN: invalid byte: 131 of 34
1520424877.621 read STDIN: invalid byte: 10 of 33
1520424877.756 read STDIN: invalid byte: 10 of 14
1520424878.026 2017-08 00042    Power DC (VA)     0.0 mVA       DCA    0.01
1520424878.296 2017-08 00042    Power DC (VA)     0.0 mVA       DCV  0.0000
1520424878.566 2017-08 00042    Power DC (VA)     0.0 mVA       DCV  0.0000
1520424878.836 2017-08 00042    Power DC (VA)     0.1 mVA       DCV  0.0000
1520424879.106 2017-08 00042    Power DC (VA)     0.1 mVA       DCV  0.0000
1520424879.376 2017-08 00042    Power DC (VA)     0.1 mVA     Low_Z    4112
1520424879.646 read STDIN: invalid byte: 10 of 34
1520424879.781 2017-08 00042    Power DC (VA)     0.0 mVA       DCV  0.0000
1520424880.051 2017-08 00042    Power DC (VA)    -0.4 mVA       DCV  0.0000
1520424880.321 2017-08 00042    Power DC (VA)    -0.4 mVA       DCV  0.0000
1520424880.591 2017-08 00042    Power DC (VA)     0.0 mVA       DCV  0.0000
1520424880.861 2017-08 00042    Power DC (VA)     0.0 mVA       DCV  0.0000
1520424881.131 read STDIN: invalid byte: 24 of 34
1520424881.131 read STDIN: invalid byte: 13 of 19
1520424881.131 read STDIN: invalid byte: 10 of 18
1520424881.266 read STDIN: invalid byte: 20 of 14
1520424881.266 read STDIN: invalid byte: 10 of 13
1520424881.536 read STDIN: invalid byte: 10 of 14
1520424881.806 2017-08 00042    Power DC (VA)     0.0 mVA       DCA    0.01
1520424882.076 2017-08 00042    Power DC (VA)     0.0 mVA       DCA    0.01
Title: Re: EEVBlog 121GW Discussion thread
Post by: Candid on March 07, 2018, 12:33:46 pm
- Existing backers with meters will get shipped a replacement switch and shim and instructions.
Thank you I am eagerly waiting for this fix!

Firmware
- We will now release version 1.07 it can be downloaded here:
Thank you for the new firmware, works fine for me and auto range is really ok now even if it is not the fastest (for me max. 4 - 5 secs).

The beeper off function needs a revise I think. Now at beeper off you don't have any beeper in all functions. No continuity beeper and no beeper in any other function.

It would be much better to get a detailed beeper configuration at least should (if only one is possible) beeper off only be for power on and switching between the functions with the switch. When I power on the 121GW I automatically look on the display and see if it turns on, no need for a beep. And when I switch the function I get a feedback from the switch and the display, no need for a beep. But in continuity and other functions I need the beep as feedback even if the display gives me a feedback too but I am not always looking on the display when using this functions (e.g. searching for a short).
Title: Re: EEVBlog 121GW Discussion thread
Post by: amspire on March 07, 2018, 01:03:00 pm
After loading 1.07, I found my current ranges no longer work. Put it back to 1.01 and they still do not work - reads overflow on many ranges. I am debugging the meter to see if I just got a switch problem at the same time as the upgrade. The meter has not been near high voltages and currents and the fuses and shunts are fine. The current ranges did work perfectly. It is not a lost calibration issue - it looks more like a floating connection that should be going to the shunt resistors.

I would presume that has to a coincidental intermittent switch issue. No other reason would make sense.
That's what I figured, but my initial look at the circuit showed a lot of the current switching is done by cmos switches. Both the buffered and unbuffered ranges are affected. The rotary switch seems to be perfect. I cannot find any obvious continuity faults right now. I will hook up some power and test the voltages tomorrow. It might be a broken track or a dry joint.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Iagash on March 07, 2018, 01:05:40 pm
Bluetooth and VA mode is still completely broken, even if you filter the invalid records.
It's also broken in the android app. It displays the same wrong readings.

The 391.2 mVA reading is the correct one.

Quote
1520427022.717 2017-08 00042    Power DC (VA)  2499.9 mVA       DCV  1.5652
1520427022.987 2017-08 00042    Power DC (VA)  2499.8 mVA       DCV  1.5652
1520427023.257 2017-08 00042    Power DC (VA)  2499.8 mVA       DCV  1.5652
1520427023.527 2017-08 00042    Power DC (VA)  2499.8 mVA       DCV  1.5652
1520427023.797 2017-08 00042    Power DC (VA)   391.2 mVA       DCV  1.5652
1520427024.067 2017-08 00042    Power DC (VA)   391.2 mVA       DCV  1.5652
1520427024.742 2017-08 00042    Power DC (VA)  1564.9 mVA       DCA  249.97
1520427025.282 2017-08 00042    Power DC (VA)  1565.2 mVA       DCA  249.97
1520427025.552 2017-08 00042    Power DC (VA)   391.2 mVA       DCA  249.97
1520427025.822 2017-08 00042    Power DC (VA)  2500.0 mVA       DCA  249.97
1520427026.565 2017-08 00042    Power DC (VA)  2499.9 mVA       DCA  249.97
1520427027.240 2017-08 00042    Power DC (VA)   391.3 mVA       DCA  249.99
1520427027.510 2017-08 00042    Power DC (VA)   391.3 mVA       DCA  249.99
1520427027.780 2017-08 00042    Power DC (VA)  1521.7 mVA       DCV  1.5653
1520427028.050 2017-08 00042    Power DC (VA)  1565.2 mVA       DCV  1.5653
1520427028.320 2017-08 00042    Power DC (VA)  1565.2 mVA       DCV  1.5653
1520427029.265 2017-08 00042    Power DC (VA)  2500.2 mVA       DCV  1.5655
1520427029.535 2017-08 00042    Power DC (VA)  2500.0 mVA       DCV  1.5655
1520427029.805 2017-08 00042    Power DC (VA)  2500.1 mVA       DCV  1.5655
1520427030.075 2017-08 00042    Power DC (VA)  2500.0 mVA       DCV  1.5655
1520427030.345 2017-08 00042    Power DC (VA)  2500.1 mVA       DCV  1.5655
1520427031.020 2017-08 00042    Power DC (VA)  1516.9 mVA       DCV  1.5655
1520427031.290 2017-08 00042    Power DC (VA)  1516.9 mVA       DCA  250.00
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on March 07, 2018, 01:09:56 pm
The 24 hour video was no longer listed when I checked, so yes I was referring to your how-to video.   

Youtube is rooted, it's there.

https://www.youtube.com/watch?v=VzS6coxYSAs (https://www.youtube.com/watch?v=VzS6coxYSAs)

It's still processing

(https://i.imgur.com/F5gGpQZ.png)
Title: Re: EEVBlog 121GW Discussion thread
Post by: idpromnut on March 07, 2018, 01:49:39 pm
@Dave: at the risk of sounding like an ungrateful asshole, while the beeper on/off option is fantastic (nice and quite now!  :-+ ), it renders the continuity beeper also silent, which I would argue either should have it's own configuration option, or at least be on all the time, even if the beeper for functions/buttons is turned off.

That being said, I don't know that I would classify this as an "issue".  A big thanks to UEi for getting issues in the FW addressed quickly!
Title: Re: EEVBlog 121GW Discussion thread
Post by: Candid on March 07, 2018, 02:26:10 pm
Maybe someone can explain to me what the problem is:
2 different function generators tested, JDS6600 and FeelTech FY6600. Identical settings, identical results.

For example: 4kHz square wave with 2.0Vpp. Measured Vac with the 121GW and as comparison a Fluke 28II (highres mode).

Range AUTO: 121GW selects 5V range, Fluke selects 6V range
121GW reads 1.37xxVac, Fluke reads 0.99xxVac

Manual range 5V 121GW, 6V Fluke 28II:
121GW reads 1.37xxVac, Fluke reads 0.99xxVac

Manual range 50V 121GW, 60V Fluke 28II:
121GW reads 0.95xVac, Fluke reads 0.94xxVac

Similar behavior for the 121GW with sine wave. It reads 1,117xV in auto range and manual 5V range and 0,664V in manual 50V range. I checked with 200Hz sine and same behavior for the 121GW, Fluke and Brymen 235 work fine.

What is the 121GW doing in auto range / 5V range?


And Bluetooth:
Still the same for me. It's more or less luck if I get a connection to the meter. Tried both apps. When I get a connection with Dave2-App I only get something displayed in the lower half of the display, the upper half stays completely blank for me on my Samsung Galaxy S8.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Iagash on March 07, 2018, 02:27:48 pm
@Dave: at the risk of sounding like an ungrateful asshole, while the beeper on/off option is fantastic (nice and quite now!  :-+ ), it renders the continuity beeper also silent, which I would argue either should have it's own configuration option, or at least be on all the time, even if the beeper for functions/buttons is turned off.

That being said, I don't know that I would classify this as an "issue".  A big thanks to UEi for getting issues in the FW addressed quickly!

On first thought I'd also say that the continuity beep should be always on. But on second thought it's maybe a matter of taste.

A bonus would be a blinking backlight if the continuity beep is off.

Anyways thanks for the beeper option.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Hydron on March 07, 2018, 03:29:44 pm
 I personally think the beeper is necessary in the following circumstances:
- Continuity (which even uses the sound symbol!)
- Diode test
- When you've been an idiot and left a probe in the A jack when the meter is in voltage mode (assuming it's using sensing jacks - can't remember if this is the case)
- Over-load warning on ranges where an overload could cause damage

Other than those, I'd normally want the beeper off, so I'd agree with everyone asking for a middle option (preferably as a third setting in addition to the current two)
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on March 08, 2018, 12:24:22 am
Bluetooth and VA mode is still completely broken, even if you filter the invalid records.
It's also broken in the android app. It displays the same wrong readings.

The 391.2 mVA reading is the correct one.

I can confirm this, I see infrequent large scale data value excursion in VA mode. Reported.
Title: Re: EEVBlog 121GW Discussion thread
Post by: mtdoc on March 08, 2018, 01:13:06 am
I personally think the beeper is necessary in the following circumstances:
- Continuity (which even uses the sound symbol!)
- Diode test
- When you've been an idiot and left a probe in the A jack when the meter is in voltage mode (assuming it's using sensing jacks - can't remember if this is the case)
- Over-load warning on ranges where an overload could cause damage

Other than those, I'd normally want the beeper off, so I'd agree with everyone asking for a middle option (preferably as a third setting in addition to the current two)

I agree. That seems like a no brainer.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Seppy on March 09, 2018, 03:27:22 am
a) Nothing was "removed in editing". The entire original 23 hour video is still being processed by youtube and will eventually be available online. It seems that only the final 2 hours is currently available.

b) By the "edited video" I presume you mean the one "How to do Lifecycle Testing". I simply extracted some content from the stream to create a new video were I talked about general range switch testing as I thought it might be interesting to people as separate video.

c) There is a uCurrent x100 amplifier used in the jig across the switch contacts, that is not shown in the equations.

The 24 hour video was no longer listed when I checked, so yes I was referring to your how-to video.   

Quote
.. r=v/2300 and R=2740/((1/r)-1) . The second note stated the first column was V.    So for v=128,  R=2740/((2300/128)-1) = 152.5. 

I assume it's not as simple as it being off by 100X or 0.152 ohms,  seems way too low but maybe.     Looking at V=1272, R = 1.516 in this case and I think it was much higher.  Strange that the basics are not clear or just coded.



There is a 100x amplifier, that formula didn't show the uCurrent gain.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Seppy on March 09, 2018, 03:43:12 am
Maybe someone can explain to me what the problem is:
2 different function generators tested, JDS6600 and FeelTech FY6600. Identical settings, identical results.

For example: 4kHz SQRT with 2Vpp. Measured ACV with the 121GW and as comparison a Fluke 28II (highres mode).

Range AUTO: 121GW selects 5V range, Fluke selects 6V range
121GW reads 1,37xxVac, Fluke reads 0,99xxVac

Manual range 5V 121GW, 6V Fluke 28II:
121GW reads 1,37xxVac, Fluke reads 0,99xxVac

Manual range 50V 121GW, 60V Fluke 28II:
121GW reads 0,95xVac, Fluke reads 0,94xxVac

Did you mean 2V peak to peak square wave, what did you mean by square root (SQRT)?
I reproduced the test and do not get your results. I get 1.0022 Vrms on a production meter for the above setup.

Did you signal generator have a DC offset, if so make sure that the 121GW isn't in DC + AC mode.
DC + AC mode for a 0 - 2V square wave results in approximately 1.4V, which is close to what you measured.

Title: Re: EEVBlog 121GW Discussion thread
Post by: Candid on March 09, 2018, 12:24:58 pm
Sorry, my mistake. square wave for sure.

Can you reproduce the following measurements?
2.0V peak to peak sine wave 4kHz, No DC offset, duty cycle 50%. Both meters in AC mode. Firmware 1.07 on my 121GW with serial number EEVblog 000084

Auto mode on both meters, Fluke in highres mode:
121GW selects 5V range, reads 1.1133Vac
Fluke 28II selects 6V range, reads 0.7031Vac

manual mode on both meters:
121GW 5V range, reads 1.1133Vac
Fluke 28II 6V range, 0.7032Vac

121GW 50V range, reads 0.659Vac (and it looses the frequency measurement and displays 0.00kHz)
Fluke 28II 60V range, reads 0.663Vac

See the attached pictures.
Title: Re: EEVBlog 121GW Discussion thread
Post by: fanOfeeDIY on March 11, 2018, 09:52:36 pm
I uploaded video regarding roughly comparing Burden Voltage.

https://youtu.be/sSyZtqiWmvg (https://youtu.be/sSyZtqiWmvg)
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on March 11, 2018, 11:26:42 pm
I uploaded video regarding roughly comparing Burden Voltage.

Quote
On your 121GW, you do have a fairly high resolution. In the Amps low range, I think its 10uA resolution which is what you have with the other meters. However, your burden voltage is to be VERY low. Maybe 200ish uv!! Try that and see what you think.? 

I posted the above comment on YT.   Looking in the manual, maybe it no longer works this but I'm pretty sure that the prototype did.

The 500mA range uses the Amps jack (and a x10 amplifier) unlike most meters. This gives a very low maximum burden voltage of 30mV/A, or 15mV for 500mA full scale.
Very few meters will be this low on the 500mA range.
With 50,000 count the resolution is 10uA.
Title: Re: EEVBlog 121GW Discussion thread
Post by: fanOfeeDIY on March 12, 2018, 12:15:47 am
I uploaded video regarding roughly comparing Burden Voltage.

Quote
On your 121GW, you do have a fairly high resolution. In the Amps low range, I think its 10uA resolution which is what you have with the other meters. However, your burden voltage is to be VERY low. Maybe 200ish uv!! Try that and see what you think.? 

I posted the above comment on YT.   Looking in the manual, maybe it no longer works this but I'm pretty sure that the prototype did.

The 500mA range uses the Amps jack (and a x10 amplifier) unlike most meters. This gives a very low maximum burden voltage of 30mV/A, or 15mV for 500mA full scale.
Very few meters will be this low on the 500mA range.
With 50,000 count the resolution is 10uA.
Thanks.   

I had DL'ed the manual when you made it available.  The one I have is 25th Nov. 17.   I see a mention of the 500mA mode on page 11. 

Quote
A and 500mA    11A/1000V DC/AC, IR 20kA HRC FAST + DIODE
and again on page 55
Quote
A/500mA current input fuse: 11A/1000V DC/AC, IR 20kA HRC FAST

The table on page 14 does not mention it.   
Quote
The following modes will use the x10 amplifier and may have additional off-set error that can be nulled out before measurement.

Maybe add something to page 32 where the current measurement is shown.   When I looked at the burden on the pre-production, is was pretty impressive.  From fanOfeeDIY's video, the manual may need a few small additions. 

Maybe you (Dave) would consider making a short video showing the meter's burden compared to a few others and how to use it properly.   

I am not quite following the discussion.  :'(
Especially "200ish uv!!" part.
Should I have used different range in my video?

Title: EEVBlog 121GW Discussion thread
Post by: fanOfeeDIY on March 12, 2018, 12:44:13 am
I am not quite following the discussion.  [emoji22]
Especially "200ish uv!!" part.
Should I have used different range in my video?

Do the same test with your 121GW except attach the leads from the A 500mA connector and the COM.   The 121GW will display the current with a resolution of 10uA just like the others you show.  However, now if you look at the burden voltage for the meter, I suspect you will see something around 200uV  rather then several mV as your video shows.   I use "ish" as close enough.   

I had modified a UNI-T UT61E which has a very high burden voltage, in an attempt to improve it.   There was only so much I could do in the area available and the way the board was laid out.  I think are real low current, the burden on this meter was lower than the 121GW but once I changed ranged, it was very clear just how good the 121GW was.   It's impressive.   Give it a try and see what happens.  Post your updates, text is good enough.

Ah, I completely understood now. [emoji4]

Let me take and upload a short video tonight as your advice with A/500mA connector.
I still have the setup on my desk.
Title: Re: EEVBlog 121GW Discussion thread
Post by: fanOfeeDIY on March 12, 2018, 10:31:45 am
I am not quite following the discussion.  :'(
Especially "200ish uv!!" part.
Should I have used different range in my video?

Do the same test with your 121GW except attach the leads from the A 500mA connector and the COM.   The 121GW will display the current with a resolution of 10uA just like the others you show.  However, now if you look at the burden voltage for the meter, I suspect you will see something around 200uV  rather then several mV as your video shows.   I use "ish" as close enough.   

I had modified a UNI-T UT61E which has a very high burden voltage, in an attempt to improve it.   There was only so much I could do in the area available and the way the board was laid out.  I think are real low current, the burden on this meter was lower than the 121GW but once I changed ranged, it was very clear just how good the 121GW was.   It's impressive.   Give it a try and see what happens.  Post your updates, text is good enough.

Thank you for your valuable comment on both YouTube and here.
I uploaded another video.
https://youtu.be/ffP1Y0zp9KE
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on March 12, 2018, 10:50:59 am
Maybe add something to page 32 where the current measurement is shown.   When I looked at the burden on the pre-production, is was pretty impressive.  From fanOfeeDIY's video, the manual may need a few small additions. 

Yep, the manual needs some updating.
The burden voltage may not be much better than, or on par with some other meters depending upon the range selected. It's a combination of what range uses the x10 amplifier and what shunt is used.
You could get the same excellent burden voltage on every range, but you'd need a effectively manual range switch positions with an optimised shunt for every range.
Very few meters will use the A jack for the 500mA range, so if your needs are on that range, it's going to be hard to beat.
Title: Re: EEVBlog 121GW Discussion thread
Post by: joeqsmith on March 12, 2018, 11:07:20 am
Thank you for your valuable comment on both YouTube and here.
I uploaded another video.
Thank you for taking the time to run the test a second time. 
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on March 13, 2018, 10:50:39 pm
V1.09 firmware https://www.eevblog.com/wp-content/uploads/2017/11/EEVBlog1_09.zip (https://www.eevblog.com/wp-content/uploads/2017/11/EEVBlog1_09.zip)
It fixes the issue with the VA mode Bluetooth connection sending garbage data.

Title: Re: EEVBlog 121GW Discussion thread
Post by: dcac on March 14, 2018, 12:31:06 pm
I am not quite following the discussion.  :'(
Especially "200ish uv!!" part.
Should I have used different range in my video?

Do the same test with your 121GW except attach the leads from the A 500mA connector and the COM.   The 121GW will display the current with a resolution of 10uA just like the others you show.  However, now if you look at the burden voltage for the meter, I suspect you will see something around 200uV  rather then several mV as your video shows.   I use "ish" as close enough.   

I had modified a UNI-T UT61E which has a very high burden voltage, in an attempt to improve it.   There was only so much I could do in the area available and the way the board was laid out.  I think are real low current, the burden on this meter was lower than the 121GW but once I changed ranged, it was very clear just how good the 121GW was.   It's impressive.   Give it a try and see what happens.  Post your updates, text is good enough.

Thank you for your valuable comment on both YouTube and here.
I uploaded another video.
https://youtu.be/ffP1Y0zp9KE

Is the 121GW current measurement really within spec. here, it seems to show something like 4.6000mA when using the mA/uA jack but using the 10A jack it shows about 4.23mA - seems quite a bit of to me.

Title: Re: EEVBlog 121GW Discussion thread
Post by: ChrisG on March 14, 2018, 08:04:03 pm
The beeping beeper is a bit funny indeed now. When switched off it does not beep at all, whilst the beeper icon is showing still. So agree and concur with the others. Suggestion for the Manual: make clear that the bin file needs to be named EEVblog.bin exactly. When I used the EEVblog1.09.bin file name it did not work, waited for 5 minutes and then decided to abort.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Iagash on March 15, 2018, 04:54:40 pm
V1.09 firmware https://www.eevblog.com/wp-content/uploads/2017/11/EEVBlog1_09.zip (https://www.eevblog.com/wp-content/uploads/2017/11/EEVBlog1_09.zip)
It fixes the issue with the VA mode Bluetooth connection sending garbage data.

Not really, the main display is correct now, but the upper display lost any connection to reality.

The corrupted data records are still there but less frequent.

 :palm:
Title: Re: EEVBlog 121GW Discussion thread
Post by: Iagash on March 15, 2018, 06:05:55 pm
I'm sure they run some sort of regression testing before they release updates and that is partly why UEI's response is slow.

Well, then you are a lot more optimistic than me.

Then again, now that Dave has stepped into the role of running life cycle testing maybe he needs to expand into some sort of firmware quality role as well.

Well I'll attach my console tool for the 121gw.
You can use it via:
Code: [Select]
gatttool -b 88:6B:XX:XX:XX:XX --char-write-req -a 0x0009 -n 0300 --listen | ./121gw.pl

To log into a file for later examination use:
Code: [Select]
gatttool -b 88:6B:XX:XX:XX:XX --char-write-req -a 0x0009 -n 0300 --listen | ./121gw.pl 2>&1 | tee logfile.txt

To find the BT address use:
Code: [Select]
hcitool lescan
and press ctrl-C when it is found.

You just need a linux system with bluetooth installed. Anything like debian jessie or newer should do. The gatttool command is in the bluez package. Nothing else is required.


Maybe Dave should make a video about what a ringbuffer is, how to find out how much space is left and skip writing a record now and then if bluetooth is too slow instead of overwriting not yet sent data.

I guess UEI is clearly in need of one.
Title: Re: EEVBlog 121GW Discussion thread
Post by: 1anX on March 15, 2018, 09:32:22 pm
V1.09 firmware https://www.eevblog.com/wp-content/uploads/2017/11/EEVBlog1_09.zip (https://www.eevblog.com/wp-content/uploads/2017/11/EEVBlog1_09.zip)
It fixes the issue with the VA mode Bluetooth connection sending garbage data.

Not really, the main display is correct now, but the upper display lost any connection to reality.

The corrupted data records are still there but less frequent.

 :palm:

Just when I think headway is being made in correcting and fixing this meter's faults, the reoccurring theme, which is a lack of testing yet again raises its head!

Like Joe said, its Dave's name/brand on the meter so he must assume ultimate responsibility as the marketer and seller of this device to ensure it actually works as specified!
Title: Re: EEVBlog 121GW Discussion thread
Post by: 1anX on March 16, 2018, 12:45:02 am
It seems 1.09 was a regression of other functionality in the VA mode.
The link has been removed.

Not sure what you mean by this? Can you please explain in a little detail just what testing is done and how you are releasing the updates!

I looked up regression testing as opposed to retesting fixed faults and found this defined as below...

"Retesting is done to make sure that the tests cases which failed in last execution are passing after the defects against those failures are fixed. Regression testing is not carried out on specific defect fixes. ... In Regression testing, you can include the test cases which passed earlier."


What process is UEi and Dave following for firmware releases?

Thanks in advance for any info you may wish to post, I find this educational and am learning how the development for this meter is evolving.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Seppy on March 16, 2018, 01:06:28 am
It appears that the firmware may not be a regression, I believe I just found a new error in AC mode and thought it was a regression.

V1.09 firmware https://www.eevblog.com/wp-content/uploads/2017/11/EEVBlog1_09.zip (https://www.eevblog.com/wp-content/uploads/2017/11/EEVBlog1_09.zip)
It fixes the issue with the VA mode Bluetooth connection sending garbage data.

Not really, the main display is correct now, but the upper display lost any connection to reality.

The corrupted data records are still there but less frequent.

 :palm:


Can you confirm your setup was in DC mode? What were the conditions which resulted in the incorrect values of the secondary display on the 121GW?

Old post about this was removed as it seems it was not a regression and instead a different error.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Iagash on March 16, 2018, 01:54:48 am

Can you confirm your setup was in DC mode? What were the conditions which resulted in the incorrect values of the secondary display on the 121GW?

Old post about this was removed as it seems it was not a regression and instead a different error.

I used DC mode, 400mA, 3.7V, 1.42VA. Both displays on the meter itself are perfect.

The display via bluetooth on the secondary display is 2.9V and 255.86A, the main display is fine.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Seppy on March 16, 2018, 02:29:08 am

Can you confirm your setup was in DC mode? What were the conditions which resulted in the incorrect values of the secondary display on the 121GW?

Old post about this was removed as it seems it was not a regression and instead a different error.

I used DC mode, 400mA, 3.7V, 1.42VA. Both displays on the meter itself are perfect.

The display via bluetooth on the secondary display is 2.9V and 255.86A, the main display is fine.

Are you on windows or Android, which version of the app?
Title: Re: EEVBlog 121GW Discussion thread
Post by: Iagash on March 16, 2018, 02:34:45 am
Are you on windows or Android, which version of the app?

I tried Android Version 0 eevblog.x121gw, but my perl script displays the same values.

It doesn't matter, fix the BT transmission with a correct buffering implementation.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Seppy on March 16, 2018, 03:46:55 am
Are you on windows or Android, which version of the app?

I tried Android Version 0 eevblog.x121gw, but my perl script displays the same values.

It doesn't matter, fix the BT transmission with a correct buffering implementation.

I understand the Perl script might be receiving the wrong thing too. Just to be thorough can you check if the updated android app resolves your issue.
Curiously the android app store might not have received the latest updates... Checking into this now... Ok it should be version 1 now :)
Title: Re: EEVBlog 121GW Discussion thread
Post by: Iagash on March 16, 2018, 11:53:31 am
I understand the Perl script might be receiving the wrong thing too. Just to be thorough can you check if the updated android app resolves your issue.
Curiously the android app store might not have received the latest updates... Checking into this now... Ok it should be version 1 now :)

Thanks.

I tried with version 1, it's still as broken as version 0.

Could you push your changes to github?

I'm more interested in receiving the data on my desktop, I use the phone just for checking.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Iagash on March 16, 2018, 12:53:32 pm
The errors on the main display are also still there if you leave it running a bit longer:

Quote
1521202937.913 2017-08 00042    Power DC (VA)  1409.7 mVA       DCA  255.34
1521202938.183 2017-08 00042    Power DC (VA)  140.97 VA        DCA  255.34
1521202938.858 2017-08 00042    Power DC (VA)  1409.7 mVA       DCA  255.34
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on March 16, 2018, 01:37:24 pm
What process is UEi and Dave following for firmware releases?

I do not know what procedures or processes UEi use.
As for this firmware release, UEi said they fixed the issues with the VA mode data corruption on Bluetooth, so we checked that and it seemed to be fixed, so I released the firmware on here so other could try it.
David has a setup that is sniffing the microcontroller UART data and comparing with received Bluetooth data. We could see the data corruption clearly before the fix and after the fix it's gone. It was reasonable to conclude they had fixed it, so pushed it out for others to confirm. We didn't test anything else on this release.

At this point we are basically using the current user base as a testing platform to find and confirm bug fixes. There is nothing better than giving it to a few hundred people and getting feedback. Would current owner prefer we not make interim firmware releases available for testing?
Title: Re: EEVBlog 121GW Discussion thread
Post by: Iagash on March 16, 2018, 02:03:48 pm
At this point we are basically using the current user base as a testing platform to find and confirm bug fixes. There is nothing better than giving it to a few hundred people and getting feedback.

This is fine, but please "fix" things and don't "cover up".

The bluetooth transmission is broken by design and by implementation.

Would current owner prefer we not make interim firmware releases available for testing?

I'm fine with testing, no problem.

But the 1.07 -> 1.09 is not a fix, it's just trying to cover up above mentioned errors a bit better.

Start with fixing the missing CRC. Then errors can be detected reliably and automatically and one can trust the data received is what the firmware wanted to send.
Title: Re: EEVBlog 121GW Discussion thread
Post by: 1anX on March 16, 2018, 10:06:04 pm
What process is UEi and Dave following for firmware releases?
At this point we are basically using the current user base as a testing platform to find and confirm bug fixes. There is nothing better than giving it to a few hundred people and getting feedback. Would current owner prefer we not make interim firmware releases available for testing?

Thanks Dave!

My concern was that in your previous post you stated that the new firmware release fixed the BT data corruption issues. You maybe could have said please test this new release which addresses the BT data corruption issue and provide feedback if any issue remains.

I know it seems pedantic but when you claim that the issue is fixed, we actually believe the issue is fixed!

I worked in a metrology lab for a few years and that required me to be pedantic. Near enough is not good enough  :)
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on March 16, 2018, 10:31:29 pm
My concern was that in your previous post you stated that the new firmware release fixed the BT data corruption issues. You maybe could have said please test this new release which addresses the BT data corruption issue and provide feedback if any issue remains.

Yes, I should have said that, sorry.
From our end it did look like the data corruption UART issue we reported had been fixed, and that seems to be the case.
I know some people are still reporting bluetooth data corruption issues, and this seems to be a different issue than the one we had UEi adress, which was corrupted data output from the UART in the micro.
Please take every release at this stage to mean "we believe it's fixed, please test it and let us know if you find any issues".
Title: Re: EEVBlog 121GW Discussion thread
Post by: Brumby on March 17, 2018, 02:29:06 am
At this point we are basically using the current user base as a testing platform to find and confirm bug fixes. There is nothing better than giving it to a few hundred people and getting feedback.
This is understandable - and very effective - but there will be some who will get their nose out of joint because everything isn't perfect ... including the software revisions.  To those I say this: When a car maker designs and builds a new car, they don't just dump the first models straight from the factory to the showroom.  It goes through a proving ground where issues are identified and dealt with.  For the 121GW - we are that proving ground and we are still in the stage of finding and fixing issues.

From our end it did look like the data corruption UART issue we reported had been fixed, and that seems to be the case.
I know some people are still reporting bluetooth data corruption issues, and this seems to be a different issue than the one we had UEi adress, which was corrupted data output from the UART in the micro.
This is a good example where different problems can have similar looking symptoms - and that the fixing of one problem may not result in a total cure.  For a complete solution, each and every problem needs to be individually identified and addressed.  Where it is stated that one particular problem has been fixed, don't immediately assume the symptoms you have observed should go away and that if they don't, that you are being misled.

Quote
Please take every release at this stage to mean "we believe it's fixed, please test it and let us know if you find any issues".
This.
Title: Re: EEVBlog 121GW Discussion thread
Post by: joeqsmith on March 17, 2018, 03:10:22 am
At this point we are basically using the current user base as a testing platform to find and confirm bug fixes. There is nothing better than giving it to a few hundred people and getting feedback.
This is understandable - and very effective - but there will be some who will get their nose out of joint because everything isn't perfect ... including the software revisions.  To those I say this: When a car maker designs and builds a new car, they don't just dump the first models straight from the factory to the showroom.  It goes through a proving ground where issues are identified and dealt with.  For the 121GW - we are that proving ground and we are still in the stage of finding and fixing issues.
It was not clear to me that people purchasing the meter were expected to be Beta tester's until I had heard Dave mention it during an AmpHour.   I'm sure he must have stated this upfront and I just missed it.   As long as it was made clear, I don't see a problem.  On the other hand, if it wasn't and people were trusting that Dave would not allow it to be sold as a Beta, then maybe that's a problem.  Seems like most in the USA are still waiting, so no concerns other than not meeting their scheduled dates. 
Title: Re: EEVBlog 121GW Discussion thread
Post by: Brumby on March 17, 2018, 03:56:42 am
I must admit that I cannot recall Dave making such a statement (I don't listen to many Amphour episodes) - but it was just my natural expectation for a brand new product having non trivial features.

To me, it is essentially the same as when a new operating system is released.  However much it has been tested and stressed, there are always some issues that show up when a broader user base gets involved.

For the 121GW, I saw this as normal.


(IMO, Dave's best move was getting that micro SD card slot included.  Without that, firmware updates would have been a lot harder for some people.)
Title: Re: EEVBlog 121GW Discussion thread
Post by: dcac on March 17, 2018, 03:07:34 pm
I don’t think anyone is surprised that there was issues still needing to be fixed - but for me beta-testing is a contract you “sign-up” for and really not anything I would “buy into”. Dave never ever used a term like beta-testing in his promotion of the 121GW and I really do not envy those backers who got semi-hassled into it. Also it’s (not) funny with those who are not backers at all having much opinions on what to expect and what not to expect. I’m a JB Goode backer my self but are no longer particularly keen on getting my 121GW delivered, if I now say it’s because I know there will still be issues needing to be fixed - I’m sure the none-backers will tell me - to not be so pessimistic.
Title: Re: EEVBlog 121GW Discussion thread
Post by: 1anX on March 17, 2018, 10:23:11 pm
A one sentence summary would be that the 121GW meter was a good idea poorly implemented!

Hindsight is a wonderful thing, but maybe if Dave ponied up and backed his own idea and design instead of a freebie UEi deal, it may have actually been developed and tested before being released to backers to buy?

The potential for getting a useful meter, (I'm Johnny Be Goode backer) is still high, but the way it has been handled with bugs and switch problems has certainly knocked the gloss of acquiring this meter for me!
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on March 19, 2018, 12:02:16 am
I am not sure why he chose to use the open forums for discussions and bug reporting versus the locked down kick start area.  Maybe he has more control over the content here. 

Kickstarter comments sucks as a place to hold discussion from a technical and usability point of view, but yes, I could have done that and "kept it quiet", but this forum is just a better place to do it, so here it is. If I wanted to "have control" then this whole thread wouldn't even exist, let alone be set as sticky.
But maybe I should have kept it on Kickstarter as those people are the ones vested in it?  :-//
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on March 19, 2018, 12:13:37 am
At this point we are basically using the current user base as a testing platform to find and confirm bug fixes. There is nothing better than giving it to a few hundred people and getting feedback.
This is understandable - and very effective - but there will be some who will get their nose out of joint because everything isn't perfect ... including the software revisions.  To those I say this: When a car maker designs and builds a new car, they don't just dump the first models straight from the factory to the showroom.  It goes through a proving ground where issues are identified and dealt with.  For the 121GW - we are that proving ground and we are still in the stage of finding and fixing issues.

We didn't want that to be the case of course, but we've been essentially forced into this situation with the unexpected problems that have popped up.
And by "forced into" I mean it's basically the best way forward at this point for all involved.
The best way to get issues found is by having as many people as possible use the meter and provide feedback as possible. Given that we have like 200 or something meters out there in the field now, it just makes sense to at least ask these owners to try new firmware and continue to provide feedback before we ship 2000 of them. They don't have to of course, they can stick with the firmware they have got.
But ultimately any new firmware on a reasonably complex product like this is going to have issues that will take time to sort out.

BTW, David in his testing has found a couple of more unreported issues that are currently being looked into, hence more delays unfortunately.
Title: Re: EEVBlog 121GW Discussion thread
Post by: The Soulman on March 19, 2018, 12:24:58 am
At this point we are basically using the current user base as a testing platform to find and confirm bug fixes. There is nothing better than giving it to a few hundred people and getting feedback.
This is understandable - and very effective - but there will be some who will get their nose out of joint because everything isn't perfect ... including the software revisions.  To those I say this: When a car maker designs and builds a new car, they don't just dump the first models straight from the factory to the showroom.  It goes through a proving ground where issues are identified and dealt with.  For the 121GW - we are that proving ground and we are still in the stage of finding and fixing issues.

We didn't want that to be the case of course, but we've been essentially forced into this situation with the unexpected problems that have popped up.
And by "forced into" I mean it's basically the best way forward at this point for all involved.
The best way to get issues found is by having as many people as possible use the meter and provide feedback as possible. Given that we have like 200 or something meters out there in the field now, it just makes sense to at least ask these owners to try new firmware and continue to provide feedback before we ship 2000 of them. They don't have to of course, they can stick with the firmware they have got.
But ultimately any new firmware on a reasonably complex product like this is going to have issues that will take time to sort out.

BTW, David in his testing has found a couple of more unreported issues that are currently being looked into, hence more delays unfortunately.

Those 2000 get the updated hardware (switch..) right?
What about the meters stuck at the harbor, are these unstuck yet?
What about selling these to "qualified" (those that are aware of what they are getting themselves into) beta testers?
Title: Re: EEVBlog 121GW Discussion thread
Post by: Brumby on March 19, 2018, 09:18:09 am
At this point we are basically using the current user base as a testing platform to find and confirm bug fixes. There is nothing better than giving it to a few hundred people and getting feedback.
This is understandable - and very effective - but there will be some who will get their nose out of joint because everything isn't perfect ... including the software revisions.  To those I say this: When a car maker designs and builds a new car, they don't just dump the first models straight from the factory to the showroom.  It goes through a proving ground where issues are identified and dealt with.  For the 121GW - we are that proving ground and we are still in the stage of finding and fixing issues.

We didn't want that to be the case of course, but we've been essentially forced into this situation with the unexpected problems that have popped up.
And by "forced into" I mean it's basically the best way forward at this point for all involved.

I have no doubt at all you didn't want to have to be in this position - but it seems fairly clear that the testing phase has been poorly executed.  Where that fell short will be a lesson for future benefit.  For now, the best effort is in sorting it out.

I will say that if the 121GW had hit the deck with no significant issues, I would have been truly impressed - but the number of issues detailed so far has been a bit of a surprise.  What I expected to be a bit of "fine tuning" has turned into a significant exercise.  I think Dave would have had a similar expectation.


There is no question, however, that the way forward has been defined by the situation.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Brumby on March 19, 2018, 09:55:51 am
A one sentence summary would be that the 121GW meter was a good idea poorly implemented!
I understand where you are coming from, but I would call that a bit harsh.  I would call that a "consumer" comment, not an "engineer" one.

Quote
Hindsight is a wonderful thing, but maybe if Dave ponied up and backed his own idea and design instead of a freebie UEi deal, it may have actually been developed and tested before being released to backers to buy?
There are a lot of factors in producing any item and I sincerely doubt Dave would have been able to bring this product to life without UEI's contribution.  Certainly, there has been an issue with the testing and that is the only criticism I have - but Dave probably didn't do himself any favours by having the development so highly visible.  The interest and yearning from so many members no doubt added a lot of pressure to get the product out.

Quote
The potential for getting a useful meter, (I'm Johnny Be Goode backer) is still high, but the way it has been handled with bugs and switch problems has certainly knocked the gloss of acquiring this meter for me!
I am quite the opposite.  Having seen the effort being put in, I am becoming more engaged.  The gloss is increasing!
Title: Re: EEVBlog 121GW Discussion thread
Post by: IanB on March 19, 2018, 10:08:41 am
I will say that if the 121GW had hit the deck with no significant issues, I would have been truly impressed - but the number of issues detailed so far has been a bit of a surprise.  What I expected to be a bit of "fine tuning" has turned into a significant exercise.  I think Dave would have had a similar expectation.

This is, IHMO, a sign of the times and an indication of the state of business and commerce today. Costs are being driven down, work is being outsourced, complicated tasks are being assigned to the young and inexperienced.

As far as the 121GW is concerned, I bet the hardware has far fewer issues than the software. It's because software design is not recognized as challenging problem requiring deep expertise, and software then gets written by "coders" instead of engineers. The word "coding" should be removed from the dictionary.

I am sure we have all experienced web sites and phone apps that are simply buggy, broken and unpredictable in use. It's all symptomatic of the same general trend.

Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on March 19, 2018, 10:31:09 am
As far as the 121GW is concerned, I bet the hardware has far fewer issues than the software. It's because software design is not recognized as challenging problem requiring deep expertise, and software then gets written by "coders" instead of engineers. The word "coding" should be removed from the dictionary.

The 121GW has an extra layer complexity in the chipset, which has crazy amounts of configurability and modes etc. UEi had to recently go to Hycontech to ask their advice on some things for example.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on March 19, 2018, 10:32:58 am
Dave probably didn't do himself any favours by having the development so highly visible. 

Yep, I'm not very smart  :palm:
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on March 19, 2018, 10:34:51 am
Those 2000 get the updated hardware (switch..) right?
[\quote]

Yes.

Quote
What about the meters stuck at the harbor, are these unstuck yet?

Yep, all finally unstuck.

Quote
What about selling these to "qualified" (those that are aware of what they are getting themselves into) beta testers?

I'd rather not, we already have enough keen people out there testing I think.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Brumby on March 19, 2018, 11:53:53 am
Dave probably didn't do himself any favours by having the development so highly visible. 

Yep, I'm not very smart  :palm:

I wouldn't say that.  Doing the 121GW was an exciting project.  Sharing it was mandatory!

What I will say is that, having been a member of the 121GW Voyeurs Club, I have a much greater "connection" to the 121GW than I do to any other meter ... and I haven't even ordered one yet!

I don't have a big problem with the issues at hand - just as long as they are addressed.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Brumby on March 19, 2018, 12:07:36 pm
Sure.  Play that card if you must, but even if I did have a 121GW in front of me right now, my answer would be the same.

I have means to make measurement with other gear I have.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Iagash on March 19, 2018, 12:26:50 pm
Well. I don't have an issue with the issues too. But I have a bit of an issue on how the issues are addressed.

Dave and Seppy know about the invalid bluetooth records. They worked around them in their app. But instead of asking UEI to include some checksum or CRC in the records, they decided on guessing if the data could be valid and try to suppress records in the application, that look wrong.

If you use your phone for logging and send yourself the logfile, you can see that also their app fails at guessing always correctly. You mostly don't see it on the phone display, as you don't look constantly at it and miss the occasional wrong value, but it's in the log of the app.

I can understand, that finding the cause of the errors might be hard, but adding a CRC to the records is a no-brainer and around 30 lines of code.

That's the part I don't understand.
Title: Re: EEVBlog 121GW Discussion thread
Post by: FrankBuss on March 19, 2018, 12:55:41 pm
At this point we are basically using the current user base as a testing platform to find and confirm bug fixes. There is nothing better than giving it to a few hundred people and getting feedback.

This is fine, but please "fix" things and don't "cover up".

The bluetooth transmission is broken by design and by implementation.
  • There is no data integrity, aka. CRC or something on records (design error)
  • The ASCII decimal/hex coding wastes more then 2/3 of the already scarce bluetooth bandwidth (design error)
  • You have to check every single byte received for plausibility (and you'll fail in a lot of cases) (implementation error)
  • If you look at the errors in the data it's clear that some buffer in the firmware get's overwritten (implementation error)

Would current owner prefer we not make interim firmware releases available for testing?

I'm fine with testing, no problem.

But the 1.07 -> 1.09 is not a fix, it's just trying to cover up above mentioned errors a bit better.

Start with fixing the missing CRC. Then errors can be detected reliably and automatically and one can trust the data received is what the firmware wanted to send.

No need to implement CRC, because BLE has this already integrated on the lower levels and automatically resends packets, if they are wrong, so no need to implement it on the data layer. Usually you can be sure that the transmitted data is right, so it must be another problem.

I personally tested a Blue Gecko chip from Silicon Labs with BLE and at the application level only the packet rate drops when I increase the distance. Here are some numbers where the device was sending 20 byte packets with max speed, which I recorded with a Python script :

Code: [Select]

measuring in 1 m distance:

number of packets: 348697
transfer time: 255 s
lost packets: 0
average transfer rate: 27310 bytes per second
max delay between two packets: 79.6 ms
min delay between two packets: 0.0 ms

measuring in 7m distance, with 2 walls in between:

number of packets: 265549
transfer time: 331 s
lost packets: 0
average transfer rate: 16044 bytes per second
max delay between two packets: 284.1 ms
min delay between two packets: 0.0 ms

This was with a standard BLE dongle on a PC, which identifies in Linux as this with lsusb:

Code: [Select]
Bus 001 Device 012: ID 0a12:0001 Cambridge Silicon Radio, Ltd Bluetooth Dongle (HCI mode)

I implemented the nRF UART protocol on the BLE chip for easier testing, as described here:

https://www.silabs.com/community/wireless/bluetooth/forum.topic.html/how_to_implementuar-ovZ7 (https://www.silabs.com/community/wireless/bluetooth/forum.topic.html/how_to_implementuar-ovZ7)

Because I really don't like all the complexity of BLE, give me just a reliable UART link, which works for me now. Maybe UEI should hire me to fix their bluetooth implementation :)

Here is the Python script which received the data on the PC:

Code: [Select]
import struct
from bluepy.btle import *

# callback class
class MyDelegate(DefaultDelegate):
    def __init__(self):
        DefaultDelegate.__init__(self)

    def handleNotification(self, cHandle, data):
        print(data)

# connect to device
per = Peripheral("00:0B:57:1D:B3:93", "public")

try:
    # set callback for notifications
    per.setDelegate(MyDelegate())

    # enable notification
    setup_data = b"\x01\x00"
    notify = per.getCharacteristics(uuid='6e400003-b5a3-f393-e0a9-e50e24dcca9e')[0]
    notify_handle = notify.getHandle() + 1
    per.writeCharacteristic(notify_handle, setup_data, withResponse=True)
   
    # send test string
    c = per.getCharacteristics(uuid='6e400002-b5a3-f393-e0a9-e50e24dcca9e')[0]
    c.write("Hello Gecko")
   
    # wait for answer
    while True:
        if per.waitForNotifications(1.0):
            continue
finally:
    per.disconnect()

And here is the Python script which evaluated the received data to create the statistics:

Code: [Select]
#!/usr/bin/python

import sys

filename = sys.argv[1]

# statistic variables
count = 0
lastPacketNumber = 0
lastTimestamp = 0
deltaSum = 0
maxDelta = 0
minDelta = 1e9
packetsLost = 0
absoluteTimestamp = 0

# read file and calculate statistics
with open(filename, "r") as ins:
    for line in ins:
        values = line.split(";")
        packetNumber = int(values[0])
        timestamp = int(values[1])
        delta = timestamp - lastTimestamp
        if count > 0:
            if timestamp < lastTimestamp:
                delta = 32768 - lastTimestamp + timestamp
            if delta > maxDelta:
                maxDelta = delta
            if delta < minDelta:
                minDelta = delta
            absoluteTimestamp = absoluteTimestamp + delta
            if packetNumber - lastPacketNumber > 1:
                packetsLost = packetsLost + packetNumber - lastPacketNumber - 1
        lastPacketNumber = packetNumber
        lastTimestamp = timestamp
        count = count + 1

# format milliseconds with suffix and one digit after the comma
def formatMs(ms):
    return "{:.1f} ms".format(ms)

# convert ticks to seconds   
def ticksToS(tick):
    return float(tick) / 32768.0

# convert ticks to miliiseconds
def ticksToMs(tick):
    return ticksToS(tick) * 1000.0

# calculate some more statistics
transferTimeInSeconds = ticksToS(absoluteTimestamp)
bytesTransfered = count * 20
bytesPerSecond = float(bytesTransfered) / transferTimeInSeconds

# show result
print("number of packets: %d" % (count))
print("transfer time: %d s" % (int(transferTimeInSeconds)))
print("lost packets: %d" % (packetsLost))
print("average transfer rate: %d bytes per second" % (int(bytesPerSecond)))
print("max delay between two packets: " + formatMs(ticksToMs(maxDelta)))
print("min delay between two packets: " + formatMs(ticksToMs(minDelta)))
Title: Re: EEVBlog 121GW Discussion thread
Post by: Iagash on March 19, 2018, 02:15:09 pm
No need to implement CRC, because BLE has this already integrated on the lower levels and automatically resends packets, if they are wrong, so no need to implement it on the data layer. Usually you can be sure that the transmitted data is right, so it must be another problem.

Yes I know. I checked the BLE spec.

The problem is with the firmware communicating with the BLE-module and the guesswork seems to be in the App since last August. So they seem to know since some time.
Title: Re: EEVBlog 121GW Discussion thread
Post by: FrankBuss on March 19, 2018, 03:52:22 pm
No need to implement CRC, because BLE has this already integrated on the lower levels and automatically resends packets, if they are wrong, so no need to implement it on the data layer. Usually you can be sure that the transmitted data is right, so it must be another problem.

Yes I know. I checked the BLE spec.

The problem is with the firmware communicating with the BLE-module and the guesswork seems to be in the App since last August. So they seem to know since some time.

Ok, but why did you write that the protocol is broken without some sort of data integrity like CRC? Even industry standard protocols like SCPI (which would be nice to have in the multimeter) don't have integrated checksums, but it is implemented in the lower levels as TCP/IP (don't know if GPIB has a checksum).
Title: Re: EEVBlog 121GW Discussion thread
Post by: Iagash on March 19, 2018, 04:01:41 pm
Ok, but why did you write that the protocol is broken without some sort of data integrity like CRC? Even industry standard protocols like SCPI (which would be nice to have in the multimeter) don't have integrated checksums, but it is implemented in the lower levels as TCP/IP (don't know if GPIB has a checksum).

Since the serial communication between the BLE module and the CPU is not protected and obviously unreliable.
I guess it's hard to impossible to add protection to the BLE-module, so just make it end-to-end.

It's cheap and easy and you're set.
Title: Re: EEVBlog 121GW Discussion thread
Post by: FrankBuss on March 19, 2018, 08:50:45 pm
Since the serial communication between the BLE module and the CPU is not protected and obviously unreliable.
I guess it's hard to impossible to add protection to the BLE-module, so just make it end-to-end.

It's cheap and easy and you're set.

This would be a bad patch, and if it is a problem in the firmware before the checksum is calculated, it wouldn't even help. But Dave wrote that one data corruption UART issue was fixed. Would be better to find all issues instead of trying to program workarounds. A few cm PCB trace UART with the typical baud rate that these chips uses, can't have transfer errors. But there can be interesting problems, if you don't set the interrupt priorities right, if you receive data over UART, or if you don't implement flow control right, if the BLE module needs this, like RTS/CTS or XON/XOFF.
Title: Re: EEVBlog 121GW Discussion thread
Post by: 1anX on March 19, 2018, 09:06:25 pm
A one sentence summary would be that the 121GW meter was a good idea poorly implemented!
I understand where you are coming from, but I would call that a bit harsh.  I would call that a "consumer" comment, not an "engineer" one.

I would call my comment accurate!

The concept for this meter has a lot of merit and those of us that have placed our order understand what the specification will provide us with as users. Then to have the "production meter" released to backers with an out of spec switch that suffers from intermittent contact is pretty much unacceptable in 2018. Even the cheapest of multimeters have reliable switches and the 121GW is not a cheap meter.

The implementation of the meter with a chipset that both Daves and UEi combined dont understand fully was risky. It was risky for the users as its their money that could have been spent on a comparable reliable meter with a fully functioning switch and mature firmware.

Finally as you, (Brumby) like car and car manufacturing metaphors, here is one to consider. Thank god UEi and the 2 Daves dont use the "lets get everyone involved to test it in the real world" concept for developing and fixing the bugs in self driving cars for our public roads  :)

Having said all of the above and meaning it, I would also like to add that I am confident that eventually the meter will evolve into and match its concept. It was and is simply a "poor implementation", lets face it, the current meter is nothing more than a prototype.
 
Title: Re: EEVBlog 121GW Discussion thread
Post by: Iagash on March 19, 2018, 10:13:16 pm
This would be a bad patch, and if it is a problem in the firmware before the checksum is calculated, it wouldn't even help.

But Dave wrote that one data corruption UART issue was fixed. Would be better to find all issues instead of trying to program workarounds.

Well, yes, you're right.

But considering the bug is there and known since last August, how do you calculate the chances that they'll find it, fix it and get it right?

The CRC is one or two man hours at UEI and one for Seppy in the app, that's worth less than two meters and you don't need to guess the data.
Title: Re: EEVBlog 121GW Discussion thread
Post by: glarsson on March 19, 2018, 11:21:06 pm
I would prefer that the bug is fixed (and get all data points) rather than just made the corruption detectable with the help of CRC (and lose data points).
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on March 20, 2018, 01:14:12 am
No need to implement CRC, because BLE has this already integrated on the lower levels and automatically resends packets, if they are wrong, so no need to implement it on the data layer. Usually you can be sure that the transmitted data is right, so it must be another problem.

Yes I know. I checked the BLE spec.

The problem is with the firmware communicating with the BLE-module and the guesswork seems to be in the App since last August. So they seem to know since some time.

The firmware and packet DOES have a XOR based checksum at the end.
Our software does multiple things to check for bad packets, but if a packet is not received in full for whatever bluetoothy reason, it might be hard to recover from that unless you do lots of stuff. David's app for example using a voting system among other things to handle non-fully received packets.
We are looking into this improving the packet protocol.
Title: Re: EEVBlog 121GW Discussion thread
Post by: nidlaX on March 20, 2018, 01:17:53 am
No need to implement CRC, because BLE has this already integrated on the lower levels and automatically resends packets, if they are wrong, so no need to implement it on the data layer. Usually you can be sure that the transmitted data is right, so it must be another problem.

Yes I know. I checked the BLE spec.

The problem is with the firmware communicating with the BLE-module and the guesswork seems to be in the App since last August. So they seem to know since some time.

The firmware and packet DOES have a XOR based checksum at the end.
Our software does multiple things to check for bad packets, but if a packet is not received in full for whatever bluetoothy reason, it might be hard to recover from that unless you do lots of stuff. David's app for example using a voting system among other things to handle non-fully received packets.
We are looking into this improving the packet protocol.
It would be useful if the user could receive some feedback regarding incomplete / lost packets in the app.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Iagash on March 20, 2018, 10:12:38 am
The firmware and packet DOES have a XOR based checksum at the end.
Thanks!

But I guess you won't tell me how it is calculated or why it doesn't seem to be used in your app. At least I can't find it.

What I find concerning data validation is this:
Code: [Select]
static bool is_valid(string input) {
       if (input.Length != 52)
                 return false;
       foreach (var c in input)             {
              if (!(Char.IsDigit(c) || Char.IsLetter(c)))
                     return false;
      }
      return true;
}
David's app for example using a voting system among other things to handle non-fully received packets.

Yeah, the data sometimes looks like the result of some democratic process.  :-DD

We are looking into this improving the packet protocol.

Thanks, I'm very much looking forward to this.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on March 20, 2018, 11:35:42 am
But I guess you won't tell me how it is calculated or why it doesn't seem to be used in your app. At least I can't find it.

Not yet, because there is a chance it might change soon.
As for use in the app, only David can answer that.
The github code is not up to date either.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on March 20, 2018, 11:45:04 am
The implementation of the meter with a chipset that both Daves and UEi combined dont understand fully was risky. It was risky for the users as its their money that could have been spent on a comparable reliable meter with a fully functioning switch and mature firmware.

Even the big names like Keysight, Fluke, Gossen, Extech etc have all released meters that are less than perfect and have had a range of issues from hardware to software, lost calibration data in updates, bricking, to safety. If you've been watching my videos for a long time you'd know that. One of them almost killed or injured me due to a design flaw. These were all "reliable" released meters from huge reputable names.
I was just talking to one of them the other day commenting on the issues we've unfortunately been having, and they laughed and said they have had much more embarrassing problems in released products. Shit happens.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Elasia on March 20, 2018, 07:17:47 pm
The implementation of the meter with a chipset that both Daves and UEi combined dont understand fully was risky. It was risky for the users as its their money that could have been spent on a comparable reliable meter with a fully functioning switch and mature firmware.

Even the big names like Keysight, Fluke, Gossen, Extech etc have all released meters that are less than perfect and have had a range of issues from hardware to software, lost calibration data in updates, bricking, to safety. If you've been watching my videos for a long time you'd know that. One of them almost killed or injured me due to a design flaw. These were all "reliable" released meters from huge reputable names.
I was just talking to one of them the other day commenting on the issues we've unfortunately been having, and they laughed and said they have had much more embarrassing problems in released products. Shit happens.


The first microcontroller bootloader I made eons ago had a nasty flaw of bricking the chip due to brown outs causing code execution jumping into the bootloader code to erase the device!  Oppps

Wasnt that hard to fix with the addition of a reset chip and also by keying the erase code to needing unlock values not stored in the device itself but still... talk about egg on face!
Title: Re: EEVBlog 121GW Discussion thread
Post by: 1anX on March 20, 2018, 09:09:07 pm
The implementation of the meter with a chipset that both Daves and UEi combined dont understand fully was risky. It was risky for the users as its their money that could have been spent on a comparable reliable meter with a fully functioning switch and mature firmware.

Even the big names like Keysight, Fluke, Gossen, Extech etc have all released meters that are less than perfect and have had a range of issues from hardware to software, lost calibration data in updates, bricking, to safety. If you've been watching my videos for a long time you'd know that. One of them almost killed or injured me due to a design flaw. These were all "reliable" released meters from huge reputable names.
I was just talking to one of them the other day commenting on the issues we've unfortunately been having, and they laughed and said they have had much more embarrassing problems in released products. Shit happens.

Well after criticizing the 121 GW for faulty switches and patches that were apparently poorly tested and then released as "production quality" I had an interesting purchase yesterday.

I purchased 3 Garmin 55 Dash Cams ($240ea) from Harvey Norman. Got home attached my power supply to the cam's charger and went thru setup and testing them. Cut a long story short, only 2 out of the 3 worked correctly. Two of these brand new units would not hold their setup data and would not write it to memory. This meant that every time the cam would power up, 20 or so button presses would be needed to get it to operate.

They will all be returned to HN today for a refund!

Garmin released a device that obviously was untested before being shipped out to sell and looking on a garmin forum it seems that the setup data failure is pretty widespread across the world. The Garmin 55 is an evolved product not a new design, so as you say Dave, shit happens and point taken!

Update!
The guy at HN this morning arranging the refund told me that he is on his 3rd iPhone X, as the previous 2 had charging and battery problems, he now wants it replaced with the iPhone Plus!
Title: Re: EEVBlog 121GW Discussion thread
Post by: imidis on March 20, 2018, 09:38:02 pm
I don't have a 121GW or own one. However, many large corporations put out bug ridden and poorly built items. I think the big difference between them and Dave, is Dave cares. Instead of brushing things under the rug, ignoring or hiding them, avoiding any responsibility like so many companies do.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Elasia on March 20, 2018, 10:15:10 pm
I don't have a 121GW or own one. However, many large corporations put out bug ridden and poorly built items. I think the big difference between them and Dave, is Dave cares. Instead of brushing things under the rug, ignoring or hiding them, avoiding any responsibility like so many companies do.

Not just large... you got a ton of hacks out there too due to companies just flat out either not understanding risk control around software or even ones that do and just dont give 2 cents... the medical device land is just littered with them and is absurd.  A lot of sectors could learn a thing or two from the avionics industry... probably the best group to have their shit together

I've mostly used agilent portable dmms but i think my next one will be a 121GW if there is a 2nd gen.. i do like the idea of it but late to the party this round
Title: Re: EEVBlog 121GW Discussion thread
Post by: lukasz.kostka on March 21, 2018, 02:23:29 pm
Hi.

Is there any chance for new batch of 121GW ? I see that it is out of stock.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Brumby on March 21, 2018, 03:56:16 pm
Dave still has a couple of thousand 121GW to deliver from his extremely successful Kickstarter campaign.  That needs to be fulfilled before any consideration can be given to him getting them "in stock" in his EEVblog store.

There was a delay from parts shortages earlier this year - and I don't know if they have been resolved or where that manufacturing is up to.  We do know the mechanical issue with the range switch has been sorted out, but considering the other problems at the moment, it is possible there may be some reservation about forging ahead with a mass run, just in case there needs to be a hardware revision.   << PLEASE NOTE, I am only guessing here. >>   If it is found these problems can be completely eliminated with firmware updates, then I would expect production to get up to speed at the earliest opportunity ... but Dave is the best person to give clear answers here.
Title: Re: EEVBlog 121GW Discussion thread
Post by: lukasz.kostka on March 21, 2018, 03:59:20 pm
Thx.

Do you know if there is any channel / information source that I can subscribe to see when multimeters will be available ?
Title: Re: EEVBlog 121GW Discussion thread
Post by: Brumby on March 21, 2018, 04:09:40 pm
I believe Dave does Twitter - @eevblog .  I'd be pretty confident he would tweet about that.

(Sorry, I don't do Twitter.)


You could also check in here for updates, as you have.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Worsdier on March 21, 2018, 04:28:44 pm
Hi.

Is there any chance for new batch of 121GW ? I see that it is out of stock.

I’m afraid you still have a long time to wait for stock. I backed one of the first 400 meters and it’s been 4 months overdue.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on March 22, 2018, 12:32:49 am
Thx.

Do you know if there is any channel / information source that I can subscribe to see when multimeters will be available ?

Sign up for the newsletter
http://www.eevblog.com/newsletter/ (http://www.eevblog.com/newsletter/)

Many people still ask, and I don't know why people seaming don't quite understand that I have to deliver the Kickstarter units first before I sell to the general public.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Seppy on March 22, 2018, 03:27:37 am
At this point we are basically using the current user base as a testing platform to find and confirm bug fixes. There is nothing better than giving it to a few hundred people and getting feedback.

This is fine, but please "fix" things and don't "cover up".

The bluetooth transmission is broken by design and by implementation.
  • There is no data integrity, aka. CRC or something on records (design error)
  • The ASCII decimal/hex coding wastes more then 2/3 of the already scarce bluetooth bandwidth (design error)
  • You have to check every single byte received for plausibility (and you'll fail in a lot of cases) (implementation error)
  • If you look at the errors in the data it's clear that some buffer in the firmware get's overwritten (implementation error)

Would current owner prefer we not make interim firmware releases available for testing?

I'm fine with testing, no problem.

But the 1.07 -> 1.09 is not a fix, it's just trying to cover up above mentioned errors a bit better.

Start with fixing the missing CRC. Then errors can be detected reliably and automatically and one can trust the data received is what the firmware wanted to send.

As stated before there was actually a checksum. What was happening was the OS was dropping half the packet on some systems, we compacted the packet so that it fits into 19 bytes.

This means that the XOR checksum now reliably makes it into the transmission. There is an update to the multimeter App and firmware that improves the situation greatly but further testing is needed. If anybody needs help developing a script to read the packet feel free to contact me.

The BLE packet format is now in a document on the 121GW product page.

If you install version 1.10 of the firmware you will also need to update the app.
You can do that on the Google Play / Window Store, (at least when they approve the update).

Links for the mentioned documents and firmware can be found at:
https://www.eevblog.com/product/121gw/ (https://www.eevblog.com/product/121gw/)
Title: Re: EEVBlog 121GW Discussion thread
Post by: Fungus on March 22, 2018, 06:28:16 am
Thx.

Do you know if there is any channel / information source that I can subscribe to see when multimeters will be available ?

Go here and search for "121G":

https://www.oreillyauto.com/ (https://www.oreillyauto.com/)

Title: Re: EEVBlog 121GW Discussion thread
Post by: Iagash on March 22, 2018, 01:30:42 pm
If you install version 1.10 of the firmware you will also need to update the app.
You can do that on the Google Play / Window Store, (at least when they approve the update).

Thanks, first check findings:

The values displayed in VA mode by the app are still wrong:
meter displays (correctly, verified with other meter): 1966.2mVA DC, 4.3672V, 450.29 mA
app displays: 1966.2mVA DC, 2.1863V, 204.52 A

If I change the input to the meter for negative current, the meter displays the negative current correctly, but the app still displays the same wrong positive current.

So the the values are off around factor 2x, current displays A instead of mA.

This is DC mode, firmware 1.10, app version 5

The update rate is much higher now, thanks!

I'll check the documents and update my script and let you know what I find there.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Iagash on March 22, 2018, 04:03:35 pm
If I change the input to the meter for negative current, the meter displays the negative current correctly, but the app still displays the same wrong positive current.

This is a bug in your app, Seppy. I get the correct sign value for the sub-display via bluetooth.

Longterm log is now running.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Elasia on March 22, 2018, 07:05:28 pm
Thx.

Do you know if there is any channel / information source that I can subscribe to see when multimeters will be available ?

Sign up for the newsletter
http://www.eevblog.com/newsletter/ (http://www.eevblog.com/newsletter/)

Many people still ask, and I don't know why people seaming don't quite understand that I have to deliver the Kickstarter units first before I sell to the general public.

Simple... because its shiny!  .....  Squirrel!  That and they most likely don't comprehend your order book nor mass production and distribution of custom small batch electronics.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Iagash on March 22, 2018, 09:10:07 pm
Ok, Version 1.10 is definitely a step forward but it still contains errors despite a correct checksum.

There is a pattern, when switching the second display from current to voltage in DC VA-mode the decimal point is wrong:
Code: [Select]
--
1521739280.909 2023-08 02342    Power DC (VA)  1966.3 mVA       DCA  205.12    0% f:  5%
1521739281.179 2023-08 02342    Power DC (VA)  1966.3 mVA       DCV  21.863    0% f:  5%
1521739281.517 2023-08 02342    Power DC (VA)  1966.3 mVA       DCV  2.1863    0% f:  5%
--
1521739349.017 2023-08 02342    Power DC (VA)  1967.2 mVA       DCA  204.99    0% f:  5%
1521739349.287 2023-08 02342    Power DC (VA)  1967.2 mVA       DCV  21.855    0% f:  5%
1521739349.557 2023-08 02342    Power DC (VA)  1967.2 mVA       DCV  2.1855    0% f:  5%
--
1521739615.442 2023-08 02342    Power DC (VA)  1966.9 mVA       DCA  204.99    0% f:  5%
1521739615.712 2023-08 02342    Power DC (VA)  1966.9 mVA       DCV  21.862    0% f:  5%
1521739615.914 2023-08 02342    Power DC (VA)  1967.1 mVA       DCV  2.1862    0% f:  5%
--

But sometimes it stays wrong:
Code: [Select]
--
1521741169.774 2023-08 02342    Power DC (VA)  1966.2 mVA       DCA  205.10    0% f:  5%
1521741170.044 2023-08 02342    Power DC (VA)  1966.3 mVA       DCV  21.866    0% f:  5%
1521741170.584 2023-08 02342    Power DC (VA)  1966.3 mVA       DCV  21.866    0% f:  5%
1521741170.854 2023-08 02342    Power DC (VA)  1966.3 mVA       DCV  21.866    0% f:  5%
1521741171.192 2023-08 02342    Power DC (VA)  1966.3 mVA       DCV  21.866    0% f:  5%
1521741171.327 2023-08 02342    Power DC (VA)  1966.3 mVA       DCV  21.866    0% f:  5%
1521741171.597 2023-08 02342    Power DC (VA)  1966.7 mVA       DCV  21.857    0% f:  5%
1521741171.799 2023-08 02342    Power DC (VA)  1966.7 mVA       DCV  21.857    0% f:  5%
1521741172.070 2023-08 02342    Power DC (VA)  1966.7 mVA       DCV  21.857    0% f:  5%
1521741172.272 2023-08 02342    Power DC (VA)  1966.7 mVA       DCV  21.857    0% f:  5%
1521741172.541 2023-08 02342    Power DC (VA)  1966.7 mVA       DCV  21.857    0% f:  5%
1521741172.880 2023-08 02342    Power DC (VA)  1966.7 mVA       DCV  21.857    0% f:  5%
1521741173.352 2023-08 02342    Power DC (VA)  1966.7 mVA       DCA  205.09    0% f:  5%
--

Sometimes I even get a wrong mode:
Code: [Select]
--
1521743502.116 2023-08 02342    Power DC (VA)  1968.8 mVA       DCA  204.66    0% f:  5%
1521743502.589 2000-00 00040 Voltage LowZ (V) -0.61975 V    48% f:  5%
1521743502.859 2023-08 02342    Power DC (VA)  1968.7 mVA       DCA  204.66    0% f:  5%
--

I collected arround 44k log records around 2k2 or 5% have a wrong checksum.

From the remaning 42k loglines with correct checksum 155 are broken, having either a wrong mode (66) a wrong decimal point(87) and 2 have some other parse error.
Title: Re: EEVBlog 121GW Discussion thread
Post by: HKJ on March 22, 2018, 09:16:10 pm
From the remaning 42k loglines with correct checksum 155 are broken

A XOR is not guaranteed to catch more than one byte errors, once in a while a multi byte error will slip through.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Iagash on March 22, 2018, 09:43:35 pm
Another error:

The bargraph display in the app doesn't match the display on the meter.
I also get "strange" values via bluetooth, but the document about the BLE format doesn't describe how the values should be interpreted and the gitlab repo of the app is not uptodate.

I question the sending of the bargraph data via BLE at all, since the bargraph is meant for fast updates, which seems useless to me via BLE with 4-5 updates per second we see now.

I would prefer if the meter would send the values it has but doesn't display on the meter, like temperature and sending always current and voltage in VA mode.
But this is not a bug, more a question of preference and usage.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Iagash on March 22, 2018, 10:08:57 pm
From the remaning 42k loglines with correct checksum 155 are broken

A XOR is not guaranteed to catch more than one byte errors, once in a while a multi byte error will slip through.

Yes of course, but I'm still very glad to be able to throw out the guessing of digits.
The remaining errors can be found quite easily by checking the log lines with grep and awk.

The goal would be getting flow-control right between the CPU and the BLE module, then even no checksum would be needed as FrankBuss pointed out.

The errors with the decimal point are probably another bug in the firmware that has nothing to do with the wrong checksums.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Seppy on March 23, 2018, 12:32:16 am
Ok, Version 1.10 is definitely a step forward but it still contains errors despite a correct checksum.

There is a pattern, when switching the second display from current to voltage in DC VA-mode the decimal point is wrong:
Code: [Select]
--
1521739280.909 2023-08 02342    Power DC (VA)  1966.3 mVA       DCA  205.12    0% f:  5%
1521739281.179 2023-08 02342    Power DC (VA)  1966.3 mVA       DCV  21.863    0% f:  5%
1521739281.517 2023-08 02342    Power DC (VA)  1966.3 mVA       DCV  2.1863    0% f:  5%
--
1521739349.017 2023-08 02342    Power DC (VA)  1967.2 mVA       DCA  204.99    0% f:  5%
1521739349.287 2023-08 02342    Power DC (VA)  1967.2 mVA       DCV  21.855    0% f:  5%
1521739349.557 2023-08 02342    Power DC (VA)  1967.2 mVA       DCV  2.1855    0% f:  5%
--
1521739615.442 2023-08 02342    Power DC (VA)  1966.9 mVA       DCA  204.99    0% f:  5%
1521739615.712 2023-08 02342    Power DC (VA)  1966.9 mVA       DCV  21.862    0% f:  5%
1521739615.914 2023-08 02342    Power DC (VA)  1967.1 mVA       DCV  2.1862    0% f:  5%
--

But sometimes it stays wrong:
Code: [Select]
--
1521741169.774 2023-08 02342    Power DC (VA)  1966.2 mVA       DCA  205.10    0% f:  5%
1521741170.044 2023-08 02342    Power DC (VA)  1966.3 mVA       DCV  21.866    0% f:  5%
1521741170.584 2023-08 02342    Power DC (VA)  1966.3 mVA       DCV  21.866    0% f:  5%
1521741170.854 2023-08 02342    Power DC (VA)  1966.3 mVA       DCV  21.866    0% f:  5%
1521741171.192 2023-08 02342    Power DC (VA)  1966.3 mVA       DCV  21.866    0% f:  5%
1521741171.327 2023-08 02342    Power DC (VA)  1966.3 mVA       DCV  21.866    0% f:  5%
1521741171.597 2023-08 02342    Power DC (VA)  1966.7 mVA       DCV  21.857    0% f:  5%
1521741171.799 2023-08 02342    Power DC (VA)  1966.7 mVA       DCV  21.857    0% f:  5%
1521741172.070 2023-08 02342    Power DC (VA)  1966.7 mVA       DCV  21.857    0% f:  5%
1521741172.272 2023-08 02342    Power DC (VA)  1966.7 mVA       DCV  21.857    0% f:  5%
1521741172.541 2023-08 02342    Power DC (VA)  1966.7 mVA       DCV  21.857    0% f:  5%
1521741172.880 2023-08 02342    Power DC (VA)  1966.7 mVA       DCV  21.857    0% f:  5%
1521741173.352 2023-08 02342    Power DC (VA)  1966.7 mVA       DCA  205.09    0% f:  5%
--

Sometimes I even get a wrong mode:
Code: [Select]
--
1521743502.116 2023-08 02342    Power DC (VA)  1968.8 mVA       DCA  204.66    0% f:  5%
1521743502.589 2000-00 00040 Voltage LowZ (V) -0.61975 V    48% f:  5%
1521743502.859 2023-08 02342    Power DC (VA)  1968.7 mVA       DCA  204.66    0% f:  5%
--

I collected arround 44k log records around 2k2 or 5% have a wrong checksum.

From the remaning 42k loglines with correct checksum 155 are broken, having either a wrong mode (66) a wrong decimal point(87) and 2 have some other parse error.

It does appear that you have the wrong app, try the other app avaliable on the app store. This is not the format that my app logs, so yeah it must be the wrong app.

https://play.google.com/store/apps/details?id=eevblog.x121gw&hl=en

Update 1:
I have reproduced the voltage reading error in VA mode, am investigating whether the packet is the cause or the app, will update this post soon.

Update 2:
There is an issue with the voltage display (in the app on the sub display) in the VA mode, it appears to behave like a signed/unsigned issue with the formation of the packet, this means that for voltages above (32768 - 1 ish +- the calibrated offset) the value appears to result in invalid readings. It is possible still that the App has caused the issue but it is looking quite unlikely.
This will be resolved as soon as possible.

Note: The decimal position for the mVA appears also to be reported incorrectly in the packet (only those modes) these issues will also be dealt with soon.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Iagash on March 23, 2018, 12:41:25 pm

It does appear that you have the wrong app, try the other app avaliable on the app store. This is not the format that my app logs, so yeah it must be the wrong app.

https://play.google.com/store/apps/details?id=eevblog.x121gw&hl=en

Yes Seppy, it's the wrong app, I'm sorry. The output is from my BLE linux script which I adapted to the new format according to the BLE documentation.

I can't do extended logging with your app, since I have only one BLE capable Android device and no BLE capable Windows and not even a Windows with a Microsoft store. The Android phone is my phone and has to follow me around. So I can't leave it untouched next to the meter for long. I just use it to compare the values displayed by the app to the output of my script.

I also had the problem with your android app, that I couldn't save the log when I left it running once over night. When pressing save the app just froze for some seconds and then continued. Maybe my phone has too little memory.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Iagash on March 24, 2018, 10:50:11 am
I added plausibility checks back into my script. I'm checking the year and month the meter is transmitting, since it seems to be always the same.
Then I added printing the data of invalid records. The log below shows the invalid data between two correct records. As you can see, they don't happen very often.

Maybe you can check, if you can also see this pattern with your app. The last column shows the percentage of records with invalid xor checksum. So around 5-6% of the records are broken. I have not yet analyzed these records.

Code: [Select]
20180324-10:07:40.176 2023-08 02342    Power DC (VA)  2005.9 mVA       DCV  2.0987    0% f:  5%
20180324-10:07:40.648 error: unparsable record: Invalid year (0)
20180324-10:07:40.648 error: data: f2 00 00 01 40 00 d5 f2 17 80 23 42 18 00 4e 60 01 04 51
20180324-10:07:40.783 error: skiped 7 input bytes
20180324-10:07:40.783 2023-08 02342    Power DC (VA)  2006.4 mVA       DCV  2.0978    0% f:  5%
--
20180324-10:08:42.006 2023-08 02342    Power DC (VA)  2006.2 mVA       DCV  2.0978    0% f:  5%
20180324-10:08:42.478 error: unparsable record: Invalid year (0)
20180324-10:08:42.478 error: data: f2 00 00 01 40 00 eb f2 17 80 23 42 18 00 4e 5e 01 04 51
20180324-10:08:42.614 error: skiped 7 input bytes
20180324-10:08:42.614 2023-08 02342    Power DC (VA)  2006.2 mVA       DCV  2.0978    0% f:  6%
--
20180324-10:09:19.199 2023-08 02342    Power DC (VA)  2006.2 mVA       DCV  2.0978    0% f:  5%
20180324-10:09:19.671 error: unparsable record: Invalid year (0)
20180324-10:09:19.671 error: data: f2 00 00 01 40 00 eb f2 17 80 23 42 18 00 4e 5e 01 04 51
20180324-10:09:19.806 error: skiped 7 input bytes
20180324-10:09:19.806 2023-08 02342    Power DC (VA)  2006.2 mVA       DCV  2.0978    0% f:  5%
--
20180324-10:11:36.427 2023-08 02342    Power DC (VA)  2006.8 mVA       DCV  2.0978    0% f:  6%
20180324-10:11:36.900 error: unparsable record: Invalid year (0)
20180324-10:11:36.900 error: data: f2 00 00 01 40 00 d1 f2 17 80 23 42 18 00 4e 64 01 04 51
20180324-10:11:37.035 error: skiped 7 input bytes
20180324-10:11:37.035 2023-08 02342    Power DC (VA)  2006.8 mVA       DCV  2.0978    0% f:  6%
--
20180324-10:12:51.825 2023-08 02342    Power DC (VA)  2006.6 mVA       DCV  2.0978    0% f:  6%
20180324-10:12:52.297 error: unparsable record: Invalid year (0)
20180324-10:12:52.297 error: data: f2 00 00 01 40 00 d7 f2 17 80 23 42 18 00 4e 62 01 04 51
20180324-10:12:52.433 error: skiped 7 input bytes
20180324-10:12:52.433 2023-08 02342    Power DC (VA)  2006.6 mVA       DCV  2.0978    0% f:  6%
--
20180324-10:16:26.477 2023-08 02342    Power DC (VA)  2006.6 mVA       DCV  2.0978    0% f:  6%
20180324-10:16:26.949 error: unparsable record: Invalid year (0)
20180324-10:16:26.949 error: data: f2 00 00 01 40 00 d7 f2 17 80 23 42 18 00 4e 62 01 04 51
20180324-10:16:27.084 error: skiped 7 input bytes
20180324-10:16:27.084 2023-08 02342    Power DC (VA)  2006.6 mVA       DCV  2.0978    0% f:  6%
--
20180324-10:18:36.415 2023-08 02342    Power DC (VA)  2006.8 mVA       DCV  2.0978    0% f:  5%
20180324-10:18:36.887 error: unparsable record: Invalid year (0)
20180324-10:18:36.887 error: data: f2 00 00 01 40 00 d1 f2 17 80 23 42 18 00 4e 64 01 04 51
20180324-10:18:37.022 error: skiped 7 input bytes
20180324-10:18:37.022 2023-08 02342    Power DC (VA)  2006.8 mVA       DCV  2.0978    0% f:  6%
--
20180324-10:37:36.767 2023-08 02342    Power DC (VA)  2006.8 mVA       DCV  2.0978    0% f:  5%
20180324-10:37:37.239 error: unparsable record: Invalid year (0)
20180324-10:37:37.239 error: data: f2 00 00 01 40 00 d1 f2 17 80 23 42 18 00 4e 64 01 04 51
20180324-10:37:37.374 error: skiped 7 input bytes
20180324-10:37:37.374 2023-08 02342    Power DC (VA)  2006.8 mVA       DCV  2.0978    0% f:  5%
--
20180324-10:40:23.155 2023-08 02342    Power DC (VA)  2006.8 mVA       DCV  2.0978    0% f:  6%
20180324-10:40:23.628 error: unparsable record: Invalid year (0)
20180324-10:40:23.628 error: data: f2 00 00 01 40 00 d1 f2 17 80 23 42 18 00 4e 64 01 04 51
20180324-10:40:23.763 error: skiped 7 input bytes
20180324-10:40:23.763 2023-08 02342    Power DC (VA)  2006.8 mVA       DCV  2.0979    0% f:  6%
--
20180324-10:41:13.916 2023-08 02342    Power DC (VA)  2006.8 mVA       DCV  2.0978    0% f:  6%
20180324-10:41:14.388 error: unparsable record: Invalid year (0)
20180324-10:41:14.388 error: data: f2 00 00 01 40 00 d1 f2 17 80 23 42 18 00 4e 64 01 04 51
20180324-10:41:14.523 error: skiped 7 input bytes
20180324-10:41:14.523 2023-08 02342    Power DC (VA)  2006.8 mVA       DCV  2.0978    0% f:  6%
--
20180324-10:45:01.864 2023-08 02342    Power DC (VA)  2007.1 mVA       DCV  2.0978    0% f:  6%
20180324-10:45:02.337 error: unparsable record: Invalid year (0)
20180324-10:45:02.337 error: data: f2 00 00 01 40 00 d2 f2 17 80 23 42 18 00 4e 67 01 04 51
20180324-10:45:02.472 error: skiped 7 input bytes
20180324-10:45:02.472 2023-08 02342    Power DC (VA)  2007.1 mVA       DCV  2.0978    0% f:  6%
--
20180324-10:48:21.463 2023-08 02342    Power DC (VA)  2006.8 mVA       DCV  2.0978    0% f:  6%
20180324-10:48:21.935 error: unparsable record: Invalid year (0)
20180324-10:48:21.935 error: data: f2 00 00 01 40 00 d1 f2 17 80 23 42 18 00 4e 64 01 04 51
20180324-10:48:22.071 error: skiped 7 input bytes
20180324-10:48:22.071 2023-08 02342    Power DC (VA)  2006.8 mVA       DCV  2.0978    0% f:  6%
--
20180324-10:51:01.102 2023-08 02342    Power DC (VA)  2006.8 mVA       DCV  2.0978    0% f:  6%
20180324-10:51:01.574 error: unparsable record: Invalid year (0)
20180324-10:51:01.574 error: data: f2 00 00 01 40 00 d1 f2 17 80 23 42 18 00 4e 64 01 04 51
20180324-10:51:01.709 error: skiped 7 input bytes
20180324-10:51:01.709 2023-08 02342    Power DC (VA)  2006.8 mVA       DCV  2.0978    0% f:  6%
--
20180324-10:52:48.427 2023-08 02342    Power DC (VA)  2008.6 mVA       DCA  204.66    0% f:  6%
20180324-10:52:48.900 error: unparsable record: Invalid year (0)
20180324-10:52:48.900 error: data: f2 00 00 01 40 00 cf f2 17 80 23 42 18 00 4e 76 15 02 4f
20180324-10:52:49.035 error: skiped 7 input bytes
20180324-10:52:49.035 2023-08 02342    Power DC (VA)  2008.6 mVA       DCA  204.66    0% f:  6%
--
20180324-11:02:35.006 2023-08 02342    Power DC (VA)  2006.8 mVA       DCV  2.0980    0% f:  5%
20180324-11:02:35.478 error: unparsable record: Invalid year (0)
20180324-11:02:35.478 error: data: f2 00 00 01 40 00 d0 f2 17 80 23 42 18 00 4e 65 01 04 51
20180324-11:02:35.613 error: skiped 7 input bytes
20180324-11:02:35.613 2023-08 02342    Power DC (VA)  2006.9 mVA       DCV  2.0978    0% f:  5%
--
20180324-11:03:35.824 2023-08 02342    Power DC (VA)  2006.4 mVA       DCV  2.0978    0% f:  5%
20180324-11:03:36.296 error: unparsable record: Invalid year (0)
20180324-11:03:36.296 error: data: f2 00 00 01 40 00 d5 f2 17 80 23 42 18 00 4e 60 01 04 51
20180324-11:03:36.431 error: skiped 7 input bytes
20180324-11:03:36.431 2023-08 02342    Power DC (VA)  2006.4 mVA       DCV  2.0978    0% f:  6%
--
20180324-11:14:06.817 2023-08 02342    Power DC (VA)  2006.8 mVA       DCV  2.0978    0% f:  6%
20180324-11:14:07.290 error: unparsable record: Invalid year (0)
20180324-11:14:07.290 error: data: f2 00 00 01 40 00 d1 f2 17 80 23 42 18 00 4e 64 01 04 51
20180324-11:14:07.425 error: skiped 7 input bytes
20180324-11:14:07.425 2023-08 02342    Power DC (VA)  2006.8 mVA       DCV  2.0978    0% f:  6%
--
20180324-11:21:51.963 2023-08 02342    Power DC (VA)  2007.0 mVA       DCV  2.0978    0% f:  6%
20180324-11:21:52.435 error: unparsable record: Invalid year (0)
20180324-11:21:52.435 error: data: f2 00 00 01 40 00 d3 f2 17 80 23 42 18 00 4e 66 01 04 51
20180324-11:21:52.570 error: skiped 7 input bytes
20180324-11:21:52.570 2023-08 02342    Power DC (VA)  2007.0 mVA       DCV  2.0978    0% f:  6%
--
20180324-11:33:36.262 2023-08 02342    Power DC (VA)  2007.8 mVA       DCA  204.75    0% f:  6%
20180324-11:33:36.734 error: unparsable record: Invalid year (0)
20180324-11:33:36.734 error: data: f2 00 00 01 40 00 db f2 17 80 23 42 18 00 4e 6e 01 04 51
20180324-11:33:36.870 error: skiped 7 input bytes
20180324-11:33:36.870 2023-08 02342    Power DC (VA)  2007.8 mVA       DCV  2.0978    0% f:  6%
--
20180324-11:36:30.886 2023-08 02342    Power DC (VA)  2007.2 mVA       DCV  2.0978    0% f:  6%
20180324-11:36:31.358 error: unparsable record: Invalid year (0)
20180324-11:36:31.358 error: data: f2 00 00 01 40 00 dd f2 17 80 23 42 18 00 4e 68 01 04 51
20180324-11:36:31.493 error: skiped 7 input bytes
20180324-11:36:31.493 2023-08 02342    Power DC (VA)  2007.2 mVA       DCV  2.0978    0% f:  6%
Title: Re: EEVBlog 121GW Discussion thread
Post by: Iagash on March 25, 2018, 07:38:48 pm
Here are some records with failing xor checksums:

Code: [Select]
20180325-21:31:47.828 error: invalid checksum: f2 17 80 23 42 18 00 25 45 01 04 70 1d 00 00 04 40 80 50
20180325-21:31:52.351 error: invalid checksum: f2 17 80 23 42 18 00 25 49 01 04 70 25 00 00 04 08 00 64
20180325-21:32:01.463 error: invalid checksum: f2 17 80 23 42 18 00 25 45 15 02 fb 1f 00 00 04 40 00 4e
20180325-21:32:06.053 error: invalid checksum: f2 17 80 23 42 06 00 25 46 01 04 70 20 00 00 04 40 00 6e
20180325-21:32:07.741 error: invalid checksum: f2 17 80 23 42 18 00 25 40 21 02 7e 22 00 00 04 40 00 76
20180325-21:32:11.521 error: invalid checksum: f2 17 80 23 42 18 00 25 47 01 04 70 01 00 00 04 40 00 6c
20180325-21:32:20.566 error: invalid checksum: f2 17 80 23 42 18 00 25 49 15 02 7e 07 00 00 04 40 00 43
20180325-21:32:25.089 error: invalid checksum: f2 17 80 23 42 18 40 25 43 01 04 70 16 00 00 04 40 00 5d
20180325-21:32:26.844 error: invalid checksum: f2 17 80 23 42 18 00 25 a9 15 02 7e 21 00 00 04 40 00 0a
20180325-21:32:29.611 error: invalid checksum: f2 17 80 88 42 18 00 25 42 01 04 70 0c 00 00 04 40 00 46
20180325-21:32:31.366 error: invalid checksum: f2 17 80 23 42 18 00 22 42 01 04 70 0c 00 00 04 40 00 46
20180325-21:32:35.889 error: invalid checksum: f2 17 80 23 42 0c 00 25 44 01 04 70 14 00 00 04 40 00 58
20180325-21:32:48.714 error: invalid checksum: f2 17 80 23 42 18 00 25 40 01 00 70 0b 00 00 04 40 00 43
20180325-21:32:53.236 error: invalid checksum: f2 17 80 23 21 18 00 25 3e 15 02 7e 1d 00 00 04 40 00 37
20180325-21:32:54.991 error: invalid checksum: f2 17 80 23 42 18 00 25 09 01 04 70 01 00 00 04 40 00 37
20180325-21:32:57.759 error: invalid checksum: f2 17 80 23 42 01 00 25 3d 15 02 7e 20 00 00 04 40 00 09
20180325-21:32:59.446 error: invalid checksum: f2 17 80 23 10 18 00 25 3d 15 02 7e 20 00 00 04 40 00 09
20180325-21:33:09.571 error: invalid checksum: f2 17 80 23 42 18 00 25 45 15 02 7e 07 00 00 04 40 00 4e
20180325-21:33:12.339 error: invalid checksum: f2 17 80 23 42 01 00 25 43 01 04 70 16 00 00 04 40 00 5d
20180325-21:33:14.161 error: invalid checksum: f2 17 80 23 42 18 00 25 43 20 04 70 16 00 00 04 40 00 5d

I don't really understand what's happening here. It looks a bit like random bit errors. could it be a birate mismatch between CPU and BLE module?

Maybe someone with more experience with this kind of errors can comment on this.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Seppy on March 26, 2018, 12:40:36 am

It does appear that you have the wrong app, try the other app avaliable on the app store. This is not the format that my app logs, so yeah it must be the wrong app.

https://play.google.com/store/apps/details?id=eevblog.x121gw&hl=en

I also had the problem with your android app, that I couldn't save the log when I left it running once over night. When pressing save the app just froze for some seconds and then continued. Maybe my phone has too little memory.

I'll look into this, not sure what caused it but i'll do my best to reproduce, it may take a while to reproduce these type of issues can sometimes take a while to figure out the exact mechanism as its likely something specific about the android API. I'll get back to you or just release a fix as an update if it is reproducible.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Iagash on March 26, 2018, 11:52:35 am
I'll look into this, not sure what caused it but i'll do my best to reproduce, it may take a while to reproduce these type of issues can sometimes take a while to figure out the exact mechanism as its likely something specific about the android API. I'll get back to you or just release a fix as an update if it is reproducible.

Thanks, but don't spend much time on this. Short logs are working fine. The fault could also be my phone I just tried it once.

I'd be much more interested if you can see the same data errors that I see with my linux script.

Maybe you could add logging of these failed records raw data to your app, so that I can compare these?
Title: Re: EEVBlog 121GW Discussion thread
Post by: FrankBuss on March 26, 2018, 06:16:13 pm
Here are some records with failing xor checksums:

Code: [Select]
20180325-21:31:47.828 error: invalid checksum: f2 17 80 23 42 18 00 25 45 01 04 70 1d 00 00 04 40 80 50
20180325-21:31:52.351 error: invalid checksum: f2 17 80 23 42 18 00 25 49 01 04 70 25 00 00 04 08 00 64
20180325-21:32:01.463 error: invalid checksum: f2 17 80 23 42 18 00 25 45 15 02 fb 1f 00 00 04 40 00 4e
20180325-21:32:06.053 error: invalid checksum: f2 17 80 23 42 06 00 25 46 01 04 70 20 00 00 04 40 00 6e
20180325-21:32:07.741 error: invalid checksum: f2 17 80 23 42 18 00 25 40 21 02 7e 22 00 00 04 40 00 76
20180325-21:32:11.521 error: invalid checksum: f2 17 80 23 42 18 00 25 47 01 04 70 01 00 00 04 40 00 6c
20180325-21:32:20.566 error: invalid checksum: f2 17 80 23 42 18 00 25 49 15 02 7e 07 00 00 04 40 00 43
20180325-21:32:25.089 error: invalid checksum: f2 17 80 23 42 18 40 25 43 01 04 70 16 00 00 04 40 00 5d
20180325-21:32:26.844 error: invalid checksum: f2 17 80 23 42 18 00 25 a9 15 02 7e 21 00 00 04 40 00 0a
20180325-21:32:29.611 error: invalid checksum: f2 17 80 88 42 18 00 25 42 01 04 70 0c 00 00 04 40 00 46
20180325-21:32:31.366 error: invalid checksum: f2 17 80 23 42 18 00 22 42 01 04 70 0c 00 00 04 40 00 46
20180325-21:32:35.889 error: invalid checksum: f2 17 80 23 42 0c 00 25 44 01 04 70 14 00 00 04 40 00 58
20180325-21:32:48.714 error: invalid checksum: f2 17 80 23 42 18 00 25 40 01 00 70 0b 00 00 04 40 00 43
20180325-21:32:53.236 error: invalid checksum: f2 17 80 23 21 18 00 25 3e 15 02 7e 1d 00 00 04 40 00 37
20180325-21:32:54.991 error: invalid checksum: f2 17 80 23 42 18 00 25 09 01 04 70 01 00 00 04 40 00 37
20180325-21:32:57.759 error: invalid checksum: f2 17 80 23 42 01 00 25 3d 15 02 7e 20 00 00 04 40 00 09
20180325-21:32:59.446 error: invalid checksum: f2 17 80 23 10 18 00 25 3d 15 02 7e 20 00 00 04 40 00 09
20180325-21:33:09.571 error: invalid checksum: f2 17 80 23 42 18 00 25 45 15 02 7e 07 00 00 04 40 00 4e
20180325-21:33:12.339 error: invalid checksum: f2 17 80 23 42 01 00 25 43 01 04 70 16 00 00 04 40 00 5d
20180325-21:33:14.161 error: invalid checksum: f2 17 80 23 42 18 00 25 43 20 04 70 16 00 00 04 40 00 5d

I don't really understand what's happening here. It looks a bit like random bit errors. could it be a birate mismatch between CPU and BLE module?

Maybe someone with more experience with this kind of errors can comment on this.

This looks like a baudrate problem, or maybe wrong start bit detection or something like this. E.g. when 0x42 turns into 0x21, one bit shifted to the right. Same for 0x18 turning int 0x0c, one bit shifted.

Very unlikely that it has anything to do with the RF transfer from the Bluetooth module to the receiver, because as I noted earlier, BLE has a sophisticated error correction. Not just xor, but CRC, which is easy to calculate with tables, I've implemented this once myself for another product. You can verify this if you increase the distance: there shouldn't be more errors, but it gets slower, because packets gets resend, at least when I tested it with my Blue Gecko Silabs IC, which had no packet errors at all at the application level.

Maybe you can measure the RX/TX lines between the Bluetooth module and the CPU to check if the baudrate is exact in your multimeter, if David can't reproduce it?
Title: Re: EEVBlog 121GW Discussion thread
Post by: plexus on March 26, 2018, 07:37:03 pm
I would love an iphone app for the 121GW that is better than the existing one in the app store. Better GUI and user experience!
Title: Re: EEVBlog 121GW Discussion thread
Post by: Seppy on March 27, 2018, 05:40:02 am
Here are some records with failing xor checksums:

Code: [Select]
20180325-21:31:47.828 error: invalid checksum: f2 17 80 23 42 18 00 25 45 01 04 70 1d 00 00 04 40 80 50
20180325-21:31:52.351 error: invalid checksum: f2 17 80 23 42 18 00 25 49 01 04 70 25 00 00 04 08 00 64
20180325-21:32:01.463 error: invalid checksum: f2 17 80 23 42 18 00 25 45 15 02 fb 1f 00 00 04 40 00 4e
20180325-21:32:06.053 error: invalid checksum: f2 17 80 23 42 06 00 25 46 01 04 70 20 00 00 04 40 00 6e
20180325-21:32:07.741 error: invalid checksum: f2 17 80 23 42 18 00 25 40 21 02 7e 22 00 00 04 40 00 76
20180325-21:32:11.521 error: invalid checksum: f2 17 80 23 42 18 00 25 47 01 04 70 01 00 00 04 40 00 6c
20180325-21:32:20.566 error: invalid checksum: f2 17 80 23 42 18 00 25 49 15 02 7e 07 00 00 04 40 00 43
20180325-21:32:25.089 error: invalid checksum: f2 17 80 23 42 18 40 25 43 01 04 70 16 00 00 04 40 00 5d
20180325-21:32:26.844 error: invalid checksum: f2 17 80 23 42 18 00 25 a9 15 02 7e 21 00 00 04 40 00 0a
20180325-21:32:29.611 error: invalid checksum: f2 17 80 88 42 18 00 25 42 01 04 70 0c 00 00 04 40 00 46
20180325-21:32:31.366 error: invalid checksum: f2 17 80 23 42 18 00 22 42 01 04 70 0c 00 00 04 40 00 46
20180325-21:32:35.889 error: invalid checksum: f2 17 80 23 42 0c 00 25 44 01 04 70 14 00 00 04 40 00 58
20180325-21:32:48.714 error: invalid checksum: f2 17 80 23 42 18 00 25 40 01 00 70 0b 00 00 04 40 00 43
20180325-21:32:53.236 error: invalid checksum: f2 17 80 23 21 18 00 25 3e 15 02 7e 1d 00 00 04 40 00 37
20180325-21:32:54.991 error: invalid checksum: f2 17 80 23 42 18 00 25 09 01 04 70 01 00 00 04 40 00 37
20180325-21:32:57.759 error: invalid checksum: f2 17 80 23 42 01 00 25 3d 15 02 7e 20 00 00 04 40 00 09
20180325-21:32:59.446 error: invalid checksum: f2 17 80 23 10 18 00 25 3d 15 02 7e 20 00 00 04 40 00 09
20180325-21:33:09.571 error: invalid checksum: f2 17 80 23 42 18 00 25 45 15 02 7e 07 00 00 04 40 00 4e
20180325-21:33:12.339 error: invalid checksum: f2 17 80 23 42 01 00 25 43 01 04 70 16 00 00 04 40 00 5d
20180325-21:33:14.161 error: invalid checksum: f2 17 80 23 42 18 00 25 43 20 04 70 16 00 00 04 40 00 5d

I don't really understand what's happening here. It looks a bit like random bit errors. could it be a birate mismatch between CPU and BLE module?

Maybe someone with more experience with this kind of errors can comment on this.

This looks like a baudrate problem, or maybe wrong start bit detection or something like this. E.g. when 0x42 turns into 0x21, one bit shifted to the right. Same for 0x18 turning int 0x0c, one bit shifted.

Very unlikely that it has anything to do with the RF transfer from the Bluetooth module to the receiver, because as I noted earlier, BLE has a sophisticated error correction. Not just xor, but CRC, which is easy to calculate with tables, I've implemented this once myself for another product. You can verify this if you increase the distance: there shouldn't be more errors, but it gets slower, because packets gets resend, at least when I tested it with my Blue Gecko Silabs IC, which had no packet errors at all at the application level.

Maybe you can measure the RX/TX lines between the Bluetooth module and the CPU to check if the baudrate is exact in your multimeter, if David can't reproduce it?

Alright so I've logged data for 2 minutes on BLE and UART then validated the packets, it doesn't appear i'm getting any of the bad packets on android.
Similarly on windows there were no bad packets.

Do you have any specific conditions which might help reproduce this issue.

NOTE: If you compile my main C++ file be sure to set struct alignment to be for bytes not like 32 bit integers or something, often the default is not byte.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Iagash on March 27, 2018, 08:50:33 am

Alright so I've logged data for 2 minutes on BLE and UART then validated the packets, it doesn't appear i'm getting any of the bad packets on android.
Similarly on windows there were no bad packets.

Do you have any specific conditions which might help reproduce this issue.

NOTE: If you compile my main C++ file be sure to set struct alignment to be for bytes not like 32 bit integers or something, often the default is not byte.

Thanks a lot. Yes, your data looks good.

Can you explain how to log the raw data on android?

Then I'd like to try this with my meter to see if the problem is still there.

I tried with 3 different linux systems, my desktop, a thinkpad X230 and a thinkpad X220. They all show the same invalid records.

Maybe I have a bad meter?
Title: Re: EEVBlog 121GW Discussion thread
Post by: Brumby on March 27, 2018, 10:04:15 am
Just a question to clear it from the discussion....

Since this communication is still an RF link - have you tried alternate orientations between Tx and Rx, different distances, different environmental elements, such as RF reflective structures, RFI, etc?
Title: Re: EEVBlog 121GW Discussion thread
Post by: Seppy on March 28, 2018, 12:41:14 am

Alright so I've logged data for 2 minutes on BLE and UART then validated the packets, it doesn't appear i'm getting any of the bad packets on android.
Similarly on windows there were no bad packets.

Do you have any specific conditions which might help reproduce this issue.

NOTE: If you compile my main C++ file be sure to set struct alignment to be for bytes not like 32 bit integers or something, often the default is not byte.

Thanks a lot. Yes, your data looks good.

Can you explain how to log the raw data on android?

Then I'd like to try this with my meter to see if the problem is still there.

I tried with 3 different linux systems, my desktop, a thinkpad X230 and a thinkpad X220. They all show the same invalid records.

Maybe I have a bad meter?

At the moment raw packet logging is not a feature of the app, I use debug outputs (in visual studio, with debug mode) to get the data.

There are a fair few apps on the play store which seem suitable, I haven't used these but they appear to do what you want:
https://play.google.com/store/apps/details?id=com.zicasoftware.ziblemonitor
https://play.google.com/store/apps/details?id=com.edodm85.bluetoothbleterminal.free


Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on March 28, 2018, 01:44:27 am
I tried with 3 different linux systems, my desktop, a thinkpad X230 and a thinkpad X220. They all show the same invalid records.
Maybe I have a bad meter?

Do you have any issues at all with the range switch?
There is a possibility that could be an issue.
Title: Re: EEVBlog 121GW Discussion thread
Post by: FrankBuss on March 28, 2018, 07:38:15 am
I tried with 3 different linux systems, my desktop, a thinkpad X230 and a thinkpad X220. They all show the same invalid records.
Maybe I have a bad meter?

Do you have any issues at all with the range switch?
There is a possibility that could be an issue.

How could the range switch cause invalid xor checksums?
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on March 28, 2018, 07:41:13 am
I tried with 3 different linux systems, my desktop, a thinkpad X230 and a thinkpad X220. They all show the same invalid records.
Maybe I have a bad meter?

Do you have any issues at all with the range switch?
There is a possibility that could be an issue.

I was thinking of the spurious VA values. We no longer get these as it's been (as far as we can tell) fixed in software. So if spurious values are being seen, maybe that's a possible cause?
But if it's a checksum thing, then forget I said it.
But as I believe David (seppy) has said, we are no longer getting corrupted data, and hence no more checksum errors.

How could the range switch cause invalid xor checksums?
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on March 28, 2018, 07:45:55 am
I'll look into this, not sure what caused it but i'll do my best to reproduce, it may take a while to reproduce these type of issues can sometimes take a while to figure out the exact mechanism as its likely something specific about the android API. I'll get back to you or just release a fix as an update if it is reproducible.

Thanks, but don't spend much time on this. Short logs are working fine. The fault could also be my phone I just tried it once.
I'd be much more interested if you can see the same data errors that I see with my linux script.
Maybe you could add logging of these failed records raw data to your app, so that I can compare these?

Is anyone else having issues with the bluetooth data? If not then we probably don't have a choice at this point but to consider the bluetooth issues fixed, as always subject the future any future identified and repeatable issues.
UEi fixed a bug in the micro send routine sending spurious data, and we have shortened (more than halved) the packet size to reduce known packet loss were were seeing. We no see no issues at all at our end on our app.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Iagash on March 28, 2018, 08:29:04 am

At the moment raw packet logging is not a feature of the app, I use debug outputs (in visual studio, with debug mode) to get the data.

There are a fair few apps on the play store which seem suitable, I haven't used these but they appear to do what you want:
https://play.google.com/store/apps/details?id=com.zicasoftware.ziblemonitor
https://play.google.com/store/apps/details?id=com.edodm85.bluetoothbleterminal.free

Thanks.

I tried these and they can talk to the meter, but seem unable to receive and log the data packets.

Title: Re: EEVBlog 121GW Discussion thread
Post by: Iagash on March 28, 2018, 08:37:37 am

I was thinking of the spurious VA values. We no longer get these as it's been (as far as we can tell) fixed in software. So if spurious values are being seen, maybe that's a possible cause?
But if it's a checksum thing, then forget I said it.
But as I believe David (seppy) has said, we are no longer getting corrupted data, and hence no more checksum errors.

How could the range switch cause invalid xor checksums?

I don't see spurious VA values as in the early versions of the firmware.

With V1.10 I still see wrong voltage and current displays in certain parts of the measuring range, I see a spurious wrong decimal point in current display and I see wrong range display (A instead of mA) in the current display. All of this in DC VA-mode.

Apart from that the displayed values are consistently wrong.

I guess the invalid checksums must then be some electrical problem in my meter if no one else can see them.

As there seems no way to debug it further, I can't help you there.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on March 28, 2018, 09:37:44 am
With V1.10 I still see wrong voltage and current displays in certain parts of the measuring range, I see a spurious wrong decimal point in current display and I see wrong range display (A instead of mA) in the current display. All of this in DC VA-mode.
Apart from that the displayed values are consistently wrong.

On the meter display or the app display? (or both)
Does the SD card logged data show correct or incorrect readings?

Quote
I guess the invalid checksums must then be some electrical problem in my meter if no one else can see them.

Again, how are you validating your checksums? with your own software?
Title: Re: EEVBlog 121GW Discussion thread
Post by: Iagash on March 28, 2018, 09:55:59 am
With V1.10 I still see wrong voltage and current displays in certain parts of the measuring range, I see a spurious wrong decimal point in current display and I see wrong range display (A instead of mA) in the current display. All of this in DC VA-mode.
Apart from that the displayed values are consistently wrong.

On the meter display or the app display? (or both)

Only in the app, the meter is correct.

Does the SD card logged data show correct or incorrect readings?

I didn't try the SD-card since the log is of no use to me without timestamps.

I guess the invalid checksums must then be some electrical problem in my meter if no one else can see them.

Again, how are you validating your checksums? with your own software?

Yes with my own software, you have the raw readings in the post above, you could verify yourself.
Title: Re: EEVBlog 121GW Discussion thread
Post by: plexus on March 28, 2018, 07:01:20 pm
I updated the meter to 1.10 and now the iphone app doesn't work. it connects (apparently) but there is no meter display in the app.

Any ideas? Fixes? Any idea when a real eevblog iOS app will be released?
Title: Re: EEVBlog 121GW Discussion thread
Post by: HKJ on March 28, 2018, 07:28:36 pm
I updated the meter to 1.10 and now the iphone app doesn't work. it connects (apparently) but there is no meter display in the app.

Any ideas? Fixes? Any idea when a real eevblog iOS app will be released?

The Bluetooth protocol changed, you have to use the correct application version (I do not know that yet, I am still waiting on my meter).
Title: Re: EEVBlog 121GW Discussion thread
Post by: plexus on March 28, 2018, 07:31:18 pm
I updated the meter to 1.10 and now the iphone app doesn't work. it connects (apparently) but there is no meter display in the app.

Any ideas? Fixes? Any idea when a real eevblog iOS app will be released?

The Bluetooth protocol changed, you have to use the correct application version (I do not know that yet, I am still waiting on my meter).

EEVBlog: any ETA on an iOS app?

Should I downgrade the firmware? Will that work? Any idea to what version? I use that app!
Title: Re: EEVBlog 121GW Discussion thread
Post by: Iagash on March 28, 2018, 08:30:57 pm
Should I downgrade the firmware? Will that work? Any idea to what version? I use that app!

Anything < 1.10 should work, so I'd say use 1.07.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on March 29, 2018, 02:54:11 am
I updated the meter to 1.10 and now the iphone app doesn't work. it connects (apparently) but there is no meter display in the app.
Any ideas? Fixes? Any idea when a real eevblog iOS app will be released?

The Bluetooth packet changed as has been discussed on here.
We (EEVblog "we", not UEi) do not endorse nor have control over the UEi application that is currently on the iPhone store. We are not aware of if or when they are updating that.
David is starting working on the iPhone version shortly, we now have a mac setup to enable the compiler to do this.
Title: Re: EEVBlog 121GW Discussion thread
Post by: plexus on March 29, 2018, 03:15:27 am
I updated the meter to 1.10 and now the iphone app doesn't work. it connects (apparently) but there is no meter display in the app.
Any ideas? Fixes? Any idea when a real eevblog iOS app will be released?

The Bluetooth packet changed as has been discussed on here.
We (EEVblog "we", not UEi) do not endorse nor have control over the UEi application that is currently on the iPhone store. We are not aware of if or when they are updating that.
David is starting working on the iPhone version shortly, we now have a mac setup to enable the compiler to do this.

Thanks Dave that's good news. Looking forward to a spiffy iOS app.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on March 29, 2018, 04:56:22 am
Thanks Dave that's good news. Looking forward to a spiffy iOS app.

In theory it's as easy as pressing Compile for iOS, but we have not done this before, so  :-//
Title: Re: EEVBlog 121GW Discussion thread
Post by: plexus on March 29, 2018, 05:01:26 am
Thanks Dave that's good news. Looking forward to a spiffy iOS app.

In theory it's as easy as pressing Compile for iOS, but we have not done this before, so  :-//

It's probably a good time to get into iOS if not just for the experience of it. Like it or not it is a significant market and it's likely a good iOS app will inspire meter sales. But remember, iOS users are used to a particular look and feel. Don't go all Android-y/Windoze on us.  :scared: :scared: :scared:
Title: Re: EEVBlog 121GW Discussion thread
Post by: Brumby on March 29, 2018, 06:24:57 am
But remember, iOS users are used to a particular look and feel.

Sleek, stylish, streamlined - and it sets the parameters and tells the user what to do, because it knows best.
Title: Re: EEVBlog 121GW Discussion thread
Post by: plexus on March 29, 2018, 06:35:44 am
But remember, iOS users are used to a particular look and feel.

Sleek, stylish, streamlined - and it sets the parameters and tells the user what to do, because it knows best.

That's pretty much true of Apple.

But I think there is enough flexibility with the iOS UX framework that a flexible app could be designed.
Title: Re: EEVBlog 121GW Discussion thread
Post by: kory on March 29, 2018, 09:20:15 am
Dave thanks for the last update on these meters.  Since some people have cancelled and the meters have already been ordered, would it be possible to order more meters?

Also, it is well worth the wait for the bugs to be worked out, especially any hardware bugs.

Take care everyone!
Title: Re: EEVBlog 121GW Discussion thread
Post by: firstcolle on March 29, 2018, 09:25:29 am
Really really looking forward to get mine :)

thanks for all your work (Dave and all the forum users that helped to find, solve and test bugs!)
Title: About changing the shipping address
Post by: VinzC on March 29, 2018, 09:56:47 am
Hi Dave.

The survey link you posted in the Kickstarter comments section (Johnny B. Goode @ https://www.kickstarter.com/projects/eevblog/eevblog-121gw-multimeter/rewards/6297526/survey (https://www.kickstarter.com/projects/eevblog/eevblog-121gw-multimeter/rewards/6297526/survey)) to change the shipping address indeed doesn't work for me; it drives me back to kickstarter home page.

@all,

EDIT: No taking the audience for dummies, this is only for the sake of completeness.

I had to use the button «Show my contribution» (translated from French: «Afficher mon engagement»). That button stands to the right of «You are a contributor» and is visible once logged in and you're viewing the multimeter project. Then select the Survey tab. From there you can change your shipping address :-+ .

Otherwise use the kickstarter menu under your login icon on the top right corner of the page, click the EEVBlog multimeter and from there «Show my contribution».

Thanks for the update. I'm still looking forward to the postman knocking at my door ;-) .

 \$\Omega\$ sweet  \$\Omega\$ 8)
Title: Re: EEVBlog 121GW Discussion thread
Post by: Cliff Matthews on March 29, 2018, 11:43:19 am
..a good iOS app will inspire meter sales.
Today's headlines: "Thousands of seniors and trendy spoon-fed millennials suddenly adopt electronics as a hobby"  :-DD
Title: Re: EEVBlog 121GW Discussion thread
Post by: Iagash on March 29, 2018, 03:37:44 pm
At the moment raw packet logging is not a feature of the app, I use debug outputs (in visual studio, with debug mode) to get the data.

I would still suggest you include the feature in your app.

It might be the linux bluetooth stack that is the reason for the errors, but it might also be some electrical problem with pullup/diode level shifter (R76/D4 in the schematic) in my (or others) meter. Maybe the resulting voltages are too narrowly specified.

With that feature more people could check easily if that's the case on more meters.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Elasia on March 29, 2018, 03:52:27 pm
At the moment raw packet logging is not a feature of the app, I use debug outputs (in visual studio, with debug mode) to get the data.

I would still suggest you include the feature in your app.

It might be the linux bluetooth stack that is the reason for the errors, but it might also be some electrical problem with pullup/diode level shifter (R76/D4 in the schematic) in my (or others) meter. Maybe the resulting voltages are too narrowly specified.

With that feature more people could check easily if that's the case on more meters.

+1 for raw packet logging / debugging, it really comes in handy to eliminate possible failure modes when making protocols
Title: Re: EEVBlog 121GW Discussion thread
Post by: Candid on March 29, 2018, 08:45:05 pm
I re-checked with 1.10 and get the same results. Can someone confirm my measurements?
Why is the 121GW reading wrong in auto range/manual 5V range in this situation?

Can you reproduce the following measurements?
2.0V peak to peak sine wave 4kHz, No DC offset, duty cycle 50%. Both meters in AC mode. Firmware 1.07 on my 121GW with serial number EEVblog 000084

Auto mode on both meters, Fluke in highres mode:
121GW selects 5V range, reads 1.1133Vac
Fluke 28II selects 6V range, reads 0.7031Vac

manual mode on both meters:
121GW 5V range, reads 1.1133Vac
Fluke 28II 6V range, 0.7032Vac

121GW 50V range, reads 0.659Vac (and it looses the frequency measurement and displays 0.00kHz)
Fluke 28II 60V range, reads 0.663Vac

See the attached pictures.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Messtechniker on March 30, 2018, 11:10:44 am
Since the 121GW seems to have an UART, I'd like to know precisely
where to get at the UART signals.
Are these at Pin 122 on U4 for Rx and Pin 119 for Tx?
Title: Re: EEVBlog 121GW Discussion thread
Post by: darrellg on March 30, 2018, 05:48:54 pm
Since the 121GW seems to have an UART, I'd like to know precisely
where to get at the UART signals.
Are these at Pin 122 on U4 for Rx and Pin 119 for Tx?

There is a schematic on the product page at https://www.eevblog.com/product/121gw/ (https://www.eevblog.com/product/121gw/).
Title: Re: EEVBlog 121GW Discussion thread
Post by: fanOfeeDIY on April 02, 2018, 01:16:14 pm
Finally conduct updating the firmware of my 121GW multimeter.

I am happy with the autorange speed.

https://youtu.be/6Y1KzSA-BUE
Title: Re: EEVBlog 121GW Discussion thread
Post by: fanOfeeDIY on April 02, 2018, 04:05:37 pm
Finally conduct updating the firmware of my 121GW multimeter.

I am happy with the autorange speed.

https://youtu.be/6Y1KzSA-BUE

I think I need to get better of improving video quality.
Title: Re: EEVBlog 121GW Discussion thread
Post by: coromonadalix on April 02, 2018, 09:41:52 pm
nice to see improvements like this :)

now Dave  design an bench meter version loll
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on April 02, 2018, 11:48:27 pm
Dave thanks for the last update on these meters.  Since some people have cancelled and the meters have already been ordered, would it be possible to order more meters?

Sorry, but no, not at this stage.
Title: Re: EEVBlog 121GW Discussion thread
Post by: JustMeHere on April 03, 2018, 12:19:22 am
Oh can't wait. Need a new DMM.
Title: Re: EEVBlog 121GW Discussion thread
Post by: carpin on April 03, 2018, 12:51:06 am
Oh can't wait. Need a new DMM.

Multimeter spreadsheet (38 brands and 210 meters listed
https://www.eevblog.com/forum/testgear/multimeter-spreadsheet/ (https://www.eevblog.com/forum/testgear/multimeter-spreadsheet/)
Title: Re: EEVBlog 121GW Discussion thread
Post by: lowimpedance on April 03, 2018, 01:18:31 am
I re-checked with 1.10 and get the same results. Can someone confirm my measurements?
Why is the 121GW reading wrong in auto range/manual 5V range in this situation?

Can you reproduce the following measurements?
2.0V peak to peak sine wave 4kHz, No DC offset, duty cycle 50%. Both meters in AC mode. Firmware 1.07 on my 121GW with serial number EEVblog 000084

Auto mode on both meters, Fluke in highres mode:
121GW selects 5V range, reads 1.1133Vac
Fluke 28II selects 6V range, reads 0.7031Vac

manual mode on both meters:
121GW 5V range, reads 1.1133Vac
Fluke 28II 6V range, 0.7032Vac

121GW 50V range, reads 0.659Vac (and it looses the frequency measurement and displays 0.00kHz)
Fluke 28II 60V range, reads 0.663Vac

See the attached pictures.

 Conducted similar measurements and can confirm similar results with regard to the frequency display. I will post the results in the 121GW issues thread where it is more appropriate.
EDIT decided to post the results here after doing some more testing and I think its not actually any bugs as such and just more like the characteristics of the meter front end.
anyway test results below........

 Ok further to Candid's test I conducted a similar test of the AC range and secondary frequency display reading.
Results for: 2V p-p 4 kHz sine wave input (terminated into 50 \$\Omega\$.). My 121GW with firmware rev 1.10.
Other meters used in comparison where Fluke 87V and Fluke 8840a

Meters in Auto ranging.
121GW reads 0.7288V RMS and the secondary display show the frequency of 3.999 kHz.
Fluke 87V in hi res reads 0.7300V RMS
Fluke 8840a reads 0.7300V RMS

Meters set to manual range.
121GW on 5V
87V on 6V
8840 on 2V
All display the same as above as expected.

Meters set to next range up.
121GW on 50V,  The voltage reading starts at 0.701V RMS for around 3 to 5 seconds then drops to 0.682V RMS and at which point the secondary frequency display goes to all zeros.
Fluke 87V on 60V, reads 0.690V RMS.
Fluke 8840a on 20V reads 0.7299V RMS and on 200V range reads 0.720V RMS.

additional measurement on the 121GW 500V range reads 0.47V RMS at both 4 kHz and 500 Hz (secondary frequency display is at 0), just for fun  :P.

NB * Further measurements of the frequency reading display show that it has a threshold of just over ~1.1 V before the secondary display starts to read frequency correctly when manual ranging to the 50V range.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Seppy on April 03, 2018, 01:58:06 am
I re-checked with 1.10 and get the same results. Can someone confirm my measurements?
Why is the 121GW reading wrong in auto range/manual 5V range in this situation?

Can you reproduce the following measurements?
2.0V peak to peak sine wave 4kHz, No DC offset, duty cycle 50%. Both meters in AC mode. Firmware 1.07 on my 121GW with serial number EEVblog 000084

Auto mode on both meters, Fluke in highres mode:
121GW selects 5V range, reads 1.1133Vac
Fluke 28II selects 6V range, reads 0.7031Vac

manual mode on both meters:
121GW 5V range, reads 1.1133Vac
Fluke 28II 6V range, 0.7032Vac

121GW 50V range, reads 0.659Vac (and it looses the frequency measurement and displays 0.00kHz)
Fluke 28II 60V range, reads 0.663Vac

See the attached pictures.

Regarding the 50V range the loss of the frequency measurement is expected, it is the wrong range for that reading and the threshold doesn't kick in for that range as it is higher.
The 5V range does appear wrong on your meter but we haven't been able to reproduce it, it could be an issue with your unit in that range.
Can you confirm that the Hz range functions correctly on your meter?

Can you also test the same range with 400Hz?
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on April 03, 2018, 12:09:05 pm
With regards to the requested 500V/5A (250VA) VA power mode. It is possible to add this (with some sacrifice in other ranges), and we have tested a solution.
But now I'm I am wondering whether or not it's actually worthwhile?
After all the meter is only capable of measuring VA and not true Watts, as the chipset does not have the phase measurement capability.
With this in mind, how useful is VA measurement in AC mode to people without a true Watts capability?
Note, that adding AC VA ranges drastically increases the number of factory calibration points required for every range added, and we are trying to minimise these ranges were possible.

SNAP POLL:
1) Should the 500V AC VA mode be added at the expense of a few of the other lower ranges?
2) Is AC VA mode even useful to people? (obviously the DC VA mode is)
Title: Re: EEVBlog 121GW Discussion thread
Post by: Fungus on April 03, 2018, 12:11:17 pm
No.

PS: What would be the "sacrifices in other ranges"?
Title: Re: EEVBlog 121GW Discussion thread
Post by: HKJ on April 03, 2018, 12:17:08 pm
1) Should the 500V AC VA mode be added at the expense of a few of the other lower ranges?
2) Is AC VA mode even useful to people? (obviously the DC VA mode is)

1) I believe this meter is for electronic, i.e. it needs the lower ranges.
2) I do not see the point in AC VA modes, I want real Watt.

The reason I bought the meter was the low burden voltage and the high diode test voltage, but if I start using it generally it will be for electronic.
Title: Re: EEVBlog 121GW Discussion thread
Post by: IanB on April 03, 2018, 01:40:07 pm
1) Should the 500V AC VA mode be added at the expense of a few of the other lower ranges?
2) Is AC VA mode even useful to people? (obviously the DC VA mode is)

No. This is an electronics meter. There are more dedicated tools available for AC power measurements that can also do Watts and power factor. It is not worth sacrificing lower ranges for this.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on April 03, 2018, 02:36:28 pm
Sorry for the confusion.
I was talking about the 500V range at lower currents.
i.e. We plan to add only a 500V/10A range, not 500V/uA/mA ranges as well, that would add far too extra many factory calibration points.
We are having accuracy problems with the 500V/10A AC VA mode at the more outside edges of the voltage and current values, they are not sure if they can fix this.
I'm now asking if it's worthwhile having the 500V/10A AC VA range at all? I can't personally, but I'm not really an AC industry guy.
Title: Re: EEVBlog 121GW Discussion thread
Post by: imk on April 03, 2018, 03:13:33 pm
Hello,
As don't have the 121GW yet was wondering before ordering if the PC Gui logging software will work with one of these please:
https://www.overclockers.co.uk/asus-usb-bt400-bluetooth-4.0-usb-adaptor-nw-076-as.html (https://www.overclockers.co.uk/asus-usb-bt400-bluetooth-4.0-usb-adaptor-nw-076-as.html)
Many thanks
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on April 03, 2018, 03:14:27 pm
Hello,
As don't have the 121GW yet was wondering before ordering if the PC Gui logging software will work with one of these please:
https://www.overclockers.co.uk/asus-usb-bt400-bluetooth-4.0-usb-adaptor-nw-076-as.html (https://www.overclockers.co.uk/asus-usb-bt400-bluetooth-4.0-usb-adaptor-nw-076-as.html)
Many thanks

Any 4.0 adapter that supports BLE mode should work.
Title: Re: EEVBlog 121GW Discussion thread
Post by: imk on April 03, 2018, 03:37:07 pm
Hello,
As don't have the 121GW yet was wondering before ordering if the PC Gui logging software will work with one of these please:
https://www.overclockers.co.uk/asus-usb-bt400-bluetooth-4.0-usb-adaptor-nw-076-as.html (https://www.overclockers.co.uk/asus-usb-bt400-bluetooth-4.0-usb-adaptor-nw-076-as.html)
Many thanks

Any 4.0 adapter that supports BLE mode should work.

Hello Dave and many thanks for the prompt reply.
So i have been driving me-self nuts trying to find a new MM for a week now and think this really fit my needs.
Only thing i would change if possible would be the ability to remove/swap  the micro sd card without taking the back off, a little hatch would be great and well if you do consider it, it could i guess a retro fit back for those lucky people that already have one.
BTW i have contacted Welectron re when they may have some but was wondering if you had a waiting customer list i could be added to please, i can pm you my email if you wish?
Again many thanks imk
Title: Re: EEVBlog 121GW Discussion thread
Post by: imk on April 03, 2018, 04:00:03 pm
1) Should the 500V AC VA mode be added at the expense of a few of the other lower ranges?
2) Is AC VA mode even useful to people? (obviously the DC VA mode is)

1. My needs are electronic so no need for 500v ac
2. Would AC VA (Watts) be useful for audio amplifier output power measurements? if so then maybe useful to me.
Title: Re: EEVBlog 121GW Discussion thread
Post by: IanB on April 03, 2018, 04:08:30 pm
I'm now asking if it's worthwhile having the 500V/10A AC VA range at all? I can't personally, but I'm not really an AC industry guy.

This is how I understood the question, and how I answered it. It doesn't seem worth sacrificing other capabilities for this.
Title: Re: EEVBlog 121GW Discussion thread
Post by: bicycleguy on April 03, 2018, 06:04:11 pm
With regards to the requested 500V/5A (250VA) VA power mode.
Is that 2500VA?
It is possible to add this (with some sacrifice in other ranges), and we have tested a solution.
What is the sacrifice exactly?  Isn't the next range down 500mVAC.
But now I'm I am wondering whether or not it's actually worthwhile?
After all the meter is only capable of measuring VA and not true Watts, as the chipset does not have the phase measurement capability.
With this in mind, how useful is VA measurement in AC mode to people without a true Watts capability?
Doe's this mean Joe noob (ie me) looking around for things to measure won't be able to look at all my energy wasting 110VAC stuff.  I think my new fangled utility meter bills me measuring only VA? 
Title: Re: EEVBlog 121GW Discussion thread
Post by: HKJ on April 03, 2018, 06:07:21 pm
Doe's this mean Joe noob (ie me) looking around for things to measure won't be able to look at all my energy wasting 110VAC stuff.  I think my new fangled utility meter bills me measuring only VA?

Usual it is Watt the utility meters are measuring. VA is just current multiplied by voltage, i.e. you can get a very good estimate of VA by measuring the current and multiply by 120.
Title: Re: EEVBlog 121GW Discussion thread
Post by: IanB on April 03, 2018, 06:23:58 pm
Doe's this mean Joe noob (ie me) looking around for things to measure won't be able to look at all my energy wasting 110VAC stuff.  I think my new fangled utility meter bills me measuring only VA?

You are better using a Kill-A-Watt (original, or one of the many clones) device for this application. It will report both true power and power factor, and will have a built-in totalizing feature. It is also much safer to plug into a power socket without dangling wires or test leads.

Your utility meter measures actual power and you get charged for actual power. You do not get charged for VA.
Title: Re: EEVBlog 121GW Discussion thread
Post by: 1anX on April 03, 2018, 10:15:56 pm
I bought the meter for electronics and like others have indicated the low burden voltage and higher zener test voltages appealed to me.
I have other meters for mains AC voltages and currents!
Title: Re: EEVBlog 121GW Discussion thread
Post by: Candid on April 03, 2018, 10:26:42 pm
The 5V range does appear wrong on your meter but we haven't been able to reproduce it, it could be an issue with your unit in that range.
Can you confirm that the Hz range functions correctly on your meter?

Can you also test the same range with 400Hz?
HZ range functions well up to about 720kHz in the Hz mode, and up to 680kHz in V mode on the second display (with a sine 2Vpp).

I tested with 400Hz sine 2Vpp and get the same wrong voltage measurement at 5Vac (auto) range mode (1,1xxx Vrms). 50Vac manual mode gives me again the correct measurement.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on April 03, 2018, 11:20:22 pm
Is that 2500VA?

5000VA actually, 10A capable.

Quote
What is the sacrifice exactly?  Isn't the next range down 500mVAC.

The next range down is 500VA, but it's a 50V range, not 500V, that's what I'm saying, there is only one 500V range and that is 10A.

Quote
Doe's this mean Joe noob (ie me) looking around for things to measure won't be able to look at all my energy wasting 110VAC stuff.  I think my new fangled utility meter bills me measuring only VA?

You should not be using a multimeter like this for your appliances, just but a cheap Kill-A-Watt unit that measures proper W and VA power.
Most utilities will charge in W, not VA for residential customers, but that varies depending upon the country and utility company.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Cliff Matthews on April 04, 2018, 12:20:07 am
This $11 inductive meter (https://www.banggood.com/100A-Power-Monitor-Module-AC-Meter-Panel-p-983057.html?cur_warehouse=CN) can be handy enclosed on the receptacle end of a DIY extension cord. Here it is in action (https://youtu.be/ZL7WTpRMNwE).
Title: Re: EEVBlog 121GW Discussion thread
Post by: Elasia on April 04, 2018, 02:28:41 am
AC fruit cake checking in

I also say no, there are more purpose built devices for this on both the low end as above and high end as well like this http://en-us.fluke.com/products/power-quality-analyzers/fluke-345-clamp-meter.html (http://en-us.fluke.com/products/power-quality-analyzers/fluke-345-clamp-meter.html) i got at work.

Or can even be made quickly and cheap but who does that when China does it for you these days

As others already said, i think the world of a good electronics meter built for that purpose.. dont spoil the goods trying to be good at to many different things.
Title: Re: EEVBlog 121GW Discussion thread
Post by: geekGee on April 04, 2018, 03:08:39 am
The meter is EEVBlog branded and I believe the first "E" stands for "electronics".  ;D

That's why I ordered one anyway.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Seppy on April 04, 2018, 03:40:52 am

I was thinking of the spurious VA values. We no longer get these as it's been (as far as we can tell) fixed in software. So if spurious values are being seen, maybe that's a possible cause?
But if it's a checksum thing, then forget I said it.
But as I believe David (seppy) has said, we are no longer getting corrupted data, and hence no more checksum errors.

How could the range switch cause invalid xor checksums?

I don't see spurious VA values as in the early versions of the firmware.

With V1.10 I still see wrong voltage and current displays in certain parts of the measuring range, I see a spurious wrong decimal point in current display and I see wrong range display (A instead of mA) in the current display. All of this in DC VA-mode.

Apart from that the displayed values are consistently wrong.

I guess the invalid checksums must then be some electrical problem in my meter if no one else can see them.

As there seems no way to debug it further, I can't help you there.

Update has been released to the app stores, likely hasn't updated on both yet but these issues should all be resolved now, we also have a new firmware version which will be resolving one of the other issues (when the voltage in VA mode is above 32767 approximately, this firmware update hasn't been released, this issue was a packet issue not a app issue so for those values you'll need to wait for the next firmware update).
Title: Re: EEVBlog 121GW Discussion thread
Post by: Brumby on April 04, 2018, 04:33:17 am
Only thing i would change if possible would be the ability to remove/swap  the micro sd card without taking the back off, a little hatch would be great and well if you do consider it

This has been mentioned before - but I believe the issue is one of safety.  The Cat ratings and safety design of the 121GW is based on the only access to the meter's circuitry being through the probe sockets on the front - which have been designed to certain standards.

To access the microSD card, you would be given access to the microSD card slot - which is connected to the meter's innards.  Such an interface would need very special consideration to be suitably rated - if, indeed, that were at all possible.  Since the microSD facility was a "fit in", the restriction on access in order to maintain safety and the Cat ratings is one that will (as I understand it) have to stand.

Using the Bluetooth facility is probably going to be a better bet for the sort of things I suspect you are contemplating.
Title: Re: EEVBlog 121GW Discussion thread
Post by: 1anX on April 05, 2018, 10:34:58 pm
Hey Dave, should I start checking my letterbox anytime soon for a delivery?
It must be getting very close by now for the Johnny B Goode shipment to be shipped.
Looking forward to playing with this meter sometime very soon  :-+
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on April 05, 2018, 10:54:43 pm
Only thing i would change if possible would be the ability to remove/swap  the micro sd card without taking the back off, a little hatch would be great and well if you do consider it

This has been mentioned before - but I believe the issue is one of safety.  The Cat ratings and safety design of the 121GW is based on the only access to the meter's circuitry being through the probe sockets on the front - which have been designed to certain standards.

To access the microSD card, you would be given access to the microSD card slot - which is connected to the meter's innards.  Such an interface would need very special consideration to be suitably rated - if, indeed, that were at all possible.  Since the microSD facility was a "fit in", the restriction on access in order to maintain safety and the Cat ratings is one that will (as I understand it) have to stand.

Yes, it's an issue of access safety.
I know it's a bit of a PITA, but it takes under 20 seconds to remove the boot, unscrew the cover and remove the SD card and insert into computer.
If you need more accessible data logging then I'd recommend a proper data logger. This is a multimeter first with some SD logging capability, not the other way around.
I guess you could always dremel a slot in the back perhaps?
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on April 05, 2018, 11:16:13 pm
Hey Dave, should I start checking my letterbox anytime soon for a delivery?
It must be getting very close by now for the Johnny B Goode shipment to be shipped.
Looking forward to playing with this meter sometime very soon  :-+

The rest of the Great Scott backer will be shipped first.
We are close to a release solution, just dealing with a few last minute things, that's my job this morning.
Title: Re: EEVBlog 121GW Discussion thread
Post by: IanB on April 05, 2018, 11:19:30 pm
Yes, it's an issue of access safety.
I know it's a bit of a PITA, but it takes under 20 seconds to remove the boot, unscrew the cover and remove the SD card and insert into computer.
If you need more accessible data logging then I'd recommend a proper data logger. This is a multimeter first with some SD logging capability, not the other way around.
I guess you could always dremel a slot in the back perhaps?

I would have imagined trying to have the SD card slot under the battery cover rather than having to open the whole meter to access it...?
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on April 06, 2018, 12:04:17 am
I would have imagined trying to have the SD card slot under the battery cover rather than having to open the whole meter to access it...?

The SD card is under the battery cover (with machine screws, so won't wear out), but like many meters you have to remove the rubber boot to access the battery compartment.
I've timed it, it took me less than 20 seconds to access.
Title: Re: EEVBlog 121GW Discussion thread
Post by: VEGETA on April 06, 2018, 02:47:38 am
Why don't you make the SD card slot from the side like laptops? just a hole\slot in the side of the multimeter and it will be perfect. The holster will hide and protect it.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Cliff Matthews on April 06, 2018, 03:25:27 am
Why don't you make the SD card slot from the side like laptops? just a hole\slot in the side of the multimeter and it will be perfect. The holster will hide and protect it.
But it's not in the same compliance category as a laptop, so it wouldn't have passed standards testing.
(EC 60950 talks about "Emission of flame or expulsion of molten metal")
Title: Re: EEVBlog 121GW Discussion thread
Post by: bitwelder on April 06, 2018, 05:22:57 am
I guess you could always dremel a slot in the back perhaps?
:scared:

Would one of those WiFi-enabled SD cards work?
Title: Re: EEVBlog 121GW Discussion thread
Post by: mtdoc on April 06, 2018, 05:34:42 am
Why don't you make the SD card slot from the side like laptops? just a hole\slot in the side of the multimeter and it will be perfect. The holster will hide and protect it.
But it's not in the same compliance category as a laptop, so it wouldn't have passed standards testing.
(EC 60950 talks about "Emission of flame or expulsion of molten metal")

IIRC the Mooshimeter had the same issue with testing and its SD card slot and also opted for a slot that required opening the case to access.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on April 06, 2018, 05:50:14 am
I guess you could always dremel a slot in the back perhaps?
:scared:

Would one of those WiFi-enabled SD cards work?

It's micro SD, do they even make those?
And no idea if it would work.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Mr.B on April 06, 2018, 06:56:43 am
IIRC the Mooshimeter had the same issue with testing and its SD card slot and also opted for a slot that required opening the case to access.

Correct.
The one I have has thinner indented plastic molding where the slot was in the original design.
The guy who designed the meter had to change the injection mold to comply with the required safety standards.
However, the end user can easily snap out the plastic to make a slot if they wish - at their own risk of course.
Title: Re: EEVBlog 121GW Discussion thread
Post by: mtdoc on April 06, 2018, 12:20:51 pm
IIRC the Mooshimeter had the same issue with testing and its SD card slot and also opted for a slot that required opening the case to access.

Correct.
The one I have has thinner indented plastic molding where the slot was in the original design.
The guy who designed the meter had to change the injection mold to comply with the required safety standards.
However, the end user can easily snap out the plastic to make a slot if they wish - at their own risk of course.

Yep. James had to change it. The result was something that passes testing but can be easily modified for easier SD card access.

I don’t know if something similar could have been done with the 121GW - maybe not since a large OEM is involved. But I agree with Dave that it’s not that hard to get to the SD slot in any case.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on April 06, 2018, 12:25:00 pm
I don’t know if something similar could have been done with the 121GW

It wasn't. The SD card was added after the case molds had been made.
Title: Re: EEVBlog 121GW Discussion thread
Post by: imk on April 06, 2018, 01:08:19 pm
Oh Dave, i wonder if this SD issues is getting more attention than it deserves?

I  need (not urgently) a new multimeter as my main one is on the blink so thought i'd treat myself to a nice new one as landmark birthday coming up.
Friend wants me to do some battery performance comparisons plus i want to do some solar cell output checks so data logging via MM seems the way to go.
Bust my brain for a week going around the reviews/shops looking for what I thought  i wanted which was a wired solution (RS232/USB).
Then a moment of clarity dawned, a MM with 4xAA built in recording/logging at a price the fits my needs+budget equation that doesn't need wires WOW!
Much searching reveals one solution the 121GW, Dave when can i have one please?

I only mentioned the SD hatch as possible scenario "Can't find my USB dongle and Bugger I need to go to workshop for Screwdriver.
Please forget i ever mentioned it and if there's anything i can do to help you get the 121GW in the shops just ask as i'm retired and have time to help good projects like this :-)
Plus lots of C/C++ PC and embedded/PIC coding miles.
 
Ian
 
Title: Re: EEVBlog 121GW Discussion thread
Post by: VEGETA on April 06, 2018, 02:19:33 pm
I wonder about something... Why don't mutlimeters come with rechargeable batteries such as Li-ion\Li-Po? with capability to charge it with micro USB plug.

I suspect that it won't pass tests for safety or so, but I need the correct answer.
Title: Re: EEVBlog 121GW Discussion thread
Post by: IanB on April 06, 2018, 02:29:12 pm
I wonder about something... Why don't mutlimeters come with rechargeable batteries such as Li-ion\Li-Po? with capability to charge it with micro USB plug.

I suspect that it won't pass tests for safety or so, but I need the correct answer.

1) Most multimeters use so little power that rechargeable batteries are unnecessary
2) If you want to use rechargeable batteries with an external charger there is nothing to stop you
3) With a built-in rechargeable battery you are left unable to use the meter while the batteries are recharging, making this an inconvenient solution
Title: Re: EEVBlog 121GW Discussion thread
Post by: Brumby on April 06, 2018, 03:38:23 pm
 4) Access for charging internal batteries would compromise safety - just as having external access to the internal microSD card would be on the 121GW
Title: Re: EEVBlog 121GW Discussion thread
Post by: HKJ on April 06, 2018, 03:53:10 pm
4) Access for charging internal batteries would compromise safety - just as having external access to the internal microSD card would be on the 121GW

It is possible to work around that (A safety rated DC/DC converter).
Title: Re: EEVBlog 121GW Discussion thread
Post by: imk on April 06, 2018, 04:08:07 pm
I wonder about something... Why don't mutlimeters come with rechargeable batteries such as Li-ion\Li-Po? with capability to charge it with micro USB plug.

I suspect that it won't pass tests for safety or so, but I need the correct answer.

Guess this is how you get around the safety issues of rechargeable MM
https://www.alibaba.com/product-detail/Rechargeable-Self-Restoring-LCD-Digital-Multimeter_60366637118.html?spm=a2700.7724857.main07.8.198777e4cV0KF7 (https://www.alibaba.com/product-detail/Rechargeable-Self-Restoring-LCD-Digital-Multimeter_60366637118.html?spm=a2700.7724857.main07.8.198777e4cV0KF7)
Title: Re: EEVBlog 121GW Discussion thread
Post by: VEGETA on April 06, 2018, 04:16:54 pm
4) Access for charging internal batteries would compromise safety - just as having external access to the internal microSD card would be on the 121GW

I think it is just an over concern. I don't think that there is anything bad gonna happen since we have tons of products with Li-ion batteries and are safe, same for SD card issue. But this is just my humble opinion... If there is an affordable good meter like 121gw but with rechargeable battery, I would buy it.

 
Quote
Guess this is how you get around the safety issues of rechargeable MM
https://www.alibaba.com/product-detail/Rechargeable-Self-Restoring-LCD-Digital-Multimeter_60366637118.html?spm=a2700.7724857.main07.8.198777e4cV0KF7 (https://www.alibaba.com/product-detail/Rechargeable-Self-Restoring-LCD-Digital-Multimeter_60366637118.html?spm=a2700.7724857.main07.8.198777e4cV0KF7)

LOL... WTF! this is very nice although being stupid!

perfect workaround  :-DD :-DD :-DD Safety my ***

These probably followed ElectroBOOM advice: "Safety always comes second priority"
Title: Re: EEVBlog 121GW Discussion thread
Post by: HKJ on April 06, 2018, 04:17:35 pm
Guess this is how you get around the safety issues of rechargeable MM
https://www.alibaba.com/product-detail/Rechargeable-Self-Restoring-LCD-Digital-Multimeter_60366637118.html?spm=a2700.7724857.main07.8.198777e4cV0KF7 (https://www.alibaba.com/product-detail/Rechargeable-Self-Restoring-LCD-Digital-Multimeter_60366637118.html?spm=a2700.7724857.main07.8.198777e4cV0KF7)

Keysight has one DMM where you apply 24VDC to the probe input to charge, this means you have a huge external power supply.
I do not really know what I like best of these two solution.
Title: Re: EEVBlog 121GW Discussion thread
Post by: IanB on April 06, 2018, 04:37:45 pm
If there is an affordable good meter like 121gw but with rechargeable battery, I would buy it.

Why would you buy it? What problem does it solve for you?
Title: Re: EEVBlog 121GW Discussion thread
Post by: ez24 on April 06, 2018, 06:25:44 pm

Guess this is how you get around the safety issues of rechargeable MM
https://www.alibaba.com/product-detail/Rechargeable-Self-Restoring-LCD-Digital-Multimeter_60366637118.html?spm=a2700.7724857.main07.8.198777e4cV0KF7 (https://www.alibaba.com/product-detail/Rechargeable-Self-Restoring-LCD-Digital-Multimeter_60366637118.html?spm=a2700.7724857.main07.8.198777e4cV0KF7)

This meter has something I like : polyfuses

Why don't other meters use them?

Title: Re: EEVBlog 121GW Discussion thread
Post by: HKJ on April 06, 2018, 06:34:16 pm
This meter has something I like : polyfuses

Why don't other meters use them?

One reason may be burden voltage, they have higher on resistance than fuses (At least the ones I have seen in multimeters).

They can probably not match a high quality fuse in safety either.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Cliff Matthews on April 06, 2018, 06:37:48 pm
DMM front-end design factors-in known resistance of fuses that recover well. Sadly, polyfuses may some undesirable specs.
Title: Re: EEVBlog 121GW Discussion thread
Post by: bitwelder on April 06, 2018, 07:19:14 pm
Would some kind of inductive powering (like Qi charging) feasible in a safe way in a meter, if the receiving antenna is e.g. well inside the body of the instrument, like the battery compartment?
Title: Re: EEVBlog 121GW Discussion thread
Post by: IanB on April 06, 2018, 08:38:08 pm
Would some kind of inductive powering (like Qi charging) feasible in a safe way in a meter, if the receiving antenna is e.g. well inside the body of the instrument, like the battery compartment?

Again, it adds complexity and cost, to what purpose? What is the point?

Cell phones get charged every few days, so convenient recharging is relevant.

Multimeters get recharged every few months, maybe once a year. So what problem does a built-in rechargeable battery solve?
Title: Re: EEVBlog 121GW Discussion thread
Post by: tautech on April 06, 2018, 10:29:05 pm
Would some kind of inductive powering (like Qi charging) feasible in a safe way in a meter, if the receiving antenna is e.g. well inside the body of the instrument, like the battery compartment?

Again, it adds complexity and cost, to what purpose? What is the point?

Cell phones get charged every few days, so convenient recharging is relevant.

Multimeters get recharged every few months, maybe once a year. So what problem does a built-in rechargeable battery solve?
Overall size and weight especially with lithium ion.

Joe Smith did some DMM logging tests with Bluetooth and it certainly can chew up batteries whereas if a DMM was logging while parked in an inductive charging cradle long term battery live would no longer be part of the picture.

Dave might like to think about a R2 version implementing these sorts of design features.
Title: Re: EEVBlog 121GW Discussion thread
Post by: IanB on April 06, 2018, 10:49:36 pm
Joe Smith did some DMM logging tests with Bluetooth and it certainly can chew up batteries whereas if a DMM was logging while parked in an inductive charging cradle long term battery live would no longer be part of the picture.

That's true, but...I am forced to wonder if a combination of "sensitive measuring instrument" and "externally imposed inductive field" would be a good idea?

I am inclined to suspect it would be a shielding nightmare.
Title: Re: EEVBlog 121GW Discussion thread
Post by: IanB on April 06, 2018, 10:52:22 pm
BTW, I have logged for hours at a time with my favorite logging meters and not had any concerns about battery drain, even though using a 9 V battery.

It's probably not the logging that's expensive, but the Bluetooth.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on April 06, 2018, 11:29:07 pm
Would some kind of inductive powering (like Qi charging) feasible in a safe way in a meter, if the receiving antenna is e.g. well inside the body of the instrument, like the battery compartment?

No point when your meter has 500+ hours battery life, and you can change the batteries available anywhere.
Title: Re: EEVBlog 121GW Discussion thread
Post by: VEGETA on April 07, 2018, 01:06:09 am
when will 121gw meters be available again? how much total price to Jordan?

Also what is the difference in performance between it and the brymen one?
Title: Re: EEVBlog 121GW Discussion thread
Post by: Brumby on April 07, 2018, 01:33:19 am
To all those who missed the point on safety I was trying to make:   :palm:

The safety concern is one where you have a breach in the isolation of the meter for a charging port.  Only this response addressed that:
Would some kind of inductive powering (like Qi charging) feasible in a safe way in a meter, if the receiving antenna is e.g. well inside the body of the instrument, like the battery compartment?


Whether any efforts along this line are worth the effort, however, is another question.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on April 07, 2018, 03:23:47 am
After quite some R&D and testing, we have decided to drop the proposed 500V VA range support.
All the existing 50V and lower ranges will be available.
Title: Re: EEVBlog 121GW Discussion thread
Post by: imk on April 07, 2018, 06:54:50 am
Lipo's, alkaline's, Nicad etc are all things of the past anyway.
TEN TIMES the energy density of the above and all you need is tea spoon of sugar to recharge them.
500 hr becomes 5000 hr and that's half a year of continues use, even electric car start to make sense :-)
https://vtnews.vt.edu/articles/2014/01/012213-cals-battery.html
Title: Re: EEVBlog 121GW Discussion thread
Post by: Messtechniker on April 07, 2018, 01:13:27 pm
Well, most news on this sugar battery is from 2014,
with not much thereafter.  Problems? Busted? April fools? :wtf:
Title: Re: EEVBlog 121GW Discussion thread
Post by: bitwelder on April 07, 2018, 01:43:33 pm
Would some kind of inductive powering (like Qi charging) feasible in a safe way in a meter, if the receiving antenna is e.g. well inside the body of the instrument, like the battery compartment?

No point when your meter has 500+ hours battery life, and you can change the batteries available anywhere.
I was thinking of very long datalogging sessions, and perhaps using a meter that is not so low-power to last 500+ hours.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Scottjd on April 07, 2018, 06:13:40 pm
Would some kind of inductive powering (like Qi charging) feasible in a safe way in a meter, if the receiving antenna is e.g. well inside the body of the instrument, like the battery compartment?

No point when your meter has 500+ hours battery life, and you can change the batteries available anywhere.
Is this 500 hours of battery life while actively logging to an SD card and broadcasting serial Bluetooth signals? I have a logging meter, it doesn’t get any battery life like a normal one does with a single 9V.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Scottjd on April 07, 2018, 06:20:08 pm
4) Access for charging internal batteries would compromise safety - just as having external access to the internal microSD card would be on the 121GW
How would access to the SD card compromise safety?
Ok, potential loop grounding issue if plugged into a computer USB port while measuring mains voltage at the same time. Or like three meters I own the simple solution is serial put data to usb via two infrared making it completely iscolated from the ground in the USB of the computer.
After all, it doesn’t need to be USB 3.1 Gen 2 sleeeds at 10Gbs data transfer, it is just little lines of text being stored. If the micro processor had a little extra code it might be able to complete one of the oldest tasks besides computers have dkne for years besides a calculator, and compress this into a zip file making it 1/100th of the original size for faster transfer speeds.

Update: I just saw the comment you made to those who missed the point. I didn’t miss it, but I do have a $20 meter in my hand that does this type of isolation made by Digitek, it’s the DT-4000ZC
if a $20 meter can do this, I’m sure the effort can be that much extra?
Title: Re: EEVBlog 121GW Discussion thread
Post by: mikeselectricstuff on April 07, 2018, 06:25:48 pm
4) Access for charging internal batteries would compromise safety - just as having external access to the internal microSD card would be on the 121GW
How would access to the SD card compromise safety?
Because the DMM's 0V rail could be connected to several hundred volts
Title: Re: EEVBlog 121GW Discussion thread
Post by: Scottjd on April 07, 2018, 06:51:39 pm
4) Access for charging internal batteries would compromise safety - just as having external access to the internal microSD card would be on the 121GW
How would access to the SD card compromise safety?
Because the DMM's 0V rail could be connected to several hundred volts

Ok, I know I dropped a $20 meter for an example,but the fluke 289 works the same way. The receiving IR and PCB/Chip is not connected to the main DMM PCB at all, in fact it’s powered by the 5VDC from the USB port. So forgive me if I wrong, but I still don’t see how that would be possible.
Title: Re: EEVBlog 121GW Discussion thread
Post by: IanB on April 07, 2018, 07:50:56 pm
Ok, I know I dropped a $20 meter for an example,but the fluke 289 works the same way. The receiving IR and PCB/Chip is not connected to the main DMM PCB at all, in fact it’s powered by the 5VDC from the USB port. So forgive me if I wrong, but I still don’t see how that would be possible.

Because the SD card does not have onboard power like a USB port, and so the SD card driver has to be powered by the meter's internal circuitry, which means there is an electrical path between the terminals of the meter and the SD card.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Scottjd on April 08, 2018, 01:38:59 am
Ok, I know I dropped a $20 meter for an example,but the fluke 289 works the same way. The receiving IR and PCB/Chip is not connected to the main DMM PCB at all, in fact it’s powered by the 5VDC from the USB port. So forgive me if I wrong, but I still don’t see how that would be possible.

Because the SD card does not have onboard power like a USB port, and so the SD card driver has to be powered by the meter's internal circuitry, which means there is an electrical path between the terminals of the meter and the SD card.

Ok, apparently I missed the point. I thought we were talking about transferring data on the SD off the meter   different ways?
I’m over it.
Title: Re: EEVBlog 121GW Discussion thread
Post by: imk on April 08, 2018, 05:34:03 pm
121GW battery life vs battery type.
As far as the 500 hr battery life claim is this for alkaline or NiCad and what mah rating
My camera packs up much earlier on nicad than on fresh alkaline as the static voltage is lower for NiCad's
Any 121GW test data for various battery chemistry yet?
Title: Re: EEVBlog 121GW Discussion thread
Post by: maukka on April 09, 2018, 08:56:11 am
You should not be using a multimeter like this for your appliances, just but a cheap Kill-A-Watt unit that measures proper W and VA power.
Most utilities will charge in W, not VA for residential customers, but that varies depending upon the country and utility company.
I did not think the Killawatt could read very low power levels. 
But a good (for a cheap) power meter like the Zhurui PR10 (https://www.aliexpress.com/store/group/Power-Recorder/427884_509189231.html) will do fine down to 5mA at 230V. Takes 0.1 watts to display power though.

HKJ's test http://lygte-info.dk/review/Power%20Zhurui%20Power%20Recorder%20PR10%20UK.html (http://lygte-info.dk/review/Power%20Zhurui%20Power%20Recorder%20PR10%20UK.html)
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on April 09, 2018, 11:25:39 am
121GW battery life vs battery type.
As far as the 500 hr battery life claim is this for alkaline or NiCad and what mah rating
My camera packs up much earlier on nicad than on fresh alkaline as the static voltage is lower for NiCad's
Any 121GW test data for various battery chemistry yet?

4.2V dropout voltage, approx 5mA consumption, you can do the math with whatever chemistry.
The spec is Alkaline.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on April 09, 2018, 11:29:08 am
Is this 500 hours of battery life while actively logging to an SD card and broadcasting serial Bluetooth signals?

No, logging is lower, but don't have accurate specs for that. SD drops it to a few hundred hours IIRC. Have not tested Bluetooth, but it's BLE at a low sample rate so shouldn't take much.
Title: Re: EEVBlog 121GW Discussion thread
Post by: coromonadalix on April 10, 2018, 02:31:31 am
would be nice to pop in something like this gadget :  http://www.icstation.com/dual-card-adapter-shield-micro-card-dual-system-switch-converter-raspberry-b2b3b-p-10868.html (http://www.icstation.com/dual-card-adapter-shield-micro-card-dual-system-switch-converter-raspberry-b2b3b-p-10868.html)

or an flexible sd card extender ???, but you have to slot the casing either way ...
Title: Re: EEVBlog 121GW Discussion thread
Post by: imk on April 10, 2018, 07:16:32 am
Is this 500 hours of battery life while actively logging to an SD card and broadcasting serial Bluetooth signals?

No, logging is lower, but don't have accurate specs for that. SD drops it to a few hundred hours IIRC. Have not tested Bluetooth, but it's BLE at a low sample rate so shouldn't take much.

Either way this 121GW is way ahead of anything else i have found, the PeakTech 3440 only does 7hr on batteries when logging so not a solution at all.
121GW is definitely going to get best meter of the year award :-)
Title: Re: EEVBlog 121GW Discussion thread
Post by: Brumby on April 10, 2018, 08:49:48 am
Getting ready to print the shipping labels is my guess.
Title: Re: EEVBlog 121GW Discussion thread
Post by: imk on April 10, 2018, 09:02:17 am
121GW battery life vs battery type.
As far as the 500 hr battery life claim is this for alkaline or NiCad and what mah rating
My camera packs up much earlier on nicad than on fresh alkaline as the static voltage is lower for NiCad's
Any 121GW test data for various battery chemistry yet?

4.2V dropout voltage, approx 5mA consumption, you can do the math with whatever chemistry.
The spec is Alkaline.

Well quick math looks like a 2400 mah AA NiCd down to 10% charge will still run the 121GW, so still in the region of 500 hr run time.
3200 mah Ni-MH would real push the envelope, think two sets of these would be why for me to go :-)

No mention of a supply date yet, so makes me wonder if not some under the covers magic being worked out  8)
Title: Re: EEVBlog 121GW Discussion thread
Post by: HKJ on April 10, 2018, 09:16:23 am
3200 mah Ni-MH would real push the envelope, think two sets of these would be why for me to go :-)

3200mAh NiMH would probably not work very long, the maximum real capacity I have seen is around 2500-2700mAh, anything rated with more usual has a lot less.
Title: Re: EEVBlog 121GW Discussion thread
Post by: imk on April 11, 2018, 02:56:06 pm
121GW battery life vs battery type.
As far as the 500 hr battery life claim is this for alkaline or NiCad and what mah rating
My camera packs up much earlier on nicad than on fresh alkaline as the static voltage is lower for NiCad's
Any 121GW test data for various battery chemistry yet?

4.2V dropout voltage, approx 5mA consumption, you can do the math with whatever chemistry.
The spec is Alkaline.

Well quick math looks like a 2400 mah AA NiCd down to 10% charge will still run the 121GW, so still in the region of 500 hr run time.
3200 mah Ni-MH would real push the envelope, think two sets of these would be why for me to go :-)

No mention of a supply date yet, so makes me wonder if not some under the covers magic being worked out  8)

Hello HKJ,
Like with most things these days what it says on the box is not what it does.
Imk
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on April 12, 2018, 01:05:16 am
@EEVBlog Just receive a "last minute address change" notification from KS. Are the US units about to be shipped?

Yes, we had to lock down the address changes and KS makes us wait 48hours. We actually have like 150 or something last minutes changes!
1000 units will be available end of April (as in available to ship to the various distributors, Welectron for the EU, here for Oz/NZ/others, EUi/KaneTest for the US)
and another 1000 units end of May
(so I guess their production capacity is 1000 units a month)
As before, the remainder of the Great Scott backers will be shipped first. But given that there will be a lot of leftover units from the first 1000 unit batch, many Johnny B. Goode backers will get theirs at the same time. 
Title: Re: EEVBlog 121GW Discussion thread
Post by: VEGETA on April 12, 2018, 05:21:25 am
So when will this be available to us regular customers?

I am in Jordan, how much will it cost to be shipped to here?
Title: Re: EEVBlog 121GW Discussion thread
Post by: tomp on April 12, 2018, 05:26:42 am
Welectron for the EU
Hi, Dave. I have also received "last minute address change" e-mail, but I have not received the PayPal VAT invoices yet. Have you sent them? I am in Johnny B. Goode group and I chose the EU shipping option. Please be so kind and post an update to Kickstarter as soon as you send the invoices, so we do not miss something.

By the way, how is the "exclusive EEVblog video of the development history of this meter"? :)
Title: Re: EEVBlog 121GW Discussion thread
Post by: imk on April 12, 2018, 10:05:40 am
@EEVBlog Just receive a "last minute address change" notification from KS. Are the US units about to be shipped?

Yes, we had to lock down the address changes and KS makes us wait 48hours. We actually have like 150 or something last minutes changes!
1000 units will be available end of April (as in available to ship to the various distributors, Welectron for the EU, here for Oz/NZ/others, EUi/KaneTest for the US)
and another 1000 units end of May
(so I guess their production capacity is 1000 units a month)
As before, the remainder of the Great Scott backers will be shipped first. But given that there will be a lot of leftover units from the first 1000 unit batch, many Johnny B. Goode backers will get theirs at the same time.


Already got my name on one at Welectron n waiting, thanks Dave for the heads up, bit of luck be here for my milestone Bday
imk
Title: Re: EEVBlog 121GW Discussion thread
Post by: Average Meatsack on April 13, 2018, 03:38:23 am
Bugger! Missed the email to confirm the delivery address. Will it be a signature required delivery? If not, that may cause problems since the front door of my flat faces the road and I wouldn't want it stolen.

Which courier company is handling the NZ deliveries. I just hope it isn't AusPost as my one and only experience with them was terrible.
Title: Re: EEVBlog 121GW Discussion thread
Post by: nickdepinet on April 13, 2018, 09:00:05 pm
@EEVBlog Just receive a "last minute address change" notification from KS. Are the US units about to be shipped?

Yes, we had to lock down the address changes and KS makes us wait 48hours. We actually have like 150 or something last minutes changes!
1000 units will be available end of April (as in available to ship to the various distributors, Welectron for the EU, here for Oz/NZ/others, EUi/KaneTest for the US)
and another 1000 units end of May
(so I guess their production capacity is 1000 units a month)
As before, the remainder of the Great Scott backers will be shipped first. But given that there will be a lot of leftover units from the first 1000 unit batch, many Johnny B. Goode backers will get theirs at the same time.

A bit confused here - are the US Great Scott units being shipped from the fixed units from before or are they coming from this new batch being shipped at the end of April? Basically just wondering what happened to the original great scott units that made it through customs into the US before they got redirected to KaneTest.
Title: Re: EEVBlog 121GW Discussion thread
Post by: TMM on April 14, 2018, 08:01:56 am
Would some kind of inductive powering (like Qi charging) feasible in a safe way in a meter, if the receiving antenna is e.g. well inside the body of the instrument, like the battery compartment?
The main issue is that the inductive field will couple into the analogue front end and maybe throw it out of spec - semiconductor junctions can act as rectifiers and cause an offset on the measurement. I design inductively powered devices and just measuring small signals in the presence of a HF band inductive field can be challenging at times. Unlike electric fields it's not trivial to make a device immune to HF band magnetic fields - thin metal cans do diddly squat. A better solution would just be to power it with a properly isolated DC-DC supply.
Title: How to purchase 121GW?
Post by: rpb1 on April 14, 2018, 03:24:08 pm
seemingly stupid question... i must have missed something? 

how do i get into the queue for one or more of the 121GW's to be released in May?  i'm in the USA

essentially, how do i purchase?

been spinning around looking in eevblog and i cant find this info.  Found it listed in the "store" but without a means to order it - only view info.

Title: Re: EEVBlog 121GW Discussion thread
Post by: Brumby on April 14, 2018, 03:34:27 pm
If you haven't got your name down in the Kickstarter, you will have to wait until Dave gets them into his online shop.  Before that happens, he has to honour the outstanding Kickstarter orders.

Keep checking on his shop - but from what I've gleaned, don't expect to see anything for a month or more.
 Check back on this thread, too - as you will likely pick up on progress here.

There is no "queue" you can get on.  Dave won't be taking back orders.  You will just have to wait until they are available and grab one - just like the rest of us.

UPDATE:
Actually, this post of Dave's gives more detail...
@EEVBlog Just receive a "last minute address change" notification from KS. Are the US units about to be shipped?

Yes, we had to lock down the address changes and KS makes us wait 48hours. We actually have like 150 or something last minutes changes!
1000 units will be available end of April (as in available to ship to the various distributors, Welectron for the EU, here for Oz/NZ/others, EUi/KaneTest for the US)
and another 1000 units end of May
(so I guess their production capacity is 1000 units a month)
As before, the remainder of the Great Scott backers will be shipped first. But given that there will be a lot of leftover units from the first 1000 unit batch, many Johnny B. Goode backers will get theirs at the same time.
Title: Re: EEVBlog 121GW Discussion thread
Post by: rpb1 on April 14, 2018, 05:14:17 pm
thanks Brumby,

ya i read that post as well... just wasnt sure.

i have no issue with waiting, my Fluke will work fine until then i'm sure !!   
would rather wait for full production anyway when all bugs are vetted.

i'll just wait until it becomes something that can be ordered from the shop.

Title: Re: EEVBlog 121GW Discussion thread
Post by: lacek on April 15, 2018, 10:21:27 am
is there somewhere a "comparison" of 121GW and say BM869s or other good multimeters say in terms of accuracy? 121GW certainly has lots to otter such as wireless PC connectivity, but this 50mV range seems really cool (though I do not understand what does it mean its only in relative mode).
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on April 15, 2018, 10:45:04 am
@EEVBlog Just receive a "last minute address change" notification from KS. Are the US units about to be shipped?

Yes, we had to lock down the address changes and KS makes us wait 48hours. We actually have like 150 or something last minutes changes!
1000 units will be available end of April (as in available to ship to the various distributors, Welectron for the EU, here for Oz/NZ/others, EUi/KaneTest for the US)
and another 1000 units end of May
(so I guess their production capacity is 1000 units a month)
As before, the remainder of the Great Scott backers will be shipped first. But given that there will be a lot of leftover units from the first 1000 unit batch, many Johnny B. Goode backers will get theirs at the same time.

A bit confused here - are the US Great Scott units being shipped from the fixed units from before or are they coming from this new batch being shipped at the end of April? Basically just wondering what happened to the original great scott units that made it through customs into the US before they got redirected to KaneTest.

Technically they are the original units.
Title: Re: EEVBlog 121GW Discussion thread
Post by: fanOfeeDIY on April 15, 2018, 01:54:34 pm
Maybe some people laugh :)

I purchased some other 50,000 count handheld DMMs just for the video,
from curiosity of the auto range speed.

I think I need to join the therapy thread. :)

https://youtu.be/3r_a7RUtwpw
Title: Re: EEVBlog 121GW Discussion thread
Post by: glarsson on April 16, 2018, 12:20:41 pm
Is it a fair teat to connect several meters together in ohms mode and drawing conclusions from how they behave? Several meters trying to push sequences of various currents and interpreting the resulting voltage. Chaos. Might work ok with shorted probes, but still...
Title: Re: EEVBlog 121GW Discussion thread
Post by: Brumby on April 16, 2018, 12:44:31 pm
Is it a fair teat to connect several meters together in ohms mode and drawing conclusions from how they behave? Several meters trying to push sequences of various currents and interpreting the resulting voltage. Chaos. Might work ok with shorted probes, but still...

That was my initial reaction when I first saw that sort of setup - but I think the answer is that it can only work with shorted probes.
Title: Re: EEVBlog 121GW Discussion thread
Post by: bicycleguy on April 16, 2018, 05:18:33 pm
...
I think I need to join the therapy thread. :)
..
Yes, you need help :-+
Title: Re: EEVBlog 121GW Discussion thread
Post by: fanOfeeDIY on April 17, 2018, 11:37:11 pm
Does your wife know?   :-DD   Looking forward to seeing the high resolution pictures of the two meters.

My wife fount it out..... She saw my video.....

So I told her that you are globally famous which is a good thing :)

Then the reply was silence....

I do not feel I could buy any more multimeter in my life  :'(
Title: Re: EEVBlog 121GW Discussion thread
Post by: fanOfeeDIY on April 17, 2018, 11:48:10 pm
Is it a fair teat to connect several meters together in ohms mode and drawing conclusions from how they behave? Several meters trying to push sequences of various currents and interpreting the resulting voltage. Chaos. Might work ok with shorted probes, but still...

That was my initial reaction when I first saw that sort of setup - but I think the answer is that it can only work with shorted probes.

I thought the same.
I am not sure it is in the video, I printed out the spec pages of all multimeters (I had them on right side of the desk) and on manual of DT4282 had the current for every ohm range used, and TY720 had the maximum current could be used for every ohm range. All of the currents were different.

I worried first of damaging the multimeters by current flowing from other multimeters when connecting together.
My brain still only has analog meter age and it might stress the battery inside.
( Then I thought if digital multimeter was so fragile, it would not survive joe's robustness test. :) )
And the shorting the probe all the current from all meters of all ranges could be the same behavior even for the individually shorting the probe.

End up connecting all multmeters together. I am too lazy to make some jig for taking video. :)

Title: Re: EEVBlog 121GW Discussion thread
Post by: Fungus on April 18, 2018, 04:18:21 am
Then the reply was silence....

:-DD :-DD
There's already a fancy Agilent and another Hioki in the background so I guess he knows what he's doing.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Fungus on April 18, 2018, 05:10:14 am
Is it a fair teat to connect several meters together in ohms mode and drawing conclusions from how they behave? Several meters trying to push sequences of various currents and interpreting the resulting voltage. Chaos. Might work ok with shorted probes, but still...

That was my initial reaction when I first saw that sort of setup - but I think the answer is that it can only work with shorted probes.

I thought the same.

I worried first of damaging the multimeters by current flowing from other multimeters when connecting together.
My brain still only has analog meter age and it might stress the battery inside.
( Then I thought if digital multimeter was so fragile, it would not survive joe's robustness test. :) )

It wouldn't damage any meter with a proper CAT rating.

OTOH it might skew the test results by giving some meters a head start. eg. Nether the Fluke nor the Hioki are showing "0L" at the start of each test.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Scottjd on April 18, 2018, 05:16:08 am
Does your wife know?   :-DD   Looking forward to seeing the high resolution pictures of the two meters.

My wife fount it out..... She saw my video.....

So I told her that you are globally famous which is a good thing :)

Then the reply was silence....

I do not feel I could buy any more multimeter in my life  :'(
Ok, so it’s a technicality but this idea might work?
You don’t BUY anymore, just do what some other youtubers do.
Contact bangood and they will send you meters. Then your not buying any of them.
I personally don’t work with bangood so I don’t know how it works. But as long as you disclose it’s from a vendor before the video review or testing I don’t think many people watching care that much these days.
Off the top of my head in the genre of electronic YouTube channels I can think of 3 or 4 that get items all the time from bangood and they still have high subs and views, so it probably doesn’t matter much.
This way you can keep your DMM addiction going without buying another one.  :-+
Title: Re: EEVBlog 121GW Discussion thread
Post by: Fungus on April 18, 2018, 05:22:56 am
Ok, so it’s a technicality but this idea might work?
You don’t BUY anymore, just do what some other youtubers do.
Contact bangood and they will send you meters. Then your not buying any of them.

There's a place that sends you free multimeters? For free?

Don't let that information reach the therapy thread.  :scared:
Title: Re: EEVBlog 121GW Discussion thread
Post by: Scottjd on April 18, 2018, 05:40:00 am
Is it a fair teat to connect several meters together in ohms mode and drawing conclusions from how they behave? Several meters trying to push sequences of various currents and interpreting the resulting voltage. Chaos. Might work ok with shorted probes, but still...

That was my initial reaction when I first saw that sort of setup - but I think the answer is that it can only work with shorted probes.

I thought the same.
I am not sure it is in the video, I printed out the spec pages of all multimeters (I had them on right side of the desk) and on manual of DT4282 had the current for every ohm range used, and TY720 had the maximum current could be used for every ohm range. All of the currents were different.

I worried first of damaging the multimeters by current flowing from other multimeters when connecting together.
My brain still only has analog meter age and it might stress the battery inside.
( Then I thought if digital multimeter was so fragile, it would not survive joe's robustness test. :) )
And the shorting the probe all the current from all meters of all ranges could be the same behavior even for the individually shorting the probe.

End up connecting all multmeters together. I am too lazy to make some jig for taking video. :)
My thoughts on the difference in speed for the readings in addition to what others mentioned.
Despite them all being 50k count meters, you will notice they have different levels of resolution for the resistance mode. Not all 50K or even 60K meters offer high resolution in resistance.
So I was wondering if the meters that show a higher resolution could be the reason for a slightly longer time. This gets tricky, because if you manually set the 121GW to display the same resolution as the others it might have an advantage also not having to auto detect the range of the resistance. I guess either way you run it, it still won’t be exactly a far comparison? Then again you could say the 121GW took a little longer because it’s factoring in a higher resolution of resistance to display even in Auto range.
I think even my Fluke 289 60K count meter shows lower resolution then the 121GW does in resistance. 
But it shows the point you were demonstrating, the average speed of the auto range detection.

I would be interesting to see how the 121GW stands against a bench meter that you can set to display the same resolution and still use auto ranging. Maybe something like a much older HP 34401A in two wire mode?
Joe, don’t you own a HP 34401A? I would try this, but I’m missing the 121GW and still waiting.
I know you have a preproduction 121GW, not sure how or if the firmware updates work on your version or if you tried to update it?

Hopefully it comes soon before I move, I figured after the Kickstarter address update request it was going to be just days away before getting a tracking number. It’s getting so close to the dates I’m looking to sell my house I might have to ask for a refund and forgo the idea of reviewing it despite being in the Great Scott group. Even if I get it before I sell my lab might be packed up by then so I wouldn’t be able to do any videos anyway.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Scottjd on April 18, 2018, 05:41:24 am
Ok, so it’s a technicality but this idea might work?
You don’t BUY anymore, just do what some other youtubers do.
Contact bangood and they will send you meters. Then your not buying any of them.

There's a place that sends you free multimeters? For free?

Don't let that information reach the therapy thread.  :scared:
There’s a therapy thread? Please share, my best friend needs multimeter obsession help.  :-DD
Title: Re: EEVBlog 121GW Discussion thread
Post by: Fungus on April 18, 2018, 06:06:02 am
There's a place that sends you free multimeters? For free?

Don't let that information reach the therapy thread.  :scared:
There’s a therapy thread? Please share, my best friend needs multimeter obsession help.  :-DD

https://www.eevblog.com/forum/testgear/test-equipment-anonymous-(tea)-group-therapy-thread/ (https://www.eevblog.com/forum/testgear/test-equipment-anonymous-(tea)-group-therapy-thread/)
Title: Re: EEVBlog 121GW Discussion thread
Post by: Scottjd on April 18, 2018, 06:43:54 am
There's a place that sends you free multimeters? For free?

Don't let that information reach the therapy thread.  :scared:
There’s a therapy thread? Please share, my best friend needs multimeter obsession help.  :-DD

https://www.eevblog.com/forum/testgear/test-equipment-anonymous-(tea)-group-therapy-thread/ (https://www.eevblog.com/forum/testgear/test-equipment-anonymous-(tea)-group-therapy-thread/)

Awesome, thanks. I sent an email to his wife, time to set up an intervention for him. It’s for his own good, he just doesn’t know it yet. Or he’s in denial, maybe he needs to hit bottom first.
Either way, this will plant the seed and it will be up to him.
Thanks for that thread.
Title: Re: EEVBlog 121GW Discussion thread
Post by: VEGETA on April 19, 2018, 05:46:42 am
How much will it cost when it is ready? how much shipping to Jordan?

I am interested in it since I used to measure low value resistors (0.15) and current flowing through it but my meters weren't optimal for the job. This one should be significantly better overall.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Scottjd on April 19, 2018, 10:03:33 am
I thought they would have shipped by now. 
According to yesterday’s update I guess the shipping information update request was only for people to receive the PCB and switch fix, not for shipping meters to others. That wasn’t clear, so as it stands not ETA on when the meters will resume shipping. Well this a the official statement “ future shipments which should be commencing again shortly.”
Who knows what shortly is? With this time line I may need to update my address, or maybe not. I guess that depends on what shortly is?
Title: Re: EEVBlog 121GW Discussion thread
Post by: Terry01 on April 19, 2018, 01:53:03 pm
I thought they would have shipped by now. 
According to yesterday’s update I guess the shipping information update request was only for people to receive the PCB and switch fix, not for shipping meters to others. That wasn’t clear, so as it stands not ETA on when the meters will resume shipping. Well this a the official statement “ future shipments which should be commencing again shortly.”
Who knows what shortly is? With this time line I may need to update my address, or maybe not. I guess that depends on what shortly is?
So much for Christmas.  Funny is that you bought it for an early review and even though we are several months into the KS, even if it takes a half year for you to see the meter, you may still be one of the first reviewers.   :-DD


Ha Ha! Hope you get it soon buddy...
Title: Re: EEVBlog 121GW Discussion thread
Post by: Scottjd on April 20, 2018, 07:56:09 am
I thought they would have shipped by now. 
According to yesterday’s update I guess the shipping information address update request was mostly for people receiving  the PCB and switch fix, not for shipping meters to those still waiting. That wasn’t clear on the address update request, so as it stands no ETA on when the meters will resume shipping. Well the official statement is  “future shipments which should be commencing again shortly.”
Who know what shortly is? With this time line I may need to update my address before shorty happens? I guess that depends on what shortly is defined as?
So much for Christmas.  Funny is that you bought it for an early review and even though we are several months into the KS, even if it takes a half year for you to see the meter, you may still be one of the first reviewers.   :-DD

LOL, some day, maybe someday? I know Vegeta just asked about it based on the resolution it displays for reading resistors. I thought to myself that is what I was planning for my review was accuracy of the meter at a decent price for the resolution.
I did invest a chunk of money for new precision resistors to go with the ones I already owned used in the BM235 review, and used to benchmark the HP 34401A when I received it 2 years ago. I still have the same voltage standard I built and it’s still accurate as the day I tuned it after it warms up. I hope to show that the HP bench meter hasn’t drifted in two years and it’s  still as accurate from when I did the BM235 review. Even bought a new low value capacitor standard to show higher resolution readings in these mode. Even my Fluke 289 has a hard time displaying this capacitor standard correctly unless I manually range it. I couldn’t find all the resistors ranges I wanted in a milspec 0.025% accuracy with low temperature coefficiency like the ones I already own, so some of the higher values I bought are 0.1% to 1% tolerances like the 10M ohm, 1G ohm values. I need to build a little box like yours, I bought a box for this, just never had the time to move all the resistors into the box yet.
The plan was to show the features, accuracy and precision of the 121GW compared to some bench meters and see ifs it can be a good mobile alternative,  or smaller option to save on bench space for the hobbiest. I have one 5 digit meter that is NIST certified that partially validates my 6.5 digit 34401A so I know it’s still reading accurate, and other logging meters  Fluke 289 I planed to compare with on long 24/48 hours logging sessions.   Now that I’m thinking of this again the NIST certification may be expired on the 5 digit meter now, or might be expired by the time I get the 121GW meter. But it was still valid in December and January.

Was looking forward to possible third party firmware for future features like power factor calculation readings with AC LED lights, but with the VA now limited to the 50V range I don’t think this would be possible anymore like on the mooshie meter.  I might end up buying another mooshie before I get the 121GW since technically it’s a Bluetooth logging meter for comparison if they have fixed the app issues. I did test it shortly after iOS 11, so this could have been a lot of the app and Bluetooth disconnect issues I was seeing? Or keep using a $29 kilowatt meter for power factor readings, but I was looking for the all in one meter.

Open source firmware was a selling point. Although not all open source t I think it’s been reversed engineered enough to make changes. I believe these talented coders are waiting for a near final firmware before making any bug changes. Maybe these same people that can code might make a better iOS Apple app also since to my knowledge the official EEVBlog iOS app still isn’t done.  Just a generic app from the manufacturer is available. I thought with the extra time on delays and shipping the EEVBlog iOS official app might have been completed by now? Heck, a one time bottom banner ad at the app launch during BT pairing could produce a residual income to pay for any yearly app fee, and if the meter takes off it might even turn a profit for future development and all improvements.

Since I invested money to do a good/bad review I’m trying to hang in with this. Ok,  I don’t really do “bad reviews” or thumbs down fail reviews, I try to do honest reviews for people to decide if the product is the best for the users needs. Sometimes you need more then one tool for the job, but it’s always nice if you can find one tool that does everything you need for your job. If I didn’t buy theses new resistors and capacitor standards I probably would have asked for a refund months ago.

Ideas, plans, life decisions, I seem to be waiting on other factors I don’t have any control over.  Once winter ends I can start to pack the house to sell. It was snowing again today and I have a birds that nested over my outside solar light and it’s snowing,  probably hope the LED lights will keep them warm. Since winter “supposedly” ended we have had a few nice mid 70’s days, but also a tornado that touch down, a few thunderstorms, then back to freezing and snow three more times. What weird weather this year. So I can’t sell stuff in my house to move until the weather gets nicer. So I guess the sale of the house is waiting on this, I don’t want to move everything.  Hopefully I’ll get the 121GW before the house sells, if not another address change? I would also need to set up the lab again after the move that will just delay the review and take more time. But maybe that works better since I prefer to test things for 2 to 4 weeks before doing any review. I’ve waited this long, and so have others so what’s another few weeks?
Title: Re: EEVBlog 121GW Discussion thread
Post by: maukka on April 21, 2018, 12:13:16 pm
FWIW here's one 121GW against Ian Johnston's PDVS2 10V reference (http://www.ianjohnston.com/index.php/onlineshop/handheld-precision-digital-voltage-source-v2-detail).

PDVS2   121GW
0.5000 V   0.5000 V
1.0000 V   1.0000 V
1.5000 V   1.5000 V
2.0000 V   2.0000 V
2.5000 V   2.4999 V
3.0000 V   2.9999 V
3.5000 V   3.4999 V
4.0000 V   3.9999 V
4.5000 V   4.4999 V
5.0000 V   5.0000 V
5.5000 V   5.499 V
6.0000 V   5.999 V
6.5000 V   6.499 V
7.0000 V   6.999 V
7.5000 V   7.499 V
8.0000 V   7.999 V
8.5000 V   8.499 V
9.0000 V   8.999 V
9.5000 V   9.499 V
10.0000 V   9.999 V
Title: Re: EEVBlog 121GW Discussion thread
Post by: maukka on April 21, 2018, 03:22:50 pm
Don't have the meter anymore.
Title: Re: EEVBlog 121GW Discussion thread
Post by: VEGETA on April 21, 2018, 11:13:27 pm
What about its capabilities in measuring small resistances like 0.1R or so?
Title: Re: EEVBlog 121GW Discussion thread
Post by: Scottjd on April 23, 2018, 06:36:58 am
Did you have your standards calibrated so we have some known reference? 

One of the videos I had pulled was comparing the pre-production meter with the 34401 and my BK LCR meter.   Dave had said early on that the meter may not have been in cal but I seem to recall it being pretty decent.   

OK, watching it now... Wow was it painful to watch it read a 150pf capacitor.  I wonder if the new firmware and final hardware is still this slow.   Accuracy wise, looks fairly impressive considering this was after I had damaged the meter twice and had modified it.   Looking forward to seeing the final version ran.
I have capacitor standards, as for the resistors they are just expensive Vishay mill spec low ppm high efficiency new resistors. Even if my lab temperature drifts 3 Celsius they will read the same, but my lab doesn’t drift that much. I already logged the lab temp for 48 hours and it was almost 1 degree Celsius max drift in temperature.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Scottjd on April 23, 2018, 06:39:36 am
What about its capabilities in measuring small resistances like 0.1R or so?
I have a precision current shunt resistor for ghaynvalie, I think I own two. And I own two 4 wire kelvin miliohm meter to confirm then accuracy. So I plan to see if it can measure that low, and lower with fuses and 100mm strips of nickel since I can easily calculate the knows resistance of nickel from my battery spot welding rig. So I’ll let you know once I get mine.

But despite the resolution with it being only a 2 wire measument, I don’t expect lower reading from a handheld meter to be that accurate. It does show a higher resolution then any of the other meters I own for resistance, so it may surprise me. I’ll have to keep waiting to find out.
Title: Re: EEVBlog 121GW Discussion thread
Post by: VEGETA on April 23, 2018, 08:12:35 am
So for example is the Chinese LCR meter (30$) on Banggood or Aliexpress a better choice for the job than this expensive DMM?
Title: Re: EEVBlog 121GW Discussion thread
Post by: BravoV on April 23, 2018, 09:06:11 am
So for example is the Chinese LCR meter (30$) on Banggood or Aliexpress a better choice for the job than this expensive DMM?

Even better, a $5 cheap DMM + a cheap DIY constant current power supply, will make you able to measure sub 1 Ohm quite accurate, as long you understand the principal of 4 wires measurement.

2 wires probe DMM even the expensive one, can NOT measure sub 1 Ohm reliably.
Title: Re: EEVBlog 121GW Discussion thread
Post by: VEGETA on April 23, 2018, 09:09:28 am
So for example is the Chinese LCR meter (30$) on Banggood or Aliexpress a better choice for the job than this expensive DMM?

Even better, a $5 cheap DMM + a cheap DIY constant current power supply, will make you able to measure sub 1 Ohm quite accurate, as long you understand the principal of 4 wires measurement.

2 wires probe DMM even the expensive one, can NOT measure sub 1 Ohm reliably.

I came to realize that by practice after making 0.15R resistor out of 15 1.5R ones to act as a power resistor. It gets even worse when I connected my multimeter to measure current passing through it, then multimeter internal resistance was added to make the whole measurement unreliable.

Title: Re: EEVBlog 121GW Discussion thread
Post by: HKJ on April 23, 2018, 09:13:38 am
I came to realize that by practice after making 0.15R resistor out of 15 1.5R ones to act as a power resistor. It gets even worse when I connected my multimeter to measure current passing through it, then multimeter internal resistance was added to make the whole measurement unreliable.

If you want about basic current measurement, maybe my article can help: https://lygte-info.dk/info/DMMCurrent%20UK.html
Title: Re: EEVBlog 121GW Discussion thread
Post by: BravoV on April 23, 2018, 09:14:04 am
I came to realize that by practice after making 0.15R resistor out of 15 1.5R ones to act as a power resistor. It gets even worse when I connected my multimeter to measure current passing through it, then multimeter internal resistance was added to make the whole measurement unreliable.

Either you've made a mistake, or you have a really crappy DMM that has internal resistance is so low in voltage mode that affect that kind of reading.
Title: Re: EEVBlog 121GW Discussion thread
Post by: coromonadalix on April 23, 2018, 09:49:33 am
if youre able to zero out the leads impedance with the meter, it may do some 0.x ohms resistors, but an dmm is not an milliohms tester with or without 4 wire modes, it has is limits too, unless specefically built for that ...

the video give an good example of low impedance measurements

@vegeta
I think youve made an error to put the meter in parallel with your 0.15 ohm resistor, you measure current in serie
 
To minimize the chance of blowing fuses or overheating the meter, i use a precision 0.1 ohms 20watt,  put the load in serie with ac or dc current,  with the formula    V = R x I

I read in millivolts the voltage across the load and do the maths,  it save tons of expensives fuses if it goes wrong.   0.1 ohm is 1/10th of the current value passing thru and read in an dmm, 

For more precise current measurements, you have clamp meters, or clamp meter attachements for dmm's, they can be very precise and go very low in current in some models, you can zero the inputs too...
Title: Re: EEVBlog 121GW Discussion thread
Post by: Scottjd on April 23, 2018, 10:23:33 am
So I’ve been testing this meter, I bought two of them. One from Ebay and one from Amazon. The Amazon came with the Kevin clips also that are useful.
I usually test thing thoroughly before I recommend them, and this meter is not advertised as a miliohm meter. It’s desinged and sold as a battery internal resistance tester. I’ve compared this to three others for batteries and this is the only one that meets the standard these days that battery manufactures are using to measuring the IR of high current discharge battery cells. All my knows cells from data sheets match near perfect when I use this meter. The battery IR standard is using a 1Khz AC signal with a known current. Both are almost exactly 1Khz compared to others that allowed a 10% variance and gave bad results.

Then I realized this could probably also do miliohm measuments since the signal and current are so stable and accurate. So far they have worked great. I’ve measured accurately down to 6.9 miliohms from a known part and lower but not confirmed if the lower readings were accurate. For example and pure nickel strip best for carrying currents between battery lithium cells from 10 to 15 amps that is 0.15mm thick, by 8mm wide and 100mm long should measure at 6.9 miliohms. Unfortunately a lot of sellers on eBay sell “pure nickel”, but it’s realy nickel plated steel/iron. Nickel plated with the same size will only carry 2 to 7 amps. The variance realy depends on the quality of your spot weld, but either ways that’s a big difference. Nicrome wire is another know easy to measure material by gauge and length, so then I realized I can confirm fake counterfeit fuses from real fuses with this meter also, and it worked great.

So if you want a cheap and accurate way to measure miliohms that you can also use to measure internal resistance of batteries with I recommend you try this meter. It’s a little more on the affordable side compared to other meters with the same accuracy and performance. The one downfall is because it’s not officially a meter like a DMM it’s not fused and has no protection like PTC to clamps down. This shouldn’t be used to try and measure any current accross something except for on batteries as it’s designed. It works on lithium, LiFe, alkaline and every type of cell I’ve tested so far.
https://www.amazon.com/gp/product/B0768WQJQC/ref=oh_aui_search_detailpage?ie=UTF8&psc=1 (https://www.amazon.com/gp/product/B0768WQJQC/ref=oh_aui_search_detailpage?ie=UTF8&psc=1)

I usually don’t talk about my reviews and upcoming videos I’m working on, but since this seems to be a hot topic lately and some ones asked me if I have and English version of the manual I figured I would add this. So I’ve also attached the draft translation of the manual, this is not completed yet, it’s about 85% done being translated and compared to the features of the meters I’m testing. If someone else owns this meters d would like to help translate and formate parts I haven’t finished near the end to a sensible translation (not translations from google or bing that have sentences that are lost in translation and don’t make sense) then let me know. I have the soft version and the draft in a word doc for easy editing.
I hope to have the review video completed soon on this meter.

I hope this helps, now we can return to the regularly scheduled topic of this thread.  :-DD
Scott

Ok, now I’m going back to sleep. Have fun.
Edit, fixed half a sleep spelling errors.  |O
Title: Re: EEVBlog 121GW Discussion thread
Post by: HKJ on April 23, 2018, 10:48:21 am
So if you want a cheap and accurate way to measure miliohms that you can also use to measure internal resistance of batteries with I recommend you try this meter.

"This little meter" is easy to get from China in two different versions, I have done review of both:

YR1030: https://lygte-info.dk/review/InternalResistanceMeterYR1030%20UK.html
YR1035: https://lygte-info.dk/review/InternalResistanceMeterYR1035%20UK.html

But if you buy from China you risk getting a model with only Chinese text (It is not that big of a problem).
Title: Re: EEVBlog 121GW Discussion thread
Post by: Scottjd on April 23, 2018, 11:27:32 am
This is the word doc I anyone else want to make corrections to the manual.
Title: Re: EEVBlog 121GW Discussion thread
Post by: HKJ on April 23, 2018, 11:47:26 am
battery company that went out of buisness.

No company went out of business. There website is here: http://www.vapcelltech.com/ (http://www.vapcelltech.com/)  with recent updates.

maybe to see if you had a user manual.

I do have a English user manual (photos) for the old version, but the new version has a few changes.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Scottjd on April 23, 2018, 12:16:51 pm
battery company that went out of buisness.

No company went out of business.

maybe to see if you had a user manual.

I was told by several that VapeCell went out of buisness. They only relabeled the meter, I wasn’t saying the one who makes it went out of buisness. But at the time when I researched it the valecell domain was sold off, the Skype account was closed, the email was rejected by the server for unknown recipient. So I confirmed it with some other contacts.  Or did they start back up again? This was in November or December I think.
Title: Re: EEVBlog 121GW Discussion thread
Post by: maukka on April 23, 2018, 12:23:30 pm
For example and pure nickel strip best for carrying currents between battery lithium cells from 10 to 15 amps that is 0.15mm thick, by 8mm wide and 100mm long should measure at 6.9 miliohms.

Sorry about the offtopic.

That's a nice tip, but are you sure it's true? I don't have a big enough stock to test and verify, but to determine if my Chinese strips are pure or just plated I have tried to dremel them and see if sparks fly or scratch them and put into salt water for a couple of days to see if they rust.

https://www.youtube.com/watch?v=Xr4gqUDWxgg (https://www.youtube.com/watch?v=Xr4gqUDWxgg)
https://www.youtube.com/watch?v=w40t0RxQd3Q (https://www.youtube.com/watch?v=w40t0RxQd3Q)

I just measured a couple nickel strips one of which I suspected to be nickel plated steel judging by the mentioned tests (it sparked when ground and rusted faster although took several days), but the resistance isn't that far off taking into account the thickness.

Strip 1: 8 x 0.27 mm:   5.70 mOhm (/10 cm) (suspected real deal)
Strip 2: 10 x 0.20 mm: 6.87 mOhm (/10 cm) (suspected nickel plated steel)

(https://i.imgur.com/PUgh4rR.jpg)
Title: Re: EEVBlog 121GW Discussion thread
Post by: Scottjd on April 23, 2018, 01:20:05 pm
Valid question, truth be told their is not much of a difference between them as you will see in the picture. But it was enough to confirm the roll I bought was real. And you rod need both pieces to be exactly the same strips in length width and thickness for a fair comparison for any of these tests to be valid.
You will also see an obvious difference in the plating texture in the pictures.
I’ve had some other thoughts also, but haven’t tried them yet. I’m not patient for some things and want the easy test now answer.
One of my other thoughts was the putting 10 amps through both and messing with the FLIR.  Ignore the temperature reading due to the in the metal reflective emissivity, but you should still see the colors indicate what one gets hotter over a minute.

I really notice the difference when welding, the nickel will burn through easier if the current is up to high. Or the steel plated will need you to turn up the machine to get a good weld.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Scottjd on April 23, 2018, 01:21:20 pm
Ifyou look at the pictures the steel plated one at about a 50mm length can support a 100g weight. The pure nickel bent and fell through the vise so I pulled the weight off and just set it aside.
It’s been a while since I was so active in a thread. Well it’s been fun, but I’m having issues typing now with my finger cramping up so I’m going offline.
Title: Re: EEVBlog 121GW Discussion thread
Post by: fanOfeeDIY on April 23, 2018, 01:33:19 pm

It wouldn't damage any meter with a proper CAT rating.

OTOH it might skew the test results by giving some meters a head start. eg. Nether the Fluke nor the Hioki are showing "0L" at the start of each test.

Thanks, Fluke 87V and Hioki DT4282 are not showing OL.
The fluke and hioki are the ones have lower current on measuring ohm and it might related to it.

Also, it might be behaving differently when scanning between the ranges to find the right range.

Well, I am a lazy person. :)
Title: Re: EEVBlog 121GW Discussion thread
Post by: fanOfeeDIY on April 23, 2018, 01:39:12 pm
Ok, so it’s a technicality but this idea might work?
You don’t BUY anymore, just do what some other youtubers do.
Contact bangood and they will send you meters. Then your not buying any of them.
I personally don’t work with bangood so I don’t know how it works. But as long as you disclose it’s from a vendor before the video review or testing I don’t think many people watching care that much these days.
Off the top of my head in the genre of electronic YouTube channels I can think of 3 or 4 that get items all the time from bangood and they still have high subs and views, so it probably doesn’t matter much.
This way you can keep your DMM addiction going without buying another one.  :-+
[/quote]

I started to take videos just for my fun in my time, one was to keep my English.

If I become more serous of taking the video in the future, then I might need to think the content of the video with more meters.

The main concern is taking spaces in the room at the moment. (I think) :)
Title: Re: EEVBlog 121GW Discussion thread
Post by: fanOfeeDIY on April 23, 2018, 01:40:14 pm
There's a place that sends you free multimeters? For free?

Don't let that information reach the therapy thread.  :scared:
There’s a therapy thread? Please share, my best friend needs multimeter obsession help.  :-DD

https://www.eevblog.com/forum/testgear/test-equipment-anonymous-(tea)-group-therapy-thread/ (https://www.eevblog.com/forum/testgear/test-equipment-anonymous-(tea)-group-therapy-thread/)

 :-DD :-DD
Title: Re: EEVBlog 121GW Discussion thread
Post by: fanOfeeDIY on April 23, 2018, 01:45:09 pm

I found this video where he pulls apart the Yokogawa.  Looks like they have some sort of gas tubes.   The Gossen used GDT's and held up very well in the transient tests.  The Keysight meter I looked at also used GDTs and was damaged early on in the testing.   

Does your meter look the same inside as this one?


Sorry for scaring people that I am not uploading images on the forum.
(I am not killed yet for having too much meters) :)

I just finished taking high resolution images.
I found some of the images which I took after the last video were not showing good for uploading to eebvlog.
I was considering to take the some images again, then I became busy.

I will upload them soon.
Title: Re: EEVBlog 121GW Discussion thread
Post by: nidlaX on April 24, 2018, 03:29:11 am
Is there a more concrete timeline available for the shipping of the US meters? I may need to change my address again if the meters don't ship within a few weeks.
Title: Re: EEVBlog 121GW Discussion thread
Post by: fanOfeeDIY on April 24, 2018, 06:52:14 am

Thanks for taking the pictures.   Looking forward to seeing them.


I finally uploaded them here.
https://www.eevblog.com/forum/testgear/ty720-kew-1062-handheld-multimeter-inside-high-resolution-images/ (https://www.eevblog.com/forum/testgear/ty720-kew-1062-handheld-multimeter-inside-high-resolution-images/)
Title: Re: EEVBlog 121GW Discussion thread
Post by: knapik on April 24, 2018, 10:20:34 am
I got the switch shim fix and new knob and installed it today. The knob itself is much tighter now, and it seems to have helped the turning off issue I was constantly having near the Ohms and power selection. For a little bit, I was still having the same issue where the multimeter was turning off, but after a little bit of time, it seems to have settled in, and I can't replicate it even with some spirited jiggling.
Title: Re: EEVBlog 121GW Discussion thread
Post by: VK5RC on April 24, 2018, 10:28:41 am
Thanks, I also got the shim and new knob, went in well, definitely a bit firmer now - but I didn't have any problems before! :-+
Title: Re: EEVBlog 121GW Discussion thread
Post by: ANTALIFE on April 24, 2018, 12:43:05 pm
Looks like I am one of the unlucky ones that only got shipped a replacement knob but no shim ; - ;
Have contacted Dave to try and get the shim re-shipped
Title: Re: EEVBlog 121GW Discussion thread
Post by: 1anX on April 25, 2018, 10:41:42 pm
Looks like I am one of the unlucky ones that only got shipped a replacement knob but no shim ; - ;
Have contacted Dave to try and get the shim re-shipped

 :palm: :palm: :palm: :palm: :palm:
Title: Re: EEVBlog 121GW Discussion thread
Post by: morrone on April 26, 2018, 03:22:29 am
I had a fairly long logging session recently that logged DC V while charging a 12V battery.  I left it on the default logging rate, thinking that was once per second, but it turns out that my meter defaulted to "0", so according to the manual was actually logging at the fastest rate of around 200ms.

Around 25-26 hours later I went to the meter and saw a voltage of around 13.67V.  My victron BMV-712 told me that current down to nothing, so that was as far as the charger was going to take it.  I stopped the logging, and the beginnings and end of the log file look like:

START,2018/04/24,16:45:07,
ID,170800000,
INTERVAL,000,sec,
,MAIN,,,SUB-1,,,SUB-2,,,Remark,
No. ,Func. ,Value,Unit,Func. ,Value,Unit,Func. ,Value,Unit,
1,DCV,013.182,V,,,,,,,,
2,DCV,013.188,V,,,,,,,,
3,DCV,013.187,V,,,,,,,,
4,DCV,013.187,V,,,,,,,,
5,DCV,013.187,V,,,,,,,,
6,DCV,013.187,V,,,,,,,,
[cut]
364219,DCV,013.529,V,,,,,,,,
364220,DCV,013.530,V,,,,,,,,
364221,DCV,013.529,V,,,,,,,,
364222,DCV,013.530,V,,,,,,,,
364223,DCV,013.529,V,,,,,,,,
364224,DCV,013.529,V,,,,,,,,
364225,DCV,013.530,V,,,,,,,,
364226,DCV,013.529,V,,,,,,,,
MAX,67374,DCV,013.531,V,
MIN,1,DCV,013.182,V,

Something is very odd here.  The last sample was 13.529V, and the max was recorded as 13.531.

I am not sure what happened here.  It doesn't help that the meter only logs sample count, and not time.  If I really assume that it took a sample every 200ms, then the meter only logged for a little over 20 hours.  But I know that I stopped it a minimum of 25 hours later.  So, OK, 200ms is approximate.  So maybe its is more like every 250ms on average...that would work out to a little over 25 hours (after 364226 samples).

But if it really was logging up until the point that I stopped it, then why were there no records of the 13.67V readings that I saw on the display (and was also reported by the Victron BMV-712)?
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on April 26, 2018, 04:37:54 am
I got the switch shim fix and new knob and installed it today. The knob itself is much tighter now, and it seems to have helped the turning off issue I was constantly having near the Ohms and power selection. For a little bit, I was still having the same issue where the multimeter was turning off, but after a little bit of time, it seems to have settled in, and I can't replicate it even with some spirited jiggling.

Maybe there was some form of contaminant on the pads or contacts that eventually wiped away?
Title: Re: EEVBlog 121GW Discussion thread
Post by: Seppy on April 26, 2018, 04:53:15 am
Looks like I am one of the unlucky ones that only got shipped a replacement knob but no shim ; - ;
Have contacted Dave to try and get the shim re-shipped

I have now shipped the part.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Seppy on April 26, 2018, 06:34:38 am
I had a fairly long logging session recently that logged DC V while charging a 12V battery.  I left it on the default logging rate, thinking that was once per second, but it turns out that my meter defaulted to "0", so according to the manual was actually logging at the fastest rate of around 200ms.

Around 25-26 hours later I went to the meter and saw a voltage of around 13.67V.  My victron BMV-712 told me that current down to nothing, so that was as far as the charger was going to take it.  I stopped the logging, and the beginnings and end of the log file look like:

START,2018/04/24,16:45:07,
ID,170800000,
INTERVAL,000,sec,
,MAIN,,,SUB-1,,,SUB-2,,,Remark,
No. ,Func. ,Value,Unit,Func. ,Value,Unit,Func. ,Value,Unit,
1,DCV,013.182,V,,,,,,,,
2,DCV,013.188,V,,,,,,,,
3,DCV,013.187,V,,,,,,,,
4,DCV,013.187,V,,,,,,,,
5,DCV,013.187,V,,,,,,,,
6,DCV,013.187,V,,,,,,,,
[cut]
364219,DCV,013.529,V,,,,,,,,
364220,DCV,013.530,V,,,,,,,,
364221,DCV,013.529,V,,,,,,,,
364222,DCV,013.530,V,,,,,,,,
364223,DCV,013.529,V,,,,,,,,
364224,DCV,013.529,V,,,,,,,,
364225,DCV,013.530,V,,,,,,,,
364226,DCV,013.529,V,,,,,,,,
MAX,67374,DCV,013.531,V,
MIN,1,DCV,013.182,V,

Something is very odd here.  The last sample was 13.529V, and the max was recorded as 13.531.

I am not sure what happened here.  It doesn't help that the meter only logs sample count, and not time.  If I really assume that it took a sample every 200ms, then the meter only logged for a little over 20 hours.  But I know that I stopped it a minimum of 25 hours later.  So, OK, 200ms is approximate.  So maybe its is more like every 250ms on average...that would work out to a little over 25 hours (after 364226 samples).

But if it really was logging up until the point that I stopped it, then why were there no records of the 13.67V readings that I saw on the display (and was also reported by the Victron BMV-712)?

Just a few questions:
- Did you read the 13.67V on the 121GW or another device (Error potentially in reference)
- Does your 121GW measure 13.5V correctly if simply given DC (Error potentially in calibration)
- What version of firmware do you currently have (So I can test against that version)
- Did sample 67374 correlate to the 13.531 V MAX value?
- What was your charging setup?
Title: Re: EEVBlog 121GW Discussion thread
Post by: knapik on April 26, 2018, 11:32:30 am
I got the switch shim fix and new knob and installed it today. The knob itself is much tighter now, and it seems to have helped the turning off issue I was constantly having near the Ohms and power selection. For a little bit, I was still having the same issue where the multimeter was turning off, but after a little bit of time, it seems to have settled in, and I can't replicate it even with some spirited jiggling.

Maybe there was some form of contaminant on the pads or contacts that eventually wiped away?

I'm not too sure actually. I accidentally had the contacts in the wrong position for the first time I put the meter together resulting in all the positions being shifted, so when I took it apart again I rotated the contacts themselves to the off position before putting the dail back in. It did happen once again after I wrote my previous post, but its not something I can replicate consistently. It could be something like a bit of contamination, or the contacts being picky with the initial position. I'll mention it if I'm having any further issues with the multimeter resetting.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Insatman on April 27, 2018, 01:05:05 am

I am not sure what happened here.  It doesn't help that the meter only logs sample count, and not time.  If I really assume that it took a sample every 200ms, then the meter only logged for a little over 20 hours.  But I know that I stopped it a minimum of 25 hours later.  So, OK, 200ms is approximate.  So maybe its is more like every 250ms on average...that would work out to a little over 25 hours (after 364226 samples).


Question...Does the 121GW log counts not time because it lacks a real-time clock?   Could some sort of time-stamp be implemented in the log data in future based on the calculated time from sampling frequency?   This would really be helpful.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Cliff Matthews on April 27, 2018, 02:29:12 am
Question...Does the 121GW log counts not time because it lacks a real-time clock?   Could some sort of time-stamp be implemented in the log data in future based on the calculated time from sampling frequency?   This would really be helpful.
RTC is U7. Here's the data sheet.
Title: Re: EEVBlog 121GW Discussion thread
Post by: morrone on April 27, 2018, 02:34:11 am

Just a few questions:
- Did you read the 13.67V on the 121GW or another device (Error potentially in reference)
Yes, I saw 13.67V on the LCD display of the 121GW, and confirmed the value with another device before I ended logging by holding down the MEM button.  Both devices agreed fairly closely.  In hind sight, I probably should have made note of what the sample counter was doing on the LCD before ending logging.
Quote
- Does your 121GW measure 13.5V correctly if simply given DC (Error potentially in calibration)
I don't have any reason to believe that particular value is wrong.  The calibration reasonably matched a couple of my other meters last time I checked.  I'm running a log of a discharge cycle at the moment, but I will double check the calibration after that.  UPDATE: Yes, it matches two other meters quite closely measuring 13.5V.
Quote
- What version of firmware do you currently have (So I can test against that version)
1.10
Quote
- Did sample 67374 correlate to the 13.531 V MAX value?
Yes, sample 67374 was the first instance of 13.531V in the file.
Quote
- What was your charging setup?
This is in a travel trailer.  A WFCO WF-8735 is charging a Greenlife GL100 LiFePo battery (with built-in BMS to tolerate being used as a lead acid battery drop in replacement, even if it isn't ideal).  At the start of the log the WF-8735 is in constant current mode and was delivering just under 36A according to the victron battery monitor (the WF-8735 is rated for 35A, so that is fairly reasonable).  The leads of the 121GW are clipped directly to terminals on the battery posts.

The voltage in the logs gradually rises from 013.182V at the start to 13.531V at sample 67374.  After that the voltage hovers around 13.527V to 13.531V for the rest of the log.  I'm willing to share the log, but it is 11MB in size.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Insatman on April 27, 2018, 08:35:35 am
Question...Does the 121GW log counts not time because it lacks a real-time clock?   Could some sort of time-stamp be implemented in the log data in future based on the calculated time from sampling frequency?   This would really be helpful.
RTC is U7. Here's the data sheet.

So...if it has an RTC...why not log timestamps?   Why make the user guess or try and figure it out...makes no sense.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Iagash on April 27, 2018, 10:40:10 am
Update has been released to the app stores, likely hasn't updated on both yet but these issues should all be resolved now, we also have a new firmware version which will be resolving one of the other issues (when the voltage in VA mode is above 32767 approximately, this firmware update hasn't been released, this issue was a packet issue not a app issue so for those values you'll need to wait for the next firmware update).

Ok, with the new firmware 1.15 the wrong values in VA mode seem to be fixed. I still get checksum error on around 2% of the packets and the update rate seems to be reduced to about 2 packets per second.

Would you please push your app changes to the gitlab repo as I suspect the RangeLookup table in Packet121GW.cs has changed. I'd like to add your changes to my script.

Thanks!
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on April 27, 2018, 12:00:24 pm
v1.15 has been released, it's on the website for download. There are various small fixes.
Please everyone use that latest version when reporting issues, we want everyone on the same page.

Update on the shipping:
50 units coming to me on May 5th (the original lost 50), 1000 more units available from May 19th, and another 1000 units ASAP after that.
Kickstarter update will come tomorrow when I get back from holidays.
Title: Re: EEVBlog 121GW Discussion thread
Post by: VK5RC on April 28, 2018, 09:34:12 am
Sorry for being a bit slow but where is the current version ie which website?
Thanks
Title: Re: EEVBlog 121GW Discussion thread
Post by: djadeski on April 28, 2018, 09:40:26 am
You can find the files here: https://www.eevblog.com/product/121gw/ (https://www.eevblog.com/product/121gw/)

-dave
Title: Re: EEVBlog 121GW Discussion thread
Post by: kalross on April 29, 2018, 05:42:39 am
Did any European early birds get the shim sent to them yet?  My meter dial has started to play up and I haven't received the shim.

Title: Re: EEVBlog 121GW Discussion thread
Post by: Vespian on April 29, 2018, 05:45:10 am
With the added shipping delays for the US meters, I am going to need to change my shipping address. I was one of the Great Scott! backers.
Title: Re: EEVBlog 121GW Discussion thread
Post by: peteb2 on April 29, 2018, 07:37:27 am
Just read Dave's latest update news of what's happening (sent as an email to Backers).

I just have gotta say from the point of view of someone who has backed a few Crowd Funded Projects now (where all of them delivered on time complete with their included Goal Additions)... this one has come unstuck a wee bit and i think it's simply because of it's own massive demand and therefore success.

With Dave having worked closely on the 121GW DMM's design and effectively endorsing it, it's a wonder it didn't blow out to 100s of 1000s of the things if not more being backed in the campaign.

I was so slow to get myself organized to do my backing in that i ended up in the Johnny Be Good group. I'd finally like to say i wouldn't want to be in Dave's role with a lot of folks who by now are sort of starting to wonder what's really happening but that i know the unit will eventually be a handy addition to my bench and that it's not the end all to wait as long as it needs for the thing to arrive....  ;)

Title: Re: EEVBlog 121GW Discussion thread
Post by: Candid on April 29, 2018, 09:38:38 am
Did any European early birds get the shim sent to them yet?  My meter dial has started to play up and I haven't received the shim.
I am still waiting for delivery. I recognize the shim problem since about 2 weeks now.

If you are one of the early birds you should have the same version as me. Can you please check something for me?

When I shorten the voltage input to com and set the 121GW to voltage AC 5V range I get a value of about 0,4999V displayed. When I open the short it is nearly the same (a little more maybe 0,5001V). In all other voltage AC or DC ranges I get 0,0xxxV when the input is shortened.

I tried to calibrate zero offset but this did not help. The last firmware (v1.15) did not too.
Title: Re: EEVBlog 121GW Discussion thread
Post by: fanOfeeDIY on April 29, 2018, 10:02:19 am
Did any European early birds get the shim sent to them yet?  My meter dial has started to play up and I haven't received the shim.
I am still waiting for delivery. I recognize the shim problem since about 2 weeks now.
 calibrate zero offset but this did not help. The last firmware (v1.15) did not too.

I am in Japan and I received the email that the shim set being sent on last Thursday and it has not been delivered to my home yet.

It could be simply it having delay at the custom. Normally it arrives in about five week days from Australia to Japan.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Scottjd on April 29, 2018, 11:54:41 am
Dave,
I honestly don’t know if I will need to change my address or not based on the update email, obviously EUI should start shipping the next 1050 units. So if I understand this correctly the first 50 goes to Australia, then the next 1000 remaining EUi sends out goes to different fulfillment shippers based on the addresses in the remaining “great Scott” option? Since the “Great Scott” was only 450 I’m to assuming this supply will cover the remaining “Great Scott” supports on May 19th?

Now the question becomes if I change my address on Kickstarter how fast does this data get to EUI or the shipper like Kane for US customers and refreshed, and then passed onto Kane for the US shipper? Can we get a hard cutoff date to when the last date will be to change the address in Kickstarter?
I can’t give or know a hard date on when my address will change, if your have ever sold a house before then you know things can change at the last minute that will also change the date of the sale.

I don’t know about other country local posts but the US post office will not forward packages. The original shipping method was to be done with DHL as original mentioned in the “Great Scott” package I selected on Kickstarter. But it seems DHL isn’t handling any of these shipments now and was originally changed in the beginning also, that’s my assumption from the beginning logistics that seemed to be changed and was part of the original hold up at US customs.

I think a little more details will help me and others in my situation figure out what steps we might need to make next. For example, I have a UPS, USPS, and FedEx account. If I at least know what shipping carrier Kane will be using and the package is tracking then I may have different options to ensure I get the package without involving the Kickstarter address change.

If Kane is using USPS then my address forwarding will just screw this up. This means I need to do the Kickstarter address update and why the hard date would be useful and hope this change of address gets from Kickstarter, to Dave, then to Kane in time before it ships.

If I know Kane is using UPS for shipping then I don’t have to worry about my USPS post office forwarding and the meter package being returned, or worse case the new owner of my house keeping it. For this reason I hope these are being shipped insured?
I can work with my UPS account once I have a tracking number and request it be delivered to my new address or I can set up a UPS/or FedEx P.O Box. I would have done this already, but we never had a sure date in when shipping would continue and I couldn’t afford paying on a P.O. box since December just for this meter.

I can’t change Kickstarter to a confirmed new address since I have to sell the house first before buying a new one. And I was hoping to take a holiday that I haven’t had in 5 years first for maybe a month before buying a new home so it might go to a UPS P.O. box. Besides I don’t think Kickstarter allows P.O. box shipments anyway.

And same goes for FedEx, I believe I can work with my FedEx account in the same way I would work with my UPS account.
FYI: For others, it’s free to set up an basic UPS, FedEx, and USPS account online. You may need to provide a payment card but it didn’t involve a monthly fee and you don’t need to be a company for these accounts. Well at least it was when I set these up a few years ago.

Can we get a little more details?
1. How many of the “Great Scott” meters were already shipped in the first round. How many of the 450 still need to be shipped? If it will follow backer order and I know mine is in the next 100 from Kane then I’ll just let things be.
2. How is Kane shipping to US customers? Are they using FedEx, USPS, UPS, DHL? Knowing this I can at least put some changes in place with those shippers accounts to ensure it won’t get lost.
3. Will you or Kane be sending out tracking numbers? If I have this and see it’s going to the wrong address I can have the shipper intercept it and change the packages route to the correct destination. This could happen if a Kickstarter address change doesn’t get filtered to the shipper fast enough.
4. Well #3 is based off the assumption these will have tracking numbers. I hope they do at this point because to not track and insure packages could cause more customers issues with some people. And I’m sure this will just cause more work for you also.
5. On a scale from 1 to 10, how sure are you on the May 19th start of shipping before I pay for a P.O. Box. But I will still need to know the shipper Kane uses for the best P.O. box to set or put a hold on my packed from that shipper.

I would think you would want this to go as smooth as possible from this point forward considering all the issues and delays already.

I would rather not take any more “chances” or “unknown’s” from this point going forward. I would think some of this information I’m asking to be shared wouldn’t be hard to confirm. Kane probably has a contract in place with one specific shipper for each region, so that should be easy to let us know who the shipper is, if it will have a tracking number and if it will be insured.

Scott
Title: Re: EEVBlog 121GW Discussion thread
Post by: Hugoagogo on April 29, 2018, 01:36:04 pm
I was in the original batch of a meters sold through the store, and as such cant see the updates posted to the kick-starter page, is there any way I can see these at all, or an alternate place I can read them.

Also finally got around to updating the firmware, going from V1.01 to V1.15 certainly speeds up the autoranging.
Title: Re: EEVBlog 121GW Discussion thread
Post by: firewalker on April 29, 2018, 03:34:01 pm
Quote
Hi Backers

Sorry for all the delays, but we have been working through various issues that are now sorted out and we are back on track for production.

UEi are ramping back up production and calibration, and have the following dates:

- 50 units are shipping to me on the 5th May (this is an original lot of units that went into limbo at the docks - long story, but we have to account for these separately and some people are aware of these and have asked about them)

- 1000 units will be available for shipping to the various distributors on the 19th May.
(EEVblog for Aus + misc countries, Kane Test for the US, Welectron for the EU)

- Another 1000 units will be available ASAP after that.

Please note that UEi can't magically produce and calibrate thousands of units at once, and especially testing and calibration takes significant time. Current capacity is basically around the 1000 units per month figure.

The first lot of 1050 units will obviously fulfill the remainder Great Scott backers (mostly US based customers), and there will be a large number left over to start fulfilling the Johhny B. Goode backers. But which of these backers will get shipped units first I can't say, as that will depend upon exact number of units available for each distribution center, and likely the order in which you backed. There will unfortunately be a large number of Johnny B/ Goode backers who will have to wait for the next 1000 unit batch.

And please note that the above dates are NOT shipping dates to backers, they are dates when units leave the factory to the distributors. Obviously there will be extra logistical handling delays involved that are unique to each distributor. So please understand that we can't give an exact date your particular unit will be shipped, so please refrain from asking. Rest assured that the wheels are in motion and you will be shipped your unit and receive your tracking number as soon as it ships.

The EU VAT invoices for Johnny B. Goode backers will be going out shortly, and there will be a separate update for this.

I will provide further updates when actual units ship to backers.

Also, for existing backers who have their meter, v1.15 of the firmware has been released with various fixes, please update and use that firmware whenever reporting any issues, we want everyone on the latest version.

As always, the best place to follow progress and discuss things is on the EEVblog forum thread for this, Kickstarter comments is just horribly suited to discussions.

https://www.eevblog.com/forum/testgear/eevblog-121gw-discussion-thread/ (https://www.eevblog.com/forum/testgear/eevblog-121gw-discussion-thread/)

Regards

Dave.
Title: Re: EEVBlog 121GW Discussion thread
Post by: JustinD on April 29, 2018, 03:56:48 pm
Hey Dave, I am ready for a refund.  I was backer #115 for great scott, early bird.  I paid in November, 2017.   Sorry man, it's just been five months after the promised date.  I will have to stick with my Fluke.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Cliff Matthews on April 29, 2018, 05:26:20 pm
Hey Dave, I am ready for a refund.  I was backer #115 for great scott, early bird.  I paid in November, 2017.   Sorry man, it's just been five months after the promised date.  I will have to stick with my Fluke.
Now that's odd.. Becoming a backer before becoming a forum member  :-//
Title: Re: EEVBlog 121GW Discussion thread
Post by: Brumby on April 29, 2018, 05:49:43 pm
Now that's odd.. Becoming a backer before becoming a forum member  :-//

Not necessarily.  The meter caught his eye before the forum did.  I can understand that.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Hugoagogo on April 29, 2018, 11:58:32 pm
Thanks Firewalker, although I probably wasn't clear enough, the copied post is public on kickstarter.

There are four locked off posts in particular I wanted to stay on top of.
- Knob and shim shimpments (I got an email saying something from the eevblog store has been shipped, but not what it is or what to do with it)
- Update on hardware on software (is there any other faults I should know about?)
- Switch contact update
- General Update
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on April 30, 2018, 02:04:06 am
I was in the original batch of a meters sold through the store, and as such cant see the updates posted to the kick-starter page, is there any way I can see these at all, or an alternate place I can read them.

Sorry, didn't think about that.
I guess I could bulk email those original 50 people?
This thread is the best place for updates really, the Kickstarter updates are more for those who haven't gotten their meter yet.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on April 30, 2018, 02:12:26 am
Dave,
I honestly don’t know if I will need to change my address or not based on the update email, obviously EUI should start shipping the next 1050 units. So if I understand this correctly the first 50 goes to Australia, then the next 1000 remaining EUi sends out goes to different fulfillment shippers based on the addresses in the remaining “great Scott” option? Since the “Great Scott” was only 450 I’m to assuming this supply will cover the remaining “Great Scott” supports on May 19th?

Now the question becomes if I change my address on Kickstarter how fast does this data get to EUI or the shipper like Kane for US customers and refreshed, and then passed onto Kane for the US shipper? Can we get a hard cutoff date to when the last date will be to change the address in Kickstarter?

I have already closed off the date to change address, but I guess there will always be one or two people who happen to change address after this and before shipment.
If you really ned to change your adress then send a message on Kickstarter and David will have to update your address manually.


Quote
I can’t give or know a hard date on when my address will change, if your have ever sold a house before then you know things can change at the last minute that will also change the date of the sale.

I don’t know about other country local posts but the US post office will not forward packages. The original shipping method was to be done with DHL as original mentioned in the “Great Scott” package I selected on Kickstarter. But it seems DHL isn’t handling any of these shipments now and was originally changed in the beginning also, that’s my assumption from the beginning logistics that seemed to be changed and was part of the original hold up at US customs.

I think a little more details will help me and others in my situation figure out what steps we might need to make next. For example, I have a UPS, USPS, and FedEx account. If I at least know what shipping carrier Kane will be using and the package is tracking then I may have different options to ensure I get the package without involving the Kickstarter address change.

If Kane is using USPS then my address forwarding will just screw this up. This means I need to do the Kickstarter address update and why the hard date would be useful and hope this change of address gets from Kickstarter, to Dave, then to Kane in time before it ships.

If I know Kane is using UPS for shipping then I don’t have to worry about my USPS post office forwarding and the meter package being returned, or worse case the new owner of my house keeping it. For this reason I hope these are being shipped insured?
I can work with my UPS account once I have a tracking number and request it be delivered to my new address or I can set up a UPS/or FedEx P.O Box. I would have done this already, but we never had a sure date in when shipping would continue and I couldn’t afford paying on a P.O. box since December just for this meter.

I can’t change Kickstarter to a confirmed new address since I have to sell the house first before buying a new one. And I was hoping to take a holiday that I haven’t had in 5 years first for maybe a month before buying a new home so it might go to a UPS P.O. box. Besides I don’t think Kickstarter allows P.O. box shipments anyway.

And same goes for FedEx, I believe I can work with my FedEx account in the same way I would work with my UPS account.
FYI: For others, it’s free to set up an basic UPS, FedEx, and USPS account online. You may need to provide a payment card but it didn’t involve a monthly fee and you don’t need to be a company for these accounts. Well at least it was when I set these up a few years ago.

And therein lies the problem, what if a thousand people are in the same situation? it becomes a nightmare!

Quote
Can we get a little more details?
1. How many of the “Great Scott” meters were already shipped in the first round. How many of the 450 still need to be shipped? If it will follow backer order and I know mine is in the next 100 from Kane then I’ll just let things be.

All but the US ones have shipped, so 256 US units left.

Quote
2. How is Kane shipping to US customers? Are they using FedEx, USPS, UPS, DHL? Knowing this I can at least put some changes in place with those shippers accounts to ensure it won’t get lost.

I don't know what service they are using, I will ask.

Quote
3. Will you or Kane be sending out tracking numbers? If I have this and see it’s going to the wrong address I can have the shipper intercept it and change the packages route to the correct destination. This
could happen if a Kickstarter address change doesn’t get filtered to the shipper fast enough.

Yes. Kane will send them out.

Quote
5. On a scale from 1 to 10, how sure are you on the May 19th start of shipping before I pay for a P.O. Box. But I will still need to know the shipper Kane uses for the best P.O. box to set or put a hold on my packed from that shipper.

I can't be sure of anything until it actually happens. Kane have said May 19th, but that's NOT shipping to customers it's units available from their warehouse to distributors.

I would think you would want this to go as smooth as possible from this point forward considering all the issues and delays already.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on April 30, 2018, 02:19:46 am
Hey Dave, I am ready for a refund.  I was backer #115 for great scott, early bird.  I paid in November, 2017.   Sorry man, it's just been five months after the promised date.  I will have to stick with my Fluke.

No problem, refunded.
Title: Re: EEVBlog 121GW Discussion thread
Post by: mtdoc on April 30, 2018, 02:20:48 am
I got an email saying something from the eevblog store has been shipped, but not what it is or what to do with it

Yep me to.  Was it the new knob and shim? 
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on April 30, 2018, 02:21:30 am
Did any European early birds get the shim sent to them yet?  My meter dial has started to play up and I haven't received the shim.
I am still waiting for delivery. I recognize the shim problem since about 2 weeks now.

If you are one of the early birds you should have the same version as me. Can you please check something for me?

When I shorten the voltage input to com and set the 121GW to voltage AC 5V range I get a value of about 0,4999V displayed. When I open the short it is nearly the same (a little more maybe 0,5001V). In all other voltage AC or DC ranges I get 0,0xxxV when the input is shortened.

I tried to calibrate zero offset but this did not help. The last firmware (v1.15) did not too.

We suspect you might have a range switch problems causing weird stuff.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on April 30, 2018, 02:22:20 am
I got an email saying something from the eevblog store has been shipped, but not what it is or what to do with it

Yep me to.  Was it the new knob and shim?

Yes, it was the knob and shim being shipped.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Average Meatsack on April 30, 2018, 04:30:47 am
Does each backer get a tracking number sent to them when their meter is dispatched on the final part of the journey?
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on April 30, 2018, 05:57:49 am
Does each backer get a tracking number sent to them when their meter is dispatched on the final part of the journey?

Yes.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Hugoagogo on April 30, 2018, 12:12:21 pm
I was in the original batch of a meters sold through the store, and as such cant see the updates posted to the kick-starter page, is there any way I can see these at all, or an alternate place I can read them.

Sorry, didn't think about that.
I guess I could bulk email those original 50 people?
This thread is the best place for updates really, the Kickstarter updates are more for those who haven't gotten their meter yet.

Is there a page anywhere where this stuff can be kept track of, maybe a pinned post? Just with a rough outline of what the issues are, what the knob fix is, and how it is installed (mine turned up today :). I t would also be nice if there was a changelog for the firmware. It is just a bit hard to keep on top of multiple 30 page threads to know whats going on.

I don't mean to be complaining, the meter has worked pretty well for me so far (even before the mechanical and software updates).
Title: Re: EEVBlog 121GW Discussion thread
Post by: kalross on May 01, 2018, 12:56:41 am
If you are one of the early birds you should have the same version as me. Can you please check something for me?

When I shorten the voltage input to com and set the 121GW to voltage AC 5V range I get a value of about 0,4999V displayed. When I open the short it is nearly the same (a little more maybe 0,5001V). In all other voltage AC or DC ranges I get 0,0xxxV when the input is shortened.

I tried to calibrate zero offset but this did not help. The last firmware (v1.15) did not too.

All measures fine when shorted on those ranges Candid.
Title: Re: EEVBlog 121GW Discussion thread
Post by: ChrisG on May 01, 2018, 05:15:53 am
All measures fine indeed on mine too.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Candid on May 01, 2018, 09:56:34 am
Ok so I wait for the shim and knob and will see, if the problem can be solved. Thanks for the answers.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Acecool on May 01, 2018, 04:41:29 pm
So it does AC as well as DC? I read somewhere it only did DC... odd...

Where can I buy it and how long does it take to ship to USA / North Carolina?

Edit: Nevermind....

https://www.kickstarter.com/projects/eevblog/eevblog-121gw-multimeter (https://www.kickstarter.com/projects/eevblog/eevblog-121gw-multimeter)

I found that and thought ok, great $250 AU - but not available so ok $260 with free shipping.. fine I'll pay that after reviewing the features - I'd love to back this project... - I log in ... not available...

I then go to the site ( You should really add a link - ie change EEVblog Electronics Community Forum text to link to the main site as the main forum has a ton of other links with breadcrumbs )... $330 AU + tax + shipping, etc... for it and the bag... $80 more - wow..... Doesn't look like I'll be able to get it...

10 days to back or take pre-orders on a project is way too low....
Title: Re: EEVBlog 121GW Discussion thread
Post by: kalross on May 01, 2018, 10:58:02 pm
Did any European early birds get the shim sent to them yet?  My meter dial has started to play up and I haven't received the shim.

I've had no notification of shipping of shim yet...was early bird backer...Dec 2017

Ta.

K
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on May 01, 2018, 11:02:05 pm
10 days to back or take pre-orders on a project is way too low....

And no matter how long I left there will be people still complaining they missed the Kickstarter.
And it's not like I didn't announce it in a video, on this forum, on Twitter, on Facebook, on my blog etc.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Brumby on May 02, 2018, 03:52:21 am
10 days to back or take pre-orders on a project is way too low....

And no matter how long I left there will be people still complaining they missed the Kickstarter.
And it's not like I didn't announce it in a video, on this forum, on Twitter, on Facebook, on my blog etc.

As it was, the support for the Kickstarter campaign resulted in AU$ 644,674 pledged of AU$ 42,000 goal.  Just slightly over-achieving (by a factor of 15!).

Was someone hoping you'd hit the AU$ 1,000,000 ?!!
Title: Re: EEVBlog 121GW Discussion thread
Post by: geekGee on May 02, 2018, 04:43:14 am
10 days to back or take pre-orders on a project is way too low....

I would say that 2,300 individuals thought 10 days was more than long enough to back the project.

I thought it was too long... I patiently held off until near the end, to hopefully avoid some of the initial product "teething" pains with a later shipment, so it was a long near 10 day wait to pull the trigger.  ;)
Title: Re: EEVBlog 121GW Discussion thread
Post by: Iagash on May 02, 2018, 08:05:32 pm
Update has been released to the app stores, likely hasn't updated on both yet but these issues should all be resolved now, we also have a new firmware version which will be resolving one of the other issues (when the voltage in VA mode is above 32767 approximately, this firmware update hasn't been released, this issue was a packet issue not a app issue so for those values you'll need to wait for the next firmware update).

Would you please push your app changes to the gitlab repo as I suspect the RangeLookup table in Packet121GW.cs has changed. I'd like to add your changes to my script.

Thanks!

Hi Seppy,

ping :-)

Is there a chance that you update the gitlab repo?
I'd like to see how you did solve the subdisplay range in [m]VA mode.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Seppy on May 03, 2018, 01:14:39 am
Update has been released to the app stores, likely hasn't updated on both yet but these issues should all be resolved now, we also have a new firmware version which will be resolving one of the other issues (when the voltage in VA mode is above 32767 approximately, this firmware update hasn't been released, this issue was a packet issue not a app issue so for those values you'll need to wait for the next firmware update).

Would you please push your app changes to the gitlab repo as I suspect the RangeLookup table in Packet121GW.cs has changed. I'd like to add your changes to my script.

Thanks!

Hi Seppy,

ping :-)

Is there a chance that you update the gitlab repo?
I'd like to see how you did solve the subdisplay range in [m]VA mode.

Sorry haven't been able to update the git for a little while, I need to be entirely sure none of the app store details are included in the GIT repo.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Oldschool_tech on May 04, 2018, 05:13:28 am
Hi, First time on the forum.  Dave and all, I have 121GW serial number 000168. Saw an email regarding the dispatch of the "Knob and shim kit" several weeks ago. Still nothing has arrived per Australia Post. Any way of tracking ?

Very happy with the meter. Purchased my first digital meter "AVO 2001" in 1984, and have various Flukes and a Tektronix TX3.

The minor issues with firmware should soon be resolved, I'm sure.
Title: Re: EEVBlog 121GW Discussion thread
Post by: cmumford on May 04, 2018, 01:34:52 pm
The minor issues with firmware should soon be resolved, I'm sure.

Hey Oldschool: Have you installed firmware v1.15?
Title: Re: EEVBlog 121GW Discussion thread
Post by: Oldschool_tech on May 04, 2018, 09:41:47 pm
Yes I have v 1.15 installed. I have not had issues. Can't say that I have used meter extensively. But I meant that at least if an issue is detected and resolved, the firmware is easy to upgrade. I have had the switch play up. The 3V / 15V diode test function I find particularly handy.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Ahaber on May 07, 2018, 06:11:02 am
I need to change my shipping address, but the survey is showing as closed on kickstarter. How can I go about doing this?
Title: Re: EEVBlog 121GW Discussion thread
Post by: plexus on May 07, 2018, 10:23:31 pm
I got the shim kit today. Thanks Daves. Installed and working fine. I wasn't really having too much trouble with the original knob but this one feels better, tigher, confidence building.

Any ETA on the iOS bluetooth app? Since the one in the app store has stopped working with the firmware updates, I miss having the remote capability which was a top-3 reason I got the 121GW. I have am going to have to downgrade back to 1.07 and hope I can use the original app until you guys release an up to date one.

Did you really have to break the iOS app with the firmware update?
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on May 07, 2018, 11:45:53 pm
Did you really have to break the iOS app with the firmware update?

Yes, we did have to, sorry, for reasons of comms integrity.
BTW, the iOS is not "ours", i.e. EEVblog's, it is UEI's app.
Title: Re: EEVBlog 121GW Discussion thread
Post by: plexus on May 08, 2018, 12:21:12 am
Did you really have to break the iOS app with the firmware update?

Yes, we did have to, sorry, for reasons of comms integrity.
BTW, the iOS is not "ours", i.e. EEVblog's, it is UEI's app.

Yes I knew that the one in the iOS app store is UEI's not yours. Ok.. well hopefully you will get an iOS app out soon!
Title: Re: EEVBlog 121GW Discussion thread
Post by: fanOfeeDIY on May 10, 2018, 05:27:50 pm
I received the new rotary switch and shim for 121GW multimeter.
I took a video of before and after of changing them.

https://youtu.be/nL7wDFNH8hM
Title: Re: EEVBlog 121GW Discussion thread
Post by: plexus on May 10, 2018, 05:31:36 pm
I received the new rotary switch and shim for 121GW multimeter.
I took a video of before and after of changing them.

Yes... do not remove the 4 small silver-capped screws on the top part of the back of the board - these hold the display down and there is no need to remove them or the display. It's a bit of a risk if you do remove the display because murphy's law can come into play.  :phew:
Title: Re: EEVBlog 121GW Discussion thread
Post by: fanOfeeDIY on May 11, 2018, 01:24:40 am
I received the new rotary switch and shim for 121GW multimeter.
I took a video of before and after of changing them.

Yes... do not remove the 4 small silver-capped screws on the top part of the back of the board - these hold the display down and there is no need to remove them or the display. It's a bit of a risk if you do remove the display because murphy's law can come into play.  :phew:

I completely understand it after I have de-soldered and soldered the LCD :)
The soldering joins are very thin.

I will probably never remove it again. I want my 121GW to last long.
Title: Re: EEVBlog 121GW Discussion thread
Post by: iainwhite on May 11, 2018, 12:06:01 pm
I got my packet with the new range switch but no yellow shim.    :(
Title: Re: EEVBlog 121GW Discussion thread
Post by: Candid on May 11, 2018, 12:45:21 pm
Lucky man, I got no shim and no switch up to now ;-)
Title: Re: EEVBlog 121GW Discussion thread
Post by: 1anX on May 11, 2018, 08:38:48 pm
I got my packet with the new range switch but no yellow shim.    :(
Your not the first to report this!
Who is sending these kits out incomplete Dave?
Title: Re: EEVBlog 121GW Discussion thread
Post by: prof on May 12, 2018, 11:09:04 pm
Received my (complete) kit today and replaced the switch. It's a bit finicky and the instructions are a bit confusing (like ensuring the proper alignment of the mechanics in the step before actually handling it or explaining to remove the fuse rather in the beginning though in retrospect it doesn't seem to be required at all?) but the results are really surprisingly different even though I wouldn't have considered the old behaviour a problem...  ;D
Title: Re: EEVBlog 121GW Discussion thread
Post by: mtdoc on May 13, 2018, 12:32:50 am
Funally got my knob snd shim, but no instructions. Are they posted somewhere?
Title: Re: EEVBlog 121GW Discussion thread
Post by: IanB on May 13, 2018, 01:04:36 am
Funally got my knob snd shim, but no instructions. Are they posted somewhere?

121GW knob installation replace rotary switch instructions

https://youtu.be/Kok7VJft3vs (https://youtu.be/Kok7VJft3vs)

http://www.eevblog.com/files/How%20to%20Replace%20121GW%20Rotary%20Switch-180411.pdf (http://www.eevblog.com/files/How%20to%20Replace%20121GW%20Rotary%20Switch-180411.pdf)
Title: Re: EEVBlog 121GW Discussion thread
Post by: bitwelder on May 13, 2018, 07:18:43 am
About the instructions:
http://www.eevblog.com/files/How%20to%20Replace%20121GW%20Rotary%20Switch-180411.pdf (http://www.eevblog.com/files/How%20to%20Replace%20121GW%20Rotary%20Switch-180411.pdf)

Step 12 reads:
Quote
12) Make sure that the 3 PTCs are lined up in a row.
Just curious, have been cases of bent PTCs or why the note? Simple basic precaution?
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on May 16, 2018, 08:36:29 am
Update coming on KS today.
All Great Scott US backers have now been shipped. If anyone in the US can post a photo of the packaging then we'd be curious to see it. Thanks.

Other remaining Great Scott backers also shipped, so that's all of them now  :phew:
Title: Re: EEVBlog 121GW Discussion thread
Post by: jgm84 on May 16, 2018, 08:46:31 am
EDIT: I received the Kickstarter update after posting this message. Now that it's clear everything is legit I will proceed with the payment. Thank you!
---
Just curious, is the update related to the Johnny B. Goode backers in Europe? I got a Paypal invoice today for something that seems to be the import VAT for Europe, but it does look a bit suspicious. I would like to have some official confirmation before I put the payment through.
Title: Re: EEVBlog 121GW Discussion thread
Post by: ding on May 16, 2018, 09:58:59 am
I'm an EU JBG backer and I can't see a paypal invoice, not sure if its a PEBKAC or not but everything looks ok on the kickstarter survey, anyone else in the same boat? :-//
Title: Re: EEVBlog 121GW Discussion thread
Post by: SmudgerD on May 16, 2018, 11:11:51 am
I'm an EU JBG backer and I can't see a paypal invoice, not sure if its a PEBKAC or not but everything looks ok on the kickstarter survey, anyone else in the same boat? :-//

Same here. Dave's update said we should have received a PayPal invoice today implying that the PayPal invoices went out before the Kickstarter update, but I haven't seen a PayPal invoice yet.

SmudgerD
Title: Re: EEVBlog 121GW Discussion thread
Post by: firewalker on May 16, 2018, 12:19:57 pm
I received my invoice 4 hours ago.

Alexander.
Title: Re: EEVBlog 121GW Discussion thread
Post by: jordanp123 on May 16, 2018, 12:20:49 pm
Haven't received my shipment notification yet (USA), but I'll just wait for it to come in for a few days, then ask for tracking if it doesn't show.
Title: Re: EEVBlog 121GW Discussion thread
Post by: pa3weg on May 16, 2018, 01:38:33 pm
Outta luck!
Paypal does not allow guest checkout in the Netherlands |O
guess I will have to risk it with customs and possible have a hefty fee applied.

Before anyone asks, no I do not want a PayPal account and no, I will not give my phone number, as it is not essential to the process
Title: Re: EEVBlog 121GW Discussion thread
Post by: IanB on May 16, 2018, 01:54:15 pm
Update coming on KS today.
All Great Scott US backers have now been shipped. If anyone in the US can post a photo of the packaging then we'd be curious to see it. Thanks.

Other remaining Great Scott backers also shipped, so that's all of them now  :phew:

Just for info, I have not received a shipping notification or tracking number. How long should I wait before querying this?
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on May 16, 2018, 02:08:26 pm
Update coming on KS today.
All Great Scott US backers have now been shipped. If anyone in the US can post a photo of the packaging then we'd be curious to see it. Thanks.

Other remaining Great Scott backers also shipped, so that's all of them now  :phew:

Just for info, I have not received a shipping notification or tracking number. How long should I wait before querying this?

Given the number of Great Scott backers on KS comments saying they haven't received a tracking number, it seems I may interpreted wording wrongly from Kane that they had all been shipped and emails sent. Checking on that now, should hear back tomorrow.
Title: Re: EEVBlog 121GW Discussion thread
Post by: jordanp123 on May 16, 2018, 02:09:56 pm
Got my tracking number in the last 5 minutes. FedEx.
Title: Re: EEVBlog 121GW Discussion thread
Post by: synapsis on May 16, 2018, 02:44:54 pm
US Great Scott backer 435, no tracking.

And Kickstarter doesn't seem the recognize the email I used to back the project, so this is the only way I can comment. :(

My BM235 is still cranking along, though!
Title: Re: EEVBlog 121GW Discussion thread
Post by: ChunkyPastaSauce on May 16, 2018, 03:14:52 pm
Got my tracking number in the last 5 minutes. FedEx.

Just received a fedex tracking number 30 mins ago as well  (from 121gwdonotreply@gmail.com)

Fedex can't find it though:

Code: [Select]
Not found
This tracking number cannot be found, please check the number or contact the sender.
Title: Re: EEVBlog 121GW Discussion thread
Post by: dr.diesel on May 16, 2018, 03:17:51 pm
Got my tracking number in the last 5 minutes. FedEx.

Just received a fedex tracking number 30 mins ago as well  (from 121gwdonotreply@gmail.com)

Fedex can't find it though:

Code: [Select]
Not found
This tracking number cannot be found, please check the number or contact the sender.

Has to actually be scanned at a FedEx location to show up on their site, you probably got the email when the shipping invoice was created.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Scottjd on May 16, 2018, 03:41:07 pm
Got my tracking number in the last 5 minutes. FedEx.
Ok, so is it safe to say US backers are receiving the meters with FedEx shipping?
Title: Re: EEVBlog 121GW Discussion thread
Post by: Bratster on May 16, 2018, 03:48:19 pm
Got my FedEx tracking at 7:47a PST.

Sent from my Moto x4 using Tapatalk

Title: Re: EEVBlog 121GW Discussion thread
Post by: Scottjd on May 16, 2018, 03:54:03 pm
Got my FedEx tracking at 7:47a PST.

Sent from my Moto x4 using Tapatalk
Great (Scott),
Can you induced anything from the email. Like and first sentence line. Or the email domain it was sent from.
This way other and I can search our inbox for this first sentence to make sure it wasn’t filtered to another folder.
Don’t include you shipping # or any personal information for your privacy.
Thanks,
Scott
Title: Re: EEVBlog 121GW Discussion thread
Post by: Bratster on May 16, 2018, 04:00:18 pm
Got my FedEx tracking at 7:47a PST.

Sent from my Moto x4 using Tapatalk
Great (Scott),
Can you induced anything from the email. Like and first sentence line. Or the email domain it was sent from.
This way other and I can search our inbox for this first sentence to make sure it wasn’t filtered to another folder.
Don’t include you shipping # or any personal information for your privacy.
Thanks,
Scott
Subject: 121gw tracking
Sender name: eevblog 121gw
Sender email: 121gwdonotreply@gmail.com
Message body: HELLO YOUR 121GW METER IS SHIPPING VIA FEDEX HERE IS YOUR TRACKING NUMBER: 

Sent from my Moto x4 using Tapatalk

Title: Re: EEVBlog 121GW Discussion thread
Post by: Scottjd on May 16, 2018, 04:06:52 pm
Got my FedEx tracking at 7:47a PST.

Sent from my Moto x4 using Tapatalk
Great (Scott),
Can you induced anything from the email. Like and first sentence line. Or the email domain it was sent from.
This way other and I can search our inbox for this first sentence to make sure it wasn’t filtered to another folder.
Don’t include you shipping # or any personal information for your privacy.
Thanks,
Scott
Subject: 121gw tracking
Sender name: eevblog 121gw
Sender email: 121gwdonotreply@gmail.com
Message body: HELLO YOUR 121GW METER IS SHIPPING VIA FEDEX HERE IS YOUR TRACKING NUMBER:

Sent from my Moto x4 using Tapatalk

Thank you, that’s. Great help.
Well I wouldn’t delete an email with that subject, md for search box works with the submit I get Kickstarter update #24, 22, and 21 from April to May. So maybe they are still sending them out.
What backer # are you?
Thanks again,
Scott
Title: Re: EEVBlog 121GW Discussion thread
Post by: Bratster on May 16, 2018, 05:25:40 pm
Got my FedEx tracking at 7:47a PST.

Sent from my Moto x4 using Tapatalk
Great (Scott),
Can you induced anything from the email. Like and first sentence line. Or the email domain it was sent from.
This way other and I can search our inbox for this first sentence to make sure it wasn’t filtered to another folder.
Don’t include you shipping # or any personal information for your privacy.
Thanks,
Scott
Subject: 121gw tracking
Sender name: eevblog 121gw
Sender email: 121gwdonotreply@gmail.com
Message body: HELLO YOUR 121GW METER IS SHIPPING VIA FEDEX HERE IS YOUR TRACKING NUMBER:

Sent from my Moto x4 using Tapatalk

Thank you, that’s. Great help.
Well I wouldn’t delete an email with that subject, md for search box works with the submit I get Kickstarter update #24, 22, and 21 from April to May. So maybe they are still sending them out.
What backer # are you?
Thanks again,
Scott
I'm in the 100 to 200 range.

Edit: tracking now shows as label created. Should be here next week. :-)

Sent from my Moto x4 using Tapatalk
Title: Re: EEVBlog 121GW Discussion thread
Post by: nickdepinet on May 16, 2018, 06:03:55 pm
I got that email yesterday, FedEx shows it currently on the way. Looks like kane is sending them out
Title: Re: EEVBlog 121GW Discussion thread
Post by: ChunkyPastaSauce on May 16, 2018, 08:47:44 pm
Got my tracking number in the last 5 minutes. FedEx.

Just received a fedex tracking number 30 mins ago as well  (from 121gwdonotreply@gmail.com)

Fedex can't find it though:

Code: [Select]
Not found
This tracking number cannot be found, please check the number or contact the sender.

Has to actually be scanned at a FedEx location to show up on their site, you probably got the email when the shipping invoice was created.

Tracking info now showing, label generated, estimated delivery for tomorrow (based on shipping today).
Title: Re: EEVBlog 121GW Discussion thread
Post by: VinzC on May 16, 2018, 08:48:54 pm
@Dave

I have indeed received the Paypal note for the EU VAT invoice. (I'm on the Johnny B. Goode batch.) However I can't seem to be able to pay via Paypal; the Australian (not Austrian) version allows me to pay without creating an account (which I of course *do* want), unfortunately after selecting my country and language, I'm taken by the balls and have to create an account... :wtf: screw them, I f*** hate that!  :--

Instead I could either pay the VAT by bank transfer (this is the term I'm used to with Digi-Key when not using a credit card), for which I'd need a bank account number (though I might have to pay more but I just don't care) or... I also use to pay the remaining taxes upon delivery to the driver, so if it's a possibility, so be it. Send cash inside an envelope? Why not. Name your price.

And thanks again for this work.
Title: Re: EEVBlog 121GW Discussion thread
Post by: rstofer on May 17, 2018, 02:39:38 am
Great Scott!  US customer.  I have a Fedex tracking number and the unit is to be delivered Friday 5/18.  The package is actually in transit.

I didn't know how to reply to Dave's Kickstarter query re: having tracking numbers so here I am.
Title: Re: EEVBlog 121GW Discussion thread
Post by: PeterL on May 17, 2018, 08:08:19 am
@Dave

I have indeed received the Paypal note for the EU VAT invoice. (I'm on the Johnny B. Goode batch.) However I can't seem to be able to pay via Paypal; the Australian (not Austrian) version allows me to pay without creating an account (which I of course *do* want), unfortunately after selecting my country and language, I'm taken by the balls and have to create an account... :wtf: screw them, I f*** hate that!  :--

Instead I could either pay the VAT by bank transfer (this is the term I'm used to with Digi-Key when not using a credit card), for which I'd need a bank account number (though I might have to pay more but I just don't care) or... I also use to pay the remaining taxes upon delivery to the driver, so if it's a possibility, so be it. Send cash inside an envelope? Why not. Name your price.

And thanks again for this work.
O c'mon Because you don't want to sign up with paypal Dave has to bend in seven ways to give a solution that suits you? Remember that this is already goodwill from Dave. If you don't like it just pay the mailman.
Title: Re: EEVBlog 121GW Discussion thread
Post by: ChrisG on May 17, 2018, 10:50:34 am
Having my 121GW since many months now. The issue with the range switch is getting worse. Anxiously awaiting the new range switch and shim. So far no news in my email or normal postal inbox. Any people in Europe received the new range switch and shim? I noticed some German 121GW users on this thread?
Title: Re: EEVBlog 121GW Discussion thread
Post by: tcottle on May 17, 2018, 02:23:45 pm
I'm a Great Scott backer (#260) and just received a e-mail with a tracking number.  W00t!   Tracking shows that it is shipping from Indianapolis
Title: Re: EEVBlog 121GW Discussion thread
Post by: VinzC on May 17, 2018, 03:15:11 pm
@Dave

I have indeed received the Paypal note for the EU VAT invoice. (I'm on the Johnny B. Goode batch.) However I can't seem to be able to pay via Paypal; the Australian (not Austrian) version allows me to pay without creating an account (which I of course *do* want), unfortunately after selecting my country and language, I'm taken by the balls and have to create an account... :wtf: screw them, I f*** hate that!  :--

Instead I could either pay the VAT by bank transfer (this is the term I'm used to with Digi-Key when not using a credit card), for which I'd need a bank account number (though I might have to pay more but I just don't care) or... I also use to pay the remaining taxes upon delivery to the driver, so if it's a possibility, so be it. Send cash inside an envelope? Why not. Name your price.

And thanks again for this work.
O c'mon Because you don't want to sign up with paypal Dave has to bend in seven ways to give a solution that suits you? Remember that this is already goodwill from Dave. If you don't like it just pay the mailman.
Where did I write Dave has to "bend"?  :palm: Does asking a question imply that the answer is Dave has to... damn'... I don't even follow your logic. If Dave doesn't agree, he can always say "no" which, if you read me again, is part of the (open) option list I gave — damn! why do I have to justify myself in the first place?

I for one just don't want to "bend" (to quote your terms) before Paypal — why are Australians allowed to pay without creating an account and Belgians not? Hmm?

I'm not *demanding* Dave to satisfy me and fix Paypal's lack of features for me, I'm just *asking (if)*, see the difference? Neither do I ask you to comment my reasons, for which you have absolutely no clue. So please stop criticizing me for asking.

Only the last part of your sentence is relevant:
If you don't like it just pay the mailman.
I suppose you're replying in Dave's behalf, right >:D ?

Tip: no need to think you've got to give lessons and ride your high horse. I don't criticize your choices (which I don't care) so don't criticize mine. Thanks for the info, by the way.
Title: Re: EEVBlog 121GW Discussion thread
Post by: DaJMasta on May 17, 2018, 03:35:06 pm
I'm a Great Scott backer (#260) and just received a e-mail with a tracking number.  W00t!   Tracking shows that it is shipping from Indianapolis

Also got mine, number 269, with the same details.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Scottjd on May 17, 2018, 08:03:40 pm
I'm a Great Scott backer (#260) and just received a e-mail with a tracking number.  W00t!   Tracking shows that it is shipping from Indianapolis

Also got mine, number 269, with the same details.
I received my tracking number today, backer 274 in the US. It say expected deliver Friday, but today is Thursday and the label still states it is only printed I have my doubts for a Friday delivery. Since FedEx doesn’t work on weekends I might see this Monday or Tuesday of next week. Seems that US Kane shipment are going in order of the backing numbers.
Scott
Title: Re: EEVBlog 121GW Discussion thread
Post by: benst on May 17, 2018, 08:13:23 pm
I got the replacement knob & shim and installed them just now. What a difference, feels much better, no more wiggling, and as far as I can tell the wonky display problems are gone.  :-DMM  :-+

Ben
Title: Re: EEVBlog 121GW Discussion thread
Post by: jordanp123 on May 17, 2018, 10:33:50 pm
Got my meter in today (USA), arrived in perfect working order.
Title: Re: EEVBlog 121GW Discussion thread
Post by: ChrisG on May 18, 2018, 07:58:57 am
Received the knob and the shim. It fits indeed. But knob is pretty if not super tight now and requires some force to turn, one hand turn with the stand unfolded is no way possible anymore. ::) Indeed no more display/power on issues anymore. I hope for you all and especially the newly shipped ones all is fine and smooth.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Scottjd on May 18, 2018, 10:35:32 am
I received my tracking number today, backer 274 in the US. It say expected deliver Friday, but today is Thursday and the label still states it is only printed I have my doubts for a Friday delivery. Since FedEx doesn’t work on weekends I might see this Monday or Tuesday of next week. Seems that US Kane shipment are going in order of the backing numbers.
Scott

They must be shipping these meters overnight express. So I received the label tracking email yesterday at 9am EDT, then it was picked up by FedEx at 4pm EDT and didn’t get to FedEx until 9pm. I figured being picked up at the end of the day Thursday their is no way it will make it by Friday. To my surprise it went back out at 1am, was in the Ohio central main hub at 3:30am, went back out and made it to the Columbus Distribution center at 4:39am and was on the truck out for delivery at 4:45am.
That’s some major hustling, I know it’s only from Indiana to Ohio, but I’ve never seen FedEx move this fast unless it’s overnight shipping. Well it looks like I might get it in time for the weekend to play with.

So did Kane decide to overnight them to try and make up some time on having to hold them and fix the PCB manufacturing mistake?
Scott
Title: Re: EEVBlog 121GW Discussion thread
Post by: IanB on May 18, 2018, 02:45:20 pm
So did Kane decide to overnight them to try and make up some time on having to hold them and fix the PCB manufacturing mistake?

No. FedEx Ground. Mine is in the middle of a long road journey and won't arrive until next week.
Title: Re: EEVBlog 121GW Discussion thread
Post by: tcottle on May 18, 2018, 03:17:06 pm
Confirming shipment is FedEx Ground.  The meter has left Indy and on its way to Colorado.  Scheduled delivery on Tuesday  :-+
Title: Re: EEVBlog 121GW Discussion thread
Post by: DaJMasta on May 18, 2018, 03:17:54 pm
Indiana to Maryland shipped on Thursday isn't expected to arrive until Monday, definitely ground service, but when you're close enough to the shipper the times can be pretty quick, even if they aren't always.
Title: Re: EEVBlog 121GW Discussion thread
Post by: prof on May 18, 2018, 03:44:15 pm
Having my 121GW since many months now. The issue with the range switch is getting worse. Anxiously awaiting the new range switch and shim. So far no news in my email or normal postal inbox. Any people in Europe received the new range switch and shim? I noticed some German 121GW users on this thread?

Yes, see quite a few posts ago on this thread.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Photoman on May 18, 2018, 05:44:44 pm
Received my meter today, FedEx ground from IN!
Title: Re: EEVBlog 121GW Discussion thread
Post by: Nerull on May 18, 2018, 09:42:25 pm
Got mine today. Just FYI, this meter has the same issue with right angle Probemaster leads that Fluke meters do - the black lead (though it may vary by batch) of my micro-tip leads doesn't quite fit, though I can get it in further than my Fluke 87. AFAIK only the right angle banana plug models do this, the straight ones are fine.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Scottjd on May 19, 2018, 04:03:47 am
So did Kane decide to overnight them to try and make up some time on having to hold them and fix the PCB manufacturing mistake?

No. FedEx Ground. Mine is in the middle of a long road journey and won't arrive until next week.
Thanks, I was able to confirm ground when I tripped over the box today arround 2pm.
Took my who day plans out of wack now. I just had to open it.
Scott
Title: Re: EEVBlog 121GW Discussion thread
Post by: JonM on May 19, 2018, 05:13:29 am
Got mine today. Just FYI, this meter has the same issue with right angle Probemaster leads that Fluke meters do - the black lead (though it may vary by batch) of my micro-tip leads doesn't quite fit, though I can get it in further than my Fluke 87. AFAIK only the right angle banana plug models do this, the straight ones are fine.

My 121GW arrived on Thursday via FedEx.

I have tried three different sets of right angle Probemaster probes with no problem.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Scottjd on May 19, 2018, 05:46:33 am
Got mine today. Just FYI, this meter has the same issue with right angle Probemaster leads that Fluke meters do - the black lead (though it may vary by batch) of my micro-tip leads doesn't quite fit, though I can get it in further than my Fluke 87. AFAIK only the right angle banana plug models do this, the straight ones are fine.

My 121GW arrived on Thursday via FedEx.

I have tried three different sets of right angle Probemaster probes with no problem.
I use the probemasters with the retractable shrouding and don’t have any issues with any of the meters including the 121GW or my Fluke. It also makes it good to be able and use the probes on power supplies in a pinch when you need one more cable since it retracts and they are two years old.

I do have an issue with the new Brymen black probe that came with the 121GW. It’s way to tight in all my meters, but the BM235 probes are ok, and so was the red one. I think it’s a faulty probe and just need to be replaced.

I would check you batteries, mine were shoved in fast and the negative springs were bent on 3 out of 4 of the batteries. You can remove the battery, bend the spring downwards with a little pressure and put the battery back. Hopefully over some time the spring with restore and retain it intended position.

Title: Re: EEVBlog 121GW Discussion thread
Post by: emece67 on May 19, 2018, 08:46:44 am
.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Candid on May 19, 2018, 09:03:26 am
I too don't have any problems with my probemaster right angle probes on my Fluke, 121GW and any other meter.

I had the same problem with the bended springs and the contacts falling out of the case of the battery compoundment. But this can be corrected. The springs I think are to long and the fastening hooks of the contacts are to soft so that they do not hold well in the compound over time after the batteries are in again. Just keep an eye on it when opening the compound.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Scottjd on May 19, 2018, 10:28:16 am
I too don't have any problems with my probemaster right angle probes on my Fluke, 121GW and any other meter.

I had the same problem with the bended springs and the contacts falling out of the case of the battery compoundment. But this can be corrected. The springs I think are to long and the fastening hooks of the contacts are to soft so that they do not hold well in the compound over time after the batteries are in again. Just keep an eye on it when opening the compound.
Yes, I agree. The springs are to long and to soft. If you look at it closely it’s a cheap 4AA battery box they just out into the back of the meter molding. It’s nkt even part of the original molding. I guess this was a cheaper way to go then making the battery box part of the molding?
Scott
Title: Re: EEVBlog 121GW Discussion thread
Post by: Brumby on May 19, 2018, 02:36:36 pm
Took my who day plans out of wack now. I just had to open it.
Scott

You're just making excuses...

No, wait ...

Yeah I'd do that too.   :-[
You're good   :-+
Title: Re: EEVBlog 121GW Discussion thread
Post by: iainwhite on May 19, 2018, 03:27:33 pm
Yes, I agree. The springs are too long and too soft.

I had noticed this - one of my springs is bent over double.  I was thinking about trimming them down to about 2/3rd of their present length.
Title: Re: EEVBlog 121GW Discussion thread
Post by: prof on May 19, 2018, 03:38:05 pm
I would check you batteries, mine were shoved in fast and the negative springs were bent on 3 out of 4 of the batteries. You can remove the battery, bend the spring downwards with a little pressure and put the battery back. Hopefully over some time the spring with restore and retain it intended position.

Same here but I'm not to worried about the springies. I think the compartment is too tight for the chosen springs which is why they tend to bend.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Jon.C on May 20, 2018, 01:38:18 pm
new video from Gadget Review Videos


https://youtu.be/50M4nMMvopU (https://youtu.be/50M4nMMvopU)
Title: Re: EEVBlog 121GW Discussion thread
Post by: JonM on May 20, 2018, 07:21:11 pm
Hi all,

I arrived really late to this, so I've missed many things and, although I have read the whole thread, I still have doubts about how to get one of this meters. As I understand, the EU distributor is Welectron but, must I contact them for and order or wait instead for the next (if any) kickstarter campaign? Will there be more kickstarter campaigns at all?

Thanks & regards.

The supply of  the 121GW is currently constrained and the pre-orders need to be fulfilled first. I'm sure that they will at least show up in the EEVblog Store when stock is available. Maybe available on Amazon in some countries as well.

Title: Re: EEVBlog 121GW Discussion thread
Post by: Scottjd on May 20, 2018, 08:31:44 pm
new video from Gadget Review Videos
Jon, thanks for the post.
I just want to be clear this is not a review as stated in the description and text in red at the beginning of the video. This was far from planned, just a fast edit to break the monotony from the other videos I’ve been working on. It’s just a quick unboxing and initial thoughts. I mention this because of all the dislikes. If your waiting for a review then please wait a few more weeks, or maybe longer depending on different factors with life in general taking up my time.
My policy has always been to use the product for at least 2 to 4 weeks before doing my review. I do this so I know the product I’m reviewing and try not to miss anything, and this way I also know that I trust and like the product I’m reviewing. I’ve only done one video amendment from missing a bug on the original review to date.

I realize when my videos get posted on other sites and that not all the viewers know me, or know my style of doing things. I’ll try to explain this for new people that have not seen my videos in the past. I’ve debated on starting my own thread on EEVBlog like Joe Smith and his great videos and thread support. I just don’t have the time to answer questions or follow a thread like he does. I do try to answer all comments on the YouTube video, so if you have any questions or constructive feedback leave a comment. I try to help others the best I can and when I can.

My lab is my hobby that I’ve built up over time, although sometimes mistaken for a professional lab or repair shop I have never claimed to be a EE or do repairs for money. I try to keep my reviews to just the facts, my opinion, and personal experiance using the product to help people decide if it’s something that will fit their needs and something they would want to buy.
My logic in what I review is simple, if it’s not something I would use or recommend/buy for family member or a friend then I don’t review it.
I try to stay away from negative reviews.  A negative review based on a software bug that can be fixed with a firmware update in the future can hurt the company, even once the issue is corrected. And since videos on YouTube stay around forever this could still affect the company after the issue is fixed. I might release a video that might seem like a negative review, but it’s more of a public service announcement that probably concerns the safety of a person or a video showing a bug so it can be fixed. Once and if it’s fixed at a later date then I will delete the video, or change the title from a “PSA” to “Recalled Safety” and update the video description.

Reviews, testing, video recordings, editing videos all take time and I can’t always do a professional video.  I’m a one man shop that does videos as a second hobby and I’m currently juggling three other review edits.
Amazon and other links in the videos description are for the viewers convenience to find the product. These are not affiliate links and I don’t get paid for them. I removed all ads from my videos despite meeting YouTube’s minimum requirements for monetization. I don’t ask for donations or use patreon. This YouTube channel and the items I review, cameras, microphone equipment, video editing software is 97% paid by me despite being on a limited budget. A few items are occasionally donated and they have to agree to mt strict terms. If the item is donated I will mention this in the video. I try not to accept free items since it makes the review look biased and paid for.
I have tested pre-production products also, but I dint do videos until the product is officially released. I do this to give feedback and help find bugs. Sometimes I don’t release the review until a new firmware fix is released. This helps make products better for the consumer when it’s released. A few pre-production items I’ve tested have also included a product review. Most pre-production units don’t get reviewed since this is not the reason they contacted me.
Free items I’m offered (more then you may realize) are usually ignored with a few exceptions. If I think its something people want to see reviewed and they agree to my terms in advance like “Having NO say over the final review” then I might make an exception. If they don’t agree, then I will not  accept the product. If they still ship it without agreeing to my terms then I assume by default they agree to an open and honest review. Just because it was shipped to me does not guarantee a product review.
Thanks,
Scott
Title: Re: EEVBlog 121GW Discussion thread
Post by: IanB on May 20, 2018, 08:43:25 pm
I mention this because of all the dislikes.

I'm not sure why there would be so many dislikes. I watched the video and it seemed fine. Some people just like to hate I guess.

You did point out a few issues from your inspection, and maybe that upset people who wanted the meter to be perfect. But that's not your fault, and no reason to dislike the video.

I notice you didn't open the battery cover and look at the battery springs. How did they look, in terms of fit and finish?
Title: Re: EEVBlog 121GW Discussion thread
Post by: Scottjd on May 20, 2018, 09:22:33 pm
I mention this because of all the dislikes.

I'm not sure why there would be so many dislikes. I watched the video and it seemed fine. Some people just like to hate I guess.

You did point out a few issues from your inspection, and maybe that upset people who wanted the meter to be perfect. But that's not your fault, and no reason to dislike the video.

I notice you didn't open the battery cover and look at the battery springs. How did they look, in terms of fit and finish?
I actually mentioned this in a different thread I think? The springs were folded over and pinched so I did recommend on a post to look at the new meters batteries and try to bend the springs down and put them back into alignment.  I know everything is going modular these days but it looks like the back battery molding was separate from the battery case, as if the battery case was a module that was just put into square placeholder on the back molding.
Title: Re: EEVBlog 121GW Discussion thread
Post by: IanB on May 20, 2018, 10:13:09 pm
I actually mentioned this in a different thread I think? The springs were folded over and pinched so I did recommend on a post to look at the new meters batteries and try to bend the springs down and put them back into alignment.  I know everything is going modular these days but it looks like the back battery molding was separate from the battery case, as if the battery case was a module that was just put into square placeholder on the back molding.

I forgot if it was you who mentioned it. I was just curious to see what the battery compartment and springs looked like on video.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Scottjd on May 21, 2018, 11:04:32 am
I actually mentioned this in a different thread I think? The springs were folded over and pinched so I did recommend on a post to look at the new meters batteries and try to bend the springs down and put them back into alignment.  I know everything is going modular these days but it looks like the back battery molding was separate from the battery case, as if the battery case was a module that was just put into square placeholder on the back molding.

I forgot if it was you who mentioned it. I was just curious to see what the battery compartment and springs looked like on video.
Unfortunately I didn’t have a camera rolling when I looked at this. I guess I didn’t expect that with the batteries. Seems like a simple old tech on how batteries are held into something. The only time I’ve had to mod a battery spring was with an LED flashlight build if the battery had a protection circuit, then I had to shorten the spring or replace the spring with a stronger shorter spring for better contact to get full looser to the LED driver. I’ll take a second look and see if the springs bent back or if they stayed after I adjudged them and let out know.
Title: Re: EEVBlog 121GW Discussion thread
Post by: IanB on May 21, 2018, 08:45:48 pm
If anyone in the US can post a photo of the packaging then we'd be curious to see it. Thanks.

See pictures below. Essentially product box placed loose in shipping box with a tiny bit of bubble wrap for padding. Really no different from how Amazon packs stuff.

Title: Re: EEVBlog 121GW Discussion thread
Post by: Average Meatsack on May 22, 2018, 03:18:03 am
Just got the notice that I have 48 hours to confirm the delivery address. Does that mean I am in the batch to receive my meter next? I just want to check as I am on a fixed term contract for the next 6 weeks and I would rather have my meter delivered to work since my house if unattended during the day and I want to ensure I get my delivery.

And if I as in the batch to get my meter next, Hell yeah!  :-+ :-DMM :clap: 
Title: Re: EEVBlog 121GW Discussion thread
Post by: dcac on May 22, 2018, 04:10:05 am
Dave,

I elected to pre-pay the EU VAT but I've still not received any PayPal invoice for it, I've also sent you a message on Kickstarter about this some days ago...



Title: Re: EEVBlog 121GW Discussion thread
Post by: SmudgerD on May 22, 2018, 06:51:12 am
Dave,

I elected to pre-pay the EU VAT but I've still not received any PayPal invoice for it, I've also sent you a message on Kickstarter about this some days ago...


Me too. I just got the last chance to confirm shipping address from Kickstarter, but have not received a PayPal invoice for the VAT. I do not want to be scalped by the courier for processing fees. Dave, please confirm that the PayPal thing is in hand.
Title: Re: EEVBlog 121GW Discussion thread
Post by: simon_staal on May 22, 2018, 07:28:30 am
Hi

I am backer #2,228, and I backed for 2 meters. As I had to pay the VAT (european recidence) I was only charged for 1 meter. I left a comment on KS and payed anyway, hoping to still receive 2 meters. However, in the latest email regarding confirmation of the shipping address, it got confirmed that ONE meter is included in the shipment.

Is this due to an error, or is the second meter shipped from the next batch of meters? (Could be done this way to ensure all backers got at least 1 meter as soon as possible.)

Cheers!
Title: Re: EEVBlog 121GW Discussion thread
Post by: atcurtis on May 22, 2018, 08:53:29 am
Backer #47 .. Received the meter today, #381.

It's going to take a while for me to get used to it since my older meters are a lot more primitive. I shall admit that my most-used meter was not auto-ranging.

Since there has been firmware updates, is the manual at http://www.eevblog.com/files/EEVblog-121GW-Manual.pdf (http://www.eevblog.com/files/EEVblog-121GW-Manual.pdf) the most current version of the manual? Mine did not arrive with any manual, only a calibration cert.
Title: Re: EEVBlog 121GW Discussion thread
Post by: firstcolle on May 22, 2018, 10:12:49 am
looking forward to receiving mine, where can I buy reliable alligator clips for the supplied probes? (if they exists)
Title: Re: EEVBlog 121GW Discussion thread
Post by: Scottjd on May 22, 2018, 10:26:38 am
Backer #47 .. Received the meter today, #381.

It's going to take a while for me to get used to it since my older meters are a lot more primitive. I shall admit that my most-used meter was not auto-ranging.

Since there has been firmware updates, is the manual at http://www.eevblog.com/files/EEVblog-121GW-Manual.pdf (http://www.eevblog.com/files/EEVblog-121GW-Manual.pdf) the most current version of the manual? Mine did not arrive with any manual, only a calibration cert.
It should be the latest manual. The manual does have a revision date in it. If the date matches close to the date of the latest firmware you can asssum it is. I think it also has a change log as well with dates changed.
Most of the firmwares have been bug fixes, I think the only change was VA now only goes to 50V, but the original manual didn’t have much listed for VA. So if anything they added the clause of the VA max now.

Enjoy using an auto ranging meter now,
Scott
Title: Re: EEVBlog 121GW Discussion thread
Post by: Candid on May 22, 2018, 03:07:48 pm
looking forward to receiving mine, where can I buy reliable alligator clips for the supplied probes? (if they exists)
Franky has these and some more parts including the leads itself from Brymen:
Alligator Clips for 2mm Brymen tips:
https://www.ebay.de/itm/Brymen-Slip-on-Crocodile-Alligator-Clips-for-2mm-Probe-Tip-Gold-Spring-Contacts/171302315753?hash=item27e269e6e9:g:jFUAAOxyeZNTTkUm (https://www.ebay.de/itm/Brymen-Slip-on-Crocodile-Alligator-Clips-for-2mm-Probe-Tip-Gold-Spring-Contacts/171302315753?hash=item27e269e6e9:g:jFUAAOxyeZNTTkUm)

Simpler ones:
https://www.ebay.de/itm/Crocodile-Alligator-Clips-for-2mm-Probe-Tips-1-Pair-Red-and-Black/171224820971?hash=item27ddcb6ceb:g:HyQAAMXQQUpRDlze (https://www.ebay.de/itm/Crocodile-Alligator-Clips-for-2mm-Probe-Tips-1-Pair-Red-and-Black/171224820971?hash=item27ddcb6ceb:g:HyQAAMXQQUpRDlze)

Gold plated 4mm tip attachments:
https://www.ebay.de/itm/Gold-Plated-Lantern-Spring-Probe-Tip-Attachment-for-Brymen-Multimeter-Test-Leads/171243956885?hash=item27deef6a95:g:3FcAAMXQC-tTADeq (https://www.ebay.de/itm/Gold-Plated-Lantern-Spring-Probe-Tip-Attachment-for-Brymen-Multimeter-Test-Leads/171243956885?hash=item27deef6a95:g:3FcAAMXQC-tTADeq)

Or alligator clips for 4mm banana:
https://www.ebay.de/itm/56mm-Crocodile-Alligator-Clips-for-Shrouded-Banana-Plugs-1-Pair-Red-Black/171220194350?hash=item27dd84d42e:g:jhQAAOxyQj9RJX6s (https://www.ebay.de/itm/56mm-Crocodile-Alligator-Clips-for-Shrouded-Banana-Plugs-1-Pair-Red-Black/171220194350?hash=item27dd84d42e:g:jhQAAOxyQj9RJX6s)

or this:
https://www.ebay.de/itm/Dolphin-Alligator-Clips-for-4mm-Shrouded-Unshrouded-Plugs-1-Pair-Red-and-Black/202276233803?hash=item2f189a624b:g:mP4AAOSwlJlav4PM (https://www.ebay.de/itm/Dolphin-Alligator-Clips-for-4mm-Shrouded-Unshrouded-Plugs-1-Pair-Red-and-Black/202276233803?hash=item2f189a624b:g:mP4AAOSwlJlav4PM)

Mini grabber hooks for 2mm:
https://www.ebay.de/itm/20cm-Silicone-Leads-with-2mm-Gold-Plated-Sockets-and-Mini-Grabber-Hooks-Pair/171085144334?hash=item27d578210e:g:UMsAAOxyD9JR8h0p (https://www.ebay.de/itm/20cm-Silicone-Leads-with-2mm-Gold-Plated-Sockets-and-Mini-Grabber-Hooks-Pair/171085144334?hash=item27d578210e:g:UMsAAOxyD9JR8h0p)

The Brymen leads:
https://www.ebay.de/itm/Brymen-Silicone-Gold-Plated-Test-Leads-Probes-for-Multimeters-CAT-IV-1000V/171162377470?hash=item27da129cfe:g:uSQAAOxyTjNShpch (https://www.ebay.de/itm/Brymen-Silicone-Gold-Plated-Test-Leads-Probes-for-Multimeters-CAT-IV-1000V/171162377470?hash=item27da129cfe:g:uSQAAOxyTjNShpch)

And more... just have a look at his eBay account.
Title: Re: EEVBlog 121GW Discussion thread
Post by: tcottle on May 22, 2018, 04:57:33 pm
And delivered.  It's Christmas in May!!!

Dave - thanks for all of your hard work bringing this meter to market.  It was a bit of a breech birth   ;D
Title: Re: EEVBlog 121GW Discussion thread
Post by: ez24 on May 22, 2018, 06:01:43 pm
https://www.ebay.de/itm/Brymen-Slip-on-Crocodile-Alligator-Clips-for-2mm-Probe-Tip-Gold-Spring-Contacts/171302315753?hash=item27e269e6e9:g:jFUAAOxyeZNTTkUm (https://www.ebay.de/itm/Brymen-Slip-on-Crocodile-Alligator-Clips-for-2mm-Probe-Tip-Gold-Spring-Contacts/171302315753?hash=item27e269e6e9:g:jFUAAOxyeZNTTkUm)


or for US ebay:

https://www.ebay.de/itm/Brymen-Silicone-Gold-Plated-Test-Leads-Probes-for-Multimeters-CAT-IV-1000V/171162377470?hash=item27da129cfe:g:uSQAAOxyTjNShpch (https://www.ebay.de/itm/Brymen-Silicone-Gold-Plated-Test-Leads-Probes-for-Multimeters-CAT-IV-1000V/171162377470?hash=item27da129cfe:g:uSQAAOxyTjNShpch)

Is seller f-t-2000  a forum member ?   If so did he (he is in a Dave video) say he was moving to Australia and closing?  Sorry for my confusion.  I want to put a link to him in my List C because he is a respected seller that many members refer to.  (but I always forget thus the list) ?

thanks

Title: Re: EEVBlog 121GW Discussion thread
Post by: gnavigator1007 on May 22, 2018, 06:27:33 pm
https://www.ebay.de/itm/Brymen-Slip-on-Crocodile-Alligator-Clips-for-2mm-Probe-Tip-Gold-Spring-Contacts/171302315753?hash=item27e269e6e9:g:jFUAAOxyeZNTTkUm (https://www.ebay.de/itm/Brymen-Slip-on-Crocodile-Alligator-Clips-for-2mm-Probe-Tip-Gold-Spring-Contacts/171302315753?hash=item27e269e6e9:g:jFUAAOxyeZNTTkUm)


or for US ebay:

https://www.ebay.de/itm/Brymen-Silicone-Gold-Plated-Test-Leads-Probes-for-Multimeters-CAT-IV-1000V/171162377470?hash=item27da129cfe:g:uSQAAOxyTjNShpch (https://www.ebay.de/itm/Brymen-Silicone-Gold-Plated-Test-Leads-Probes-for-Multimeters-CAT-IV-1000V/171162377470?hash=item27da129cfe:g:uSQAAOxyTjNShpch)

Is seller f-t-2000  a forum member ?   If so did he (he is in a Dave video) say he was moving to Australia and closing?  Sorry for my confusion.  I want to put a link to him in my List C because he is a respected seller that many members refer to.  (but I always forget thus the list) ?

thanks
Yes. I believe his brother in law or someone was taking over most of the ebay business.

https://www.eevblog.com/forum/profile/?u=26834 (https://www.eevblog.com/forum/profile/?u=26834)

His sales thread:
https://www.eevblog.com/forum/buysellwanted/franky_s-sales-thread/ (https://www.eevblog.com/forum/buysellwanted/franky_s-sales-thread/)
Title: Re: EEVBlog 121GW Discussion thread
Post by: Scottjd on May 22, 2018, 06:57:41 pm
https://www.ebay.de/itm/Brymen-Slip-on-Crocodile-Alligator-Clips-for-2mm-Probe-Tip-Gold-Spring-Contacts/171302315753?hash=item27e269e6e9:g:jFUAAOxyeZNTTkUm (https://www.ebay.de/itm/Brymen-Slip-on-Crocodile-Alligator-Clips-for-2mm-Probe-Tip-Gold-Spring-Contacts/171302315753?hash=item27e269e6e9:g:jFUAAOxyeZNTTkUm)


or for US ebay:

https://www.ebay.de/itm/Brymen-Silicone-Gold-Plated-Test-Leads-Probes-for-Multimeters-CAT-IV-1000V/171162377470?hash=item27da129cfe:g:uSQAAOxyTjNShpch (https://www.ebay.de/itm/Brymen-Silicone-Gold-Plated-Test-Leads-Probes-for-Multimeters-CAT-IV-1000V/171162377470?hash=item27da129cfe:g:uSQAAOxyTjNShpch)

Is seller f-t-2000  a forum member ?   If so did he (he is in a Dave video) say he was moving to Australia and closing?  Sorry for my confusion.  I want to put a link to him in my List C because he is a respected seller that many members refer to.  (but I always forget thus the list) ?

thanks
Yes. I believe his brother in law or someone was taking over most of the ebay business.

https://www.eevblog.com/forum/profile/?u=26834 (https://www.eevblog.com/forum/profile/?u=26834)

His sales thread:
https://www.eevblog.com/forum/buysellwanted/franky_s-sales-thread/ (https://www.eevblog.com/forum/buysellwanted/franky_s-sales-thread/)
Confirmed. His brother-in-law did take over the store, Franky and his family did move to Australia.
I’ve still ordered from the shop a few times since he moved and the quality of the products have stayed the same, most of the inventory stayed the same. Even recent items that I ordered in the past were the same things. The shipping my times and packing is just as good as when Frankie ran the store.
And he replies to messages in the Frankie sales thread on the forum for good support. I just don’t bother to correct people, since it’s the same it’s easier to let them think it’s stjll Frankie since the store name and sales thread title didn’t change.
No worries, still the same great service and quality products. I would definitely put him on the list.
Scott
Title: Re: EEVBlog 121GW Discussion thread
Post by: Scottjd on May 23, 2018, 09:27:08 pm
Here is a follow up on my initial thoughts. The way the switch was feeling bothered me, so I decided to take a look and found something unexpected. Now when I look at Dave’s video on 10K switch cycles it shows the shim with the routed area facing down over the C-Clip (or called e-clip in the instructions).
But if you look at the instructions is states the routed part must face “UPWARD” - see attached picture.

So my question comes with this “upward” statement, is this talking about upward meaning up as “facing up to the front of the meter towards the buttons? Or up as in up towards the ceiling or the sky so it will be facing the PCB when put back together?
Seems to me the routed area should go over the clip as shown in Dave’s switch testing video? The contact rotor disc that the shim meets with attached to the board doesn’t have anything sticking up that this routed out area on the shim would benefit from. Maybe it’s just how I’m interrupting the instructions, but if it’s supposed to go over the clip and the meter is taken apart facing front down on the table then it seems to make more sense the instructions say the router area needs to point downward, not upwards. Or just say it needs to go over the clip since the clip is mentioned and clearly pointed out in the instructions?

Does anyone have any clearifcation in this?
Thanks,
Scott
Title: Re: EEVBlog 121GW Discussion thread
Post by: ChunkyPastaSauce on May 23, 2018, 10:16:22 pm
Fairly sure the recess is to give room for the raised shaft bore on the contact plate, so so spacer recessed face should face PCB when assembled (away from circlip).

(https://i.imgur.com/SDNuvbJ.png?1)

borrowed base image from BiOzZ https://imgur.com/a/vHISAb5
Title: Re: EEVBlog 121GW Discussion thread
Post by: Scottjd on May 24, 2018, 12:12:58 am
Fairly sure the recess is to give room for the raised shaft bore on the contact plate, so so spacer recessed face should face PCB when assembled (away from circlip).

(https://i.imgur.com/SDNuvbJ.png?1)

borrowed base image from BiOzZ https://imgur.com/a/vHISAb5
I think you may be correct. Mine did still work better, but I also dremeled off those three breakaway mold points as well and just didn’t put this in the video. Dave’s test video does show it backwards, and I saw that video before I realized instruction were available for those who had the switch sent to them.
I removed the video, updated it. And will lit the updated version up later. It still showed an issue with the 50M ohm range being affected by temperature. I’ve done some more testing since that video and confirmed this, just waiting for someone else to confirm this as well. I posted it in the bug reporting thread.
Thanks,
Scott
Title: Re: EEVBlog 121GW Discussion thread
Post by: chicken on May 25, 2018, 05:00:42 am
Are there any release notes for the firmware updates?

I finally received my 121GW, and I wonder whether the update from 1.15 to 1.17 is worth the hassle.
Title: Re: EEVBlog 121GW Discussion thread
Post by: ChunkyPastaSauce on May 25, 2018, 05:10:29 am
Are there any release notes for the firmware updates?

https://www.eevblog.com/forum/testgear/eevblog-121gw-multimeter-firmware-details/msg1563451/#msg1563451 (https://www.eevblog.com/forum/testgear/eevblog-121gw-multimeter-firmware-details/msg1563451/#msg1563451)
Title: Re: EEVBlog 121GW Discussion thread
Post by: vk2amv on May 26, 2018, 01:38:03 pm
Backer #525 here
I received meter #527

Two numbers off haha.
Meh close enough.

The meter actually turned up Monday last week, but only this weekend getting a chance to have a play due to work.

So far it is looking nice, and should go very nicely on my bench next to my Bryman BM235.

My first ever Kickstarter thing I have ever backed, and I only did so because I trusted Dave to deliver.
I can report that I am one very happy backer here and my faith was well placed.
Title: Re: EEVBlog 121GW Discussion thread
Post by: ChrisG on May 26, 2018, 02:07:34 pm
Indeed you're right. The E or C-clip needs to go first over the knob and then the shim over the shaft. I tried to get the C (E) clip over the shaft on top of the shim and this was not possible and nearly broke the C (E) clip. I apologize if I'm complaining too much but my meter is mechanically not super well before and certainly after the shim installation. Too tight to turn the selector knob. I did notice just now one small incorrect statement in the manual (v17) on the buzzer on/off set-up option. It reads on page 59 " 4. Hold SETUP until a beep is heard to save the value. "  this is not true when saving for buzzer off setting.
Title: Re: EEVBlog 121GW Discussion thread
Post by: nidlaX on May 26, 2018, 10:16:49 pm
Are the meters supposed to come with a pre-installed microSD card?
Title: Re: EEVBlog 121GW Discussion thread
Post by: ChunkyPastaSauce on May 26, 2018, 11:06:44 pm
Are the meters supposed to come with a pre-installed microSD card?
Yes. Sandisk edge 8gb in mine, but don't know if all the same.
Title: Re: EEVBlog 121GW Discussion thread
Post by: ChunkyPastaSauce on May 26, 2018, 11:11:20 pm
I apologize if I'm complaining too much but my meter is mechanically not super well before and certainly after the shim installation. Too tight to turn the selector knob.
Double check which way the shim is facing. Mine came with the shim flipped the wrong way, the knob was way too tight as a result. The recessed face of the shim should face the PCB when assembled (away from retaining ring on the shaft).
Title: Re: EEVBlog 121GW Discussion thread
Post by: Scottjd on May 26, 2018, 11:34:02 pm
Are the meters supposed to come with a pre-installed microSD card?
Yes. Sandisk edge 8gb in mine, but don't know if all the same.
So far they have all been 8GB sandisk cards from what others have said.
Title: Re: EEVBlog 121GW Discussion thread
Post by: IanB on May 27, 2018, 02:07:09 am
I found that when I took my meter apart the range selection knob had a smooth clicky feel to it, but when assembled with the shim it had a rough, grindy feel that I didn't like.

I observed that my meter had the same raised molding artifacts that Scottjd pointed out. So I did two things: I smoothed down the raised projections using fine sandpaper, and I applied a small amount of white lithium grease on the contact surface where the shim rubs against the meter back. Upon reassembly my range selection knob now has a smooth, silky and clicky action that it didn't have before.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Scottjd on May 27, 2018, 02:21:46 am
I found that when I took my meter apart the range selection knob had a smooth clicky feel to it, but when assembled with the shim it had a rough, grindy feel that I didn't like.

I observed that my meter had the same raised molding artifacts that Scottjd pointed out. So I did two things: I smoothed down the raised projections using fine sandpaper, and I applied a small amount of white lithium grease on the contact surface where the shim rubs against the meter back. Upon reassembly my range selection knob now has a smooth, silky and clicky action that it didn't have before.
That’s great. I did the same thing. But I used a fine grit polishing dremel bit instead of sand paper. So far so good. I didn’t do any grease yet because I want to see if any dust is created or rubbing is still happening. I feared the grease would collect the dust from any other rubbing parts and it would make it hard to find the rubbing parts. And the grease may thicken if it had dust collected in it.  I’ll probably do anther tear down for a quick inspection in a month. But even without the grease it feel like most meters, if not better then some of the meters I own.
Keep us uodated on your meter and if you have any switch issues. So far mine is good, I don’t see removing those posts causing any issues. If you watch Dave’s switch testing video half of the circle posts wore down from the shim anyway and was probably the cause if the dust. And his shim had a small burr on it from the mounting wholes drilled in it, but my shim was smooth so I probably won’t see that.
I figure removing them just speed up the break in process without creating any dust.
Glad yours is working good now.
Scott
Title: Re: EEVBlog 121GW Discussion thread
Post by: Candid on May 27, 2018, 11:47:56 am
Yes, 4GB when I remember correctly.
Title: Re: EEVBlog 121GW Discussion thread
Post by: ANTALIFE on May 27, 2018, 01:00:21 pm
For those with a 3D printer, I made a wall-mount holder which you can get here:
https://www.thingiverse.com/thing:2932921 (https://www.thingiverse.com/thing:2932921)
Title: Re: EEVBlog 121GW Discussion thread
Post by: IanB on May 27, 2018, 05:16:26 pm
Can someone do a test on their 121GW to see if it's the same as mine?

1. Put the meter in resistance mode
2. Manually set the range to 0.000 Ω
3. Short the probes (use alligator clips so you don't have to hold them)
4. Expect to see a fluctuating reading in the 0.03 to 0.05 range depending on the probe resistance
5. Press the min/max button to capture the max reading
6. Now lightly touch the HOLD button with your finger and pull it away again (don't press it, just touch it gently)

What does the display capture?

On my meter the reading jumps up dramatically as high as 0.2, 0.3 or even 0.5 Ω

Something similar happens if I press the REL button to null out the probe resistance. Pressing the REL button makes the reading jump high, making it impossible to null out the probe resistance in this range.

Also, occasionally step 4 will show an anomalous reading, for example yesterday the meter showed about 3 ohms. It persistently showed 3 ohms even after turning the meter off and on again and after sweeping the dial through all the other ranges. The shorted probe resistance reading only went back to normal after I put the meter in DC volts and measured a battery. Then suddenly I got the expected 0.035 ohm probe resistance. I have not figured out what event causes the meter to get into this state.
Title: Re: EEVBlog 121GW Discussion thread
Post by: ChunkyPastaSauce on May 27, 2018, 05:51:23 pm
Can someone do a test on their 121GW to see if it's the same as mine?

1. Put the meter in resistance mode
2. Manually set the range to 0.000 Ω
3. Short the probes (use alligator clips so you don't have to hold them)
4. Expect to see a fluctuating reading in the 0.03 to 0.05 range depending on the probe resistance
5. Press the min/max button to capture the max reading
6. Now lightly touch the HOLD button with your finger and pull it away again (don't press it, just touch it gently)

What does the display capture?

On my meter the reading jumps up dramatically as high as 0.2, 0.3 or even 0.5 Ω

Something similar happens if I press the REL button to null out the probe resistance. Pressing the REL button makes the reading jump high, making it impossible to null out the probe resistance in this range.

Yes I'm having this, meter goes way out of spec, 0.5 \$\Omega\$ or more, v1.17. It happens whether max mode is on or not. I also see it in dc mv range (especially 500mv) and the temp thermocouple mode. On mine range, hold, rel, and min/max buttons will do it.I pulled apart the meter to see if anything under the button membranes, but didnt see anything weird. Right now the REL and min/max functions often not usable in mv,ohm,temp modes. https://www.eevblog.com/forum/testgear/eevblog-121gw-multimeter-issues/msg1561363/#msg1561363 (https://www.eevblog.com/forum/testgear/eevblog-121gw-multimeter-issues/msg1561363/#msg1561363)

Since you're checking hardware related things, could you check the 1kHz LPF? My unit seems to be way too low below 1kHz (starts to atten around 30hz). https://www.eevblog.com/forum/testgear/eevblog-121gw-multimeter-issues/msg1563436/#msg1563436 (https://www.eevblog.com/forum/testgear/eevblog-121gw-multimeter-issues/msg1563436/#msg1563436)

Also, occasionally step 4 will show an anomalous reading, for example yesterday the meter showed about 3 ohms. It persistently showed 3 ohms even after turning the meter off and on again and after sweeping the dial through all the other ranges. The shorted probe resistance reading only went back to normal after I put the meter in DC volts and measured a battery. Then suddenly I got the expected 0.035 ohm probe resistance. I have not figured out what event causes the meter to get into this state.
I don't think I've seen this one

Title: Re: EEVBlog 121GW Discussion thread
Post by: IanB on May 27, 2018, 06:06:22 pm
Yes I'm having this, meter goes way out of spec, 0.5 Ω or more, v1.17. It happens whether max mode is on or not.

Yes, the display jumps regardless. Pressing the MIN/MAX button just makes it easier to capture the reading.
Title: Re: EEVBlog 121GW Discussion thread
Post by: IanB on May 27, 2018, 09:37:04 pm
How to make the meter show weird readings:

1. Put the meter on the Low Z range
2. Measure the mains voltage (let's say 120.0 V AC)
3. Put the meter on the Resistance range
4. Short the probes

You may observe an anomalous reading of about 3 ohms, slowly declining towards zero.

On other ranges (like DC mV) you may observe anomalous readings too.

It's as if a capacitor is charged up and is taking time to discharge back to zero volts. (Or did something heat up and it's taking time to cool down?)
Title: Re: EEVBlog 121GW Discussion thread
Post by: nidlaX on May 27, 2018, 09:42:25 pm
6. Now lightly touch the HOLD button with your finger and pull it away again (don't press it, just touch it gently)
E field sensitivity perhaps? I've noticed the meter can be relatively sensitive near the LCD display. In fact, the display itself is very sensitive as evidenced by segments activating when pulling away the screen protector. That said, I don't think this meter is abnormally sensitive compared to other meters in its class.

In any case, can you check whether this is the source of the weird behavior?
Title: Re: EEVBlog 121GW Discussion thread
Post by: tautech on May 27, 2018, 09:46:17 pm
How to make the meter show weird readings:

1. Put the meter on the Low Z range
2. Measure the mains voltage (let's say 120.0 V AC)
3. Put the meter on the Resistance range
4. Short the probes

You may observe an anomalous reading of about 3 ohms, slowly declining towards zero.

On other ranges (like DC mV) you may observe anomalous readings too.

It's as if a capacitor is charged up and is taking time to discharge back to zero volts. (Or did something heat up and it's taking time to cool down?)
Watch the vid Joe did recently where he's stressing MOV's and PTC's and I think you'll find answers there:
https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg1552690/#msg1552690 (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg1552690/#msg1552690)
Title: Re: EEVBlog 121GW Discussion thread
Post by: nidlaX on May 27, 2018, 09:55:18 pm
6. Now lightly touch the HOLD button with your finger and pull it away again (don't press it, just touch it gently)

What does the display capture?

On my meter the reading jumps up dramatically as high as 0.2, 0.3 or even 0.5 Ω

Something similar happens if I press the REL button to null out the probe resistance. Pressing the REL button makes the reading jump high, making it impossible to null out the probe resistance in this range.
I just did a quick replication of this behavior for the resistance mode. I get no sensitivity on the Peak and Setup buttons, a little sensitivity on the Rel and Mem buttons, and high sensitivity on the Range, Hold, Mode, and Min/Max buttons around the magnitude you described.

The reading jumps are triggered by touching the buttons without depressing them and typically settle after 1 or 2 screen updates.
Title: Re: EEVBlog 121GW Discussion thread
Post by: ChunkyPastaSauce on May 27, 2018, 10:07:07 pm
How to make the meter show weird readings:

1. Put the meter on the Low Z range
2. Measure the mains voltage (let's say 120.0 V AC)
3. Put the meter on the Resistance range
4. Short the probes

You may observe an anomalous reading of about 3 ohms, slowly declining towards zero.

On other ranges (like DC mV) you may observe anomalous readings too.

It's as if a capacitor is charged up and is taking time to discharge back to zero volts. (Or did something heat up and it's taking time to cool down?)
I just tried and does same on mine.
Stranger yet,
1 Take Low Z reading from 120Vac source
2 Switch to Hz and take reading from 120Vac source - watch the temperature plummet in the secondary display to well below freezing and then quickly recover to normal temp
3. After temp has recovered in secondary display, now check resistance with probes shorted - shows 0 ohms (somehow this corrects the ~3ohm offset) - edit, this doesn't correct the offset, zero ohm is shown when shorted, but non-zero resistances are still now incorrect.
Title: Re: EEVBlog 121GW Discussion thread
Post by: IanB on May 27, 2018, 10:11:14 pm
a little sensitivity on the Rel and Mem buttons

The trouble is that when the meter is in the mΩ resolution range (0.000 Ω) the resistance you are trying to null out with the REL button is likely to be the same order of magnitude (20-40 mΩ) as the sensitivity of the button to the proximity of your finger, which renders the REL button ineffective. Also it doesn't even have to be a finger. I tested pressing the button with a plastic ball point pen and got much the same results.

Another factor that increases the problem is that the buttons only seem to react when released, not when pressed. Since it is the release action on the REL button that seems trigger the problem there is no way to "lock in" the action of the press before withdrawing your finger. (I can guess why this is though--the buttons are trying to tell the difference between a short press and a long press.)
Title: Re: EEVBlog 121GW Discussion thread
Post by: Candid on May 28, 2018, 10:38:42 am
Doing LowZ measurement on mains power you stress the PTC that warms up and so the readings need to settle until the PTC has cooled down to normal temperature again. Until this is done you will get wrong ohms readings.

As tautech already wrote watch Joe's video and you will unterstand why this and what happens.
Title: Re: EEVBlog 121GW Discussion thread
Post by: IanB on May 28, 2018, 05:05:31 pm
Doing LowZ measurement on mains power you stress the PTC that warms up and so the readings need to settle until the PTC has cooled down to normal temperature again. Until this is done you will get wrong ohms readings.

As tautech already wrote watch Joe's video and you will unterstand why this and what happens.

That isn't the point. Explaining a wrong behavior doesn't make it less wrong.

It is quite reasonable that someone might be testing voltages on mains circuits and soon after might be testing wiring resistance/continuity (e.g. checking for a good ground connection) where a resistance in the order of half an ohm might be expected. So in this scenario the observed behavior of the meter would be wrong and misleading.
Title: Re: EEVBlog 121GW Discussion thread
Post by: ChunkyPastaSauce on May 28, 2018, 05:50:30 pm
Doing LowZ measurement on mains power you stress the PTC that warms up and so the readings need to settle until the PTC has cooled down to normal temperature again. Until this is done you will get wrong ohms readings.

It's not just resistance, there's a large voltage offset in the dc millivolt range under short. 
Title: Re: EEVBlog 121GW Discussion thread
Post by: Kean on June 01, 2018, 03:51:56 pm
I've been travelling overseas, but now I am back in the lab earlier this week I finally upgraded my 121GW firmware and installed the shim on the selection knob.

Today I went to measure a 12V DC source and the meter displayed 166V.  :scared:  Then it decided to show OFL, even when measuring a 9V battery!

My initial thought was I had accidentally manually selected a low range, or it was in mV mode, or I stuffed up in alignment of the knob position during reassembly.  But the display matched the various selected range positions.  I took the meter apart and couldn't see any issue... until I removed the range selection switch... and the below image is what I found  :wtf:

(https://www.eevblog.com/forum/testgear/eevblog-121gw-discussion-thread/?action=dlattach;attach=445876;image)

I have not been measuring any mains or other high voltages on the meter.  The only thing that comes to mind is that the 12V I was measuring was at the input to a couple of POL DC/DC converters which was at the end of a long cable, and the DC/DC converters only had ceramic caps.  The DC/DC converter (my own design using TPS54622) is rated at 5.2V 6A out but was struggling to power a Raspberry Pi & pocket 3G router.  Measured with another (Tenma or EEVblog/Brymen) meter I was seeing only about 3.8V instead of the expected 5.2V.

I added a 330uF electrolytic capacitor at the input to each of two the DC/DC converters and it solved the problem, so I guess with the long cable from PSU to the ceramic caps was creating a nasty LC circuit and maybe causing some voltage spikes.  The cable was ~3m of 18AWG figure 8 speaker cable to simulate what was on-site, and it did help to clearly identify the equipment issue I was tracking down.

No (obvious) damage to the DC/DC converters, Raspberry Pi, or connected equipment, but apparently the meter didn't like it.  Or the meter came to me this way as I've hardly used it apart from measuring low voltages mostly out of my sig gen.  I doubt that as I'm sure I would have noticed this measurement issue in previous testing.

It was late when this happened and I haven't done further inspection or tried cleaning the PCB yet.

Any thoughts?
Title: Re: EEVBlog 121GW Discussion thread
Post by: Brumby on June 01, 2018, 11:51:23 pm
Looks like something arced over on the Ohms range.  Nasty.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Iwanushka on June 03, 2018, 07:11:45 pm
Did everyone in EU got their shims/knobs? I still didn't receive them nor got an email that they were shipped
Backer #146 2xDMM
Title: Re: EEVBlog 121GW Discussion thread
Post by: Candid on June 03, 2018, 07:54:33 pm
I got mine on 17th May in Germany. And I got an email 4 weeks before that it was sent to me.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Iwanushka on June 03, 2018, 10:07:51 pm
I got mine on 17th May in Germany. And I got an email 4 weeks before that it was sent to me.

Thanks, most likely mine slipped through all the spreadsheets, will ping Dave later.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Seppy on June 05, 2018, 07:55:09 am
I've been travelling overseas, but now I am back in the lab earlier this week I finally upgraded my 121GW firmware and installed the shim on the selection knob.

Today I went to measure a 12V DC source and the meter displayed 166V.  :scared:  Then it decided to show OFL, even when measuring a 9V battery!

My initial thought was I had accidentally manually selected a low range, or it was in mV mode, or I stuffed up in alignment of the knob position during reassembly.  But the display matched the various selected range positions.  I took the meter apart and couldn't see any issue... until I removed the range selection switch... and the below image is what I found  :wtf:

(https://www.eevblog.com/forum/testgear/eevblog-121gw-discussion-thread/?action=dlattach;attach=445876;image)

I have not been measuring any mains or other high voltages on the meter.  The only thing that comes to mind is that the 12V I was measuring was at the input to a couple of POL DC/DC converters which was at the end of a long cable, and the DC/DC converters only had ceramic caps.  The DC/DC converter (my own design using TPS54622) is rated at 5.2V 6A out but was struggling to power a Raspberry Pi & pocket 3G router.  Measured with another (Tenma or EEVblog/Brymen) meter I was seeing only about 3.8V instead of the expected 5.2V.

I added a 330uF electrolytic capacitor at the input to each of two the DC/DC converters and it solved the problem, so I guess with the long cable from PSU to the ceramic caps was creating a nasty LC circuit and maybe causing some voltage spikes.  The cable was ~3m of 18AWG figure 8 speaker cable to simulate what was on-site, and it did help to clearly identify the equipment issue I was tracking down.

No (obvious) damage to the DC/DC converters, Raspberry Pi, or connected equipment, but apparently the meter didn't like it.  Or the meter came to me this way as I've hardly used it apart from measuring low voltages mostly out of my sig gen.  I doubt that as I'm sure I would have noticed this measurement issue in previous testing.

It was late when this happened and I haven't done further inspection or tried cleaning the PCB yet.

Any thoughts?

Do you remember what jacks were in use when measuring the DC/DC?
Were you using the meter for measurement of current, power or voltage?
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on June 05, 2018, 08:16:18 am
Any thoughts?

The energy to do that couldn't have come via the V jack, there is at least a PTC + 1K in series with every path. Even if the contacts shorted the VA range contacts and the ohms contacts, worst case path is V jack to GND via a PTC + 1K. So, it's weird  :-//
So I can only presume the path is via the low impedance A jack somehow...
Maybe one of the range switch contacts wasn't installed properly and was floating around? I presume you hadn't taken off the range switch before?, as that's required for the shim replacement.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on June 05, 2018, 08:22:24 am
Kean, can you post a photo of the range switch contacts please.
Title: Re: EEVBlog 121GW Discussion thread
Post by: joeqsmith on June 06, 2018, 05:36:39 pm
IMO, the weak link of the meter's front end is that 15V diode check mode.   I marked the switch to make it easy to follow on the schematic.   

Also, note that a while back another member had posted some good pictures of their switch showing a fair amount of contamination in this same area.  I am not sure why it would accumulate here. 

A bit of damage for a low energy source.  Is there more to this story??
Title: Re: EEVBlog 121GW Discussion thread
Post by: Kean on June 06, 2018, 06:29:23 pm
Do you remember what jacks were in use when measuring the DC/DC?
Were you using the meter for measurement of current, power or voltage?
The probes were definitely in the V and COM jacks for voltage measurement, and meter in auto ranging DC V.

I wasn't expecting to find this kind of damage, or any damage at all.  When I was getting stange measurements (like 166V at first and then OFL) I removed the probes, and then double checked the range switch position and jacks I was using, and tried the measurement again.  Then I switched to another meter.  It was only because an astrophysicist friend/client was visiting and he saw the PCB (he noted the 3 different crystals) that he asked about the rotary switch mechanism.  So I removed the contact housing to show him it in all its glory, and thus found the damage.

The energy to do that couldn't have come via the V jack, there is at least a PTC + 1K in series with every path. Even if the contacts shorted the VA range contacts and the ohms contacts, worst case path is V jack to GND via a PTC + 1K. So, it's weird  :-//
So I can only presume the path is via the low impedance A jack somehow...
Maybe one of the range switch contacts wasn't installed properly and was floating around? I presume you hadn't taken off the range switch before?, as that's required for the shim replacement.
Agreed, that's basically what I thought - the protections circuits (even if not quite up to Joes standards...) shouldn't have allowed this.

Yes, I had swapped out the range switch and installed the shim, but I had not at this point taken off the part of the switch that houses the contacts off the PCB.  I had been pretty careful to ensure (per the instructions) that the orientation of that didn't change.  It actually takes a fair amount of force to remove the contact housing, and even then the contacts were well seated.  The contacts coming astray and connecting the wrong circuits was one of my thoughts as well - but I can't imagine the low impedance current path would go through the switch, just the kelvin connections off the shunt.

Kean, can you post a photo of the range switch contacts please.
Sure, see attached photo.  They look squeaky clean to me.  Sorry for the potato cam photos - best I can do at 4AM after a couple of rather awful days...  but I'm happy to arrange a meet up with you for a closer look and some forensics.

I also cleaned up the PCB with some IPA, and the PCB contacts actually look basically undamaged.  It almost looks like a track in the middle layers has burnt and created a crater.  It is a 4 layer PCB isn't it?  Maybe a PCB fault, a slightly under etched track clearance.

Edit: you can probably work out the orientation of the range switch based on the contamination shown on the plastic underside.  You can see the carbon deposit is not near any of the contacts points.

Joe, I'm not sure what other damage you are referring to.  A bit of carbon contamination has spread, but once cleaned nothing else but the crater - and other side of PCB looks OK.
Title: Re: EEVBlog 121GW Discussion thread
Post by: ChunkyPastaSauce on June 06, 2018, 07:52:20 pm
Edit: you can probably work out the orientation of the range switch based on the contamination shown on the plastic underside.  You can see the carbon deposit is not near any of the contacts points.
To me, it looks like switch would have been in V, or possibly completing a switch between mv and V (closer to V)


Also, note that a while back another member had posted some good pictures of their switch showing a fair amount of contamination in this same area.  I am not sure why it would accumulate here. 
If it was this one https://www.eevblog.com/forum/testgear/eevblog-121gw-multimeter-issues/msg1561861/#msg1561861 (https://www.eevblog.com/forum/testgear/eevblog-121gw-multimeter-issues/msg1561861/#msg1561861) it don't think it's related (the contamination plastic and possibly some mask as the unit was shipped with switch shim washer installed upside down, causing switch to rub against pcb).

Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on June 07, 2018, 12:58:17 am
Do you remember what jacks were in use when measuring the DC/DC?
Were you using the meter for measurement of current, power or voltage?
The probes were definitely in the V and COM jacks for voltage measurement, and meter in auto ranging DC V.

So you weren't measuring Power (VA) at all?
Hmm, there goes one theory.

Quote
Sure, see attached photo.  They look squeaky clean to me.

And there goes theory #2

I'm now at a loss as to how this happened. Need to think some more...
Title: Re: EEVBlog 121GW Discussion thread
Post by: Kean on June 07, 2018, 02:28:36 am
So you weren't measuring Power (VA) at all?
Nope, don't think I've even tried the VA mode as yet.

Quote
I'm now at a loss as to how this happened. Need to think some more...
Indeed.  Here is a couple of close ups of the PCB - one with backlighting.  You can actually see some minor damage to the gold plating in the corners, so maybe there was an arc across those (36&37) but via what path?
I'm not so sure about the internal trace now, but you can see there is one that goes directly under that crater.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Seppy on June 07, 2018, 02:39:50 am
IMO, the weak link of the meter's front end is that 15V diode check mode.   I marked the switch to make it easy to follow on the schematic.   

Also, note that a while back another member had posted some good pictures of their switch showing a fair amount of contamination in this same area.  I am not sure why it would accumulate here. 

A bit of damage for a low energy source.  Is there more to this story??

Hello, thanks for the post yeah still a little at a loss. I think there might be an issue with your labeling here is why I think so:

The inside row on the PCB has pad pattern when read from right to left (ignoring routed connections):

ROW 1 _ _ _ __ _ __


One row further in you see:

ROW 2 __ _ __ _ __


On the schematic:
Reading pins 34, 33, 13, 36, 12, 11 follows the following pattern:

_ _ _ __ _ __ <- Pattern matches ROW 1

Reading pins 35, 16, 37, 15, 14 has the following pattern:
__ _ __ _ __ <- Pattern matches ROW 2


However, a discrepancy exists where:

1. 13 and 11 are ground, buzzed out to the current shunt
2. 14 and 16 are connected to FB4, buzzed out to ferrite

Lets refer to these as Pair 1 and Pair 2 respectively.
It appears these pairs have been swapped on the PCB.

From Joe's annotation if you measure what is labeled 37 and 15 you get an open circuit, on the schematic these should be a short.
Whereas if you measure between 12 and 36 it is a closed circuit indicating these rows are swapped.

Attached are what I believe the connections to be.
(https://www.eevblog.com/wp-content/uploads/2018/06/Buzzed-Out-Rotary-Switch.png)
Title: Re: EEVBlog 121GW Discussion thread
Post by: Kean on June 07, 2018, 03:31:50 am
Thanks Seppy.  So, the switch contacts concerned are still 36 & 37?
I'm tied up with clients till the weekend, so I haven't even had a chance to reassemble it and see what still works.
Title: Re: EEVBlog 121GW Discussion thread
Post by: joeqsmith on June 07, 2018, 10:52:15 am
From Joe's annotation if you measure what is labeled 37 and 15 you get an open circuit, on the schematic these should be a short.
Whereas if you measure between 12 and 36 it is a closed circuit indicating these rows are swapped.

Attached are what I believe the connections to be.

I had not checked my work.  The short between 15 & 37 should have been a dead give away.   :palm:  :-DD  Good catch.   

The problem is still the same.  I wonder what R82, U9 area looks like.   I've said it a few times that the HEF parts have an absolute maximum VDD of 18V.  When I modified the pre-production meter,  I was having a problem finding a part with a sharp enough knee to stay under this.  I ended up changing to the part for a CD which added two more volts of margin.  Enough to get it to survive some basic transients after this.  But again, these are very low energy transients.  Nothing that would do this level of damage. 
Title: Re: EEVBlog 121GW Discussion thread
Post by: Kean on June 07, 2018, 11:58:46 am
I was thinking during dinner tonight that I should probably check with my colleague.  Maybe he visited the office while I wasn't around and used this meter in a "problematic way".  I doubt it, and I can't imagine what he could have done to cause this anyway  :-//

* I did allocate him an EEVblog BM235 meter when he started working for me to try keep him away from my "toys"  :-DMM
Title: Re: EEVBlog 121GW Discussion thread
Post by: PA0PBZ on June 07, 2018, 05:55:46 pm
I'm not so sure about the internal trace now, but you can see there is one that goes directly under that crater.

That track has nowhere to go but 36.
Title: Re: EEVBlog 121GW Discussion thread
Post by: IanB on June 09, 2018, 05:36:38 am
Can someone explain how to display the burden voltage when measuring current?

I can follow the instructions by pressing the SETUP button and changing the setting to "bd.on", but after that I cannot see how to get a voltage shown on the display? (I assume the voltage should appear in the secondary display above the current reading?)
Title: Re: EEVBlog 121GW Discussion thread
Post by: ChunkyPastaSauce on June 09, 2018, 03:33:42 pm

Can someone explain how to display the burden voltage when measuring current?

I can follow the instructions by pressing the SETUP button and changing the setting to "bd.on", but after that I cannot see how to get a voltage shown on the display? (I assume the voltage should appear in the secondary display above the current reading?)

Noticed the same and reported in https://www.eevblog.com/forum/testgear/eevblog-121gw-multimeter-issues/msg1566907/#msg1566907 (https://www.eevblog.com/forum/testgear/eevblog-121gw-multimeter-issues/msg1566907/#msg1566907)
Title: Re: EEVBlog 121GW Discussion thread
Post by: firewalker on June 09, 2018, 04:34:16 pm
Is there any news from the Europe distributor? Did they received the meters?

Alexander.
Title: Re: EEVBlog 121GW Discussion thread
Post by: joeqsmith on June 09, 2018, 08:31:18 pm
Any thoughts?

The energy to do that couldn't have come via the V jack, there is at least a PTC + 1K in series with every path. Even if the contacts shorted the VA range contacts and the ohms contacts, worst case path is V jack to GND via a PTC + 1K. So, it's weird  :-//
So I can only presume the path is via the low impedance A jack somehow...
Maybe one of the range switch contacts wasn't installed properly and was floating around? I presume you hadn't taken off the range switch before?, as that's required for the shim replacement.

At 600V 2.5Kohm would still be 250mA.  Maybe enough to cook the PCB.  Seems possible.   

https://youtu.be/6j8i3LfKm5A
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on June 10, 2018, 02:23:23 am
Any thoughts?

The energy to do that couldn't have come via the V jack, there is at least a PTC + 1K in series with every path. Even if the contacts shorted the VA range contacts and the ohms contacts, worst case path is V jack to GND via a PTC + 1K. So, it's weird  :-//
So I can only presume the path is via the low impedance A jack somehow...
Maybe one of the range switch contacts wasn't installed properly and was floating around? I presume you hadn't taken off the range switch before?, as that's required for the shim replacement.

At 600V 2.5Kohm would still be 250mA.  Maybe enough to cook the PCB.  Seems possible.   

Yes, you are right, seems possible if you can get the contacts to arc over.
Here is quick video showing 1200VDC sustaining, twice the rated voltage of the 121GW.
A test which i have done many time before.

https://www.youtube.com/watch?v=YPUJipe8Loo (https://www.youtube.com/watch?v=YPUJipe8Loo)
Title: Re: EEVBlog 121GW Discussion thread
Post by: Rutherfordium on June 10, 2018, 03:21:45 am
Is it reasonable to feel nervous when your hand goes near where the banana jacks are plugged in Dave?  Looks like exposed contacts.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on June 10, 2018, 03:38:20 am
Another test at 1100V AC

https://www.youtube.com/watch?v=vwVXl-RQWXs (https://www.youtube.com/watch?v=vwVXl-RQWXs)
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on June 10, 2018, 04:49:25 am
It looks like your DC supply is good for about 10mA.  You could try to turn it up to 600V with the 121GW set to the DCV mode, then turn it to ohms.  You may not have enough current to damage it, if your goal was to replicate the damage. 

My goal was only to show that the contacts do not arc over at these voltages.
Title: Re: EEVBlog 121GW Discussion thread
Post by: IanB on June 10, 2018, 05:16:45 am
My goal was only to show that the contacts do not arc over at these voltages.

Yes, but the important factor is turning the selection knob while the voltage is connected. Under these conditions the contact springs can partially bridge the gap between traces on the circuit board and increase the chance of an arc occurring. That's exactly the test Joe was doing in his videos.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Kean on June 10, 2018, 10:14:52 am
Please take a few pictures of R82 and U9 under the microscope.  Maybe even ohm out R82.  What ever went though these two traces had to go through more parts.   There should be some pretty good damage to the top side as well.
R82 measures fine (100.3ohm), and no visible damage in the U9/R82 area.  In fact no visible damage anywhere else on the PCB, although I haven't looked under the LCD assembly.  The fuses are intact.

I also checked with my colleague, and he hasn't use this meter at all.  I will reassemble it and run some functional tests shortly, but don't want to do too much before I meet up with Dave.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Kean on June 10, 2018, 10:22:29 am
Please take a few pictures of R82 and U9 under the microscope.  Maybe even ohm out R82.  What ever went though these two traces had to go through more parts.   There should be some pretty good damage to the top side as well.
R82 measures fine (100.3ohm), and no visible damage in the U9/R82 area.  In fact no visible damage anywhere else on the PCB, although I haven't looked under the LCD assembly.  The fuses are intact.

I also checked with my colleague, and he hasn't use this meter at all.  I will reassemble it and run some functional tests shortly, but don't want to do too much before I meet up with Dave.
And here is the photo I meant to attach to that post.
Title: Re: EEVBlog 121GW Discussion thread
Post by: FrankBuss on June 10, 2018, 11:12:59 am
My goal was only to show that the contacts do not arc over at these voltages.

Yes, but the important factor is turning the selection knob while the voltage is connected. Under these conditions the contact springs can partially bridge the gap between traces on the circuit board and increase the chance of an arc occurring. That's exactly the test Joe was doing in his videos.

Is it allowed that you turn the knob when voltage is connected? But this could be a problem in combination with the lose knob without the shim.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Kean on June 10, 2018, 11:40:23 am
OK, I just ran through a reasonably comprehensive functional test of my "damaged" 121GW, and it all tested out perfectly, even BT.  The only mode that I didn't test (and haven't used) is the VA ranges.

I used an Advantest R6142 programmable voltage & current generator, an ITECH IT7321 programmable AC source, some resistance & capacitance decade boxes, a function generator, and some random diodes to hand.

Although I've returned to the customer the original equiment I was measuring when I think the meter failed, I will set up a similar scenario and see what measurements I get.  I suspect it will be fine now that I've cleaned the carbon residue off the switch contacts.  It was definitely reading crazy voltages before cleaning it.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on June 10, 2018, 01:56:39 pm
Is it allowed that you turn the knob when voltage is connected? But this could be a problem in combination with the lose knob without the shim.

Not really, no, and I don't know any meter where they would specify that was a thing.
I've tested it with 240V mains whilst switching, but not with a low impedance HV DC source like has been discussed here.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Kean on June 10, 2018, 02:12:34 pm
Dave & other interested parties...

I have now remembered a time in the last few weeks I was measuring the 1200V AC output from a 100W Ultrasonic Transducer driver.  At the time I was pretty sure I only used my 15kV and differential oscilloscope probes - but based on the damage and Joe Smiths excellent test video, it seems likely that I must have tried to measure the voltage with the 121GW.

Very embarrasing, as I should gave known better!

Amazingly the meter still seems to function perfectly after cleaning the burnt area, and appears to still be in spec against my Keysight 34465A.
Title: Re: EEVBlog 121GW Discussion thread
Post by: joeqsmith on June 10, 2018, 02:54:22 pm
Dave & other interested parties...

I have now remembered a time in the last few weeks I was measuring the 1200V AC output from a 100W Ultrasonic Transducer driver.  At the time I was pretty sure I only used my 15kV and differential oscilloscope probes - but based on the damage and Joe Smiths excellent test video, it seems likely that I must have tried to measure the voltage with the 121GW.

Very embarrasing, as I should gave known better!

Amazingly the meter still seems to function perfectly after cleaning the burnt area, and appears to still be in spec against my Keysight 34465A.

No reason to be embarrassed.  This is actually pretty good news.   
Title: Re: EEVBlog 121GW Discussion thread
Post by: VK5RC on June 10, 2018, 09:45:27 pm
'Glad' to hear that someone else does stuff like I do! I just tried arc welding a dmm probe that slipped, measuring a 30v dc rail across a 10mF cap. D'oh.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on June 12, 2018, 12:02:23 am
Dave & other interested parties...

I have now remembered a time in the last few weeks I was measuring the 1200V AC output from a 100W Ultrasonic Transducer driver.  At the time I was pretty sure I only used my 15kV and differential oscilloscope probes - but based on the damage and Joe Smiths excellent test video, it seems likely that I must have tried to measure the voltage with the 121GW.

Very embarrasing, as I should gave known better!

Amazingly the meter still seems to function perfectly after cleaning the burnt area, and appears to still be in spec against my Keysight 34465A.

 :phew:

Glad to see it still works (all functions?)
Title: Re: EEVBlog 121GW Discussion thread
Post by: Kean on June 12, 2018, 01:30:15 am
:phew:

Glad to see it still works (all functions?)

Yep - as mentioned above...

OK, I just ran through a reasonably comprehensive functional test of my "damaged" 121GW, and it all tested out perfectly, even BT.  The only mode that I didn't test (and haven't used) is the VA ranges.

I used an Advantest R6142 programmable voltage & current generator, an ITECH IT7321 programmable AC source, some resistance & capacitance decade boxes, a function generator, and some random diodes to hand.

I am actually pretty impressed it survived with so little damage actually, assuming that I did hit it with that 1200V 28kHz supply... which now seems entirely likely.
Title: Re: EEVBlog 121GW Discussion thread
Post by: IanB on June 12, 2018, 06:29:27 am
Apropos of nothing, either both of these meters are correct, or both of them are wrong:  :)

(https://www.eevblog.com/forum/testgear/eevblog-121gw-discussion-thread/?action=dlattach;attach=454336;image)
Title: Re: EEVBlog 121GW Discussion thread
Post by: IanB on June 12, 2018, 06:50:35 am
Seems like a bunch of posts above just disappeared?
Title: Re: EEVBlog 121GW Discussion thread
Post by: Seppy on June 12, 2018, 06:52:43 am
Ok just checked on my iPhone 5s. Logging “save” button works fine there. But still no joy on the iPad mini.
Seems like a bunch of posts above just disappeared?
I split the topic so that we can keep app beta testing separate from discussion, only a few testers around :)
Title: Re: EEVBlog 121GW Discussion thread
Post by: IanB on June 12, 2018, 06:54:56 am
I split the topic so that we can keep app beta testing separate from discussion, only a few testers around :)

OK, can you then move Reply #910 above to the other thread?
Title: Re: EEVBlog 121GW Discussion thread
Post by: Seppy on June 12, 2018, 07:13:57 am
I split the topic so that we can keep app beta testing separate from discussion, only a few testers around :)

OK, can you then move Reply #910 above to the other thread?

Done, new topic called "121GW App Testing". This is for the beta testers of the iOS App
Title: Re: EEVBlog 121GW Discussion thread
Post by: TMM on June 12, 2018, 10:11:06 am
Got mine today, working great. Only problem is that someone on the production line was a bit too much in the spirit of "don't turn it on, take it apart" because it is missing the screws from the back cover :-//
Title: Re: EEVBlog 121GW Discussion thread
Post by: mikeselectricstuff on June 12, 2018, 05:22:00 pm
Not read through all the posts to check if this has been discussed (and AFAICS the forum can't search a single thread), but it isn;t mentioned in the manual
 I notice that the mode setting is retained after power-off. Although this can be useful it can also be annoying, especially if the meter isn't used often. It would also be a pain for a meter that was shared by several users, or used by someone unfamiliar with it.
AFAICS there is no option to make it always power up in a consistent mode - I think this would be a useful addition.
 
Title: Re: EEVBlog 121GW Discussion thread
Post by: 1anX on June 13, 2018, 02:03:25 am
Got mine today, working great. Only problem is that someone on the production line was a bit too much in the spirit of "don't turn it on, take it apart" because it is missing the screws from the back cover :-//

 :palm:
Title: Re: EEVBlog 121GW Discussion thread
Post by: morris on June 14, 2018, 12:36:47 am
Got mine today ;D. Good job, Dave :-+
Can someone tell me how do I open the battery cover though? I have removed the two screws at the back but the cover just won’t come off.  Which direction shall I push/ lift? I don’t want to break anything  this soon :-[ Thanks!


Oh...got it :-+.  But mine was kind of tight. ;D
https://youtu.be/nL7wDFNH8hM

Thank you Seppy and Admin   :-+
Title: Re: EEVBlog 121GW Discussion thread
Post by: Seppy on June 14, 2018, 01:24:46 am
Got mine today ;D. Good job, Dave :-+
Can someone tell me how do I open the battery cover though? I have removed the two screws at the back but the cover just won’t come off.  Which direction shall I push/ lift? I don’t want to break anything  this soon :-[ Thanks!


Oh...got it :-+.  But mine was kind of tight. ;D
https://youtu.be/nL7wDFNH8hM

For the battery cover it is difficult to remove if you don't pull precisely upwards.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on June 14, 2018, 03:51:24 am
Got mine today ;D. Good job, Dave :-+
Can someone tell me how do I open the battery cover though? I have removed the two screws at the back but the cover just won’t come off.  Which direction shall I push/ lift? I don’t want to break anything  this soon :-[ Thanks!
Oh...got it :-+.  But mine was kind of tight. ;D

You have to grab both sides and pull directly up. Yes it's a rather tight fit.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on June 14, 2018, 03:52:39 am
Not read through all the posts to check if this has been discussed (and AFAICS the forum can't search a single thread), but it isn;t mentioned in the manual
 I notice that the mode setting is retained after power-off. Although this can be useful it can also be annoying, especially if the meter isn't used often. It would also be a pain for a meter that was shared by several users, or used by someone unfamiliar with it.
AFAICS there is no option to make it always power up in a consistent mode - I think this would be a useful addition.

I don't believe there is an option to turn it off. The BM235 does the same.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on June 14, 2018, 03:54:26 am
Apropos of nothing, either both of these meters are correct, or both of them are wrong:  :)

Don't bother getting more, because it's turtles all the way down.
Title: Re: EEVBlog 121GW Discussion thread
Post by: bicycleguy on June 14, 2018, 04:36:18 am
Not read through all the posts to check if this has been discussed (and AFAICS the forum can't search a single thread), ...

To search a single thread go to the end of the thread and hit the print button.  You will get a single long page of html that you can do a text search on with cmd-F.

Edit:  Just testing this post I see you had 31 posts in this thread.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Seppy on June 15, 2018, 12:42:17 am
We need a beta tester with an iPad Pro or an iPad with a resolution of 2732 x 2048. We need a few screen shots in that size for the App Store, its part of the submission process.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Octane on June 15, 2018, 01:01:56 am
I have a 10.5” (2224-by-1668 Pixel) iPad Pro, but my meter didn’t arrive yet. Still happy to help if necessary.

Michael
Title: Re: EEVBlog 121GW Discussion thread
Post by: Kean on June 15, 2018, 01:45:06 am
We need a beta tester with an iPad Pro or an iPad with a resolution of 2732 x 2048. We need a few screen shots in that size for the App Store, its part of the submission process.
Could you not add a simulated device in the app that generates a slow sine wave or something.  Then you can just generate a nice screen shot via the iOS simulator, and people still waiting for the 121GW can start playing with the app.   ;D

I have to admit I've not submitted a screen shot at that resolution in the past - maybe it isn't/wasn't mandatory.
Title: Re: EEVBlog 121GW Discussion thread
Post by: IanB on June 15, 2018, 02:43:10 am
I imagine you need a screen shot so that Apple can verify that you are scaling to that screen resolution correctly. And in fact, the higher resolution of the iPad Pro will be a problem without scaled fonts as the small text for < Settings > and < Maths > is already very small and difficult to read on an ordinary iPad. On a higher resolution device you will need a microscope...  :P
Title: Re: EEVBlog 121GW Discussion thread
Post by: Seppy on June 15, 2018, 05:05:46 am
We need a beta tester with an iPad Pro or an iPad with a resolution of 2732 x 2048. We need a few screen shots in that size for the App Store, its part of the submission process.
Could you not add a simulated device in the app that generates a slow sine wave or something.  Then you can just generate a nice screen shot via the iOS simulator, and people still waiting for the 121GW can start playing with the app.   ;D

I have to admit I've not submitted a screen shot at that resolution in the past - maybe it isn't/wasn't mandatory.

This is an option but it is a fair amount of work (I also have to fake the multimeter screen, which is programmed to respond to packets, so I need to record a sessions packets and then replay them).
It would be more accurate and honest getting a real screen shot. I also am also not entirely sure it works on iPad Pro, wouldn't want to make it look like it did if it didn't.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Brumby on June 15, 2018, 05:03:38 pm
It would be more accurate and honest getting a real screen shot. I also am also not entirely sure it works on iPad Pro, wouldn't want to make it look like it did if it didn't.

You are right to not want to fake it.  It's not just dishonest, it is asking for trouble.  Actual screenshots on actual devices is the only real option.

Besides, the effort to fake a screen would be a one-off exercise = wasted time ... and any problems on those resolutions would need to be fixed anyway.  It's more efficient to just do it properly.
Title: Re: EEVBlog 121GW Discussion thread
Post by: benst on June 17, 2018, 01:02:11 am
We need a beta tester with an iPad Pro or an iPad with a resolution of 2732 x 2048. We need a few screen shots in that size for the App Store, its part of the submission process.

I have an iPad Pro 12.9 inch. (And a 121GW obviously. :) ) Let me know if I can help.

Ben
Title: Re: EEVBlog 121GW Discussion thread
Post by: IanB on June 17, 2018, 01:19:06 am
I have an iPad Pro 12.9 inch. (And a 121GW obviously. :) ) Let me know if I can help.

I dare say, if you went here and signed up as a beta tester, and then posted a full res screen shot after getting an email with an installation link, that would be welcomed:

https://www.eevblog.com/forum/testgear/re-eevblog-121gw-discussion-thread/msg1594333/#msg1594333 (https://www.eevblog.com/forum/testgear/re-eevblog-121gw-discussion-thread/msg1594333/#msg1594333)

Title: Re: EEVBlog 121GW Discussion thread
Post by: Seppy on June 18, 2018, 01:25:12 am
We need a beta tester with an iPad Pro or an iPad with a resolution of 2732 x 2048. We need a few screen shots in that size for the App Store, its part of the submission process.

I have an iPad Pro 12.9 inch. (And a 121GW obviously. :) ) Let me know if I can help.

Ben

Yes please! that would be very helpful! We definately need a beta tester for iPad Pro
Title: Re: EEVBlog 121GW Discussion thread
Post by: firstcolle on June 26, 2018, 06:52:51 am
is there any news about the EU backer (Johnny B. Goode) shipment? Has someone received the meter or at least the tracking number?
Title: Re: EEVBlog 121GW Discussion thread
Post by: TopLoser on June 26, 2018, 07:16:32 am
is there any news about the EU backer (Johnny B. Goode) shipment? Has someone received the meter or at least the tracking number?

UK arrived yesterday
Title: Re: EEVBlog 121GW Discussion thread
Post by: firstcolle on June 26, 2018, 07:42:37 am
thanks, I hope that arrive soon mine in Italy!
Title: Re: EEVBlog 121GW Discussion thread
Post by: firewalker on June 26, 2018, 01:09:14 pm
is there any news about the EU backer (Johnny B. Goode) shipment? Has someone received the meter or at least the tracking number?

UK arrived yesterday

Was your meter shipped through Welectron (Germany) or shipped directly from Daveland?

Alexander.
Title: Re: EEVBlog 121GW Discussion thread
Post by: skogen75 on June 26, 2018, 01:30:52 pm
Still no meter here in the USA.  Backer #528.  Did Kane ever ship the meters?
Title: Re: EEVBlog 121GW Discussion thread
Post by: TopLoser on June 26, 2018, 01:48:16 pm
is there any news about the EU backer (Johnny B. Goode) shipment? Has someone received the meter or at least the tracking number?

UK arrived yesterday

Was your meter shipped through Welectron (Germany) or shipped directly from Daveland?

Alexander.

Shipped from Australia late on Friday 22nd and delivered to the UK Monday midday 25th. DHL delivery with StarShipIt providing notifications.

I chose to pay all taxes and clearance directly to DHL came to £22 in total.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Hydron on June 26, 2018, 08:15:17 pm
I was expecting UK taxes+fees to end up at least twice that (~30 GBP in VAT alone) - how did they manage to calculate only 22 GBP inc fees?
I got my meter shipped to family in NZ (planned to pick it up personally in April, but the delay ruined that idea), would have gone the UK route had I known the charges would be that low!
Title: Re: EEVBlog 121GW Discussion thread
Post by: TopLoser on June 26, 2018, 09:17:25 pm
Not seen the paperwork, I’m out of the country and somebody signed for it on my behalf after I paid the tax/clearance online on Friday.

I’d be interested to know how much people paid in advance. Very impressed with DHL collecting at 6pm on Friday in Australia and delivering at 1pm on Monday in the UK!
Title: Re: EEVBlog 121GW Discussion thread
Post by: Hydron on June 26, 2018, 09:38:50 pm
I’d be interested to know how much people paid in advance. Very impressed with DHL collecting at 6pm on Friday in Australia and delivering at 1pm on Monday in the UK!
That is indeed quick - mine took longer to cross the ditch to NZ!
Title: Re: EEVBlog 121GW Discussion thread
Post by: IanJ on June 27, 2018, 10:44:59 am
I was expecting UK taxes+fees to end up at least twice that (~30 GBP in VAT alone) - how did they manage to calculate only 22 GBP inc fees?
I got my meter shipped to family in NZ (planned to pick it up personally in April, but the delay ruined that idea), would have gone the UK route had I known the charges would be that low!


I had elected not to Pay VAT etc in advance and take my chances (I'm Scottish!). I got the DHL request to pay 22 UKP also, I paid it, and the 121GW departed DHL-Sydney today and  is now on it's way. Will be here in UK 2nd July.
Hmmm, maybe there will be more to pay once it hits the UK.....dunno!

Ian.
Title: Re: EEVBlog 121GW Discussion thread
Post by: TopLoser on June 27, 2018, 11:33:31 am
"We will not be able to deliver your goods to you until we have paid the duties and taxes to customs on your behalf"

Sounds like the £22 is the only payment you need to make.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Lion_Tamer on June 27, 2018, 12:55:17 pm
I’d be interested to know how much people paid in advance.
I paid £32.77 ($56.05AUD) in advance, now I am waiting for the meter to be shipped to me.

Jem
Title: Re: EEVBlog 121GW Discussion thread
Post by: firstcolle on June 27, 2018, 12:57:01 pm
I paid in advance to speed up the process but still not received the tracking number..
Title: Re: EEVBlog 121GW Discussion thread
Post by: IanJ on June 29, 2018, 12:17:06 pm
I had elected not to Pay VAT etc in advance and take my chances (I'm Scottish!). I got the DHL request to pay 22 UKP also, I paid it, and the 121GW departed DHL-Sydney today and  is now on it's way. Will be here in UK 2nd July.
Hmmm, maybe there will be more to pay once it hits the UK.....dunno!
Ian.

Hi all,

My 121GW got delivered today......so I installed Firmware V1.22 over V1.17 straight away and ran my first test........I'll call that a PASS.
Will be using this as my go-to bench meter for a while and see how things go.
Nice one Dave, great to have that extra digit down on the workbench.
Ian.

Edit:
June 27, 2018 12:47 Sydney - Australia Shipment picked up
June 29, 2018 11:03 Aberdeen - UK Shipment delivered

(http://www.ianjohnston.com/pdvs2/121GW_PDVS2.jpg)
Title: Re: EEVBlog 121GW Discussion thread
Post by: firewalker on June 29, 2018, 02:33:02 pm
Any news from Welectron? Did they received any meter yet?

Alexander.
Title: Re: EEVBlog 121GW Discussion thread
Post by: dcac on June 29, 2018, 02:52:37 pm
Any news from Welectron? Did they received any meter yet?

Alexander.

From Dave's latest updates
Quote
EU backers, sorry but your units will be delayed a bit because of production volume. They plan to finish production on 22nd June. After that the units will be shipped to Welectron in Germany for distribution. So hopefully shipping will be in June.

It would be good to know if the meters got produced yet and perhaps are on their way to Welectron.

But no pressure Dave - we know this is out of your control - it just would be good to know.

Title: Re: EEVBlog 121GW Discussion thread
Post by: firewalker on June 29, 2018, 04:46:49 pm
I bet that they will ship when I will be away for vacations...  :scared: :scared: :scared:

Alexander.
Title: Re: EEVBlog 121GW Discussion thread
Post by: innkeeper on June 30, 2018, 07:38:26 pm
can we get an update on the Kane shipments of meters in the USA??

Kane should have had them in their hands shortly after June 11, so i had hope with that news id have mine by now, but no joy yet...
I'm pretty far down in the list, #935, still, it would be nice to know how they're progressing.
Others higher on the list haven't gotten theirs, so, I am curious if they have even started shipping, or maybe even that they didn't receive them yet...
Title: Re: EEVBlog 121GW Discussion thread
Post by: Finder on July 03, 2018, 12:19:17 pm
Hi is there any information available, I would personally welcome even reply of "nothing new to report" regarding the meters delivery.
Title: Re: EEVBlog 121GW Discussion thread
Post by: innkeeper on July 05, 2018, 06:36:14 pm
an update recently posted on  Kickstarter
https://www.kickstarter.com/projects/eevblog/eevblog-121gw-multimeter/posts/2230795 (https://www.kickstarter.com/projects/eevblog/eevblog-121gw-multimeter/posts/2230795)
Title: Re: EEVBlog 121GW Discussion thread
Post by: firewalker on July 06, 2018, 08:26:01 am
I am expecting delivery from Welectron is there any way to change my address now? Is there any way to talk to the Welectron person responsible for shipping?

Alexander.
Title: Re: EEVBlog 121GW Discussion thread
Post by: firewalker on July 07, 2018, 09:47:01 am
I had a talk with Welectron. It's not late for an address change but it would be better to go through Dave.

Alexander.
Title: Re: EEVBlog 121GW Discussion thread
Post by: innkeeper on July 10, 2018, 07:55:17 pm
Good news from the USA...
I got a notice from FedEx that my meter is on its way in the from U E I TEST INSTRUMENTS in the USA ....
Should be here Thursday!  :-+

Arriving on my birthday...now how did they know ... :-//
Title: Re: EEVBlog 121GW Discussion thread
Post by: firewalker on July 11, 2018, 06:35:54 am
Latest Kickstarter updateQ

Quick update.

US meters have finally started shipping!

217 units shipped today and they will shoot for a minimum of another 200 tomorrow. They got up to backer 1661 in the first lot, so seems they are doing them in order. You should get a tracking number by email when it ships.

Regards

Dave.
Title: Re: EEVBlog 121GW Discussion thread
Post by: darrellg on July 11, 2018, 03:52:18 pm
Backer #2250. Just received a notification from FedEx that UEI has created the label for mine and I should get it next Tuesday.
Title: Re: EEVBlog 121GW Discussion thread
Post by: skogen75 on July 11, 2018, 08:32:32 pm
Guess, I’m out of luck.  Backer #528 in the US, and no shipment notification.  Are they going in an order other than backer number?  Alphabetical perhaps?  Guess the wait continues...
Title: Re: EEVBlog 121GW Discussion thread
Post by: treesap on July 11, 2018, 10:13:45 pm
This is my first ever time to post a question on a forum thread without reading every single page, but there are currently 39, and after reading several, it seems most replies are questions from those who have purchased them.

Has it been announced that production and sales of these will continue once all of these initial (quite late) shipments are made? I got to the party a bit too late to participate in the Kickstarter campaign(s), and am extremely interested in purchasing one when (or if?) they are made be available for regular sale.

Thanks!
Title: Re: EEVBlog 121GW Discussion thread
Post by: qu1ck on July 11, 2018, 11:38:51 pm
Backer #549 here, got not one but two tracking numbers today. Are they shipping the leads separately?

Edit: I'm in US.

Sent from my moto g(6) using Tapatalk
Title: Re: EEVBlog 121GW Discussion thread
Post by: Brumby on July 12, 2018, 01:14:48 am
Catching up with the 121GW threads from this point is not something for the faint-hearted.  There has been a LOT of interest and discussion.

Has it been announced that production and sales of these will continue once all of these initial (quite late) shipments are made? I got to the party a bit too late to participate in the Kickstarter campaign(s), and am extremely interested in purchasing one when (or if?) they are made be available for regular sale.

Dave has made a significant investment of his resources in getting the 121GW together and is still working hard at resolving issues that have been identified.  You wouldn't do that if the Kickstarter was all you intended to fulfill.  Once the Kickstarter supporters have been sent their meters and the kinks ironed out, you can expect Dave to get the 121GW into his EEVblog shop for anyone to buy.  (I would expect he will have other sales channels available as well - such as Amazon - but that will be up to him.)

When is the question - and I'm sure Dave has been thinking about that.  I suspect he will be looking for a fairly stable product before venturing further.

Patience is key.
Title: Re: EEVBlog 121GW Discussion thread
Post by: darik on July 12, 2018, 01:26:27 am
When is the question - and I'm sure Dave has been thinking about that.  I suspect he will be looking for a fairly stable product before venturing further.

Patience is key.

I'm sure once the Kickstarters are out it won't take long. It's a good meter, it would be insane not to sell them. Especially after going through all the stress of the Kickstarter.
Title: Re: EEVBlog 121GW Discussion thread
Post by: innkeeper on July 12, 2018, 01:13:05 pm
it arrived.
backer #935
Happy birthday to me! :-DMM
Title: Re: EEVBlog 121GW Discussion thread
Post by: innkeeper on July 12, 2018, 02:32:00 pm
CHECK YOUR BATTERY COMPARTMENT
also not liking the solder job I can see on the 10A jack but will need to disassemble to see more.

(http://i.imgur.com/QIBpWSpl.jpg) (https://imgur.com/QIBpWSp)
(http://i.imgur.com/zHnDOE7l.jpg) (https://imgur.com/zHnDOE7)

Title: Re: EEVBlog 121GW Discussion thread
Post by: innkeeper on July 12, 2018, 03:14:31 pm
on the front side of the board, the jack connector solder joints are very grainy compared to the rest of the solder work, though, i suspect its due to different solder they may have used compared to the rest of the board vs them being cold joints. if it's lead-free, it is likely ok, if this is lead solder then these joints are very bad.

Id post pics, but I misplaced my usb microscope at the moment,  i was using my microscope on the bench which doesn't have a camera.
found the usb microscope.. pics posted below

They apper to be hand soldered and they didn't clean the flux off.
I want to touch up a few of the joints so they flow through to the backside (particularly the 10A jack) and clean up the flux, but i don't want to use dissimilar solder.

Does anyone know if they used lead or lead free on the jacks?

found the USB microscope .. sorry for the crappy image quality... i could not find the original software so used video capture.
sample of two jack solder joints
(http://i.imgur.com/J9rq6SGl.jpg) (https://imgur.com/J9rq6SG)
(http://i.imgur.com/HTfBOuTl.jpg) (https://imgur.com/HTfBOuT)
Title: Re: EEVBlog 121GW Discussion thread
Post by: IanB on July 12, 2018, 05:53:43 pm
Does anyone know if they used lead or lead free on the jacks?

Nobody is able to use lead solder in industrial products any more. It has to be lead free.
Title: Re: EEVBlog 121GW Discussion thread
Post by: bicycleguy on July 12, 2018, 06:01:20 pm
Ugh, not Duracell  :-[
https://www.eevblog.com/forum/testgear/leaking-alkaline-batteries-and-expensive-equipment-a-rogues-gallery/msg1471555/#msg1471555 (https://www.eevblog.com/forum/testgear/leaking-alkaline-batteries-and-expensive-equipment-a-rogues-gallery/msg1471555/#msg1471555)

Look carefully at that picture I posted and use at your own risk.
Title: Re: EEVBlog 121GW Discussion thread
Post by: darrellg on July 12, 2018, 06:03:06 pm
Has anyone tried the Energizer Ultimate Lithium cells in it yet?
Title: Re: EEVBlog 121GW Discussion thread
Post by: darik on July 12, 2018, 06:44:02 pm
I've noticed alkalines in general seem way more prone to leakage now than they were several years ago. They don't even have to run dry. I've had newish batteries with lots of charge leak on me. It seems like mild heat, 90 fahrenheit or so, can create enough pressure to burst the seals, especially in AA and AAA. I've gotten in the habit of checking all my batteries regularly, just last week I found a pair of < 1 year old Energizer AAAs in a laser pointer that were just starting to leak while still reading almost 1.4 volts.

I wish I could narrow it down to one brand but I've been burned by them all.

Ugh, not Duracell  :-[
https://www.eevblog.com/forum/testgear/leaking-alkaline-batteries-and-expensive-equipment-a-rogues-gallery/msg1471555/#msg1471555 (https://www.eevblog.com/forum/testgear/leaking-alkaline-batteries-and-expensive-equipment-a-rogues-gallery/msg1471555/#msg1471555)

Look carefully at that picture I posted and use at your own risk.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Mr.B on July 12, 2018, 08:52:26 pm
Has anyone tried the Energizer Ultimate Lithium cells in it yet?

Yes.
I immediately replaced the 'as shipped' batteries with Energizer Ultimate Lithium.
Works just fine.


Editing my original post for the benefit of new users:
Do not use Lithium batteries in your 121GW.
Confirmation post from Dave here:
https://www.eevblog.com/forum/testgear/eevblog-121gw-multimeter-issues/msg1782236/#msg1782236 (https://www.eevblog.com/forum/testgear/eevblog-121gw-multimeter-issues/msg1782236/#msg1782236)
Title: Re: EEVBlog 121GW Discussion thread
Post by: Octane on July 14, 2018, 12:27:45 am
Hi all,

I’m backer #2235 and I was surprised by the meter showing up on my doorstep today!
No shipping notification... anyways, I have firmware 1.18 installed and I like how the knob feels.
So far so good...

Michael
Title: Re: EEVBlog 121GW Discussion thread
Post by: firewalker on July 16, 2018, 12:38:43 pm
Welectron has some meters to deliver!  :-+ :-+ :-+

https://www.kickstarter.com/projects/eevblog/eevblog-121gw-multimeter/posts/2239318 (https://www.kickstarter.com/projects/eevblog/eevblog-121gw-multimeter/posts/2239318)

(https://i.imgur.com/mD8qjSos.jpg) (https://i.imgur.com/mD8qjSo.jpg)
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on July 16, 2018, 12:54:56 pm
I’m backer #2235 and I was surprised by the meter showing up on my doorstep today!
No shipping notification...

Strange how some people are reporting not getting the tracking email. Spam box?
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on July 16, 2018, 12:56:08 pm
I immediately replaced the 'as shipped' batteries with Energizer Ultimate Lithium.
Works just fine.

Don't think I ever did a full life test with those, should be substantially more than Alkaline
Title: Re: EEVBlog 121GW Discussion thread
Post by: firewalker on July 16, 2018, 12:59:08 pm
If the tracking email has terms like USD money address etc, yes it could interpreted from an automated system like scam email. Special for emails with custom filters and servers (nor gmail etc).

If the emails that didn't receive isn;t free public emails (gmail, yahoo etc), it could be the case.

Alexander.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Octane on July 16, 2018, 01:38:39 pm
I checked my spam/junk folders. It was not in there. And I usually get all the shipment notifications from UPS, Fedex, and the like... anyways, it is more important that the meter arrived.

Thanks Dave!

Michael
Title: Re: EEVBlog 121GW Discussion thread
Post by: darrellg on July 16, 2018, 03:40:38 pm
I’m backer #2235 and I was surprised by the meter showing up on my doorstep today!
No shipping notification...

Strange how some people are reporting not getting the tracking email. Spam box?

The only tracking email I got was from FedEx. I have a FedEx account, so I get notified whenever a package is sent to my address. I never got tracking info from the shipper.
Title: Re: EEVBlog 121GW Discussion thread
Post by: rrinker on July 16, 2018, 06:05:43 pm
 Got my meter Friday, still learning my way around it. Quite impressive. Downloaded the updated firmware, but have not installed it yet.

I got a tracking notices last Monday or Tuesday, from FedEx, not from UEI. That was the only notification I got. Per the notice, expected delivery date was Friday, and indeed it was waiting for me when I got home. Complete with the EEVBlog No-BS packaging. Carry case, Bryman leads included.

Title: Re: EEVBlog 121GW Discussion thread
Post by: KV6O on July 17, 2018, 02:55:51 am
Backer 1788 in the US, and I received mine over the weekend - yay!  I was notified by FedEx when it shipped as well.  And I unboxed it WITHOUT making a video, just like back in the day when you got stuff you just opened it up and used it.  I know, seems strange...

Initial impressions positive, it came loaded with 1.18 firmware (which isn't even listed on the website), I upgraded it to 1.22 yesterday. 

I'll have to do some speed comparisons with my Fluke, it feels slow on resistance measurements as I believe others have reported.  The rotary switch feels solid.  I dunno which leads I got, but they feel a bit cheap. I'll used it in the field today to check on some -48VDC battery plant float voltages, and it worked just fine and was easy to use.  I also linked it to my Android tablet, but the app seems like a beta app - not much too it, and display doesn't update.  Not sure the usefulness there that I can see just yet. 

I'll have to dig further to see how it performs, just glad to have it after 7+ months!
Title: Re: EEVBlog 121GW Discussion thread
Post by: AgiRigSig on July 17, 2018, 07:37:10 pm
Backer 2269..Germany
just received a tracking number from DHL (Welectron), the multimeter will be delivered on Thursday. Super-fast processing time from Welectron, super done.. :-+ :-+ :-+
Title: Re: EEVBlog 121GW Discussion thread
Post by: Zucca on July 18, 2018, 07:59:53 am
Backer 1268. Germany.

Same as above.
Title: Re: EEVBlog 121GW Discussion thread
Post by: firstcolle on July 18, 2018, 08:13:04 am
Backer 803 italy via Welectron, nothing  :'( :'( :'(
Title: Re: EEVBlog 121GW Discussion thread
Post by: chefkoch84 on July 18, 2018, 09:34:27 am
FYI:
Backer 971, Germany (Munich)

DHL tried to deliver my meter just now.   
(Sadly I mooved out of that flat (yesterday...) ;-) ... so now it is at the post-office.)

Greetings
Title: Re: EEVBlog 121GW Discussion thread
Post by: firewalker on July 18, 2018, 09:49:25 am
I guess they are shipping local units first.

Alexander.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Zucca on July 18, 2018, 10:29:23 am
Germany (Munich)

DHL tried to deliver my meter just now.   
(Sadly I mooved out of that flat (yesterday...) ;-) ... so now it is at the post-office.)

I am in Munich too... and guess what mine meter is also at the bloody post-office.
PS: We need a nex concept of mailbox. We need a packagebox in 2018.
Title: Re: EEVBlog 121GW Discussion thread
Post by: firewalker on July 18, 2018, 10:50:11 am
Just received tracking number for mine (Greece)!

Is there a way to see the destination address with the tracking number?

Alexander.
Title: Re: EEVBlog 121GW Discussion thread
Post by: newbrain on July 18, 2018, 11:00:25 am
And here comes my tracking code from DHL Germany.

Of course, I'm abroad at the moment...hopefully they'll give me the usual option "Home or collecting point?" when it comes to Sweden.
Title: Re: EEVBlog 121GW Discussion thread
Post by: ding on July 18, 2018, 11:18:50 am
Backer 716 from the UK, just got my tracking number from Welectron :-+
Title: Re: EEVBlog 121GW Discussion thread
Post by: glarsson on July 18, 2018, 11:56:32 am
Backer 795 in Sweden just received SENDUNGSBENACHRICHTIGUNG from DHL.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on July 18, 2018, 11:58:56 am
Backer 2269..Germany
just received a tracking number from DHL (Welectron), the multimeter will be delivered on Thursday. Super-fast processing time from Welectron, super done.. :-+ :-+ :-+

Yes, Marco at Welectron is super quick  :-+
The delays were getting them to him.
Title: Re: EEVBlog 121GW Discussion thread
Post by: racemaniac on July 18, 2018, 12:09:17 pm
I just received tracking info for mine, and am about to leave on vacation for 2 weeks >_<
Anyone got an idea how to arrange this with DHL, or will it just end up going back to sender, and i'll have to arrange a next shipment?

A bit impractical to just send them out in the middle of holiday season without asking if people can receive it
Title: Re: EEVBlog 121GW Discussion thread
Post by: Candid on July 18, 2018, 02:13:27 pm
When delivered by DHL normally you should be able to give an advice online where to deliver if you cannot personally accept the parcel.
Title: Re: EEVBlog 121GW Discussion thread
Post by: HKJ on July 18, 2018, 02:30:45 pm
When delivered by DHL normally you should be able to give an advice online where to deliver if you cannot personally accept the parcel.

Mostly when I get DHL from Germany it is delivered by the local postal service and takes a few days. When I get DHL from China it is delivered by DHL and I get an email to redirect the parcel.
Title: EEVBlog 121GW Discussion thread
Post by: Dr. Frank on July 18, 2018, 02:56:30 pm
I'm Backer To The Future #649.

How Time McFly's, so today I finally received my Dave-O-Meter, from Welectron.

The DHLorean just stopped by in front of Doc Franks house.

Was expected to appear much earlier in the past, but anyhow, now it's  present, to often use it in the future.

It came flashing @ 1.21 GW, with unzippered EEVBLog1_22, so this Mc Fly is closed:

(https://www.eevblog.com/forum/testgear/eevblog-121gw-discussion-thread/?action=dlattach;attach=478823;image)

Then I hooked it up on High Voltage, to check its Lightning Rod capabilities, the DC and AC values turned out to be ok.

(https://www.eevblog.com/forum/testgear/eevblog-121gw-discussion-thread/?action=dlattach;attach=478829;image)

(https://www.eevblog.com/forum/testgear/eevblog-121gw-discussion-thread/?action=dlattach;attach=478835;image)

Biff Tanner (BT) is also polishing the data fine onto my mobile, and the 8 GB micro SD can biffer a lot of data.

The 1 MOhm range is quite noisy, and 10 MOhm is way off:

(https://www.eevblog.com/forum/testgear/eevblog-121gw-discussion-thread/?action=dlattach;attach=478841;image)

let's wait until it cools down after the timely journey, maybe a little bit of calibration is required.

Greetings from Doc Frank
Title: Re: EEVBlog 121GW Discussion thread
Post by: chefkoch84 on July 18, 2018, 03:02:00 pm
+1 on the need of a solution for receiving goods.

1922 they had a pretty impressive pneumatic post system ... even in Munich.
https://de.wikipedia.org/wiki/Rohrpost_in_M%C3%BCnchen#/media/File:RohrpostnetzplanM%C3%BCnchen.png
(my meeter is at station #8 )

Just imaging the people, how they must have visioned the future.

2018 - we wait in the line at the fucking post-office, like an idiot. of course they close at 6pm - so somebody who has a job almost needs to take a day off  |O




Title: Re: EEVBlog 121GW Discussion thread
Post by: bicycleguy on July 18, 2018, 09:59:43 pm
Really enjoying the new meter.  Always wondered what my freezer was up to...

The saved file always has 2/9/06 9:30 pm as the created date, luckily first line of data is correct time and date.
Title: Re: EEVBlog 121GW Discussion thread
Post by: innkeeper on July 19, 2018, 03:45:52 am
spot check for voltage accuracy

vref         121gw measurement
2.50025  2.5004
4.99970  5.0002
7.49904  7.499
9.99770  9.997

vref calibrated at 21c temperature at the time of test 23.8c

good enough for me  8)



Title: Re: EEVBlog 121GW Discussion thread
Post by: Jon.C on July 19, 2018, 03:51:59 am
WTF ?    :palm:


(https://i.gyazo.com/f2de2a879f0202bac8fd1b78b715c350.png)
Title: Re: EEVBlog 121GW Discussion thread
Post by: Welectron on July 19, 2018, 08:30:56 am
WTF ?    :palm:
Your meter was shipped yesterday, but we had to do a second label for your shipment due to the need of a customs declaration to Andorra. Let me know if you did not receive the valid tracking number yet.

@All: The last batch of 121GW landed a few minutes ago. All backers that have not been served from the first batch will be shipped today.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Jon.C on July 19, 2018, 09:39:18 am
WTF ?    :palm:
Your meter was shipped yesterday, but we had to do a second label for your shipment due to the need of a customs declaration to Andorra. Let me know if you did not receive the valid tracking number yet.

@All: The last batch of 121GW landed a few minutes ago. All backers that have not been served from the first batch will be shipped today.


Hello

I see that he is already in the La Poste

it's strange because I put the address of Spain and pay the VAT

but if it comes by La Poste much better for me (La Poste = directly to my house )

Now I have to investigate how to recover the VAT

Thank you very much

I recently bought in welectron an 869s a fantastic service on your part


(https://i.gyazo.com/a9192b66ee4a664d3baa77ed025be128.png)


(https://i.gyazo.com/cb1fec7ca436c52f753690fd4db278c9.png)
Title: Re: EEVBlog 121GW Discussion thread
Post by: firstcolle on July 19, 2018, 09:47:06 am
Hi,

the meter will be delivered by DHL courier outside Germany? or it's DHL until the custom an then via standard national post service? in this case what about the local VAT? I elected and paid in advance the fee..

thanks
Title: Re: EEVBlog 121GW Discussion thread
Post by: firewalker on July 19, 2018, 12:08:05 pm
As I can understand from my tracking number the parcel is send using DHL normal posting service and not courier? Just a registered mail?

If that is the case, the parcel will be handed over the local post of each country. It usually takes 10 days (for Greece) for a delivery notice...

Alexander.
Title: Re: EEVBlog 121GW Discussion thread
Post by: firstcolle on July 19, 2018, 12:23:23 pm
Mm.. Shure, for shipping within run no vat is required
Title: Re: EEVBlog 121GW Discussion thread
Post by: Jon.C on July 19, 2018, 12:46:54 pm
within the European Union it is normal to have the VAT of the country of origin in this case Germany

in my case the exception is because the sales to Andorra have no VAT

Andorra has an internal VAT of 4.5%

or if I buy something from the European Union and it costs more than 220 € the customs of Andorra will charge me 4.5%
Title: Re: EEVBlog 121GW Discussion thread
Post by: Zom-B on July 19, 2018, 01:31:37 pm
Meter arrived.
Title: Re: EEVBlog 121GW Discussion thread
Post by: FrankBuss on July 19, 2018, 11:52:03 pm
The 1 MOhm range is quite noisy, and 10 MOhm is way off:

(https://www.eevblog.com/forum/testgear/eevblog-121gw-discussion-thread/?action=dlattach;attach=478841;image)


It has a 5 MOhm and 50 MOhm range. According to the manual, the 50 MOhm range has a +/-1.2% accuracy. Looks like your meter has a +1.9% error in this range. I wouldn't say that's way off, but technically you are right, looks like it doesn't meet the specification.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Dr. Frank on July 20, 2018, 06:50:34 am


It has a 5 MOhm and 50 MOhm range. According to the manual, the 50 MOhm range has a +/-1.2% accuracy. Looks like your meter has a +1.9% error in this range. I wouldn't say that's way off, but technically you are right, looks like it doesn't meet the specification.


That was a quick 'n dirty check only, but in the meantime I made an overview of most modes and ranges.

These are mostly a factor of ten more accurate than in the specification, as would be required by proper bandguarding  guardbanding ratio, and also for the annual drift.
A high bandguarding guardbanding ratio is always an indicator, that the instrument was properly designed.. Keysight or Fluke DMMs are always much more precise, than their specification tells.

The 500k Ohm, 5 MOhm and 50MOhm ranges stand out in this aspect, as these are either spuriously unstable, or are on the edge, or over the limits of their specifications.

examples:
500k : +0.02% (compared to 0.2% spec.) and noisy,
but: 1.9M +0.2% (compared to 0.3% spec) and noisy
and: 19M +1.4%, that's been another measurement, (compared to 1.2% spec), and unstable with longer time constant


That's both a bad indicator, that there is something fishy.. others also already reported  about that instability of these Ohm ranges.

I assume, that due to this instability, initial calibration was also affected.

Frank

PS.: I will post the complete verification table later
Title: Re: EEVBlog 121GW Discussion thread
Post by: firewalker on July 20, 2018, 08:03:37 am
For the rest of you (waiting from Welectron), do you see the parcel being processed daily? Mine is at

Code: [Select]
Bruchsal, Germany.

The international shipment has been processed in the parcel center of origin

Since Wednesday.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Jon.C on July 20, 2018, 08:27:23 am
For the rest of you (waiting from Welectron), do you see the parcel being processed daily? Mine is at

Code: [Select]
Bruchsal, Germany.

The international shipment has been processed in the parcel center of origin

Since Wednesday.

yes

(https://i.gyazo.com/22fc63ff958e298e717e9dedc359f68c.png)
Title: Re: EEVBlog 121GW Discussion thread
Post by: Zom-B on July 20, 2018, 08:45:09 am
I've never heard of bandguarding ratio and a few Google searches also turn up nothing.

[Edit] From the context it sounds like either Test Accuracy Ratio or Test Uncertainty Ratio (found on a metrological page)
Title: Re: EEVBlog 121GW Discussion thread
Post by: HKJ on July 20, 2018, 08:48:52 am
For the rest of you (waiting from Welectron), do you see the parcel being processed daily? Mine is at

For me there is another tracking number on the DHL site I can use with the local postal service and this morning it arrived at the local distribution center.
Title: Re: EEVBlog 121GW Discussion thread
Post by: firewalker on July 20, 2018, 09:12:59 am
For the rest of you (waiting from Welectron), do you see the parcel being processed daily? Mine is at

Code: [Select]
Bruchsal, Germany.

The international shipment has been processed in the parcel center of origin

Since Wednesday.

yes

(https://i.gyazo.com/22fc63ff958e298e717e9dedc359f68c.png)

:( :( :(

(https://i.imgur.com/3y6ynUV.png)
Title: Re: EEVBlog 121GW Discussion thread
Post by: Finder on July 20, 2018, 09:55:41 am

(https://i.imgur.com/3y6ynUV.png)
That's moved more than mine

(https://i.imgur.com/RbTv7PB.jpg)
Title: Re: EEVBlog 121GW Discussion thread
Post by: firewalker on July 20, 2018, 10:04:59 am
I don't know why normal post was used to send the meters out.

Alexander.
Title: Re: EEVBlog 121GW Discussion thread
Post by: firstcolle on July 20, 2018, 10:06:05 am
mine is "out for delivery" with DHL express
Title: Re: EEVBlog 121GW Discussion thread
Post by: firewalker on July 20, 2018, 10:07:36 am
mine is "out for delivery" with DHL express

Yours was sent with DHL express?
Title: Re: EEVBlog 121GW Discussion thread
Post by: firstcolle on July 20, 2018, 10:14:08 am
mine is "out for delivery" with DHL express

Yours was sent with DHL express?

was sent via DHL post, i suppose..
Title: Re: EEVBlog 121GW Discussion thread
Post by: hammy on July 20, 2018, 10:47:27 am
That's both a bad indicator, that there is something fishy.. others also already reported  about that instability of these Ohm ranges.

Just a observation: The noise is much less, if you put a precision resistor directly into the socket. A measurement with leads is way more noisy.
Not unusual for a DMM for this price.
 :-/O
Title: Re: EEVBlog 121GW Discussion thread
Post by: Dr. Frank on July 20, 2018, 12:28:06 pm
I've never heard of bandguarding ratio and a few Google searches also turn up nothing.

[Edit] From the context it sounds like either Test Accuracy Ratio or Test Uncertainty Ratio (found on a metrological page)

Nope, was kinda typo, or Freudian Error, I meant Guardbanding.

That's a different story than the simple T.U.R. ..

It means that you judge a calibration to be 'Fail', if the measured value is too close at/below the specification limit, so you define an additional band of tolerance to safeguard the calibration against additional sources of error.

It's explained here, by Keysights Chief Metrologist, Bob Stern: https://www.youtube.com/watch?v=p_BHEWzP11A (https://www.youtube.com/watch?v=p_BHEWzP11A)

In this context, a freshly calibrated instrument should always be far below the specified limits, otherwise it would be an indicator, that either there's something wrong with the calibration, or with the instrument under test.

That same way, I also found out in 2015, that my then brand new 34465A had several bugs in the firmware for the high voltage dc ranges, 100V and 1kV. And also that the KS calibration verification for this instrument contained a gap.

Frank
Title: EEVBlog 121GW Discussion thread - Initial Verification
Post by: Dr. Frank on July 20, 2018, 02:44:46 pm
Here we go,

I have compiled the basic accuracy verification, (comma used for the decimal point.)

(https://www.eevblog.com/forum/testgear/eevblog-121gw-discussion-thread/?action=dlattach;attach=480269;image)

All ranges are very well inside the (barn door wide) specification, mostly a factor of 10 more accurate than specified.

The linearity of the A/D_1 is quite good, but it shows a very pronounced Rollover Error of about 3 6 digits. I've expressed these both characteristics commonly by the overall DNL, Differential Non Linearity, over the nominal +/- 5.0000 V range, which computes to 2 digits, which is quite OK.


(https://www.eevblog.com/forum/index.php?action=dlattach;topic=101816.0;attach=480275;image)

Only the 500k, 5M and 50M Ohm ranges show a strange behavior.

500k and 5M might be quite jumpy all of a sudden, or rock stable the other instance, always with the same physical setup.
The accuracy changes from one day to the other, or from one power-on to the other.
Latter goes also for the 50M range, which integrates much slower; 2 days ago it was out of specification, as it was today morning, but in the afternoon, it was inside spec, but varying from one power-on to the other.

Seems to me, that some internal interference occurs, as if the firmware creates spurious interrupts which affect the readings.

I monitored these different behaviors and will report elsewhere.

Otherwise, that instrument seems to be of very good quality, but not so well specified or qualified by UEI.
I think, that it performs much better, in the same league like other, more expensive DMMs.

Frank
Title: Re: EEVBlog 121GW Discussion thread
Post by: HKJ on July 20, 2018, 04:18:48 pm
It arrived today, that was 3 days from Germany, same time as DHL can move a parcel from China to me.
The meter was with V1.22 software, i.e. the newest
Title: Re: EEVBlog 121GW Discussion thread
Post by: DavidDLC on July 20, 2018, 10:55:17 pm
Auto-range broken on V1.22

At work I'm measuring resistance and the auto-range cycles for ever. If I remember correctly there was an issue with this in the past and it was fixed with firmware change

In my case there is a capacitor that gets charged when measuring resistance. I did the same test with a Fluke in auto-range with no problem

Any comments ?

David DLC
Title: Re: EEVBlog 121GW Discussion thread
Post by: Zom-B on July 21, 2018, 04:12:27 pm
Auto-range broken on V1.22

At work I'm measuring resistance and the auto-range cycles for ever. If I remember correctly there was an issue with this in the past and it was fixed with firmware change

In my case there is a capacitor that gets charged when measuring resistance. I did the same test with a Fluke in auto-range with no problem

Any comments ?

David DLC
Better move that to the 121 issues thread in the same subforum
Title: Re: EEVBlog 121GW Discussion thread
Post by: bicycleguy on July 21, 2018, 10:13:55 pm
Tried some more data logging of my freezer, 2 days, 18 hours at 10 second intervals.  Observations:
1. 23690 measurements, no missed or corrupted data.
2. Partially discharged Energizer NiMH batteries dropped from 5.21 to 5.02V so could probably go a week with a fresh charge.
3. Not able to check battery (on display) during logging  :(.  Also the 4.2V warning is to low for NiMH if you want them to last... I know thats not what it's for.

4. My freezer defrost cycle is not time synchronous so I can't predict when to eat soft ice cream  :(
5. With regard to some of the temp spikes my wife admits to sticking her head in the freezer after working in the garden  |O
Title: Re: EEVBlog 121GW Discussion thread
Post by: firstcolle on July 22, 2018, 11:21:44 am
I'm doing some tests and i have some trouble with the uA range.

I set up a basic led circuit and measured the current on the mA range and the probe inserted into the A/500mA socket, the led is powered on and i measured 9mA.
I switched the range into the uA range and the probe into the mA/uA socket but the led does not power on and nothing is measured on the meter. I checked the 400mA fuse and there is no continuity... fuse blown?? I think that this range should measure 9mA..
Title: Re: EEVBlog 121GW Discussion thread
Post by: Robreeves on July 22, 2018, 02:17:03 pm
What is the status of US distribution?  I am backer 878 and I have heard nothing.   :(
Title: Re: EEVBlog 121GW Discussion thread
Post by: bicycleguy on July 22, 2018, 05:22:25 pm
I'm doing some tests and i have some trouble with the uA range.

I set up a basic led circuit and measured the current on the mA range and the probe inserted into the A/500mA socket, the led is powered on and i measured 9mA.
I switched the range into the uA range and the probe into the mA/uA socket but the led does not power on and nothing is measured on the meter. I checked the 400mA fuse and there is no continuity... fuse blown?? I think that this range should measure 9mA..
The maximum allowed in the uA position is 500uA so should indicate OFL.  It takes a second to show.  Fuse should have continuity.  Does probe in mA/uA socket, switch in ma work?

Finding the maximum range for each position is a little problematic.  The chart on page 16 of manual is useful if available.  The auto range position doesn't indicate the max just the current auto range.
So you have to:
1. With probes not hooked up but inserted into desired sockets (required for current)
2. Rotate switch as desired.
3. Select mode.
4. Press range and note the max range value in the lower right corner of display.  Continue pressing range until you find the max.

I don't think this is much different than other meters but the text for the value is so miniature I can't even see it without my glasses.  On other meters it is much more prominent.


Title: Re: EEVBlog 121GW Discussion thread
Post by: sebmadgwick on July 22, 2018, 09:03:26 pm
Hi Dave and Dave2.  I guess this is the best thread for some quick UI feedback concerning the printing on the plastic:

1) Don't print the backlight icon in yellow.  Doing so suggests that the yellow icon is linked to the yellow button in the same way that the red icons are linked to the red button.  It is not.  The backlight icon should be in white.

2) The the alternative 'red' modes for each rotatory position should not be remembered in software as this (a) breaks the relationship between red icons and the red button, and (b) means that you have to check that the mode is correct immediately after selecting a mode.  Even just writing that sentence spells out a clear UI fail.

3) I'll accept this last one as subjective but make the Bluetooth icon white.  There is no blue button but the icon colour suggests meaning where there is none.

..otherwise, I really like the meter :) Well done.
Title: Re: EEVBlog 121GW Discussion thread - Initial Verification
Post by: Seppy on July 23, 2018, 02:14:27 am
Here we go,

I have compiled the basic accuracy verification, (comma used for the decimal point.)

(https://www.eevblog.com/forum/testgear/eevblog-121gw-discussion-thread/?action=dlattach;attach=480269;image)

All ranges are very well inside the (barn door wide) specification, mostly a factor of 10 more accurate than specified.

The linearity of the A/D_1 is quite good, but it shows a very pronounced Rollover Error of about 3 6 digits. I've expressed these both characteristics commonly by the overall DNL, Differential Non Linearity, over the nominal +/- 5.0000 V range, which computes to 2 digits, which is quite OK.


(https://www.eevblog.com/forum/index.php?action=dlattach;topic=101816.0;attach=480275;image)

Only the 500k, 5M and 50M Ohm ranges show a strange behavior.

500k and 5M might be quite jumpy all of a sudden, or rock stable the other instance, always with the same physical setup.
The accuracy changes from one day to the other, or from one power-on to the other.
Latter goes also for the 50M range, which integrates much slower; 2 days ago it was out of specification, as it was today morning, but in the afternoon, it was inside spec, but varying from one power-on to the other.

Seems to me, that some internal interference occurs, as if the firmware creates spurious interrupts which affect the readings.

I monitored these different behaviors and will report elsewhere.

Otherwise, that instrument seems to be of very good quality, but not so well specified or qualified by UEI.
I think, that it performs much better, in the same league like other, more expensive DMMs.

Frank

We have tested 10 units now all within spec for 10 M, is there any chance environmental noise made the measurement wobbly? We can test more, but it is going to take some time.
Title: Re: EEVBlog 121GW Discussion thread - Initial Verification
Post by: IanB on July 23, 2018, 02:55:54 am
We have tested 10 units now all within spec for 10 M, is there any chance environmental noise made the measurement wobbly? We can test more, but it is going to take some time.

I just tried a couple of 10 MΩ resistors, which read 10.x MΩ on my BM869s, but they read 9.6 MΩ on my 121GW. (Connection made with alligator clips to ensure a stable connection.)

(Also, I have to note that the auto-ranging would first show a value of 14 MΩ for a second before updating to 9.6 MΩ. I really think the auto-range in resistance on the latest firmware is not right.)

Is it possible that disassembly of the meter to install/check the shim might cause accuracy problems from contamination of the circuit board?
Title: Re: EEVBlog 121GW Discussion thread
Post by: firstcolle on July 23, 2018, 06:35:13 am
I'm doing some tests and i have some trouble with the uA range.

I set up a basic led circuit and measured the current on the mA range and the probe inserted into the A/500mA socket, the led is powered on and i measured 9mA.
I switched the range into the uA range and the probe into the mA/uA socket but the led does not power on and nothing is measured on the meter. I checked the 400mA fuse and there is no continuity... fuse blown?? I think that this range should measure 9mA..
The maximum allowed in the uA position is 500uA so should indicate OFL.  It takes a second to show.  Fuse should have continuity.  Does probe in mA/uA socket, switch in ma work?

Finding the maximum range for each position is a little problematic.  The chart on page 16 of manual is useful if available.  The auto range position doesn't indicate the max just the current auto range.
So you have to:
1. With probes not hooked up but inserted into desired sockets (required for current)
2. Rotate switch as desired.
3. Select mode.
4. Press range and note the max range value in the lower right corner of display.  Continue pressing range until you find the max.

I don't think this is much different than other meters but the text for the value is so miniature I can't even see it without my glasses.  On other meters it is much more prominent.

Thanks for your help.
no, with the probe in mA/uA socket and the switch in mA range is not working. for sure the fuse is blown. i'm looking for a replacement.

thanks for all the tips!

Title: Re: EEVBlog 121GW Discussion thread
Post by: glarsson on July 23, 2018, 08:31:32 am
Backer 795 in Sweden just received SENDUNGSBENACHRICHTIGUNG from DHL.
Delivered to my door a couple of minutes ago.

Only one serial number on the back. The shiny eevblog serial sticker is missing. Was this sticker only on the first batch or did mine skip this manufacturing step?
Title: Re: EEVBlog 121GW Discussion thread
Post by: firstcolle on July 23, 2018, 09:29:44 am
I'm doing some tests and i have some trouble with the uA range.

I set up a basic led circuit and measured the current on the mA range and the probe inserted into the A/500mA socket, the led is powered on and i measured 9mA.
I switched the range into the uA range and the probe into the mA/uA socket but the led does not power on and nothing is measured on the meter. I checked the 400mA fuse and there is no continuity... fuse blown?? I think that this range should measure 9mA..
The maximum allowed in the uA position is 500uA so should indicate OFL.  It takes a second to show.  Fuse should have continuity.  Does probe in mA/uA socket, switch in ma work?

Finding the maximum range for each position is a little problematic.  The chart on page 16 of manual is useful if available.  The auto range position doesn't indicate the max just the current auto range.
So you have to:
1. With probes not hooked up but inserted into desired sockets (required for current)
2. Rotate switch as desired.
3. Select mode.
4. Press range and note the max range value in the lower right corner of display.  Continue pressing range until you find the max.

I don't think this is much different than other meters but the text for the value is so miniature I can't even see it without my glasses.  On other meters it is much more prominent.

Thanks for your help.
no, with the probe in mA/uA socket and the switch in mA range is not working. for sure the fuse is blown. i'm looking for a replacement.

thanks for all the tips!

could this be a valid replacement? because I can't find any fuse at 400mA 1000VDC..
https://www.tme.eu/it/details/zgssh-0.4a/fusibili-63x32mm-super-veloci/siba/701254004/ (https://www.tme.eu/it/details/zgssh-0.4a/fusibili-63x32mm-super-veloci/siba/701254004/)
Title: Re: EEVBlog 121GW Discussion thread
Post by: kenneth1212 on July 23, 2018, 10:01:53 am
How about this 400mA fuse?
https://www.welectron.com/Multimeter-Fuses


Skickat från min SM-G930F via Tapatalk

Title: Re: EEVBlog 121GW Discussion thread
Post by: firewalker on July 23, 2018, 10:22:25 am

(https://i.imgur.com/3y6ynUV.png)
That's moved more than mine

(https://i.imgur.com/RbTv7PB.jpg)

Was there any status update for you? Mine is the same. I don't why it takes so long for German post to process parcels. In the mean time I have ordered and received parcels from UK, Italy and France...

Alexander.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Jon.C on July 23, 2018, 04:52:16 pm
a bit .... :=\


(https://i.gyazo.com/6ee327eeb4535b037ceef2d620b37915.png)
Title: Re: EEVBlog 121GW Discussion thread
Post by: Lion_Tamer on July 23, 2018, 05:13:58 pm
My meter finally arrived today and although I have yet to use it in a real situation here are a couple of observations/thoughts about the meter and android app (I don't have any Apple devices so can't say if they are the same or not):

1. The blue tooth and 1Khz filter are below their respective buttons whereas everything else is above, until I read the manual I thought that they were controlled by the buttons below them not above.

2. When connected by blue tooth to the app and you cycle through the "setup" menu you get the setup values showing on the secondary display of the phone - is it possible to put a bit more detail on the phone screen e.g. "Year 2018" instead of "18", "Buzzer Off" instead of "0v" etc.

3. With the meter in setup mode "b-OFF", "Meter ID" and Logging Interval it shows it as a voltage in the app.

4. With the meter in setup mode month and day "07-23" it shows it as 1815 in the app

5. With the meter in setup mode hour and minutes "18-00" it shows it as 4412 in the app

6. In the user manual section "Setup Menu" on page 57 you are missing the "Buzzer On/Off" which should be between "Auto Power Off" and "LCD Contrast"

7. In the buzzer option of the setup menu maybe change it to say "buz.on" and "buz.of" instead of "b-on" and "b-off" - it might be a clearer what the menu item is then without having to consult the manual.

I know that some of these may not be easy or possible to change but thought that you might appreciate some more feedback.
Wow its far more compact than I was imagining and may well end up joining my everyday carry in the tool box.
Now I just need to find the time to use it on a project (I have several in mind if i get the chance).

Jem

Edit: added point 7
Title: Re: EEVBlog 121GW Discussion thread
Post by: Seppy on July 24, 2018, 01:33:14 am
My meter finally arrived today and although I have yet to use it in a real situation here are a couple of observations/thoughts about the meter and android app (I don't have any Apple devices so can't say if they are the same or not):

1. The blue tooth and 1Khz filter are below their respective buttons whereas everything else is above, until I read the manual I thought that they were controlled by the buttons below them not above. We might be able to fix that, would take a while though.

2. When connected by blue tooth to the app and you cycle through the "setup" menu you get the setup values showing on the secondary display of the phone - is it possible to put a bit more detail on the phone screen e.g. "Year 2018" instead of "18", "Buzzer Off" instead of "0v" etc.

3. With the meter in setup mode "b-OFF", "Meter ID" and Logging Interval it shows it as a voltage in the app.

4. With the meter in setup mode month and day "07-23" it shows it as 1815 in the app

5. With the meter in setup mode hour and minutes "18-00" it shows it as 4412 in the app

6. In the user manual section "Setup Menu" on page 57 you are missing the "Buzzer On/Off" which should be between "Auto Power Off" and "LCD Contrast"

7. In the buzzer option of the setup menu maybe change it to say "buz.on" and "buz.of" instead of "b-on" and "b-off" - it might be a clearer what the menu item is then without having to consult the manual.

I know that some of these may not be easy or possible to change but thought that you might appreciate some more feedback.
Wow its far more compact than I was imagining and may well end up joining my everyday carry in the tool box.
Now I just need to find the time to use it on a project (I have several in mind if i get the chance).

Jem

Edit: added point 7

1. Yeah, that has caught out a few people, but once you know its all fine, I think its the light icon that throws people off as its the only one below the buttons.

2 - 6. The App doesn't yet have any reason to support the setup menu (the app cannot interact with the setup menu, it cannot press setup), but it might eventually make it in an update but it doesn't have any pressing need.

7. Z doesn't display particularly well on a 7 segment display, see screenshot
Title: Re: EEVBlog 121GW Discussion thread
Post by: geab on July 25, 2018, 01:55:38 pm
Happily received the unit and am testing the bluetooth connectivity for temperature readings

Have searched the forum for the possibility to change the reporting rate of the external temperature probe - any clues if that can be adapted to like reading every 50 ms ?

Thanks, Gernot
Title: Re: EEVBlog 121GW Discussion thread
Post by: exe on July 25, 2018, 02:21:29 pm
adapted to like reading every 50 ms ?

But can a temp probe be so fast? I thought they have some (thermal) inertia...
Title: Re: EEVBlog 121GW Discussion thread
Post by: kulla on July 25, 2018, 03:01:16 pm
Backer #746, got mine today.

 >:D
Title: Re: EEVBlog 121GW Discussion thread
Post by: bicycleguy on July 25, 2018, 08:05:30 pm
When logging AC Volts and secondary display is frequency what is the frequency accuracy?  The display shows xx.xx but the log file shows xx.xxx which is contradictory and implies different accuracies.

Here is a log of the line voltage and frequency during our current heat spell in California.  Is the frequency data meaningful?
Title: Re: EEVBlog 121GW Discussion thread
Post by: geekGee on July 26, 2018, 02:56:42 am
So with the meter now available in the store, is it safe to assume that all the Kickstarter units have shipped?

If so, I'm backer 2059 and have yet to receive a shipping notification.
Title: Re: EEVBlog 121GW Discussion thread
Post by: firewalker on July 26, 2018, 07:04:19 am
Just received mine!

Alexander.
Title: Re: EEVBlog 121GW Discussion thread
Post by: firewalker on July 26, 2018, 07:55:32 am
When in AC+DC mode the meter only display the sum? Can I select seeing the dc/ac component on the secondary display?

Alexander.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Zucca on July 26, 2018, 07:58:45 am
After wasting 15minutes to find the 121GW page:  >:( :-[

https://www.eevblog.com/product/121gw/ (https://www.eevblog.com/product/121gw/)

Please Dave1+2 update the website, there is no link to the new 121GW meter on the drop down menu:
(https://www.eevblog.com/forum/testgear/eevblog-121gw-discussion-thread/?action=dlattach;attach=484106;image)
Title: Re: EEVBlog 121GW Discussion thread
Post by: geab on July 26, 2018, 09:26:25 am
adapted to like reading every 50 ms ?

But can a temp probe be so fast? I thought they have some (thermal) inertia...

Thats a good point - anyway is there a way to change the reading interval ?
Title: Re: EEVBlog 121GW Discussion thread
Post by: Dr. Frank on July 26, 2018, 09:41:49 am
adapted to like reading every 50 ms ?

But can a temp probe be so fast? I thought they have some (thermal) inertia...

Thats a good point - anyway is there a way to change the reading interval ?

A thermocouple has very low mass, and therefore reacts extremely fast.. probably even faster than 50 ms.

The problem here, is that the 121GW (or any other handheld DMM) has a fastests sample rate of 200ms, or 5 Sa. /sec, as specified for DC V, afaik.

Other ranges like 50M Ohm are even slower.

Anyhow, for a faster response, you'll need a bench DMM, which provides NPLC 1sampling, for example.

Frank
Title: Re: EEVBlog 121GW Discussion thread
Post by: exe on July 26, 2018, 11:27:58 am
A thermocouple has very low mass, and therefore reacts extremely fast.. probably even faster than 50 ms.

Okay, let's put it this way: is measured object changes temperature that frequently? I'm just asking. This depends on what to measure, but for me 50ms interval doesn't look like really necessary in most situations.

The problem here, is that the 121GW (or any other handheld DMM) has a fastests sample rate of 200ms, or 5 Sa. /sec, as specified for DC V, afaik.

There might be faster update rates at reduced resolution. That was one of the reasons I tried to roll out my own firmware: let user trade accuracy for update speed. But I miserably failed, stm32 is not my thing.
Title: Re: EEVBlog 121GW Discussion thread - Initial Verification
Post by: Zucca on July 26, 2018, 01:10:23 pm

I just tried a couple of 10 MΩ resistors, which read 10.x MΩ on my BM869s, but they read 9.6 MΩ on my 121GW. (Connection made with alligator clips to ensure a stable connection.)

(Also, I have to note that the auto-ranging would first show a value of 14 MΩ for a second before updating to 9.6 MΩ. I really think the auto-range in resistance on the latest firmware is not right.)

Is it possible that disassembly of the meter to install/check the shim might cause accuracy problems from contamination of the circuit board?

https://www.eevblog.com/forum/testgear/eevblog-121gw-multimeter-issues/msg1701221/#msg1701221 (https://www.eevblog.com/forum/testgear/eevblog-121gw-multimeter-issues/msg1701221/#msg1701221)
Title: EEVBlog 121GW Discussion thread: Error in Calibration and REL on low Ohm Ranges
Post by: Dr. Frank on July 26, 2018, 01:36:28 pm
Hi,
I investigated on the obvious threshold of the 50 Ohm and 500 Ohm ranges.
It was strange, that in both ranges 0.000 Ohm were displayed, even when the input was shorted by a cable, which should give a few 10 mOhms.

So I measured a resistor box with short cables on my 3458A, and then applied the same configuration to the 121GW:

Setting        3458A          121GW
0.0              0.02743       0.000
0.1              0.12948       0.079
0.2              0.22764       0.178
...
50.0          50.03912      50.005

Especially at 0.1 Ohm setting, and also with rising settings of 0.2, 0.3, 0.4, you can directly see, that my 121GW had a constant threshold of 0.050 Ohm. (gain error does not apply at low values)
At 50.039 Ohm, the gain error of the 121GW additionally chimes in, virtually reducing that threshold value.

This threshold originates from the zero calibration process. UEI probably does not use a direct, low Ohm shunt, but instead uses a cable and a calibrator, set to zero Ohm, which in sum have these 50mOhm, which are always subtracted from the raw Ohm reading.
If a lower resistance short is applied, this would give a negative reading, so the instruments sets all negative readings to zero (threshold).

What confuses much more, that this threshold also shows up using REL.
If you try to zero the value at 0.1 Ohm setting, you will get a 0.050 reading when setting the decade to 0.2.
That's obviously an error in the firmware:
I suppose, that the REL value is taken from the raw reading, then subtracted subsequently from the raw reading first, and then the calibrated zero value is subtracted additionally, which should not happen.

So I made a re-calibration of the 50 Ohm and 500 Ohm ranges only, using a short of < 1.5mOhm for zero calibration, and reference resistors, including cables with 49.971 Ohm and 499.990 Ohm, as measured again with my 3458A, and good enough for calibration.

Now, this threshold is not visible anymore, and you can also make reasonable REL measurements on the mOhm scale, because these 1.5mOhm do no longer play a role.

Frank

PS: Before this investigation, I stored the original calibration values on the SD card, and during that process recalled these from the SD card several time, that's been very practical.
Anyhow,the cal.bin file, also contains some SETUP parameters like APO, BUZZER, LCD, as these were also restored to their original values.
Title: Re: EEVBlog 121GW Discussion thread
Post by: FireFlower on July 26, 2018, 02:37:21 pm
Received mine and followed the gospel to take it apart first...

Seems like hand soldering is challenging because 4 failure points (1 unsoldered joint, 1 disturbed joint and 2 joints without enough solder).

Others have probably posted the J1 and J2 look like my attachment.
Title: Re: EEVBlog 121GW Discussion thread
Post by: firewalker on July 26, 2018, 03:32:58 pm
Din;t take apart mine yet.

One thing I don;t like is that it doesn't default to the main function of the knob position. It remember the last mode it was.

What about the AC+DC mode? Can it use the second display to show the components?

Alexander.
Title: Re: EEVBlog 121GW Discussion thread
Post by: glarsson on July 26, 2018, 04:03:30 pm
One thing I don;t like is that it doesn't default to the main function of the knob position. It remember the last mode it was.
That is a very nice feature.
Title: Re: EEVBlog 121GW Discussion thread
Post by: ELzekio on July 26, 2018, 04:59:18 pm
Looks like The 121 GW just officially sold out on the store.

There was something Like 80 units available 40 mins after the message from Dave was sent at 9:39 pm US eastern time Yesterday.

Can’t wait!  :)
Title: Re: EEVBlog 121GW Discussion thread
Post by: 2bob on July 26, 2018, 05:29:19 pm
One thing I don;t like is that it doesn't default to the main function of the knob position. It remember the last mode it was.
That is a very nice feature.

I agree, but suggest that making the secondary functions on the dial white instead of red would make more sense - and also easier to see  :D
Title: Re: EEVBlog 121GW Discussion thread
Post by: glarsson on July 26, 2018, 05:59:01 pm
As the primary and secondary functions are equal they don't need different colours. Furthermore, the red is difficult to read.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Candid on July 26, 2018, 06:42:07 pm
Different colors are ok in order to recognize that not both are active at one time. White should be for standard after reset. The dark red is bad, could be yellow or light orange like on Fluke e.g. Needs to have a good contrast to the housing color.
Title: Re: EEVBlog 121GW Discussion thread
Post by: darrellg on July 26, 2018, 06:42:55 pm
It's red to match the color of the button used to activate it.
Title: Re: EEVBlog 121GW Discussion thread
Post by: glarsson on July 26, 2018, 06:52:44 pm
Then the color of the button is wrong.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Candid on July 26, 2018, 06:55:56 pm
Color button for Mode and Setup could be changed against each other.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Welectron on July 26, 2018, 08:59:21 pm
Happy to read your feedback here. :-+

As the official EEVBlog distributor, we now also have the 121GW available for purchase in Europe:
https://www.welectron.com/EEVBlog-121GW-Data-Logging-Multimeter-with-Bluetooth (https://www.welectron.com/EEVBlog-121GW-Data-Logging-Multimeter-with-Bluetooth)
Title: Re: EEVBlog 121GW Discussion thread
Post by: Dr. Frank on July 26, 2018, 09:07:26 pm
Great, but check your description.. Copy & Paste error, obviously
Title: Re: EEVBlog 121GW Discussion thread
Post by: ornea on July 27, 2018, 12:07:08 am
Can I download the Windows software for the 121GW without having to jump thru the microsoft hoops.  After logging in with my Microsoft account it now wants me to Add a Device, and seems only Windows 10 is supported.  This seems out of character for EEVBLOG.  Dave himself hates having to create accounts just to try some software to get a widget to work.

I am planning to use it to include as a screen capture along with screen captures from the DS1054Z  while testing various cheap ebay buck converters which I will then upload to youtube.

I have the android app which works ok.

Any direct links or suggestions on how to get the Windows software without the hoop jumping would be very much appreciated.
 
Title: Re: EEVBlog 121GW Discussion thread
Post by: ez24 on July 27, 2018, 03:39:45 am
I am planning to use it to include as a screen capture along with screen captures from the DS1054Z  while testing various cheap ebay buck converters which I will then upload to youtube.

What is your YT channel?

thanks
Title: Re: EEVBlog 121GW Discussion thread
Post by: Seppy on July 27, 2018, 04:27:35 am
Can I download the Windows software for the 121GW without having to jump thru the microsoft hoops.  After logging in with my Microsoft account it now wants me to Add a Device, and seems only Windows 10 is supported.  This seems out of character for EEVBLOG.  Dave himself hates having to create accounts just to try some software to get a widget to work.

I am planning to use it to include as a screen capture along with screen captures from the DS1054Z  while testing various cheap ebay buck converters which I will then upload to youtube.

I have the android app which works ok.

Any direct links or suggestions on how to get the Windows software without the hoop jumping would be very much appreciated.
 

It is only available through the Windows Store as that was a convent avenue for distribution and automatic updates
(I'm not a fan at all of every other App installing its own updater application that runs on boot, slowing down the computer).

I might be able to release an AdHoc installer. At the moment the Windows App is awaiting a major update, but I cannot release it until the a library glitch is fixed. Its on my todo but message me again if I forget because an AdHoc installer would be good, it would still only run on Windows 10 though...
Title: Re: EEVBlog 121GW Discussion thread
Post by: npelov on July 27, 2018, 12:44:54 pm
It seams that different people have. Different opinion how the UI and everything should work. When it comes to firmware that's not too hard problem to solve. It could be an option. It could be set in setup menu. For exmple 1 = remember last mode, 0 - aleays enter default  mode (marked with white).
But there is another thong that would be nice to remember - range. When you measure resistance 500k is usually enough for everything. I'd stay in that range all times and not wait the slow auto-ranging. Just now and then you need the 50 ohms range. When I go to diode and get back to resistance I want the last rane I used. Unfortunately it's not that simple. 15V dionde range will beep on a normal diode, so I don't want to remember that.  You can't be fully happy. Even if you could set mode memory for each mode individually it will still annoy you if you enter flip the switch and it's not the mode you need right now.
Title: Re: EEVBlog 121GW Discussion thread
Post by: firewalker on July 27, 2018, 02:17:05 pm
Does anyone know what this segments are for?

(https://i.imgur.com/kqwqGUJ.png)

Alexander.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Zkronk on July 27, 2018, 08:31:51 pm
I find it really annoying that the meter remember which secondary mode I've used last time, even if I turn it off!
It would be very easy for doing mistakes if one would be sharing the same meter with other people, constantly need to double check that the meter is in the correct secondary mode :(
Title: Re: EEVBlog 121GW Discussion thread
Post by: Messtechniker on July 28, 2018, 06:56:55 am
Some 45 years back, the physics lab manager asked us to set all
multimeters after use to a 220 V AC compatible range setting.  :-+
Something I still do today automatically after using any DMM anywhere,
if possible.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Woodsy on July 28, 2018, 08:55:49 am
Hey all.

I ordered one of the 60-ish 121's a few days ago after seeing the in-stock newsletter.
Just wondering what the average wait time is until i should see it being posted?

Cheers.
Woodsy
Title: Re: EEVBlog 121GW Discussion thread
Post by: ornea on July 28, 2018, 09:56:52 am
I am planning to use it to include as a screen capture along with screen captures from the DS1054Z  while testing various cheap ebay buck converters which I will then upload to youtube.

What is your YT channel?

thanks

https://www.youtube.com/channel/UCr5_D-9_ZZEQQ8rVGuDbbkg (https://www.youtube.com/channel/UCr5_D-9_ZZEQQ8rVGuDbbkg) It is embarrassingly amateurish with just one upload.  I have been making Escape Room tech and want to make it a repository for related info.  I have just had some boards made that are based on the Wemos and wanted to demonstrate its use with a more polished upload.   
Title: Re: EEVBlog 121GW Discussion thread
Post by: GermanMarkus on July 28, 2018, 09:10:31 pm
How to measure "burden voltage"?
On page 40 of the GW121 manual is decribed that you could measure the burden voltage in mA current mode.
I was able to set the "bd.off" to "bd.on", but how will I get the burden voltage to be shown in the secondary display?
I´m using the latest FW 1.22 and the only thing is that I can roll through all the setup parameters with the "setup" button, but I´m not able to show the burden voltage on the display...
For sure I was connecting the additional cable like shown to measure current and (burden) voltage simultaneously.
What´s my problem? PEBCAC?
Title: Re: EEVBlog 121GW Discussion thread
Post by: IanB on July 28, 2018, 10:15:13 pm
How to measure "burden voltage"?

To make the burden voltage appear you have to do two things. Firstly after setting "bd.on" you need to press the Setup button again so that "bd.on" is replaced with the voltage measurement. Secondly you need to connect a jumper from the A or mA terminal of the meter to the VΩ terminal so the meter can actually measure the voltage.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Dr. Frank on July 29, 2018, 08:56:56 am
How to measure "burden voltage"?
On page 40 of the GW121 manual is decribed that you could measure the burden voltage in mA current mode.
I was able to set the "bd.off" to "bd.on", but how will I get the burden voltage to be shown in the secondary display?
I´m using the latest FW 1.22 and the only thing is that I can roll through all the setup parameters with the "setup" button, but I´m not able to show the burden voltage on the display...
For sure I was connecting the additional cable like shown to measure current and (burden) voltage simultaneously.
What´s my problem? PEBCAC?

That's an initialization bug in the latest firmware, or production run.
See here how to overcome that, also have a look inside my errata, where I describe the SETUP in more detail:

https://www.eevblog.com/forum/testgear/eevblog-121gw-multimeter-issues/msg1696409/#msg1696409 (https://www.eevblog.com/forum/testgear/eevblog-121gw-multimeter-issues/msg1696409/#msg1696409)

Frank
Title: Re: EEVBlog 121GW Discussion thread
Post by: GermanMarkus on July 29, 2018, 11:27:36 am
Thank you very much Dr. Frank!
Great you did that perfect job and the thorough investigation and I also hope that this bug will get corrected fast in the next firmware so that no more customers will get caught in that bug-trap.
Due to your description I´m able to do the workaround for displaying the burden voltage in the secondary display now.
But I have to do this workaroud again every time I want to use the burden voltage as secondary display, so the setting is not permanent in my 1.22 unit after the first correct initialization.
So it´s a bit frustration fiddeling back and forth all the time I need this secondary burden voltage measurement (this is a great feature and I really already like it a lot).

Also I hope that the manual will be a bit more comprehensive soon.
The GW121 unit is great, but there are a lot of misunderstandings due to lacking information. I was searching a lot for understanding the use of "LowZ". It would be nice if such issues will be described a bit in depth in the manual, so that other users do not have to dig in forums and webpages for hours.

Also there should be a release date mentioned in the documented firmware version table, this makes things much easier and is a defacto standard for documentation.

I´m one of the guys who do not like the automatic saving of the modes when powering off and on the unit. I like to power on the unit always in default configuration. But for sure I accept that there are people who like this "feature" of saving the last operating mode. So, take best of both worlds and make this "auto - last used mode saving" as an option which is configurable in the setup menu. That should be quite easy...

Anyway, in general I´m quite happy with the GW121 - it´s a "big bang for the bucks" and I know that it was (and still is) a lot of work to get it fully running. So huge thumbs up for Dave and the team behind GW121.
But this work could be rewarded for the developers and contributors much more if all the small bugs and issues will be solved quite quick.
 ^-^
Title: Re: EEVBlog 121GW Discussion thread
Post by: firstcolle on July 30, 2018, 05:55:48 pm
I'm doing some tests and i have some trouble with the uA range.

I set up a basic led circuit and measured the current on the mA range and the probe inserted into the A/500mA socket, the led is powered on and i measured 9mA.
I switched the range into the uA range and the probe into the mA/uA socket but the led does not power on and nothing is measured on the meter. I checked the 400mA fuse and there is no continuity... fuse blown?? I think that this range should measure 9mA..
The maximum allowed in the uA position is 500uA so should indicate OFL.  It takes a second to show.  Fuse should have continuity.  Does probe in mA/uA socket, switch in ma work?

Finding the maximum range for each position is a little problematic.  The chart on page 16 of manual is useful if available.  The auto range position doesn't indicate the max just the current auto range.
So you have to:
1. With probes not hooked up but inserted into desired sockets (required for current)
2. Rotate switch as desired.
3. Select mode.
4. Press range and note the max range value in the lower right corner of display.  Continue pressing range until you find the max.

I don't think this is much different than other meters but the text for the value is so miniature I can't even see it without my glasses.  On other meters it is much more prominent.

Thanks for your help.
no, with the probe in mA/uA socket and the switch in mA range is not working. for sure the fuse is blown. i'm looking for a replacement.

thanks for all the tips!

fuse changed and all works fine now.
by mistake, I plug the probes one into the mA range and the other into the uA range and tried to measure current. could I have damaged something? all seems to work fine with the probes in the correct plugs..
Title: Re: EEVBlog 121GW Discussion thread
Post by: Ranayna on July 31, 2018, 08:04:31 pm
Just a small head-up for the europeans:
Welectron has the GW121 in stock: https://www.welectron.com/EEVBlog-121GW-Data-Logging-Multimeter-mit-Bluetooth (https://www.welectron.com/EEVBlog-121GW-Data-Logging-Multimeter-mit-Bluetooth)

I wanted to stop buying stuff, but i just cannot resist...
Title: Re: EEVBlog 121GW Discussion thread
Post by: xani on August 01, 2018, 02:09:23 am
Some 45 years back, the physics lab manager asked us to set all
multimeters after use to a 220 V AC compatible range setting.  :-+
Something I still do today automatically after using any DMM anywhere,
if possible.

I also do that, but that's more because for a long time I had shitty meter and no money so I was afraid that if I break it I just won't be able to replace it for long time.

That's my minor gripe with Low Z range, first range from off position puts 3k to the load while I'd prefer to have normal volts go first so it goes off ->3k->10M which can disturb the circuit if probes are already connected when I turn on the meter.

The other, bigger one, is ignoring voltages <12V, I'd love low-z mode that worked with low voltages for stuff like checking power on sensors with long wires. I feel like it should be at least switchable option somewhere in settings
Title: Re: EEVBlog 121GW Discussion thread
Post by: HKJ on August 01, 2018, 03:45:14 pm
My review of the meter: https://lygte-info.dk/review/DMMEEVBlog%20121GW%20UK.html
Title: Re: EEVBlog 121GW Discussion thread
Post by: ELzekio on August 02, 2018, 01:35:09 am
My meter just came in earlier today. I was one of the first to buy a meter after it became available on the EEVBlog store (about an hour after it was announced) And it arrived in the United States (Calumet Michigan) this morning.

I am guessing this means most of the people who have backed the project have already received the meter? Anyone who has not yet?



As you can see, I did indeed receive the zippy case and nickel plated probes.

On the 121GW Issues thread, a user complained that he did not receive a case and probes even though he was supposed to. Dave responded saying he made a mistake and forgot to check a shipment box to make sure they had the case and probes as he thought they were present. Not sure how many were affected by this, but I did indeed receive a case and set of probes.
Title: Re: EEVBlog 121GW Discussion thread
Post by: jopie on August 03, 2018, 12:38:30 pm
Got my meter this morning, I live in the Netherlands.   :-+

I followed the package through the DHL website for 17 days after I got their tracing code. For some reason it was stuck in a DHL distribution centre for nearly 2 weeks, which was quite exciting...
Title: Re: EEVBlog 121GW Discussion thread
Post by: M4x on August 03, 2018, 12:59:32 pm
Happy to read your feedback here. :-+

As the official EEVBlog distributor, we now also have the 121GW available for purchase in Europe:
https://www.welectron.com/EEVBlog-121GW-Data-Logging-Multimeter-with-Bluetooth (https://www.welectron.com/EEVBlog-121GW-Data-Logging-Multimeter-with-Bluetooth)
Thanks for pointing that out! Too bad this information got to me too late (I've followed Daves "limited amount of meters in stock" e-mail and ordered directly from him.) The meter is sitting in Frankfurt right now...
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on August 04, 2018, 04:00:20 am
FYI, Welectron in Germany have some meters in stock:
https://www.welectron.com/EEVBlog-121GW-Data-Logging-Multimeter-with-Bluetooth (https://www.welectron.com/EEVBlog-121GW-Data-Logging-Multimeter-with-Bluetooth)
Title: Re: EEVBlog 121GW Discussion thread
Post by: M4x on August 04, 2018, 04:07:16 pm
Very funny ;-)
Title: Re: EEVBlog 121GW Discussion thread
Post by: eV1Te on August 04, 2018, 05:02:54 pm
My review of the meter: https://lygte-info.dk/review/DMMEEVBlog%20121GW%20UK.html
Interesting review, I found the input impedance measurements especially surprising. The fact that the meter has different input impedances in different mode and ranges would make it incompatible with high-voltage probes etc. that rely on having exactly 10 MOhm for voltage division.

Having an input impedance as low as ca 2 kOhm for frequency measurement makes limiting for many things. For example measuring the frequency at different points of a 555 timer (or other oscillator) circuit without knowing about the low impedance could result in many strange readings (different frequency at different points, since the meter would affect the circuit by a lot).



Title: Re: EEVBlog 121GW Discussion thread
Post by: HKJ on August 04, 2018, 05:06:46 pm
Having an input impedance as low as ca 2 kOhm for frequency measurement makes limiting for many things. For example measuring the frequency at different points of a 555 timer (or other oscillator) circuit without knowing about the low impedance could result in many strange readings (different frequency at different points, since the meter would affect the circuit by a lot).

Nearly all multimeters have that low input impedance on the frequency input (I measure input impedance for different modes in all my reviews).
Title: Re: EEVBlog 121GW Discussion thread
Post by: jancumps on August 04, 2018, 05:09:10 pm
Is there any uncertainty? Something you can't take into account while measuring?
Title: Re: EEVBlog 121GW Discussion thread
Post by: HKJ on August 04, 2018, 05:14:36 pm
Is there any uncertainty? Something you can't take into account while measuring?

If it is my impedance measurement you ask about, I am using a SMU to supply (DC) voltage and measure current, it is fairly sensitive to noise and I use a shielded cable for the test. There is a few meters that do not terminate the input at 0 volt, but at maybe 2V.
Title: EEVBlog 121GW Discussion thread - Ohm - 50MOhm recalibration
Post by: Dr. Frank on August 05, 2018, 04:28:05 pm
I have reported https://www.eevblog.com/forum/testgear/eevblog-121gw-discussion-thread/msg1687298/#msg1687298. (https://www.eevblog.com/forum/testgear/eevblog-121gw-discussion-thread/msg1687298/#msg1687298.) that the 50MOhm range of my new 121GW was out of specification, by 1.4 ..2%.
Today, I have re-adjusted this range.
At first, the manual was wrong, as a 50 MOhm reference resistor is required, instead of a 40 MOhm one.

Then, due to higher leakage currents over protection diodes at 50 MOhm, compared to 10 or 20 MOhm, this range is quite non-linear, like I have found with my BM869.

So the readings at 10M and 19M are about 0.2% higher than nominal, when the 121GW is correctly calibrated at 50.000MOhm.

To compensate for this effect, it makes sense to use a 50.05 MOhm reference instead, so that at 50MOhm, the nominal reading is 0.1% low, but at lower values, like 10MOhm, the reading is only 0.1% high.

So the 50MOhm range is now very precise and stable, and also is not affected by mains disturbances.
The 5MOhm range though, is noisy, due to lacking 50/60Hz suppression, and probably a missing filter capacitor.
I could silence this range, even with strong interference from mains, by a parallel low leakage foil capacitor, 100nF, MKP.
I still hope for FW change by UEI, to correct both features.

Frank
Title: Re: EEVBlog 121GW Discussion thread - Ohm - 50MOhm recalibration
Post by: tpw_rules on August 05, 2018, 05:24:39 pm
I have reported https://www.eevblog.com/forum/testgear/eevblog-121gw-discussion-thread/msg1687298/#msg1687298. (https://www.eevblog.com/forum/testgear/eevblog-121gw-discussion-thread/msg1687298/#msg1687298.) that the 50MOhm range of my new 121GW was out of specification, by 1.4 ..2%.
Today, I have re-adjusted this range.
At first, the manual was wrong, as a 50 MOhm reference resistor is required, instead of a 40 MOhm one.

Then, due to higher leakage currents over protection diodes at 50 MOhm, compared to 10 or 20 MOhm, this range is quite non-linear, like I have found with my BM869.

So the readings at 10M and 19M are about 0.2% higher than nominal, when the 121GW is correctly calibrated at 50.000MOhm.

To compensate for this effect, it makes sense to use a 50.05 MOhm reference instead, so that at 50MOhm, the nominal reading is 0.1% low, but at lower values, like 10MOhm, the reading is only 0.1% high.

So the 50MOhm range is now very precise and stable, and also is not affected by mains disturbances.
The 5MOhm range though, is noisy, due to lacking 50/60Hz suppression, and probably a missing filter capacitor.
I could silence this range, even with strong interference from mains, by a parallel low leakage foil capacitor, 100nF, MKP.
I still hope for FW change by UEI, to correct both features.

Frank

The meter has a bonus 50MΩ nonlinearity calibration mode, which seems undocumented and I can't claim to understand. Regardless, maybe you can back up your calibration and give the following procedure a try:

This procedure just changes the influence of a hardcoded nonlinearity offset table. That table might be wrong, or it might not accurately capture the error of all meters. It also could be plausible that you use a 40.000M resistor as indicated in the manual in place of the 30.000M resistor, or you use a 40.000M resistor for both steps. I'm not entirely sure.

The 5M range also has a nonlinearity correction applied, but it cannot be calibrated.
Title: Re: EEVBlog 121GW Discussion thread - Ohm - 50MOhm recalibration
Post by: Dr. Frank on August 07, 2018, 06:36:26 am


Dr Frank, if you have a way to run some sort of temperature study on this meter,  I would be very interested in seeing you install TPW_rules's patched version of 1.02 and trying it out.   The prototype has always drifted pretty badly which I assume is why they changed the reference circuit.    It sounds like you are already trying to find the sweet spots to use for the alignment to bring it in tighter.   I wonder how the TC matches what is specified in the manual.

Well, I don't need FW 1-02 to recognize a very high T.C. on the 50M Ohm range.
We have a heat wave since weeks here in Germany, outside it's 35..38°C every day, so meanwhile even my cal lab is  affected, the basement and the 121GW currently have 24°C .. 24.5°C instead of the nominal 21.5°C, and I even get 29°C inside the instrument, when I take it from my room on the first floor down to the lab.

This 5°C difference causes maybe 0.5% change in the 50M Ohm range, so the 10M reference resistor seems to be of very bad quality... the voltage reference should not play a role, as Ohm will be realized in ratio mode, but I may check DCV separately (did not notice such a high T.C., though).

That explains, why UEI has specified such a bad accuracy of 1.3%, but w/o declaration of  temperature range.

Frank
Title: Re: EEVBlog 121GW Discussion thread
Post by: racemaniac on August 07, 2018, 08:59:35 am
I just received tracking info for mine, and am about to leave on vacation for 2 weeks >_<
Anyone got an idea how to arrange this with DHL, or will it just end up going back to sender, and i'll have to arrange a next shipment?

A bit impractical to just send them out in the middle of holiday season without asking if people can receive it
Ended up being lucky XD
i still had 1 day to get it from the post office when i returned from vacation XD.
(another kickstarter arrived one day earlier and wasn't so lucky)
What's up with kickstarters being like "you know what, after all this time, let's send it in the middle of holiday season XD".
The undelivered rates must be higher these months.
Title: Re: EEVBlog 121GW Discussion thread
Post by: jancumps on August 07, 2018, 12:56:26 pm
FYI, Welectron in Germany have some meters in stock:
https://www.welectron.com/EEVBlog-121GW-Data-Logging-Multimeter-with-Bluetooth (https://www.welectron.com/EEVBlog-121GW-Data-Logging-Multimeter-with-Bluetooth)

I ordered one from Welectron.Good that there are suppliers wihin the European trade zone.
I received shipping notification yesterday.
Title: Re: EEVBlog 121GW Discussion thread
Post by: M4x on August 07, 2018, 01:59:37 pm
FYI, Welectron in Germany have some meters in stock:
https://www.welectron.com/EEVBlog-121GW-Data-Logging-Multimeter-with-Bluetooth (https://www.welectron.com/EEVBlog-121GW-Data-Logging-Multimeter-with-Bluetooth)

I ordered one from Welectron.Good that there are suppliers wihin the European trade zone.
I received shipping notification yesterday.
Good for you! Mine is still in Frankfurt since August 1 "Arrived at transit facility"
Title: Re: EEVBlog 121GW Discussion thread
Post by: Dr. Frank on August 07, 2018, 02:05:45 pm
OK,
here are my brief quantitative T.C. measurements:

50M: 9.965M @ 24.0°C; 10.503M @ 32.4°C    => 0.64 %/°C  (I = 20nA)
5M: 1.0003M @ 24.0°C; 1.0061M @ 32.3°C    => 0.07 %/°C  (I=200nA)
500k: 99.97k @ 25.6°C; 100.04k @ 32.2°C    => 0.01 %/°C  (I= 1.37 .. 2.2µA)

You know what?
No usual resistor technology, even at 10M, has a T.C. of 6400 ppm/K, you get these components easily at < 200ppm/K, in Thick Film technology.
And that change correlates with the range..

Therefore, this enormous change over temperature in 50M range, and 1/10 of that in 5M range, is caused by a (parasitic) change of the measuring current, that would be about 130pA/°C for both, and that makes sense, if it is a change of bias currents, like caused by the HY3131's amplifier, CMOS MUX, or protection circuitry.
If you select DCV, 50mV range, and leave the input open, you'll get a reading of about 1.700mV, which means that the HY3131 has about 170pA bias current..which also should be strongly dependent on temperature (not tested yet).. but it's in the same ballpark.

Don't know, if the BM869 is better in that aspect, but I assume so, because that uses a higher test current (100nA) in the 50M range.

The 10V DC range is practically not affected by this temperature change, maybe < 2 counts, which implies < 3 ppm/K

Frank
Title: Re: EEVBlog 121GW Discussion thread
Post by: IanB on August 07, 2018, 06:24:44 pm
The most sensitive part appears to be the HY3131 itself.  I'm not making the part even warm enough to detect the change in temp with my fingers.   

Curious. If you use the meter to measure mains voltage on Low-Z for a few seconds and then try to take some readings on other ranges, some of those readings will be way off. Could it be that heat generated inside the meter case is responsible for some of this?
Title: Re: EEVBlog 121GW Discussion thread
Post by: PA0PBZ on August 07, 2018, 06:55:58 pm
Are you maybe heating up a PTC? What range(s) and how long until things go back to normal?
Title: Re: EEVBlog 121GW Discussion thread
Post by: IanB on August 07, 2018, 07:16:28 pm
To be clear, I do not have the current version of the meter.   Any idea how much "way off" is and what modes?  Could you post some details?

I posted about it before, and my observation was brushed off with comments like "expected", "PTC", and so on.

Are you maybe heating up a PTC? What range(s) and how long until things go back to normal?

The heat is what I'm curious about.

For me I think it was some of the resistance ranges, but someone else mentioned that temperature measurements might go crazy too.

Sorry, it's not easy for me to go back and check right now. Here's a post I made way ago about this:

How to make the meter show weird readings:

1. Put the meter on the Low Z range
2. Measure the mains voltage (let's say 120.0 V AC)
3. Put the meter on the Resistance range
4. Short the probes

You may observe an anomalous reading of about 3 ohms, slowly declining towards zero.

On other ranges (like DC mV) you may observe anomalous readings too.

It's as if a capacitor is charged up and is taking time to discharge back to zero volts. (Or did something heat up and it's taking time to cool down?)
Title: Re: EEVBlog 121GW Discussion thread
Post by: PeterL on August 09, 2018, 07:19:03 am
Just a note for Dave or David:
The review section on the products page for this meter is starting to attract spam. You might want to take measures to prevent these (I'm not sure if email confirmation is required), or do some moderation.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Messtechniker on August 09, 2018, 04:33:05 pm
Planning to join the esteemed EEVBlog 121GW owners club after the next hardware revision or in one years time or so, after the firmware has matured a bit. I really don't need a further DMM, but this voltnut thing seems to be biting me a bit. :scared:
Anyway: thanks to all helping to improve this DMM and iron out bugs and idiosyncrasies. :clap:
Title: Re: EEVBlog 121GW Discussion thread
Post by: jancumps on August 10, 2018, 06:45:25 pm
FYI, Welectron in Germany have some meters in stock:
https://www.welectron.com/EEVBlog-121GW-Data-Logging-Multimeter-with-Bluetooth (https://www.welectron.com/EEVBlog-121GW-Data-Logging-Multimeter-with-Bluetooth)

I ordered one from Welectron.Good that there are suppliers wihin the European trade zone.
I received shipping notification yesterday.
Good for you! Mine is still in Frankfurt since August 1 "Arrived at transit facility"
It arrived today. I ordered the 4th from Welectron. I received a first notification from the post services on the 6th, arrived in Belgium the 8th and at my door the 10th.
Title: Re: EEVBlog 121GW Discussion thread
Post by: M4x on August 10, 2018, 06:51:52 pm
I've ordered directly com Dave :-(
Title: Re: EEVBlog 121GW Discussion thread
Post by: firewalker on August 11, 2018, 09:27:57 am
How do you use the hook-n-loop fasteners of the case?

Alexander.
Title: Re: EEVBlog 121GW Discussion thread
Post by: IanB on August 11, 2018, 11:34:17 am
More importantly, why do this and other Brymen cases have the bizarre half-pouch in the cover? Anything you try to put in there immediately falls out when you open the lid. It would be much preferable to have a full size pouch in the lid with a velcro tab to keep it closed.

(In fact, one reason to consider having a sewing machine in a home workshop is to be able to make cases, covers and bags to your own specifications and not have to rely on finding something off the shelf that is never quite right.)
Title: Re: EEVBlog 121GW Discussion thread
Post by: firewalker on August 11, 2018, 05:39:03 pm
There was a python script for communication with the meter under GNU/Linux? Do I remember correctly? Any links?

Alexander.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Seppy on August 15, 2018, 02:51:45 am
Just a note for Dave or David:
The review section on the products page for this meter is starting to attract spam. You might want to take measures to prevent these (I'm not sure if email confirmation is required), or do some moderation.

Thanks! I have resolved that, its a daily thing. I've been doing it manually, our Spam filter is a bit broken I think.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on August 15, 2018, 06:51:29 am
A video testing the 50 ohm range at low values:

https://www.youtube.com/watch?v=pUFerCkVtgk (https://www.youtube.com/watch?v=pUFerCkVtgk)
Title: Re: EEVBlog 121GW Discussion thread
Post by: Dr. Frank on August 15, 2018, 07:44:56 pm
Hi Dave,
I don't recognize, which problem you wanted to examine...

The 50 Ohm range had two different probs, than simply being in/out of  spec.

First, if you apply F.S. of 50 Ohm, you may encounter an unstable reading on the last two digits, although it should be stable at this high test current, and also compared to the ranges of 500 Ohm to 500 kOhm. Even the 5M Ohm is stable to the last digit with FW 1-26.
Also, it's a bit tricky to make a correct REL setting, when shorting its input.

The 50 Ohm range resolves 1mOhm, which is a great favor of your 121GW. Clearly, you need to use REL to zero any cable resistance, so afterwards to measure precisely resistance in the Ohm range, with 1mOhm resolution, and even accuracy.

I was disappointed though, because the calibration of UEI had introduced a threshold, by too high residual zero calibration, which also seemed to affect this described low ohm measurement.

[EDIT:]
So if you short the 121GW with successively lower resistance from your resistor box with 10 mOhm resolution, you can check,  when this obvious threshold steps in.. maybe at about 100..200mOhm, which might suddenly give a straight reading of 0.000 Ohm.

Anyhow, I have improved the zero calibration by using a massive short, and then the gain by a precise 50.000 Ohm reference.

After that procedure, I really can use the 121GW to precisely measure resistance in the mOhm range, either correctly zeroing cables, or determine residual resistance of my resistor box, or making measurements of 10.000... 50.000 Ohm resistors, much better than the spec.

That 1 mOhm resolution feature is a great plus of the 121GW, so I would recommend to make an effort on proper calibration.

Frank
Title: Re: EEVBlog 121GW Discussion thread
Post by: M4x on August 15, 2018, 08:19:39 pm
I've received my meter together with the probes from UEI. I can take of a kind of plastic / rubber cap to get to the thread on the tips. I assume that the idea behind these threads is to be able to screw a banana plug tip to it to be able to connect it to some clamps for example (to to to ;-) ).

When I'm checking out the Brymen test leads online, it looks to me like they always come with those banana plug tips.
https://www.welectron.com/Brymen-BL21S2-T4SC-Silicone-Test-Leads
I've assumed that the UEI leads would come with something like that too.

Are they missing in my package or does nobody have received them?

Max(https://uploads.tapatalk-cdn.com/20180815/e96d8a29aea5226dbaf636acc1673ab6.jpg)
Title: Re: EEVBlog 121GW Discussion thread
Post by: 1anX on August 15, 2018, 09:42:17 pm
Gold plated, screw on banana adapters like in the picture you posted came with my leads!
Title: Re: EEVBlog 121GW Discussion thread
Post by: ornea on August 15, 2018, 11:12:20 pm
The threaded lead banana tip adapters came with my leads.
Title: Re: EEVBlog 121GW Discussion thread
Post by: IanB on August 15, 2018, 11:36:50 pm
I think the meters were meant to come with the Brymen leads that have the banana plug adapters, but due to a shortage of supply some meters were shipped with leads from another vendor. You would have to search back through the thread history to find the post where Dave mentioned that.
Title: Re: EEVBlog 121GW Discussion thread
Post by: darik on August 16, 2018, 01:22:16 am
A video testing the 50 ohm range at low values:

@1:42 - There's one of those spurious 50 Mohm range readings popping up and holding up the autoranging. They look so much like a real reading. You have to think about what you're seeing. And I'm pretty sure they delay the autoranging by a half second or more when they happen. Mine will do that 90% of the time when I short the probes.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Candid on August 16, 2018, 06:29:33 am
I can second that.
Title: Re: EEVBlog 121GW Discussion thread
Post by: M4x on August 16, 2018, 09:05:21 am


I think the meters were meant to come with the Brymen leads that have the banana plug adapters, but due to a shortage of supply some meters were shipped with leads from another vendor. You would have to search back through the thread history to find the post where Dave mentioned that.

I would have preferred the Brymen leads but you can read on the product page that the meter comes with the Brymen OR the UEI leads, depending on the supply situation.
Quote
NOTE: The meter may come with either Brymen (gold) probes or UEI (nickel) probes depending upon availability at the time. Both are high quality silicone rubber probes.
Source: https://www.eevblog.com/product/121gw/

Therefore Brymen or UEI are both fine. What I'm missing is the banana plug adapter.

Max
Title: Re: EEVBlog 121GW Discussion thread
Post by: Muttley Snickers on August 16, 2018, 09:21:33 am
Did your UEI leads come with a part or model number ?.   

I suspect they might be the UEI ATL57 silicone leads which don't come with the screw on banana plug adaptors, they are supplied with screw on alligator clips instead from what I saw on the UEI web page.
Title: Re: EEVBlog 121GW Discussion thread
Post by: M4x on August 16, 2018, 10:46:32 am
Unfortunately I can't find a model number. From the UEI website, the leads could although be the ATL55 (Cat III 1000V in the description; https://www.ueitest.com/products/accessories?page=1&tid_1=All&tid=24).

I've received the 121GW with 8GB SD-card inserted, temperature probe, certificate, a case and the test leads WITHOUT banana plugs or crocodile clips or something like that.

I've attached the product picture of the ATL55 from www.ueitest.com and some pictures I took from the test leads I've received with the 121GW.

Max(https://uploads.tapatalk-cdn.com/20180816/9e34ee10b841354ca73e5382e8c13b1c.jpg)(https://uploads.tapatalk-cdn.com/20180816/0529f5bf9541b5cbc8f0d3f7595bb920.jpg)(https://uploads.tapatalk-cdn.com/20180816/1242ee72cc4368df4096eb8527090943.jpg)(https://uploads.tapatalk-cdn.com/20180816/58173fee9a0dbd3d7656a07942c05c25.jpg)
Title: Re: EEVBlog 121GW Discussion thread
Post by: Candid on August 16, 2018, 11:05:26 am
Yours seem to be the ATL55 because they are "only" CAT III 1000V. The ATL57 should be CAT IV 1000V and silicone cables. So it looks as if you got the wrong leads because EEVBlog shop states that both are silicone wires and this is not for the ATL55 as far as I can see from the UEI data sheets. And, because when you get it with Brymen leads they are part of it, you should get the 4mm banana shrouded plugs too. So I would contact Dave/David and clear this.
Title: Re: EEVBlog 121GW Discussion thread
Post by: M4x on August 16, 2018, 11:36:25 am
Oh, I think you're right! I've attached a picture from the "data sheet": https://www.ueitest.com/sites/default/files/product-resources/L322_Accessories%202017.pdf(https://uploads.tapatalk-cdn.com/20180816/e92e76b256605b1db15cfbe0d00a6a21.jpg)
Title: Re: EEVBlog 121GW Discussion thread
Post by: Candid on August 16, 2018, 11:42:40 am
That's it. If you got silicone leads they should be very flexible. The PVC ones are most time very shiny, the silicone ones are often more mat.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Muttley Snickers on August 16, 2018, 11:46:45 am
The leads shown in the image posted above are definitely the ATL57 silicone series which are identifiable by the ridiculously long strain relief, the ATL55 series have a shorter strain relief.

Use this UEI page for better images and detail.
https://www.ueitest.com/search/node/leads (https://www.ueitest.com/search/node/leads)
Title: Re: EEVBlog 121GW Discussion thread
Post by: ELzekio on August 16, 2018, 11:51:01 am
I really don’t know to much about probe material, but the UEI probes I received with my meter seem a lot more malleable than any of my other pvc probes I’ve got. They sure feel like silicone.



Also if you type in the UL number printed on the meter probes on google

E496219

This link to the UL website will pop up saying they are the ATL57 probes.
http://productspec.ul.com/document.php?id=PICQ.E496219 (http://productspec.ul.com/document.php?id=PICQ.E496219)
Title: Re: EEVBlog 121GW Discussion thread
Post by: M4x on August 16, 2018, 12:34:55 pm
You're both right, from the touch and look, I think it's silicone. And if you click on "HI-RES PICTURE" on the UEI site, you'll get another picture for the ATL55 than shown as a thumbnail image in the overview. I've attached both pictures. Like Muttley Snickers said, I've definitely received the ATL57 leads.

And I can't find banana plug addons at the UEI website. The banana plugs would be very useful to me. By searching for "Screw-On" I can only find the AAC3 Alligator Clips (https://www.ueitest.com/products/accessories/aac3 (https://www.ueitest.com/products/accessories/aac3)). I'm thinking about getting the Brymen BL21S2-T4SC Silicone Test Leads (https://www.welectron.com/Brymen-BL21S2-T4SC-Silicone-Test-Leads (https://www.welectron.com/Brymen-BL21S2-T4SC-Silicone-Test-Leads)).

Anyway, I'm wondering if my test leads should've come with some "tip addons".

Max
Title: Re: EEVBlog 121GW Discussion thread
Post by: Muttley Snickers on August 16, 2018, 01:51:38 pm
Anyway, I'm wondering if my test leads should've come with some "tip addons".

As mentioned earlier, I don't think UEI does the screw on banana plug adaptors which you have seen supplied with the Brymen leads, nothing is wrong with that either as various manufacturers do things in different ways and have differing products lines.

I think UEI need to tidy up some of those accessory pages as some of the images appear to be incorrect or misleading, particularly in regards to the test leads which makes it confusing for some. The images also give the impression that alligator clips are supplied with certain test lead sets but are instead a separate accessory.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Candid on August 16, 2018, 09:51:36 pm
The leads shown in the image posted above are definitely the ATL57 silicone series which are identifiable by the ridiculously long strain relief, the ATL55 series have a shorter strain relief.

Use this UEI page for better images and detail.
https://www.ueitest.com/search/node/leads (https://www.ueitest.com/search/node/leads)
UEI uses the same picture for both on their website so you cannot belief what you see. When you open the data sheet you get a pdf where they use the exact same picture for both ATL55 and ATL57.

When you click on the link "HI-RES PICTURE" for the ATL55 you get a picture of completely other leads (???) and when you click on the "HI-RES PICTURE" link for the ATL57 you get a low res picture of the leads from the PDF.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Muttley Snickers on August 17, 2018, 12:17:59 am
The leads shown in the image posted above are definitely the ATL57 silicone series which are identifiable by the ridiculously long strain relief, the ATL55 series have a shorter strain relief.

Use this UEI page for better images and detail.
https://www.ueitest.com/search/node/leads (https://www.ueitest.com/search/node/leads)
UEI uses the same picture for both on their website so you cannot belief what you see. When you open the data sheet you get a pdf where they use the exact same picture for both ATL55 and ATL57.

When you click on the link "HI-RES PICTURE" for the ATL55 you get a picture of completely other leads (???) and when you click on the "HI-RES PICTURE" link for the ATL57 you get a low res picture of the leads from the PDF.

This is not correct, if you follow the link I provided shown in the first image below it offers a 360° view of the ATL57 lead set which clearly shows the extended strain relief as can be seen in the third image, the web page that M4x linked does not offer up the 360° view option which aids to hinder proper identification as can be seen in the second image, my work here is done.   ::) :P

Title: Re: EEVBlog 121GW Discussion thread
Post by: Candid on August 17, 2018, 07:05:11 am
So you can see that UEI made the mistake and placed wrong pictures and 360° views. At the ATL57 e.g. they write "CATIV Test Leads (Silicone)". The leads on the picture are red and/black. When you open the 360° view of the ATL57 you see red/grey test leads with the text "CATII 1000V" on it. In the "data sheet" for both ATL55 and 57 they take the exact same picture (what I think is the ATL57).

At the ATL55 look on the HIGH-RES PICTURE what is totally different again. And at the ATL55 there is no 360° view. I am pretty sure we would find a fourth variant of leads there  ;D

So we both are correct and UEI is the culprit  8) I am starting to see why the firmware of the 121GW is a little "confused" so seemes the company to be.  ;D ;D ;D

The links I checked are:
https://www.ueitest.com/products/accessories/atl57 (https://www.ueitest.com/products/accessories/atl57)
https://www.ueitest.com/products/accessories/atl55 (https://www.ueitest.com/products/accessories/atl55)
Title: Re: EEVBlog 121GW Discussion thread
Post by: logictom on August 17, 2018, 07:09:54 am
Can anyone point me in the direction of a supplier for replacement fuses at reasonable price and preferably in Australia, failing that a UK supplier? I am after the 400mA but I may as well pick up both while I'm at it :-+
Title: Re: EEVBlog 121GW Discussion thread
Post by: tautech on August 17, 2018, 07:21:38 am
Can anyone point me in the direction of a supplier for replacement fuses at reasonable price and preferably in Australia, failing that a UK supplier? I am after the 400mA but I may as well pick up both while I'm at it :-+
Daves shop but it show he's out of stock.
https://www.eevblog.com/product/multimeter-fuse-pack/ (https://www.eevblog.com/product/multimeter-fuse-pack/)

Send him a message.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Seppy on August 23, 2018, 02:34:46 am
I've received my meter together with the probes from UEI. I can take of a kind of plastic / rubber cap to get to the thread on the tips. I assume that the idea behind these threads is to be able to screw a banana plug tip to it to be able to connect it to some clamps for example (to to to ;-) ).

When I'm checking out the Brymen test leads online, it looks to me like they always come with those banana plug tips.
https://www.welectron.com/Brymen-BL21S2-T4SC-Silicone-Test-Leads (https://www.welectron.com/Brymen-BL21S2-T4SC-Silicone-Test-Leads)
I've assumed that the UEI leads would come with something like that too.

Are they missing in my package or does nobody have received them?

Max(https://uploads.tapatalk-cdn.com/20180815/e96d8a29aea5226dbaf636acc1673ab6.jpg)

Edited: misread your comment.

The UEI leads do not come with the banana plug tips, however the bryman leads do.
Title: Re: EEVBlog 121GW Discussion thread
Post by: JS on August 25, 2018, 05:50:26 am
Again, I am not suggesting this is a problem.  Obviously, if you are expecting data to be collected with tighter sampling, it could be a problem. 

I was original going to modulate the frequency and amplitude but the results from my initial test was so poor, you could not make sense of the data.  So I simplified it to two states at a fixed frequency.   
  If you are talking about my posts (I haven't seen any other FFT on the data) I was trying to characterize the filtering and define where the noise was coming. In your test, in the samples between one resistor and the other doesn't make much sense to talk about noise, that's the response of the filter which will show intermediate data in the step, so that's what's closing your eyes (in the diagram, not that you are becoming blind).

  From a datalogging point of view I like the 1.26 signal better as it has raw-er data, looking at the meter the 1.00 looks better as you can get a more stable reading, but what is more evident in the eye diagram is that V1.00 is "over simplifying" the data as it's showing one value or the other, and I think there are traces that might look like the intermediate step I see while switching between one value and the other. The closer values (than some random one and a short) and repeated it over time gives more data on that step. Also, the longer run might start to show the glitches on the V1.26.

  I haven't made my mind yet on which one I prefer, as I suggested, if it were in my hands I'd make a selection on speed for that and any other range as I expect a similar behavior (I tested the noise in the mV range with similar values, glitches are observed to be more periodical here, in the 50Ω looks more random to me)

JS
Title: Re: EEVBlog 121GW Discussion thread
Post by: M4x on August 25, 2018, 08:46:43 am
I've received my meter together with the probes from UEI. I can take of a kind of plastic / rubber cap to get to the thread on the tips. I assume that the idea behind these threads is to be able to screw a banana plug tip to it to be able to connect it to some clamps for example (to to to ;-) ).

When I'm checking out the Brymen test leads online, it looks to me like they always come with those banana plug tips.
https://www.welectron.com/Brymen-BL21S2-T4SC-Silicone-Test-Leads (https://www.welectron.com/Brymen-BL21S2-T4SC-Silicone-Test-Leads)
I've assumed that the UEI leads would come with something like that too.

Are they missing in my package or does nobody have received them?

Max(https://uploads.tapatalk-cdn.com/20180815/e96d8a29aea5226dbaf636acc1673ab6.jpg)

Edited: misread your comment.

The UEI leads do not come with the banana plug tips, however the bryman leads do.
Alright, thank you very much!
Title: Re: EEVBlog 121GW Discussion thread
Post by: JS on August 26, 2018, 01:06:42 am
In your test, in the samples between one resistor and the other doesn't make much sense to talk about noise, that's the response of the filter which will show intermediate data in the step, so that's what's closing your eyes (in the diagram, not that you are becoming blind).

When evaluating the Fourier transform the samples must be evenly spaced.   This noise I am interested in is the jitter.   The purpose of the two resistors is only to provide a known step change at discrete intervals.   It could have been voltage or any other mode.   That assumes that they all have the same jitter.

When Dave had first sent the meter, the fastest it could sample the data was at a one second interval.  I had mentioned that there seemed to be a problem when writing to the SD card that it would hang (crash eventually).   I suspect the some of this large error in sampling (time) is due to writing to the SD card.   The BT may have less jitter.  The prototype does not currently have the ability to use this feature.

Again, I am not normally concerned with noise in the time domain when using a handheld meter.   It does make me wonder why they added the ability to log faster than a second with such high jitter.


****************
I should have made one other small point clear.  The reason I am using the two small resistors close to the same value is that I did not want to add the effects of the auto range into the mix for this test.

  I understand the problem with jitter with the FFT, but I don't see such high jitter in the plots you make, in V1.00 is pretty easy to see the each sample might be within ±50ms at most while your plots suggests 10 times that, I'm not sure how you generated the PLL, but it does trigger in 4 different samples going each way. Also, the 1.26 version plot gets dirtier but that has to do with the levels for the intermediate samples between one value and the other, where the V1.00 is staying for about 3 samples while V1.26 isn't. I think your PPL is messing with in which sample the read reflects the resistor change, which very well be within a few samples with no problem, and you are confusing that with sampling jitter. I don't understand how you could evaluate jitter from the sampled data, you need a reference clock to work that, maybe a smooth voltage ramp could show it, knowing the linearity of the reference ramp is good and the deviation from there is coming from the meter measuring at different points. What I can see is the meter can miss a few samples from the time the resistor was swapped and the reading is shown, I can live with that. Maybe I'm missing the point here and you did used the reference signal going to the switch to lock your PLL, but I don't know how would you correlate that with the samples from the meter.
  Would be nice to see those plots with aligned rising edges, meaning the last sample within specs for each resistor is aligned between all steps, which will show a bit better the step response than the single step measurement I did.

  In my plots I get two peaks in noise, which might very well be just one but due to this jitter appears as two different ones in the FFT. Even then, if what I want to see is the digital filtering made with the samples, an FFT will still show that pretty well, as the firmware will process sample by sample and wouldn't care varying sampling time, so you could have much bigger phase noise than you say and what I'm looking for  in the FFT still be useful.

  In any case, as you said, and I agree with you, the time data isn't the important factor in a DMM reading, the amplitude value is what's useful here, and my complain has to do with glitches in the measured data which are not in the input signal, as I had correlated the effect between different ranges and in different environments. Then, if I'm logging I don't want the meter to do any filtering with the samples, I want the raw data so I can choose to see small changes fast and try to make sense from it out of the noise or filter and get a more steady value, but also I don't want the readings to be false, as it does when it jumps up to 50 counts, well outside the 10 specified counts. I also don't care when it changed value (precisely in time, within a few samples should be good enough most of the time).

JS
Title: Re: EEVBlog 121GW Discussion thread
Post by: firewalker on August 26, 2018, 09:17:54 am
What quantity is the vertical axis?

Alexander.
Title: Re: EEVBlog 121GW Discussion thread
Post by: firstcolle on August 27, 2018, 06:42:55 am
I'm trying to connect the meter with my desktop using a BT dongle but I can't pair them. I'm using an old dongle. can you suggest me one working dongle?
no problem with my smartphone.
Title: Re: EEVBlog 121GW Discussion thread
Post by: IanB on August 27, 2018, 07:07:09 am
I'm trying to connect the meter with my desktop using a BT dongle but I can't pair them. I'm using an old dongle. can you suggest me one working dongle?
no problem with my smartphone.

I just did the same thing using this dongle, so I know it works:

http://www.hornettek.com/wireless-networking/hornettek-ultra-mini-usb-bluetooth-v4-0-dongle-ht-bt40b.html (http://www.hornettek.com/wireless-networking/hornettek-ultra-mini-usb-bluetooth-v4-0-dongle-ht-bt40b.html)

I paid $18 for it, not the $40 list price. It uses a Broadcom chip, in case that helps.

In order to successfully use the dongle I had to shut down the Windows app, then pair the meter, then restart the app. When I first paired the meter while the app was running the app couldn't see the meter until I restarted it.
Title: Re: EEVBlog 121GW Discussion thread
Post by: JS on August 27, 2018, 08:03:14 am
Let's start by just looking at some raw data.  Again, the actual period of the toggle is fixed.  Because the jitter in the meters sampling, it is not a nice periodic waveform.   Should be easy enough to replicate.
  I see, there are flats from 10 to almost 20 samples. Are you suggesting the ADC reading is in such different intervales? I don't think the ADC would change so much, the readings from the µC is more likely the problem. Also, from the smaller look at your older pict of the raw data, V1.26 seems much more stable, isn't? The conversion results are jittery, no doubt, I wouldn't lock my clock onto the readings of that taking the reference somewhere else. My question now would be if the readings are shifting badly or the long term average out to a fixed-ish sampling rate.

  I do think V1.00 is using some non linear filter, I read somewhere it was a moving average which resets when a big change is detected, but I don't know the version corresponding to that. V1.26 response looks pretty different, much sharper edges (without the step in the middle which drives me nuts when I see it) and tighter when crossing from one to the other.

  I should replicate the test and check for myself, I will at some point, busy weekend for me this time.

JS
Title: Re: EEVBlog 121GW Discussion thread
Post by: firewalker on August 27, 2018, 11:03:08 am
What quantity is the vertical axis?

Alexander.

Are my previous posts not clear enough?


Yes it is! I had both 121GW threads opened and thought I read that one to the issues thread... :P
Title: Re: EEVBlog 121GW Discussion thread
Post by: IanB on August 28, 2018, 03:26:13 am
Here's a repeat of a test I was performing earlier. I wanted to compare the 121GW with something else for reference, so I dug out the interface cable for my BM869.

Here I show the results of logging a 500 microvolt source over a period of about 1000 seconds. I set up both 121GW and BM869s to measure the same voltage source at the same time with the same arrangement of meters and test connections, as near identical as I could manage. Both meters are sampling about twice per second at the maximum rate the software supports. The 121GW has the v1.26 firmware.

The average reading of the BM869s is nearly flat over the test duration, starting out at about 0.492 mV and ending at about 0.4925 mV. There are no glitches or outliers in the data.

The average reading of the 121GW shows a significant upward trend, starting at about 0.481 mV and ending at about 0.4865 mV. There are several apparent artifacts in the data where the meter deviates widely from the average reading. No explanation exists as yet for these glitches.

(https://www.eevblog.com/forum/testgear/eevblog-121gw-discussion-thread/?action=dlattach;attach=508346;image)

Title: Re: EEVBlog 121GW Discussion thread
Post by: IanB on August 28, 2018, 03:29:22 am
I have not ran a test like this with any of the other handheld meters I have.  None of them can capture data this fast.   It would be a nice feature if the meter could actually keep up storing the data or getting it across the wireless link.    It is a bit odd that the resistance seems to have higher jitter than the voltage mode.

The BM869s can sample data over the USB cable at a rate of 4 or 5 samples per second if you write your own software for it. The standard software is limited to twice per second. I have not yet explored the maximum capability of the meter (whether the meter's acquisition rate is as fast as the output data rate).
Title: Re: EEVBlog 121GW Discussion thread
Post by: IanB on August 28, 2018, 04:07:14 am
I had the 121GW switched on in mV DC mode with the BT interface running for quite some time before starting this test. As described in another thread I couldn't get it to connect to Windows 10 and I spent about 20 minutes trying to get it to work. So it should have warmed up reasonably well before I started.

The upward drift could conceivably have been due to a change in ambient temperature affecting my voltage source, but the BM869s as a control suggests this was not the case.

BTW, my Radio Shack 22-812 meters can log about 5 samples per second at a smooth, even cadence. I like them so much as data logging meters that I bought three of them. (I made my own logging software so that I can record from several meters at the same time to the same log file for multi-variable experiments.)
Title: Re: EEVBlog 121GW Discussion thread
Post by: IanB on August 28, 2018, 01:04:18 pm
I neglected to record the on screen temperature display over the duration of the test. However, the temperature would have been reasonably constant (no AC running during or before the test).

Here is a sample of the raw data from around the 550 second mark. You can see the data is being sampled twice per second, but apparently quite heavy filtering is being applied, so the update rate appears slower than that. The filtering is quite apparent from the spike contained within this sample. The time constant appears to be in the order of a few seconds.

Code: [Select]
550.0406, 0.485
550.525, 0.485
551.0563, 0.485
551.5406, 0.484
552.025, 0.484
552.5563, 0.484
553.0406, 0.484
553.525, 0.484
554.5422, 0.484
555.0266, 0.484
555.5578, 0.483
556.0422, 0.489
556.5266, 0.489
557.0578, 0.489
557.5422, 0.489
558.0266, 0.489
558.5578, 0.488
559.0422, 0.488
559.5176, 0.487
560.0645, 0.487
560.5488, 0.486
561.0266, 0.487
561.5578, 0.487
562.0422, 0.486
562.5891, 0.486
563.0579, 0.486
563.5385, 0.486
564.0295, 0.486
564.5608, 0.486
565.0475, 0.485
565.5787, 0.485
566.104, 0.485
566.5461, 0.485
567.0305, 0.486
567.5618, 0.486
568.0421, 0.486
568.5889, 0.486
569.5421, 0.485
570.0264, 0.485
570.5665, 0.485
571.0352, 0.485
571.5821, 0.486
572.0665, 0.486
572.5352, 0.485
573.0821, 0.485
573.5665, 0.485
574.0352, 0.485
574.5352, 0.485
575.5352, 0.485
576.0821, 0.485
576.5665, 0.485
577.0352, 0.485
577.5821, 0.484
578.0665, 0.484
578.5352, 0.484
579.0821, 0.484
579.5665, 0.484
580.0352, 0.484
Title: Re: EEVBlog 121GW Discussion thread
Post by: IanB on August 28, 2018, 01:29:52 pm
Here is estimating a time constant from one of the spikes:

(https://www.eevblog.com/forum/testgear/eevblog-121gw-discussion-thread/?action=dlattach;attach=508673;image)
Title: Re: EEVBlog 121GW Discussion thread
Post by: JS on August 28, 2018, 08:03:48 pm
  From the sine wave it's pretty clear the loss in samples, I see how that can become a problem, in fact is about half period, so 5s or 20 samples. I'd expected to see a sample or two missing in case on some calibration routine, but the spikes bother me more than the jitter, which can also be a serious problem for some measurement but I think we agree the timing is not so important while data-logging with a DMM as the value.

  Those spikes appear at a pretty constant rate in mV range, but looks pretty random in the 50Ω, that might have something to do with the difference in jitter between both ranges.

  About the drift, I've seen some in the 50Ω range at start up, but not so much once warmer, haven't tested in mV range, I should put a stable reference to work...

  All and all, I find the meter pretty useful as it is, but I think it has the potential to polish this rough edges and would be nice to have it as nice as it can be.

JS
Title: Re: EEVBlog 121GW Discussion thread
Post by: IanB on August 29, 2018, 01:37:04 am
The noise of the 121GW prototype dominates the signal.  The higher amplitude spikes appear very periodic.

That noise is extreme. It's like you have a totally different meter. Maybe I should try logging to the SD card instead of BT and see what difference it makes with my one.

Quote
You show about 8uV of drift over that 1000 seconds.  It looks like my HP is about 4uV.   It's strange how different the two meters behave.

If the HP is the red line, it seems to drift down by less than half a division in 4000 sec, and one division is 5 µV, so that is about 2 µV in 4000 sec, or 0.5 µV in 1000 sec. Or am I reading it wrong?
Title: Re: EEVBlog 121GW Discussion thread
Post by: darik on August 29, 2018, 01:43:54 am
Periodic spikes and dropped samples could be related to the logging. Like for example the SD card could be buffering writes and then flushing them when they get to a certain size, which would be at regular intervals. And those particular writes would take longer than others and maybe cause a spike in power consumption.

I have written Arduino based apps for logging sensor data to SD cards. It took a little finesse to make sure the file I/O didn't throw off the sample timing too much and when monitoring the current use, there was a noticeable power spike (around 15 mA IIRC) when the buffers were flushed and SD writes happened.

The Bluetooth interface could be doing the same thing but differently. It must have it's own weird power consumption issues as it surely must be doing a lot of asynchronous radio transmission to send whatever packets it needs to to maintain the connection.
Title: Re: EEVBlog 121GW Discussion thread
Post by: IanB on August 29, 2018, 01:53:25 am
I believe the spikes happen the same way whether logging is happening or not. Logging is merely a good way to make the spikes visible. So I am not sure the logging is the cause of the spikes.
Title: Re: EEVBlog 121GW Discussion thread
Post by: joeqsmith on August 29, 2018, 02:00:47 am
The noise of the 121GW prototype dominates the signal.  The higher amplitude spikes appear very periodic.

That noise is extreme. It's like you have a totally different meter. Maybe I should try logging to the SD card instead of BT and see what difference it makes with my one.

Quote
You show about 8uV of drift over that 1000 seconds.  It looks like my HP is about 4uV.   It's strange how different the two meters behave.

If the HP is the red line, it seems to drift down by less than half a division in 4000 sec, and 1 division is 5 µV, so that is about 2 µV in 4000 sec, or 0.5 µV in 1000 sec. Or am I reading it wrong?

The X-axis is in samples, not seconds.  At 4Hz we have 1000 seconds.  So the same as your setup.   Yes, the Y-axis is 5uV per division.  The HP's output is too small to read on the screen but there is a readout in the lower right.  The max is 501.05 and the min is 497.63 or 3.42.  That's with the noise and everything included.  Then I padded it up to 4uV. 

I do have a totally different meter.  It's a prototype that has been damaged three times, repaired by me and then modified.  Then it was completely realigned to a NON-NIST traceable standard.  :-DD  So I can fully believe this meter behaves differently in any of the data I show.   Which is why I started out stating there is nothing to take away with this.  In other words, don't read more into it than what's there.   

Again, sadly no image is available for the BT so I have yet to see it work.  So any results I show in for foreseeable future will be from logging on the SD card.   
Title: Re: EEVBlog 121GW Discussion thread
Post by: IanB on August 29, 2018, 02:16:41 am
I find it amusing that you now seem to have three production samples of the Fluke 189 and as yet no production sample of the 121GW. Can we infer that you don't think the 121GW is worthy of being owned?  >:D

(I am slightly envious of your 189 ownership, by the way.)
Title: Re: EEVBlog 121GW Discussion thread
Post by: JS on August 29, 2018, 03:10:59 am
The noise of the 121GW prototype dominates the signal.  The higher amplitude spikes appear very periodic.

That noise is extreme. It's like you have a totally different meter. Maybe I should try logging to the SD card instead of BT and see what difference it makes with my one.

Quote
You show about 8uV of drift over that 1000 seconds.  It looks like my HP is about 4uV.   It's strange how different the two meters behave.

If the HP is the red line, it seems to drift down by less than half a division in 4000 sec, and one division is 5 µV, so that is about 2 µV in 4000 sec, or 0.5 µV in 1000 sec. Or am I reading it wrong?

I've done a test in the other topic, I see spikes up to 50 counts down in the mV range,  I didn't say anything about drift as it was with shorted inputs, just 200 samples 3 spikes are observed, in samples 61, 121 and 181. Mine is from the kickstarter, so noise still there.. I run the comparison with V1.00 and the spikes are also there but muffled. In the 50Ω range the spikes are also present but the interval is much random. A few of my measurements are in the other topic. I live a link to the message of the mV range.
https://www.eevblog.com/forum/testgear/eevblog-121gw-multimeter-issues/msg1767461/#msg1767461 (https://www.eevblog.com/forum/testgear/eevblog-121gw-multimeter-issues/msg1767461/#msg1767461)

JS
Title: Re: EEVBlog 121GW Discussion thread
Post by: joeqsmith on August 29, 2018, 03:14:27 am
Feeding the 121GW prototype with a chirp and comparing firmware 1.0 with 1.26.  The chirp is from 20mHz to 5Hz with a 500 second sweep time. The meter is sampling at 4Hz.  X-axis is in samples.   Y-axis is in voltage.  Arb is programmed to 100mVp-p.   
Title: Re: EEVBlog 121GW Discussion thread
Post by: FrankBuss on August 29, 2018, 06:42:23 am
Sorry, I'm a bit slow, if this was already mentioned: I just realized that "121GW" sounds pretty much like 1.21 gigawatts :)
Title: Re: EEVBlog 121GW Discussion thread
Post by: 1anX on August 29, 2018, 06:45:30 am
Sorry, I'm a bit slow, if this was already mentioned: I just realized that "121GW" sounds pretty much like 1.21 gigawatts :)

You got it right Frank, and as the saying goes, "better late than never"!
Title: Re: EEVBlog 121GW Discussion thread
Post by: Brumby on August 29, 2018, 12:03:40 pm
Exactly right.

Some time ago there was a discussion about naming the meter and the "121GW" proposition took an unbeatable lead in its support.
Title: Re: EEVBlog 121GW Discussion thread
Post by: IanB on August 31, 2018, 02:59:26 am
I have not ran a test like this with any of the other handheld meters I have.  None of them can capture data this fast.

Last night I ran a crude test on my BM869s by driving the data interface cable as fast as possible with a test program. I was able to obtain readings over the cable at a rate of about 200 ms per sample. This was done by starting the next read as soon as the previous read was completed and measuring the interval. I may post more on this in another thread after I do a few more experiments.
Title: Re: EEVBlog 121GW Discussion thread
Post by: MiroS on September 06, 2018, 10:03:38 am
Dr Frank was suggesting a higher test current for the low ranges.

I do  not have this metter, but majority of multimeters I touched have always problem with low and high margin of ranges, especialy for lowest  range is a good test for mesuremant capabilities, e.g. current like 100nA, or 1nA.  Even if spec is claiming 0.5 % or so at marginal values for ranges  this might be quite high like 10% for lowest range and test current like 10nA, or 1nA , or 1uA at 1000V etc.

I wonder if GW121 is much different from other mutimeters?  I would think that it might be  actually worst than others due to low burden volatege (?)

Title: Re: EEVBlog 121GW Discussion thread
Post by: HKJ on September 06, 2018, 10:22:47 am
Even if spec is claiming 0.5 % or so at marginal values for ranges  this might be quite high like 10% for lowest range and test current like 10nA, or 1nA , or 1uA at 1000V etc.

You have to look at the full specifications. A tolerance may be 0.5% + 4, the 4 is a very important part of the tolerance specification when measuring low values.
There is also a detail about AC, there the tolerances is usual not valid below 5% to 10% of the range.

I wrote a bit about it here: https://lygte-info.dk/info/DMMTolerances%20UK.html
Title: Re: EEVBlog 121GW Discussion thread
Post by: MiroS on September 06, 2018, 10:27:56 am
I wrote a bit about it here: https://lygte-info.dk/info/DMMTolerances%20UK.html

Nice article, thanks for sharing. Btw, I know rules , but  I wonder how is doing 121GW comparing to others by tests.
Title: Re: EEVBlog 121GW Discussion thread
Post by: HKJ on September 06, 2018, 10:38:58 am
I wonder how is doing 121GW comparing to others by tests.

When I tested it, it was inside the specified tolerances (with one exception).
https://lygte-info.dk/review/DMMEEVBlog%20121GW%20UK.html
Title: Re: EEVBlog 121GW Discussion thread
Post by: MiroS on September 06, 2018, 10:54:04 am
I wonder how is doing 121GW comparing to others by tests.

When I tested it, it was inside the specified tolerances (with one exception).
https://lygte-info.dk/review/DMMEEVBlog%20121GW%20UK.html

I can  not find  test with nA test current. Did I missed this?
Title: Re: EEVBlog 121GW Discussion thread
Post by: HKJ on September 06, 2018, 10:59:39 am
I can  not find  test with nA test current. Did I missed this?

My lowest test current is usual 1uA, I did mention that you need to use REL mode.
Title: Re: EEVBlog 121GW Discussion thread
Post by: MiroS on September 06, 2018, 11:31:40 am
.....range and test current like 10nA, or 1nA , or 1uA at 1000V etc.

Are you trying to apply 1000V with a supply that is limited to a uA and measure the voltage?  If you are trying to measure current, where does the 1KV fit in?   I am not sure what you are asking.

Not uA and not like this, as simple as that:
- 100nA at any voltage (better 10 or 1nA, no idea how 121GW sensitive is)
- 100nA (better 10 or 1nA, no idea how 121GW sensitive is) at 1kV (1kV relative to ground , not accross multiemer)


Title: Re: EEVBlog 121GW Discussion thread
Post by: HKJ on September 06, 2018, 11:57:46 am
Not uA and not like this, as simple as that:
- 100nA at any voltage (better 10 or 1nA, no idea how 121GW sensitive is)
- 100nA (better 10 or 1nA, no idea how 121GW sensitive is) at 1kV (1kV relative to ground , not accross multiemer)

That would be outside the specifications for the meter, it is only rated for 600V to earth.
Title: Re: EEVBlog 121GW Discussion thread
Post by: MiroS on September 06, 2018, 02:14:17 pm
That would be outside the specifications for the meter, it is only rated for 600V to earth.

I would  not care for specifiation for such tests, but other hand I cannot ask anyone for potentialy destructive tests.
I would also not buy 121GW at this moment for own  tests, it looks not mature to me.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Seppy on September 10, 2018, 12:11:09 am
That would be outside the specifications for the meter, it is only rated for 600V to earth.

I would  not care for specifiation for such tests, but other hand I cannot ask anyone for potentialy destructive tests.
I would also not buy 121GW at this moment for own  tests, it looks not mature to me.

Are you looking to find leakage current of the voltage range? If so, the leakage at 1kV isn't likely to fit on a straight line curve down to zero, so we would need a few different points.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Visitor on September 16, 2018, 04:03:24 pm
Hi!

Got my 1.21GW a few days ago.
My first impression was like  :palm: when i saw the glonky springs trying to hold the batteries in place.
Oh my god, what a bad quality battery holder for a 240 EUR Multimeter.
Without aranging the Springs after puting the batries in  the holder they would almost jump out of it.

But the Multimeter itself looks pretty god  :-+
Some measurements in relatve mode makes no sense for me, but i need some more practice.
Title: Re: EEVBlog 121GW Discussion thread
Post by: chronos42 on September 16, 2018, 06:34:21 pm
Hi,
that is true, the battery holders are terrible. That was also my first impression.
The worst springs of all my battery powerd instruments. I have aligned the springs with a small tweezer, so now it lookes a bit better.
Beside of this a great meter with some room of improvement in the firmware.
Title: Re: EEVBlog 121GW Discussion thread
Post by: 1anX on September 16, 2018, 09:51:39 pm
Hi,
that is true, the battery holders are terrible. That was also my first impression.
The worst springs of all my battery powerd instruments. I have aligned the springs with a small tweezer, so now it lookes a bit better.
Beside of this a great meter with some room of improvement in the firmware.
I think all of us who bought this meter were shocked at the springs fitted in the battery holder. A well made battery holder fitted with springs which are simply too long.

To use a "Dave" expression when reviewing products the springs are a "FAIL"!

Good meter fitted with the wrong length battery springs, how did this get into the production run?
Title: EEVBlog 121GW Discussion thread ESR of capacitors measurment
Post by: stig on September 17, 2018, 07:32:39 am
Was just wondering if it would get ESR in the capacitance measurment aswell :)
Title: Re: EEVBlog 121GW Discussion thread
Post by: CDaniel on September 17, 2018, 10:36:48 am
This multimeter has in theory an 50000 counts display , than range switching upward  at 55000 counts but downward at 40000 counts  is supposed to be a feature ?
I find this rather annoying ... lets say  I want to adjust a 5.0000V voltage refference , if I go up beyond 5.5000V I lose the last digit of resolution because is switching the 50V range , but then if I adjust downward I can't get it back since it remains in 50V range until it reaches 4V

Title: Re: EEVBlog 121GW Discussion thread
Post by: Cliff Matthews on September 17, 2018, 12:20:07 pm
@CDaniel - Why not use the provided range switch?
Title: Re: EEVBlog 121GW Discussion thread
Post by: CDaniel on September 17, 2018, 12:32:54 pm
@CDaniel - Why not use the provided range switch?

Because it has autorange ...  |O
Title: Re: EEVBlog 121GW Discussion thread
Post by: Cliff Matthews on September 17, 2018, 02:54:51 pm
@CDaniel - You said you can't get it back after you turned down V-ref.. go manual to desired range, then flip it back to auto.
Title: Re: EEVBlog 121GW Discussion thread
Post by: CDaniel on September 17, 2018, 04:27:11 pm
Sure I could , but I don't think is normal to be 2 thresholds , that is my point .
And that was just an example .
Title: Re: EEVBlog 121GW Discussion thread
Post by: newbrain on September 17, 2018, 04:28:50 pm
This multimeter has in theory an 50000 counts display , than range switching upward  at 55000 counts but downward at 40000 counts  is supposed to be a feature ?
I find this rather annoying ... lets say  I want to adjust a 5.0000V voltage refference , if I go up beyond 5.5000V I lose the last digit of resolution because is switching the 50V range , but then if I adjust downward I can't get it back since it remains in 50V range until it reaches 4V
I would consider this quite normal, though the hysteresis is a bit on the wide side.

This is what happens with my Fluke 87V:
Counts
Up at
%
Down at
%
6000
6.600
+10
5.40
-10
20000
19.999
+0
16.80
-16(Of course, it can't display > 19999)

The 121GW does it at +10% and -20%.

Sure I can , but I don't think is normal to be 2 thresholds , that is my point .
It's definitely normal! Without hysteresis you would have continuous range change at the threshold, a much worse experience.
Title: Re: EEVBlog 121GW Discussion thread
Post by: darik on September 17, 2018, 04:40:49 pm
Sure I could , but I don't think is normal to be 2 thresholds , that is my point .
And that was just an example .

I have 4 meters. They all have two thresholds like that. I would imagine to prevent excessive autoranging when taking measurements near the threshold value. I believe it's called hysteresis.
Title: Re: EEVBlog 121GW Discussion thread
Post by: CDaniel on September 17, 2018, 04:45:54 pm
Ok , you are wright , I cheked my other multimeter who has 6,6V up and 6,2V down , which is much smaller and I never noticed since is not around 5V ( I don't think that's random design )
Title: Re: EEVBlog 121GW Discussion thread
Post by: IanB on September 17, 2018, 06:19:56 pm
Sure I could , but I don't think is normal to be 2 thresholds , that is my point.
And that was just an example.

There will always be two thresholds to prevent "hunting" of the auto-range circuit when close to the switch point.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Seppy on September 24, 2018, 01:40:38 am
V1.51 Firmware released, change log will be in the manual soon.
www.eevblog.com/product/121gw/ (http://www.eevblog.com/product/121gw/)
Title: Re: EEVBlog 121GW Discussion thread
Post by: bicycleguy on September 24, 2018, 01:58:57 am
FYI, Installed, no problems. 
Title: Re: EEVBlog 121GW Discussion thread
Post by: Jon.C on September 24, 2018, 05:21:19 am
(https://i.gyazo.com/57b7dd7cccb1786f86b46ed540638f60.png)
Title: Re: EEVBlog 121GW Discussion thread
Post by: bicycleguy on September 24, 2018, 09:21:18 pm
I couldn't take it any longer :-/O

(https://www.eevblog.com/forum/testgear/eevblog-121gw-discussion-thread/?action=dlattach;attach=547718;image)
Title: Re: EEVBlog 121GW Discussion thread
Post by: 1anX on September 24, 2018, 10:19:21 pm
I couldn't take it any longer :-/O

Great idea!
The meter could be made with a small removable cover for this very purpose and retain rating?
Title: Re: EEVBlog 121GW Discussion thread
Post by: bicycleguy on September 24, 2018, 10:24:42 pm
...
Great idea!
The meter could be made with a small removable cover for this very purpose and retain rating?

Don't know about whatever governments rules and regs but a piece of electrical tape seems to seal it pretty good. ^-^
Title: Re: EEVBlog 121GW Discussion thread
Post by: bicycleguy on September 24, 2018, 11:29:52 pm
...
Ok, I have to ask.  Did you make this modification because you log a lot to the SC card or was it because of the number of firmware updates you have done?
...

Yes >:D
Title: Re: EEVBlog 121GW Discussion thread
Post by: Bratster on September 25, 2018, 05:18:00 am
I couldn't take it any longer :-/O
Brilliant!
Edit: but keep in mind that this does either partially or completely negate the CAT safety rating of the meter.

Sent from my Fi Moto x4 using Tapatalk
Title: Re: EEVBlog 121GW Discussion thread
Post by: Brumby on September 25, 2018, 07:31:17 am
Has anyone stopped for a second and asked why such a cutout might NOT be a good move?


The issue isn't new.  It has been discussed during earlier development.
Title: Re: EEVBlog 121GW Discussion thread
Post by: 1anX on September 25, 2018, 09:32:44 am
Has anyone stopped for a second and asked why such a cutout might NOT be a good move?


The issue isn't new.  It has been discussed during earlier development.
Its his meter and he can hack it to how it works best for him!

Just as you can do whatever you want to your meter, hack away or not, its your choice!
Title: Re: EEVBlog 121GW Discussion thread
Post by: firewalker on September 25, 2018, 09:49:42 am
I would prefer a more rectangular hole for a rubber cap. To stop moisture and dust. I believe moisture could effect the current amplifier fronted.
 
Alexander.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Brumby on September 25, 2018, 12:07:16 pm
Has anyone stopped for a second and asked why such a cutout might NOT be a good move?


The issue isn't new.  It has been discussed during earlier development.
Its his meter and he can hack it to how it works best for him!

Just as you can do whatever you want to your meter, hack away or not, its your choice!

I never said he couldn't do whatever he wanted to do to his own meter.  I just raised the point as to why it might not be a good move.

If someone KNOWS what the implications are and chooses to make such a modification, then fine.  But DON'T start espousing this as a GREAT IDEA - whether or not you appreciate the risk.

SO if you want to blindly advocate such a modification - then you need to pull your head in.   IMHO.
Title: Re: EEVBlog 121GW Discussion thread
Post by: dcac on September 25, 2018, 01:55:17 pm
The backcover om my 121gw is a very tight fit and would never fall off by it self - so I just don’t tighten the two screws at all if I’m doing any logging.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Bratster on September 25, 2018, 08:36:08 pm
Has anyone stopped for a second and asked why such a cutout might NOT be a good move?


The issue isn't new.  It has been discussed during earlier development.
Correct,
NOT a good move if you want to keep the full CAT safety rating intact.

I added that note to my prior post just in case any newbies come across it.


But personally I would never use this meter on anything more powerful than a 120v  wall outlet. Nor would I trust it.

That's what the Fluke meters are for.

I did a similar modification to my mooshimeter to allow access to the SD card and button. And while that one may get connected to something powerful, it's Bluetooth with no display so it wouldn't be handheld.

Sent from my Fi Moto x4 using Tapatalk
Title: Re: EEVBlog 121GW Discussion thread
Post by: 1anX on September 25, 2018, 10:07:39 pm

I never said he couldn't do whatever he wanted to do to his own meter.  I just raised the point as to why it might not be a good move.

If someone KNOWS what the implications are and chooses to make such a modification, then fine.  But DON'T start espousing this as a GREAT IDEA - whether or not you appreciate the risk.

SO if you want to blindly advocate such a modification - then you need to pull your head in.   IMHO.

Brumby, Brumby, Brumby, what are we going to do about your lack of reading comprehension and BS statement?

Ok, firstly I didn't advocate for everyone to make the modification, thats your BS spin on it. I liked the idea of having the SD card accessible and even asked the question, if it might have a cover provided to keep the rating!

Have you actually purchased this meter yet Brumby?

Your entitled to your opinion, but I would expect you to keep touch with reality and actually read what I have posted before making such misleading and mischievous comments!

If you struggle to comprehend the english language then maybe you should take a refresher course or you may have just had a bad day and needed to blow of some steam?
 
Title: Re: EEVBlog 121GW Discussion thread
Post by: 1anX on September 25, 2018, 10:41:40 pm
Your   "You're"  entitled to your opinion, but I would expect you to keep touch with reality and actually read what I have posted before making such misleading and mischievous comments!

If you struggle to comprehend the english language then maybe you should take a refresher course or you may have just had a bad day and needed to blow of some steam?

Sorry, couldn't help myself.   :-DD :-DD  Believe me, this is a case of the pot calling the kettle black.

Joe, grammar and comprehension are two different things!
In any case, thanks for picking up on the grammatical error and I stand corrected and can indeed see the humour in it   :)
Title: Re: EEVBlog 121GW Discussion thread
Post by: Brumby on September 26, 2018, 03:25:09 am

I never said he couldn't do whatever he wanted to do to his own meter.  I just raised the point as to why it might not be a good move.

If someone KNOWS what the implications are and chooses to make such a modification, then fine.  But DON'T start espousing this as a GREAT IDEA - whether or not you appreciate the risk.

SO if you want to blindly advocate such a modification - then you need to pull your head in.   IMHO.

Brumby, Brumby, Brumby, what are we going to do about your lack of reading comprehension and BS statement?

Ok, firstly I didn't advocate for everyone to make the modification, thats your BS spin on it.
Great idea!
This sounded like encouragement to me.  It certainly was an endorsement.

Quote
I liked the idea of having the SD card accessible and even asked the question, if it might have a cover provided to keep the rating!
A subtle difference from your original statement.  It still didn't acknowledge the potential issues of trying to do that.

Quote
Have you actually purchased this meter yet Brumby?
I knew you would throw this up.  You might be surprised to learn that I don't need to have the meter in my possession to be able to make valid comment about some aspects of it - especially when the subject had already been discussed some time ago.  You might also note that, at no time, have I entered into any discussion on the 121GW where I have offered comment or information that was based on possession.

Quote
Your entitled to your opinion, but I would expect you to keep touch with reality and actually read what I have posted before making such misleading and mischievous comments!

If you struggle to comprehend the english language then maybe you should take a refresher course or you may have just had a bad day and needed to blow of some steam?
Here's a pot and kettle moment if there ever was one.  :palm:

IF you had comprehended what I had written you should have noticed that AT NO TIME did I say someone shouldn't "hack" their meter as described.  I simply asked a question.  It was you who invented such a direction.

Respond if you must - but this has been enough of a tangent and I won't drag it out any more.

Finis
Title: Re: EEVBlog 121GW Discussion thread
Post by: 1anX on September 26, 2018, 03:59:28 am
Quote
Have you actually purchased this meter yet Brumby?

"I knew you would throw this up.  You might be surprised to learn that I don't need to have the meter in my possession to be able to make valid comment about some aspects of it - especially when the subject had already been discussed some time ago.  You might also note that, at no time, have I entered into any discussion on the 121GW where I have offered comment or information that was based on possession."

I beg to differ, if you actually owned this meter and used the SD card for data logging as well as for firmware updates you would understand that easy access to this card would be a huge benefit!

I am hoping that one day soon the BT radio function will eliminate the need for the SD card shuffle!

Wait and see how BT works out, as the potential is there.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Brumby on September 26, 2018, 04:28:45 am
Apologies for not walking away as I promised - but this just has to be addressed...

I beg to differ, if you actually owned this meter and used the SD card for data logging as well as for firmware updates you would understand that easy access to this card would be a huge benefit!
I'm sorry for saying this - but you are an ass.  One does not have to own or use this meter to appreciate the hassle involved.  It's been mentioned many times.  To say I would not understand the benefit of the hack is dumb and just seems to be a way for you to try and justify yourself.

Please read what I wrote about the hack.  My involvement was to question the wisdom of doing so - not the benefit.


While I don't claim the high levels of comprehension skills you seem to be espousing, perhaps you should take another lesson or two.
Title: Re: EEVBlog 121GW Discussion thread
Post by: 1anX on September 26, 2018, 06:03:23 am
Apologies for not walking away as I promised - but this just has to be addressed...

No apologies necessary Brumby!

The SD card is only one aspect of the meter, and that may evolve over time! The meter has many functions and still a few bugs to be ironed out. The thing is Brumby, you don't own and use the meter or have any hands on real experience with it.

I would go so far as to say your comments are simply your opinion and not based on any experience of using the 121GW meter. Your simply commenting because you like the sound of your own voice, and not offering anything of substance to this thread.

My advice would be to "pony up" and buy the meter, then add your 5 cents worth on the function of the 121GW!

Brumby = wild horse, "pony up" is an intended horse pun, just in case you don't comprehend the intention  :)
Title: Re: EEVBlog 121GW Discussion thread
Post by: Brumby on September 26, 2018, 07:13:24 am
Ah - the "Exclusivity" club - and I'm not a member.

You've made that very clear from months ago.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Fryguy on September 28, 2018, 09:46:49 am
Did anyone notice this . . . . ?   :-/O

Yes i know it is not important at all . Just found it doing a little RTFM .

Is it possible to get the android app .apk file for offline installation ?  I hate the google spy play store !  >:D
Title: Re: EEVBlog 121GW Discussion thread
Post by: TikhonovC on October 01, 2018, 04:39:41 pm
Page №15 of the manual (Manual-24-September-2018), DC V accuracy:
Range: 5 V
Resolution: 0.1 ?
Title: Re: EEVBlog 121GW Discussion thread
Post by: Brumby on October 01, 2018, 05:13:16 pm
Obviously missing the "mV" - but it is a typo nonetheless.
Title: Re: EEVBlog 121GW Discussion thread
Post by: skyjumper on October 02, 2018, 05:51:54 am
Is there an estimate when these will be available to those of us who didn't see the Kickstarter? Dave's product page lists it as out of stock. If it matters I'm in the US.

Thanks!
Title: Re: EEVBlog 121GW Discussion thread
Post by: HKJ on October 02, 2018, 06:14:50 am
Is there an estimate when these will be available to those of us who didn't see the Kickstarter? Dave's product page lists it as out of stock. If it matters I'm in the US.

They are available:
https://www.welectron.com/Handheld-Multimeters_s2 (https://www.welectron.com/Handheld-Multimeters_s2)
Title: Re: EEVBlog 121GW Discussion thread
Post by: skyjumper on October 02, 2018, 09:05:44 pm
Thanks! I see they charge $23 euro (about) to ship to the US via some insured / tracked method. Does anyone else sell these?
Title: Re: EEVBlog 121GW Discussion thread
Post by: GeoffreyF on October 02, 2018, 10:36:16 pm
I have noted that the 121GW goes "in stock" in lots of 32 units.  These units are usually sold within a week.  Just keep checking every couple of days and keep that credit card handy.   Check on the site too because (if memory serves) they ship on Tuesday and Thursday (australia time).   I got my meter in the Boston, MA, USA  area about 5 days after shipping, which is pretty good.  This was a few weeks ago and so this is a fairly up-to-date description of the process. 
Title: Re: EEVBlog 121GW Discussion thread
Post by: skyjumper on October 03, 2018, 04:52:45 am
I have noted that the 121GW goes "in stock" in lots of 32 units.  These units are usually sold within a week.  Just keep checking every couple of days and keep that credit card handy.   Check on the site too because (if memory serves) they ship on Tuesday and Thursday (australia time).   I got my meter in the Boston, MA, USA  area about 5 days after shipping, which is pretty good.  This was a few weeks ago and so this is a fairly up-to-date description of the process.

Yippie, they are back in stock! Order placed, thank you! Dave could use a US based distributor though...
Title: Re: EEVBlog 121GW Discussion thread
Post by: Yannik on October 03, 2018, 04:34:03 pm
Is it really impossible to have the backlight on by default? It's pretty annoying to turn it on by hand everytime you use the meter.
Title: Re: EEVBlog 121GW Discussion thread
Post by: TikhonovC on October 03, 2018, 08:12:35 pm
Yes,
I would like the multimeter to remember the last state of the backlight.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Kim on October 05, 2018, 02:39:17 pm
While we're on the subject of the backlight, how about an option to light it up along with (or instead of) the beep in continuity test mode?  It's a small feature that would make a big difference to people with hearing loss, or just for when you're trying to troubleshoot a dicky connection without annoying everyone else in the room.

(Received my 121GW last week, really liking it so far.)
Title: Re: EEVBlog 121GW Discussion thread
Post by: Brumby on October 06, 2018, 02:14:47 am
That would be useful for people with hearing loss or just someone working in a very noisy environment.

Well, I don't have a 121GW yet, so I can't comment, but the BM235 flashes the backlight in continuity mode - and it does so whether the backlight is off or had been turned on.  (Yes, I have a BM235).

If the 121GW doesn't have this feature, I would like to see it implemented.  The option to switch off the beeper is one I would be guarded about.  That is a setting I would want to have automatically reset at switching off so the next time I turn the meter on, I don't interpret silence as a lack of continuity.
Title: Re: EEVBlog 121GW Discussion thread
Post by: GeoffreyF on October 06, 2018, 10:40:48 pm
I think that actually there should be an option for the beep to transmit the readout and state in morse code.   Blind people could then work with high voltages too.  Anyway, that's the kind of thing Brumby would want.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Brumby on October 07, 2018, 02:33:21 am
I'm not advocating such stupidity, so don't dump this crap on me - OK?  You are just being childish.  Or is this another case of "I'm not a member of the club, so my opinion is offensive"?

This is not something I've dreamed up.  It's already been implemented in other meters.  If you want to properly consider the use case for backlight being used with continuity, then check out the discussion on this exact point with the BM235.

Title: Re: EEVBlog 121GW Discussion thread
Post by: dcac on October 07, 2018, 12:34:30 pm
That would be useful for people with hearing loss or just someone working in a very noisy environment.

Well, I don't have a 121GW yet, so I can't comment, but the BM235 flashes the backlight in continuity mode - and it does so whether the backlight is off or had been turned on.  (Yes, I have a BM235).

If the 121GW doesn't have this feature, I would like to see it implemented.  The option to switch off the beeper is one I would be guarded about.  That is a setting I would want to have automatically reset at switching off so the next time I turn the meter on, I don't interpret silence as a lack of continuity.

You’re quite right it would be a useful feature and it would also be nice if it was made a configurable option in the setup. But UEi will probably be focusing on bugfixes for quite a while though - before implementing new features. But perhaps it is possible to hack/modify the firmware to achieve something like this.

Title: Re: EEVBlog 121GW Discussion thread
Post by: Visitor on October 07, 2018, 05:22:32 pm
Does anybody know if there will be an option to NOT store the last settings of the functions?
Title: Re: EEVBlog 121GW Discussion thread
Post by: Bratster on October 07, 2018, 05:24:37 pm
Does anybody know if there will be an option to NOT store the last settings of the functions?
That is sorely needed IMO.

Sent from my Fi Moto x4 using Tapatalk

Title: Re: EEVBlog 121GW Discussion thread
Post by: CDaniel on October 07, 2018, 07:46:26 pm
Many little features can be added , but there are some important ones not very good implemented .
For exemple capacitance measurement has low resolution , only 3 digits 1000 counts , so for 220nF you can't see anything extra . And very , very slow autoranging in comparison with other multimeters. HY3131 is capable for more performance
Title: Re: EEVBlog 121GW Discussion thread
Post by: Visitor on October 08, 2018, 07:18:35 am
You are right.
The ultra slow autoaranging ist the second big mistake after the ugly battery holder.
Every 30$ China crap is at least 2 times faster.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Seppy on October 09, 2018, 12:07:58 am
Nope, doesn't do ESR, you would need an LCR meter.
Title: Re: EEVBlog 121GW Discussion thread
Post by: CDaniel on October 09, 2018, 06:36:24 pm
We don't want ESR , but could we get in near future a rework of the capacitance measurement ?

1 . More resolution , 3digits 1000counts for lower ranges is too low , even the entry level meters in these days have 4000-6000 counts for capacitance . The chipset HY3131 is for sure more capable .
2 . Bargraph if possible
3 . Improved autorange speed
4 . I don't think the firmware has the feature "discharge capacitors" implemented . Anyway when you connect ( by mistake ) a charged capacitor the display should show "discharge" or something while performing this.

Maybe someone could add more to this list
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on October 10, 2018, 02:15:10 am
Many little features can be added , but there are some important ones not very good implemented .
For exemple capacitance measurement has low resolution , only 3 digits 1000 counts , so for 220nF you can't see anything extra . And very , very slow autoranging in comparison with other multimeters. HY3131 is capable for more performance

We'll add it to the list to be looked at.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on October 10, 2018, 02:21:41 am
The backcover om my 121gw is a very tight fit and would never fall off by it self - so I just don’t tighten the two screws at all if I’m doing any logging.

I don't understand the fuss over the SD card access. It is the way it is for compliance reasons.
If anyone is using the data logger function so often that the access is a problem then I suggest you get a real data logger with convenient data access and/or transfer.
The SD card was designed for firmware updates that could also be used as a data logger at a pinch if needed. You wouldn't buy this meter to replace a "data logger", that's not it's job.
Title: Re: EEVBlog 121GW Discussion thread
Post by: dcac on October 10, 2018, 09:50:02 am
Logging to a SD card is a very nice feature on the 121gw, and even if getting access to the card - does not take that much time - I can understand people leaving the backcover off completely if they know they soon going to pull that card anyway. And still with the backcover off - pulling and mounting the card in the holder is a bit fiddly so sooner or later you probably end up breaking the holder as there’s no guides or anything to protect it.

All this could be solved with a function to dump the log file over the Bluetooth interface, you’d think that shouldn’t be too hard to implement, I mean there’s already a function to view and step through the log on the meter.
Title: Re: EEVBlog 121GW Discussion thread
Post by: chronos42 on October 10, 2018, 04:00:41 pm
Hi,

I agree, access to the SD card filesystem (readonly is sufficient) via bluetooth would solve all these discussions. That should be possible with this ARM processor that is build in the meter.
Title: Re: EEVBlog 121GW Discussion thread
Post by: chronos42 on October 10, 2018, 07:13:44 pm
Hi,
This is indeed slow, but I assume the logging data transfer is synchronised with the ADC sampling and would be faster with a datatransfer from the SD card?
Title: Re: EEVBlog 121GW Discussion thread
Post by: Seppy on October 15, 2018, 12:15:44 am
Hi,
This is indeed slow, but I assume the logging data transfer is synchronised with the ADC sampling and would be faster with a datatransfer from the SD card?

Well, I'm not so sure.  They write to the SD card much faster than they send the data over BLE.  They have even slowed down the BLE transfers compared with the early firmware versions.  I assume they were trying to improve reliability by going from ASCII to binary, reducing the payload and then slowing it down  but I'm not sure.   The meter can certainly update faster than 2Hz so I don't believe it would speed up if they were doing a data transfer.   

Again, I am not suggesting it could not be done only that from what I see, it appears throttled like Barbie's Mustang and not Grind Hard Plumbing's version.   

https://www.youtube.com/channel/UCivi_f1nniBzEOfKhRoN12Q (https://www.youtube.com/channel/UCivi_f1nniBzEOfKhRoN12Q)

Your speculation is accurate for the most part.
We might be able to improve BLE speed now that we have reduced the packet size. But, we have some outstanding issues that will take precedence so it could be a while before this change occurs (if its possible).
Title: Re: EEVBlog 121GW Discussion thread
Post by: nealz on October 16, 2018, 02:16:27 am
Does anyone know where I can get a magnetic hanger for the 121GW meter? I say some posts on the forum that mentioned compatible with Klein hangers but I found a few different styles/models.

If you know of a confirmed compatible hanger please let me know.

Thanks
Neal
Title: Re: EEVBlog 121GW Discussion thread
Post by: Seppy on October 16, 2018, 06:21:49 am
There is a fair bit of overhead sending that one byte packet.   :-DD

There were other motivating factors also which included differences in implementation for BLE on different platforms. Some platforms have a longer buffer than others and it needed to come in one packet.
The number of platforms this device supports was also a factor in the reduction of the packet size.
Title: Re: EEVBlog 121GW Discussion thread
Post by: FrankBuss on October 16, 2018, 06:49:09 am
The max payload for a GATT Characteristic, which can be sent in one physical BLE packet, is 20 bytes. Once I implemented the nRF UART protocol on a Silabs Blue Gecko (https://www.silabs.com/community/wireless/bluetooth/forum.topic.html/how_to_implementuar-ovZ7), with a length of 20 for the TX and RX characteristics, and with a stress test I never lost a packet from the device to the PC (running a Python script with bluepy). So I assume it is good to have a packet size of 20 bytes or less, but wouldn't make sense to limit it to a smaller size. Each physical packet has a CRC checksum (additional bytes, not part of the payload) and a packet is either received fully or not received at all.

I guess there can be problems, if you set the length of a GATT Characteristic to more than 20 bytes, because then the underlying BLE implementation has to split it in multiple physical packets.
Title: Re: EEVBlog 121GW Discussion thread
Post by: joeqsmith on October 16, 2018, 11:09:49 am
There is a fair bit of overhead sending that one byte packet.   :-DD

There were other motivating factors also which included differences in implementation for BLE on different platforms. Some platforms have a longer buffer than others and it needed to come in one packet.
The number of platforms this device supports was also a factor in the reduction of the packet size.

Right but it sends two messages, not one.   One with a 1-Byte payload and the other with an 18-Byte payload.  :-DD  If they had considered programming the BLE112 from the MCU, they could correct it. 

The little interface I put together for the 121 would not care how they slice up a packet.  It just stitches the messages together and parses them once it has enough data.   So if the ever did decide to change the code for the BLE112 in production to go to  a single message format, it has no effect.  I do wonder if this is where the higher checksum failure rates are coming from.   
Title: Re: EEVBlog 121GW Discussion thread
Post by: FrankBuss on October 16, 2018, 12:10:47 pm
I guess there are other problems. With the Blue Gecko chip I had no problems sending data from 7 m distance, through a wall, and no packets were lost. The packet rate just dropped, maybe because of resending. But this was all automatic in the Bluetooth layer. In my application layer it looked perfect. And the product page of the BLE112 says "Typical Range: 150 Meters" (https://www.silabs.com/products/wireless/bluetooth/bluetooth-low-energy-modules/ble112-bluetooth-smart-module) (middle of the page, search for "meters"). Of course, problably they measure this in a desert, far away from all other RF sources, and at night, with new moon :) but it should be still no problem in a normal setting for a dozen meters.

But the BLE112 is a very low power CPU, with only 8 kB RAM and a 8 bit CPU. The BGM11S I was using has a 32 bit ARM core, with 32 kB RAM. Maybe it doesn't buffer much and the protocol of the main CPU doesn't pay attention if sending data to it is allowed, like when it tries to resend data, or a RTS/CTS problem, if they are using a serial connection.

Or maybe it is a wrong GATT specification. For example if you really need 2 packets, you could specify a characteristic as "reliable write (https://stackoverflow.com/questions/24485536/what-is-reliable-write-in-ble)". But this is only available for message sending from the PC/phone to the meter. But for the other way for me a simple "Notify" characteristics worked. Looks like they are reliable, too (https://e2e.ti.com/support/wireless-connectivity/bluetooth/f/538/t/103327?Are-Characteristic-Value-Notification-Reliable-), which would explain the packet rate drop in my tests, but no loss of packets. So there shouldn't be a problem with the bluetooth transfer itself.
Title: Re: EEVBlog 121GW Discussion thread
Post by: FrankBuss on October 16, 2018, 12:21:58 pm
Found another page (note that "server" is the meter and "client" is the smartphone/PC, that's the silly BLE speak) :

https://community.nxp.com/docs/DOC-328525

This says the opposite of the TI page: A "notification" is not reliable, but an "indication" is reliable. So maybe changing the characteristics property from a notification to an indication would help (or vice versa)? Could someone post the GATT definition? If they are using the Simplicity Studio IDE, they will have a nice .isc file in XML format, but you could extract this from the device itself with "gatttool" and some work as well.
Title: Re: EEVBlog 121GW Discussion thread
Post by: GeoffreyF on October 19, 2018, 07:51:29 pm
Some 121GW come with Bryman probes and some with UEI Test Probes (silver not gold plated).  I got the UEI probes and they are just fine.

These UEI Test alligator clips (AAC3) screw to the UEI Test probes very well.  The Rubber sleeve fits over the probe and can slide down further to more fully expose the metal of the Alligator clip. The clip  is really strong and well made.

https://www.amazon.com/gp/product/B007HQZB18 (https://www.amazon.com/gp/product/B007HQZB18)

Actually the resistance through the probes, with the clips is a little less than holding the probe tips firmly together.  Also, when the clips are used to connect to the temperature probe, instead of plugging it in, there is no difference in the reading.   This indicates to me that there is no measurable loss compared to direct probe contact.

The clips are a bit large and so less suited to some applications than "grabber" type.

Title: Copy Fluke 87v power up options to 121GW?
Post by: GeoffreyF on October 21, 2018, 03:26:04 pm
This video explains power up options for the Fluke 87v.  It seems to me somethings like this would be easily implemented in the 121GW. 
https://www.youtube.com/watch?v=MyyySNcjfzA (https://www.youtube.com/watch?v=MyyySNcjfzA)
Title: Re: EEVBlog 121GW Discussion thread
Post by: FrankBuss on October 21, 2018, 04:24:15 pm
Useful options. But might be better if it is in some config menu. Otherwise it gets tricky, if you want multiple power-on functions.
Title: Re: EEVBlog 121GW Discussion thread
Post by: CDaniel on October 22, 2018, 10:35:06 am
Auto power off is inteligent in some meters , not just a timer . It resets itself if the reading is changing as you would measure something .
Anyway many other meters have at least some beeping sounds to warn you before the time is up .
Title: Re: EEVBlog 121GW Discussion thread
Post by: Seppy on October 29, 2018, 12:28:39 am
Sigrock support for the 121GW was added:

https://sigrok.org/blog/libsigrok-051-released
https://sigrok.org/wiki/EEVBlog_121GW

This was done by a user of the 121GW, pretty neat.
Title: Re: EEVBlog 121GW Discussion thread
Post by: 1anX on October 30, 2018, 10:28:30 pm
Seppy, any word on why firmware V1.51 has been removed from the 121GW firmware list for download?
Is there a problem with the version or is it just missing after a website update? Need to know if the missing version has caused a problem and what the effect on the meter might be.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Seppy on November 02, 2018, 06:07:16 am
We don't think so, but there was an issue with one person. I thought it prudent to pause the update, looks like its safe I'll release it again when we are sure.
Their post on the forum is:
https://www.eevblog.com/forum/testgear/121gw-calibration-killed-after-firmware-update (https://www.eevblog.com/forum/testgear/121gw-calibration-killed-after-firmware-update)!/

They did not have a backup of their calibration prior to updating and seem to have bricked their cal, this has been investigated and at this point it it seems that their unit might have a physical defect or the cal was accidentally overridden by the user.
Title: Re: EEVBlog 121GW Discussion thread
Post by: GeoffreyF on November 02, 2018, 01:13:53 pm
Seppy, I did not know of the need for backing up Calibration and installed 1.51.   I don't know if my Cal is bricked. How do I check?  What instructions did I miss about backing it up?

From your post, it sounds though like this one incident cannot be duplicated in house?
Title: Re: EEVBlog 121GW Discussion thread
Post by: sirtet on November 04, 2018, 11:23:41 pm
Android app:
I miss a feature to read/Export logs.
The gw 121 product page links to a UEi app, but the link is dead...
What is/was this app?
I did find a app named "UEi apps" , and in it, a  app "525DMM" is listed.
This latter app has a logs function and does connect to the 121 (shows error if bt is off on 121), but shows no measurements...
What is the Story here?

Gesendet von meinem H8324 mit Tapatalk

Title: Re: EEVBlog 121GW Discussion thread
Post by: sirtet on November 04, 2018, 11:33:43 pm
Temp sensor:
The 121 is rated up to 1350Deg. C. Or so. The sensor's insulation is obviously not, the Photo shows the effect of 1040deg. IT still seems to work, but I wonder What temp. Limit the fabric has, and What it is for anyways. The wires must be insulated different, but how.
And, What are the sensor's specs, in case i want to replace it?

Gesendet von meinem H8324 mit Tapatalk

Title: Re: EEVBlog 121GW Discussion thread
Post by: metta on November 14, 2018, 12:21:36 am
Hi Everyone,

I'm getting a little concerned with my order that I made back in September. I'm posting here as a last resort because the person I was in touch with, Suse, has not responded to any of my follow-up emails concerning the tracking of my order or a resolution. My 121GW was destined for Vancouver, Canada but the last tracking update was on September 16th when it passed through Germany: https://ecommerceportal.dhl.com/track/?ref=AUBCN001823543.

If you check the tracking yourself you'll see that it ghosted on me. Hopefully a little exposure in this thread will get some action or response.

Thanks for reading.
Title: Re: EEVBlog 121GW Discussion thread
Post by: GeoffreyF on November 14, 2018, 03:11:00 am
From the link that you  provided, your issue is with DHL, not with Suse or Jonestronics.   I am dumbfounded that you didn't contact the carrier back in September.
Title: Re: EEVBlog 121GW Discussion thread
Post by: metta on November 14, 2018, 09:50:25 pm
From the link that you  provided, your issue is with DHL, not with Suse or Jonestronics.   I am dumbfounded that you didn't contact the carrier back in September.

I followed up on this order on October 21st when I was told by Suse to email back in November if I hadn't received by then. I'm not the one arranging shipment so I don't think it's unreasonable to expect the folks over at Jonestronic to follow-up on their end. In my experience, when you purchase something online and it doesn't come through, usually the vendor is the one that has to follow up with the shipping company. Is this not your experience as well?

Edit: Just got off the phone with DHL, and just as I suspected, they tell me this is something that needs to be resolved from the merchant's side. I don't think your snark is warranted.
Title: Re: EEVBlog 121GW Discussion thread
Post by: GeoffreyF on November 14, 2018, 10:08:24 pm
If it were me, I would work it with the delivery company.   I think your strategy is really more the cause of your problem than anything.  As your link demonstrates, Jonestronics provided the shipment to DHL.   DHL then lost it.

If you had worked this with your local DHL office, the problem would be solved. At the least they could admit that they didn't have the package anymore. Then their insurance would compensate you.

Now through your stuborness, the trail has grown cold.  Did you even complain to DHL?  I don't fault with Jonestronic's here.  I find it with DHL and your failing to complain they didn't deliver.  Nothing you have written is even remotely  relevant to anything I care about.  You have no issue with the 121 GW because, obviously, you never got one.  So please don't clutter up this thread.   
Title: Re: EEVBlog 121GW Discussion thread
Post by: jack-daniels on November 14, 2018, 10:13:13 pm

I'm not the one arranging shipment so I don't think it's unreasonable to expect the folks over at Jonestronic to follow-up on their end. In my experience, when you purchase something online and it doesn't come through, usually the vendor is the one that has to follow up with the shipping company. Is this not your experience as well?


Definitely down to the seller to sort out.
Title: Re: EEVBlog 121GW Discussion thread
Post by: metta on November 14, 2018, 10:17:25 pm

I'm not the one arranging shipment so I don't think it's unreasonable to expect the folks over at Jonestronic to follow-up on their end. In my experience, when you purchase something online and it doesn't come through, usually the vendor is the one that has to follow up with the shipping company. Is this not your experience as well?


Definitely down to the seller to sort out.

 :-+ I'm happy to take it offline, but I have to try other means if I'm not getting any communication. I understand things get busy.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Simon on November 14, 2018, 10:32:17 pm
It is the person that made the contract with the shipper that has to deal with it. DHL are not renowned in a good way all over the world. I tend to use different carriers depending on destination country.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Brumby on November 15, 2018, 01:33:11 am
It is the person that made the contract with the shipper that has to deal with it.

This.

The merchant enters into a contract with the purchaser to supply the goods purchased.  The merchant then enters into a contract with the carrier to deliver it.

As I understand it, any assistance the carrier may provide to the purchaser is a courtesy.  Their obligation to deliver is with the merchant - and it is the merchant's obligation to the purchaser that delivery is made.
Title: Re: EEVBlog 121GW Discussion thread
Post by: metta on November 15, 2018, 02:12:42 am
Thanks for the confirmation everyone! I’ve opened up a PayPal case as a last resort - hopefully it’s a little more visible.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Terry01 on November 15, 2018, 01:58:10 pm
I just ordered 1 today! Yikes!!  :o
Title: Re: EEVBlog 121GW Discussion thread
Post by: Simon on November 15, 2018, 02:24:36 pm
I just ordered 1 today! Yikes!!  :o

Currently out of stock. I will have them in the UK as well when things get moving.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Terry01 on November 20, 2018, 06:06:41 pm
I got mine delivered today. Ordered from Welectron and shipped the whole way by DHL. Pretty poor packing to be honest. The meter is fine and no bashes on the box so I take it it was handled well by the carriers, if it had taken a bump "en route" I doubt very much it would have survived. The fact it arrived unscathed was more down to luck than it being well packed.

Hey Ho!   ???
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on November 22, 2018, 05:00:31 am
I have a few available on ebay for those in Oz:
https://www.ebay.com.au/itm/223244201244 (https://www.ebay.com.au/itm/223244201244)
My web shopping cat is currently rooted, being in investigated.

Big shipment of meters finally due next week.
Title: Re: EEVBlog 121GW Discussion thread
Post by: kahuna0k on November 22, 2018, 08:38:48 am
I have a few available on ebay for those in Oz:
https://www.ebay.com.au/itm/223244201244 (https://www.ebay.com.au/itm/223244201244)
My web shopping cat is currently rooted, being in investigated.

Big shipment of meters finally due next week.

It seems that there were 10 in stock in the web but when trying to add them I get -3 available, unable to fulfill. About the ebay option, I understand that you will only ship to Australia right?
Title: Re: EEVBlog 121GW Discussion thread
Post by: Simon on November 22, 2018, 08:43:44 am
ebay is a pain in the ass which is why I packed it in. I have actually just bought the shiiping plugin for woocommerce so that I can do flexible shipping in my shop based on weight so that i can sell some small parts without having to charge one shiping rate no matter what.

Last time I had a problem buying on ebay I found it impossible to contact ebay when the seller would not play ball. so I avoid ebay for buying as well now.
Title: Re: EEVBlog 121GW Discussion thread
Post by: kahuna0k on November 22, 2018, 08:51:21 am
ebay is a pain in the ass which is why I packed it in. I have actually just bought the shiiping plugin for woocommerce so that I can do flexible shipping in my shop based on weight so that i can sell some small parts without having to charge one shiping rate no matter what.

Last time I had a problem buying on ebay I found it impossible to contact ebay when the seller would not play ball. so I avoid ebay for buying as well now.

I was referring to the ebay item sold by eevblogstore himself (https://www.ebay.com.au/itm/223244201244 (https://www.ebay.com.au/itm/223244201244)) that I suppose I should trust as much as I trust the cart in this webpage (or more given what he said :)
Title: Re: EEVBlog 121GW Discussion thread
Post by: Simon on November 22, 2018, 08:57:32 am
I meant Dave is probably only doing AUS shipping due to the pain in the ass it becomes on ebay to ship all over the place and deal with any fallout. Not to mention the 14% charge between ebay and paypal.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Terry01 on November 22, 2018, 10:22:51 am
Why don't you get one from Welectron?

https://www.welectron.com/ (https://www.welectron.com/)

That's where I got mine. Sipped in just under 5 days from Germany to the UK.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Simon on November 22, 2018, 10:29:26 am
Why don't you get one from Welectron?

https://www.welectron.com/ (https://www.welectron.com/)

That's where I got mine. Sipped in just under 5 days from Germany to the UK.

Soon I will hopefully have quite a few directly from Dave to resell. I also have one of the first batches for me personally already. I was simply musing on the feseabilities of selling on ebay. I considered selling Daves products on ebay but decided that given the following Dave has and i am his UK distributor why bother. I would have to add at least 10% to the price and in fact due to the hassle factor of doing business on ebay I would put way more than 10% on. As i have just discovered ebay is shit for buyers as well as sellers so avoid it entirely unless i am prepared to loose my money as a buyer like i have done once already.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on November 22, 2018, 11:51:42 am
Soon I will hopefully have quite a few directly from Dave to resell. I also have one of the first batches for me personally already. I was simply musing on the feseabilities of selling on ebay. I considered selling Daves products on ebay but decided that given the following Dave has and i am his UK distributor why bother. I would have to add at least 10% to the price and in fact due to the hassle factor of doing business on ebay I would put way more than 10% on. As i have just discovered ebay is shit for buyers as well as sellers so avoid it entirely unless i am prepared to loose my money as a buyer like i have done once already.

I do an ok amount of business on ebay, and the fees are of course much higher. But like Amazon it's about the extra reach you get with Joe Average. Not great for niche products like this, but it at least helps get some extra sales.
Ebay is tied into my StarShipIt system like my Woocommerce store, so it just pulls in orders from both places. So in theory I never have to actually touch ebay to handle the orders.

Title: Re: EEVBlog 121GW Discussion thread
Post by: Simon on November 22, 2018, 12:03:36 pm
Yes, I did early on put µCurrents on with a +£20 markup and a couple sold. My main concern is trying to keep stuff all in one place with money to make accounts simpler which I suppose happens with ebay anyway and as a sole trader i probably don't need such stringent paperwork just a paypal log and they can pick the bones out of that. If people will pay +10% + a hassle fee (buyer is not always right but buyers don't know that yet) I suppose it is worth it. µCurrents sell so well I stopped bothering with ebay as it would just be ripping people off. I don't do enough to pay for a third party tool that brings stock together, maybe it's worth a look but really people need to get that ebay is not automatically safe and painless to buy from.
Title: Re: EEVBlog 121GW Discussion thread
Post by: kahuna0k on November 22, 2018, 05:47:29 pm
Why don't you get one from Welectron?

https://www.welectron.com/ (https://www.welectron.com/)

That's where I got mine. Sipped in just under 5 days from Germany to the UK.

I'm in the US, finding a US retailer would be best, if not probably ebay is going to be cheaper. In the worst case I prefer to buy directly from the eevblog store.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Simon on November 22, 2018, 05:51:05 pm
why is ebay cheaper? you will pay at least as much if not more. If I did ebay for example i would spend more time per sale with ebay sales versus my own store.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Terry01 on November 22, 2018, 08:33:39 pm
Why don't you get one from Welectron?

https://www.welectron.com/ (https://www.welectron.com/)

That's where I got mine. Sipped in just under 5 days from Germany to the UK.

I'm in the US, finding a US retailer would be best, if not probably ebay is going to be cheaper. In the worst case I prefer to buy directly from the eevblog store.

It's free shipping with Welectron and 5 days is really not a long time to wait. I'd rather by from a proper store that Ebay any day!
Title: Re: EEVBlog 121GW Discussion thread
Post by: Simon on November 22, 2018, 08:38:53 pm
Well you never know who is behind the store (and thank you for your order :)) but ebay separates you from the seller so if they don't help you are screwed and paypal do not want to know either so actually you are paying more for nothing.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Terry01 on November 22, 2018, 09:08:37 pm
I was checking your shop periodically for the Probe Masters for a while but last I looked they were "out of stock", that was a while ago though.
I got a set with my 121GW just a couple days ago and liked them so I'll get a another set for now for when I need 2 meters but may end up getting more. They're great wee leads!
Also, i'll keep checking in for the Probe Master leads racks to be back in stock but if you remember when you get more in would you let me know and i'll take a couple of those too please?
Title: Re: EEVBlog 121GW Discussion thread
Post by: Simon on November 22, 2018, 09:15:37 pm
Well it may be time i got more stuff from probemaster the first time i just got the sprung probes, this last time i spread out a lot more and found that the other probes are even more popular and wish I had bought more lead racks, i have the portable probe holders .
Title: Re: EEVBlog 121GW Discussion thread
Post by: Terry01 on November 22, 2018, 10:50:17 pm
I know this is not the thread for discussing this so will delete these messages ASAP so as not to clog the thread up.

It's more a couple of the racks I was after as I have quite a few sets of croc clip leads and 4mm banana leads along with quite a few sets of normal leads to hang up. Can you remember of hand roughly how long the lead racks are? A guess of 6" or 12" or 18" will be close enough if you can remember? 
I intend to screw a couple of them to one edge of my desk.
Title: Re: EEVBlog 121GW Discussion thread
Post by: ELzekio on November 28, 2018, 04:30:39 am
Just as a heads up it looks like the 121 gw is back in stock in the store.

https://www.eevblog.com/product/121gw/ (https://www.eevblog.com/product/121gw/)

I believe Dave posted somewhere of getting a boat load of units so the 121 gw should be in stock for a while.
Title: Re: EEVBlog 121GW Discussion thread
Post by: 1anX on November 28, 2018, 08:51:17 am
Just as a heads up it looks like the 121 gw is back in stock in the store.

https://www.eevblog.com/product/121gw/ (https://www.eevblog.com/product/121gw/)

I believe Dave posted somewhere of getting a boat load of units so the 121 gw should be in stock for a while.

I wonder if the new batch of meters has the correct thickness PCB and no longer needs a shim under the switch to correct the switch wiper pressure?

It would be good to see some close ups of the PCB to see if any components have been updated or replaced. Anyone getting a new meter please supply some photos if at all possible!
Title: Re: EEVBlog 121GW Discussion thread
Post by: lowimpedance on November 28, 2018, 10:45:21 pm
The correct fix would be to adjust the thickness of the switch rotor (the bit that holds the contacts  :D), to add the required amount to take up the slack between the top case and the PCB mounted rotor,
The PCB is a fixed size (within usual tolerance limits.).
Title: Re: EEVBlog 121GW Discussion thread
Post by: 1anX on November 28, 2018, 11:09:13 pm
The correct fix would be to adjust the thickness of the switch rotor (the bit that holds the contacts  :D), to add the required amount to take up the slack between the top case and the PCB mounted rotor,
The PCB is a fixed size (within usual tolerance limits.).

The problem was that the kickstarter meters were manufactured with an out of spec PCB, (too thin) as has been documented by Dave.
It dosen't really matter which course of action is taken, just so long as a shim is no longer required to make the meter work reliably!
Title: Re: EEVBlog 121GW Discussion thread
Post by: lowimpedance on November 29, 2018, 12:15:08 am
My 121GW PCB is 1.45mm and the supplied shim is 0.94mm , so with a 1.6mm standard PCB it still needs 0.79mm more to take it to the same mechanical spec as my kickstarter meter. So more than just changing PCB thickness, which BTW also would affect the input terminals depth behind the top cover as well.
 But still maybe the shim is still the best economical/engineering solution without costly injection mould redo's.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Brumby on November 29, 2018, 12:40:07 am
Why is the shim a bad idea?  Just because it wasn't in the original design doesn't mean it should be exiled.

But still maybe the shim is still the best economical/engineering solution without costly injection mould redo's.
This.

If the shim provides and acceptable engineering result at a more economical cost than other alternatives, then it's a simple decision.

Such a solution also has a benefit: It allows manufacturing flexibility.  Two thicknesses of PCB can be used with the shim included or not, as the case may be.  I know this is a rather unlikely scenario, but it also avoids the alternate need for two different selector knobs.


This is, really, no different to "engineering changes" made to other products.  Something which happens all the time.
Title: Re: EEVBlog 121GW Discussion thread
Post by: 1anX on November 29, 2018, 12:57:06 am
It has been found that the switch contact issues were ultimately caused by a slight PCB thickness difference between the pre-production and production boards.
Pre-production boards were on the high side of the tolerance allowance, and production boards on the low side. Actually, the production board thickness was actually slightly outside of UEi's board spec.
A 0.95mm shim (as has been found by others) is the fix for existing units and current stock boards (i.e. all Kickstarter ones and for sometime afterwards). Future volume production boards shouldn't need a shim however.
Shims are on the way to me now for cycle testing.
Does "the low side" mean that the board is too thin? Is the 0.95mm shim meant to be attached to the circuit board? Just confused a bit.

Yes, on the thin side.
The shim goes between the plastic range switch and the case, as per how others have done their own DIY solution.
For those that want to do it themselves, the shim thickness is 0.95mm.

I was referring to this post for my info!

Dave states "future volume production boards" when placed in meters wont need the shim.
Title: Re: EEVBlog 121GW Discussion thread
Post by: lowimpedance on November 29, 2018, 01:10:18 am
Good luck with that , guess time will tell.
Title: Re: EEVBlog 121GW Discussion thread
Post by: 1anX on November 29, 2018, 04:55:17 am
The question is are the new batch of meters any better than the kickstarter meter?
Is the new meter still using the spacer?
Has the new meter any new components and specification?
Does the new meter still have the existing firmware bugs?

Dave is there any difference with the new over the old?
Title: Re: EEVBlog 121GW Discussion thread
Post by: npelov on November 30, 2018, 04:35:40 pm
Hi,

First a suggestion - it would be nice to have a change log in txt format in the firmware zip. The last firmware version is not present in the change log in the manual, because (probably) the manual is still being updated. Having a copy of the change log with the binary file let's you know what's fixed and what to test after updating.


And another thing - the 50MOhm range is currently slow. If it needs to be slow for stability I'm ok with that, but it should be "manual only" range, because it's slowing down all resistance measurements. You don't measure resistance 5-50 MOhms that often - it's ok if it's not included in auto ranging. Or at least have a setup option if it should be included in auto-ranging.

Also the 50 ohm range is redundant. It does not give you any more information than 500 Ohm. When shorting the probes  (even the gold coated ones) the last digit cannot show the same result twice (not even close) for measurements few minutes apart, without temperature changes. The short term measurements show difference more than 10mOhms, which makes the last digit useless (and distracting). I think 500 ohm is pretty good compared to other DMMs, although as many other ranges you have to wait few seconds for the last digit to settle. My request is if possible to turn 50 Ohm range off in SETUP.

I'm happy with the DMM - it has few interesting features that are not present on most. Of course you pay the price of low burden voltage - zero offset is drifting all over the pace on most of the ranges. It must be calibrated pretty often. It could be the case with full scale error, but I haven't tested it yet over time. The other annoying thing is that it takes quite a few seconds for the last digit to settle. I haven't tested this since fw 1.26 - ohms still settles slow. On most of the other DMMs I have the digits stop moving withing 1 second, even the cheap Chinese ones ($40). I think there is something wrong with the filtering on some ranges.
Title: Re: EEVBlog 121GW Discussion thread
Post by: CDaniel on November 30, 2018, 09:34:52 pm
This issues are known for a long time if you read the posts .
Autorange is slow .
50ohm range may be redundant because they did it wrong . The protection thermistor PTC3 little drift with temperature is responsible for getting different results all the time . Maybe there is some self heating from the measurement current itself , not just the internal temperature variation .  2 wire low ohm measurement is not that simple to do it right .

Later edit

I played a little with the board out and ... it's not the thermistor heating up ... The problem is that the measurement current is low ( maybe too low )  and it's using the lowest range possible with 10 times internal amplification ( in HY3131 configuration is like that ) . Every solder joint is a thermocouple at this  low level . That's why it drifts all the time and can't be stable .

With  the thermistors shunted , any solder joint I heat up ( in input zone ) results in massive 1000 counts drift . Thats 1 ohm . In other ranges the drift is lower , as expected . What's impossible to say at this point is if they use HY3131 correctly in 50ohm range as in configuration pdf document .

Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on December 03, 2018, 01:11:41 am
The question is are the new batch of meters any better than the kickstarter meter?
Is the new meter still using the spacer?
Has the new meter any new components and specification?
Does the new meter still have the existing firmware bugs?
Dave is there any difference with the new over the old?

The latest meters shipping have two hardware changes. A copper shield, and a two transistor daughter board to replace the TVS.
They still use the spacer shims until existing blank PCB stock is used up.
Firmware is the current release 1.57
Specs have not changed.
Title: Re: EEVBlog 121GW Discussion thread
Post by: IanB on December 03, 2018, 01:18:17 am
The latest meters shipping have two hardware changes. A copper shield, and a two transistor daughter board to replace the TVS.

Can we see pictures, especially of the shield?

These seem like things that might be relevant retro-fits.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on December 03, 2018, 01:33:46 am
The latest meters shipping have two hardware changes. A copper shield, and a two transistor daughter board to replace the TVS.
Can we see pictures, especially of the shield?
These seem like things that might be relevant retro-fits.

Attached.
The shield is a multi-layer plastic sandwich construction. You could DIY, but watch for shorts and clearances etc. Connected to the negative battery clip on the other side.
Again, this will only be for existing stock of blank PCBs.

I don't believe the DIY transistor mod is recommended because it likely requires recalibration.
Title: Re: EEVBlog 121GW Discussion thread
Post by: joeqsmith on December 03, 2018, 02:05:59 am
Sure, there's some new shield and clamping...   but what's this I see!!!???? 

Is that a TI CD4053B with an absolute maximum Vsupply of 20V??  The same part I have said several times that I went to in an attempt to get the meter to survive some basic transients???!!!!   Looks like someone is trying to spoil my fun.    If they get the clamping right, this meter should do just fine. 

Looking forward to seeing the meter finished up.   :-+
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on December 03, 2018, 02:55:33 am
Is that a TI CD4053B with an absolute maximum Vsupply of 20V??

Yes, sorry, forgot about that change.
Title: Re: EEVBlog 121GW Discussion thread
Post by: 1anX on December 03, 2018, 03:30:37 am
Sure, there's some new shield and clamping...   but what's this I see!!!???? 

Is that a TI CD4053B with an absolute maximum Vsupply of 20V??  The same part I have said several times that I went to in an attempt to get the meter to survive some basic transients???!!!!   Looks like someone is trying to spoil my fun.    If they get the clamping right, this meter should do just fine. 

Looking forward to seeing the meter finished up.   :-+

Joe, does changing to this spec chip alter calibration?
What "basic transients" or voltage levels did you apply during your testing which destroyed the 4053?
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on December 03, 2018, 03:57:05 am
Sure, there's some new shield and clamping...   but what's this I see!!!???? 

Is that a TI CD4053B with an absolute maximum Vsupply of 20V??  The same part I have said several times that I went to in an attempt to get the meter to survive some basic transients???!!!!   Looks like someone is trying to spoil my fun.    If they get the clamping right, this meter should do just fine. 

Looking forward to seeing the meter finished up.   :-+
Joe, does changing to this spec chip alter calibration?

No, it doesn't. It's a DIY mod if you are really that keen, I personally would not bother.

Quote
What "basic transients" or voltage levels did you apply during your testing which destroyed the 4053?

I can't speak for Joe's tests, but FYI the previous chip passed all UL CAT III standard tests just fine.
Title: Re: EEVBlog 121GW Discussion thread
Post by: 1anX on December 03, 2018, 04:23:13 am
Thanks for the info Dave!

I have bought the BM235 and the 121GW from you and have given the BM235 to my son for his automotive work. I'm looking to buy another 121GW type spec meter and have been considering the Brymen 869. How long before the next gen 121GW becomes available with the new PCB and updates?

I'm quite happy to hardware mod my current 121GW and would love to see a video on EEVBlog on the modding and re-calibrating this meter. I'm sure plenty of others with the kickstarter meter would also like to mod and update this meter with a instructional video from you!

Still need to buy another meter, but making the current kickstarter meter a project would be fun and educational.
Title: Re: EEVBlog 121GW Discussion thread
Post by: joeqsmith on December 03, 2018, 04:37:39 am
Changing to the CD4053B in of itself would do nothing to improve the meters robustness.   We are talking about a couple of volts vs thousands of volts we are applying.    The problem is coming up with a clamp that is not set so low that it interferes with the high voltage supply used for the diode check.  Yet it can't be so high that it allows us to exceed the absolute Vs rating of the mux.   You have a 15-16V supply and an IC rated for 18V (I think) absolute max.   Increasing this margin a couple of volts eased the effort of sorting out the clamp.   

I am hoping that what led them to use the TI part was to try to improve the meter's robustness.  I won't know how it behaves until I run one. 

The video for the prototype is still on-line.  It was first damaged with a 2KV peak, 100us FWHH with a 2ohm source.   There were a lot of low cost meters that were damaged at these low levels.    For those wanting to point out the 87V as a gold standard, make sure you check all the facts first.   Again, the data is here:

https://docs.google.com/spreadsheets/d/1cXzYpIoyVm9QJUju4KXqM22CEQZP3_xwWvDyeVwxTy4/edit#gid=400910915

Video of the 121 proto can be found here:
https://youtu.be/X28bwdTBW8g?list=PLZSS2ajxhiQDBDdtQNjVnGxShaVQ3nUMY&t=1444
Title: Re: EEVBlog 121GW Discussion thread
Post by: ChunkyPastaSauce on December 03, 2018, 04:47:44 am
The latest meters shipping have two hardware changes. A copper shield, and a two transistor daughter board to replace the TVS.
Can we see pictures, especially of the shield?
These seem like things that might be relevant retro-fits.

Attached.
The shield is a multi-layer plastic sandwich construction. You could DIY, but watch for shorts and clearances etc. Connected to the negative battery clip on the other side.
Again, this will only be for existing stock of blank PCBs.

The shield - a fix for the jumping values when interacting with the membrane buttons?
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on December 03, 2018, 05:39:02 am
How long before the next gen 121GW becomes available with the new PCB and updates?

Well past this batch of 700, they have a lot of blank boards yet. Can't give a timeline.

Quote
I'm quite happy to hardware mod my current 121GW and would love to see a video on EEVBlog on the modding and re-calibrating this meter.

Most people do not have the capability to calibrate the meter, it requires precise generated values from a proper meter calibrator.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on December 03, 2018, 05:40:12 am
The shield - a fix for the jumping values when interacting with the membrane buttons?

Correct.
Title: Re: EEVBlog 121GW Discussion thread
Post by: GeoffreyF on December 03, 2018, 12:58:39 pm
Is there a suggested process to make (or purchase from EEVBlog) a shield in earlier models?
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on December 03, 2018, 02:24:29 pm
Is there a suggested process to make (or purchase from EEVBlog) a shield in earlier models?

I could ask Kane to send me a whole bunch I guess for those that want them.
Title: Re: EEVBlog 121GW Discussion thread
Post by: 1anX on December 03, 2018, 09:29:10 pm
Is there a suggested process to make (or purchase from EEVBlog) a shield in earlier models?

I could ask Kane to send me a whole bunch I guess for those that want them.

Dave, start a list of those wanting the button shield and add me to it!
I would appreciate the added stability it would bring to the meter.
Title: Re: EEVBlog 121GW Discussion thread
Post by: darik on December 03, 2018, 09:37:14 pm
Is there a suggested process to make (or purchase from EEVBlog) a shield in earlier models?

I could ask Kane to send me a whole bunch I guess for those that want them.

Dave, start a list of those wanting the button shield and add me to it!
I would appreciate the added stability it would bring to the meter.

I'm interested.
Title: Re: EEVBlog 121GW Discussion thread
Post by: TikhonovC on December 04, 2018, 04:23:53 pm
Is there a suggested process to make (or purchase from EEVBlog) a shield in earlier models?

I could ask Kane to send me a whole bunch I guess for those that want them.


And a two transistor daughter board to replace the TVS.
Title: Re: EEVBlog 121GW Discussion thread
Post by: lowimpedance on December 04, 2018, 10:47:52 pm
Is there a suggested process to make (or purchase from EEVBlog) a shield in earlier models?

I could ask Kane to send me a whole bunch I guess for those that want them.


And a two transistor daughter board to replace the TVS.
As Dave stated above this would mean a re-calibration which uses equipment that most users would not have ready access to, so is best to leave as is. Of course having the PCB available to those that do have the required gear would be nice too  ;).
Title: Re: EEVBlog 121GW Discussion thread
Post by: TikhonovC on December 05, 2018, 07:25:50 am
I think that the cost of this board is 2-5 USD.
The cost of the shield is 5-10 USD.
Shipping costs will be at least 10-15 USD.
This PCB can be added to the package. For future calibration. Anyway it can be useful.
Title: Re: EEVBlog 121GW Discussion thread
Post by: CDaniel on December 05, 2018, 07:32:31 am
That's the output protection for resistence / capacitance ranges , so it's not that difficult to recalibrate . Only high resistance ranges and maybe low capacitance range will be affected anyway .
Title: Re: EEVBlog 121GW Discussion thread
Post by: Brumby on December 05, 2018, 07:35:33 am
The comment was not on how easy/difficult recalibration might be - but about the equipment required to do so properly.
Title: Re: EEVBlog 121GW Discussion thread
Post by: CDaniel on December 05, 2018, 07:40:38 am
equipment = some high precision resistors and maybe capacitors
Title: Re: EEVBlog 121GW Discussion thread
Post by: Brumby on December 05, 2018, 07:44:12 am
What?  No high precision voltage standards?

Therein lies the question: what equipment and standards are required?  Do you know?
Title: Re: EEVBlog 121GW Discussion thread
Post by: CDaniel on December 05, 2018, 07:54:42 am
Anybody familiar with the schematic will see from the picture that the replacement 2 transistor board is for output protection in resistace/capacitance mode ... D7-D8 1N4007 . Output = the current source or charge / discharge circuit used for measuring resistors or caps .
Title: Re: EEVBlog 121GW Discussion thread
Post by: 1anX on December 05, 2018, 07:26:52 pm
How long before the next gen 121GW becomes available with the new PCB and updates?

Well past this batch of 700, they have a lot of blank boards yet. Can't give a timeline.

Quote
I'm quite happy to hardware mod my current 121GW and would love to see a video on EEVBlog on the modding and re-calibrating this meter.

Most people do not have the capability to calibrate the meter, it requires precise generated values from a proper meter calibrator.
Its a pity that UEI and EEVBlog didn't bite the bullet and scrap the 700 out of spec PCBs that require shims for the switch to work properly. The hardware upgrades could have been incorporated on the new PCB giving the meter the stability and speed it requires to lift itself from being just another kickstarter prototype.

I needed another similar spec meter and would have waited for the upgraded 121GW to appear if it featured the necessary upgraded hardware. As you could not provide a time frame or even list the fixes that would appear in the next production model I have purchased another meter.

I purchased the similar priced Brymen BM867s, ($300) as I know what the performance and accuracy are and how reliable this meter has shown to be under many different tests. This is a professional and proven design that features fast update rates and stable display readings. IMO this older Brymen meter's performance is what the 121GW needs to match and better if it is to stand the test of time and continue to sell.
Title: Re: EEVBlog 121GW Discussion thread
Post by: CDaniel on December 05, 2018, 09:37:13 pm
The big issues are firmware related , the shim is working fine for the majority ( I don't want to say that they shouldn't do it right ). And that little shield for buttons + modified protection in resistance mode won't change much .
Title: Re: EEVBlog 121GW Discussion thread
Post by: ChrisG on December 06, 2018, 06:13:26 am
The big issues are firmware related , the shim is working fine for the majority ( I don't want to say that they shouldn't do it right ). And that little shield for buttons + modified protection in resistance mode won't change much .

Funny.  I don't see the firmware being big issues.  Certainly there are more firmware problems reported than hardware and they may be more visible to the average joe but I see getting a stable hardware platform as being a larger problem.   

Seeing them change from the single dimple contact to double and now back to single.  Looking at photos of the wear, I'm not convinced the meter will hold up.  Dave did run a life test on some version of it but it seems odd they are changing the design if all is well.     The same is true for the transient protection.  If Dave is going to make a statement that the meter passed cert and that's the end of the story,  then there should be no reason to change the front end.   It's good to hear they continue to develop the hardware.  I'm looking forward to seeing what they come up with.

I still believe both need to be taken care off but the biggest concern I now start to have is transparency on why the changes are happening single to double and back etc. For me there was never a good  response on why my meter had so much crud on the contacts after less then 100 power cycles. It took also quite some time to acknowledge the mechanical issue with the selector knob. All and all I am personally okay to support such an initiative, spend the money accept the risk of a possible lemon or brick but then I see room for improvement on the development process going forward. I do want to acknowledge here too that we can on this forum give plenty of updates, issue reporting or even rant on whatever we think should have been done and that in itself is worth something already.
Title: Re: EEVBlog 121GW Discussion thread
Post by: ChrisG on December 06, 2018, 06:54:31 am
How long before the next gen 121GW becomes available with the new PCB and updates?

Well past this batch of 700, they have a lot of blank boards yet. Can't give a timeline.

Quote
I'm quite happy to hardware mod my current 121GW and would love to see a video on EEVBlog on the modding and re-calibrating this meter.

Most people do not have the capability to calibrate the meter, it requires precise generated values from a proper meter calibrator.
Its a pity that UEI and EEVBlog didn't bite the bullet and scrap the 700 out of spec PCBs that require shims for the switch to work properly. The hardware upgrades could have been incorporated on the new PCB giving the meter the stability and speed it requires to lift itself from being just another kickstarter prototype.

I needed another similar spec meter and would have waited for the upgraded 121GW to appear if it featured the necessary upgraded hardware. As you could not provide a time frame or even list the fixes that would appear in the next production model I have purchased another meter.

I purchased the similar priced Brymen BM867s, ($300) as I know what the performance and accuracy are and how reliable this meter has shown to be under many different tests. This is a professional and proven design that features fast update rates and stable display readings. IMO this older Brymen meter's performance is what the 121GW needs to match and better if it is to stand the test of time and continue to sell.

Could not agree more with that. Though we were all very anxious to get our hands on the item. I remember I was really looking forward to it.  :) I have a BM869s and BM235 too and when I open these up I see no wear, no crud no nothing after years of usage.
Title: Re: EEVBlog 121GW Discussion thread
Post by: CDaniel on December 06, 2018, 08:47:40 am
The big issues are firmware related , the shim is working fine for the majority ( I don't want to say that they shouldn't do it right ). And that little shield for buttons + modified protection in resistance mode won't change much .

Funny.  I don't see the firmware being big issues.  Certainly there are more firmware problems reported than hardware and they may be more visible to the average joe but I see getting a stable hardware platform as being a larger problem.   

Seeing them change from the single dimple contact to double and now back to single.  Looking at photos of the wear, I'm not convinced the meter will hold up.  Dave did run a life test on some version of it but it seems odd they are changing the design if all is well.     The same is true for the transient protection.  If Dave is going to make a statement that the meter passed cert and that's the end of the story,  then there should be no reason to change the front end.   It's good to hear they continue to develop the hardware.  I'm looking forward to seeing what they come up with.

Ok , you are very interested in testing the switch , and surviving XXX KV transients , that's your job or hobby ( or both ) , and it's fine , but what hardware issues that we know are important for an average customer that will buy this meter ?

The shim is working fine , the 2 diodes 1N4007 are leaky and temperature dependent but affect mostly 50Mohm range .
I made a shield for membrane buttons as in David's picture , so far it is still sensitive to touching that zone , I will test more .

Firmware bugs are numerous , from slow autorange , missing features , etc , maybe someone should compile a list .
To make a good and efficient firmware , not just working , needs money ( a team , not one or two people working in spare time  :-\ ) , skill and will .

Title: Re: EEVBlog 121GW Discussion thread
Post by: Terry01 on December 06, 2018, 09:13:17 am
I got side tracked yesterday so didn't get to test the "hysteresis" but I will do it today for sure and post the results.
Title: Re: EEVBlog 121GW Discussion thread
Post by: joeqsmith on December 06, 2018, 11:57:10 am
The big issues are firmware related , the shim is working fine for the majority ( I don't want to say that they shouldn't do it right ). And that little shield for buttons + modified protection in resistance mode won't change much .

Funny.  I don't see the firmware being big issues.  Certainly there are more firmware problems reported than hardware and they may be more visible to the average joe but I see getting a stable hardware platform as being a larger problem.   

Seeing them change from the single dimple contact to double and now back to single.  Looking at photos of the wear, I'm not convinced the meter will hold up.  Dave did run a life test on some version of it but it seems odd they are changing the design if all is well.     The same is true for the transient protection.  If Dave is going to make a statement that the meter passed cert and that's the end of the story,  then there should be no reason to change the front end.   It's good to hear they continue to develop the hardware.  I'm looking forward to seeing what they come up with.

I still believe both need to be taken care off but the biggest concern I now start to have is transparency on why the changes are happening single to double and back etc. For me there was never a good  response on why my meter had so much crud on the contacts after less then 100 power cycles. It took also quite some time to acknowledge the mechanical issue with the selector knob. All and all I am personally okay to support such an initiative, spend the money accept the risk of a possible lemon or brick but then I see room for improvement on the development process going forward. I do want to acknowledge here too that we can on this forum give plenty of updates, issue reporting or even rant on whatever we think should have been done and that in itself is worth something already.

I don't see larger companies ever becoming transparent about their designs.  It's just not a realistic goal.  At best you may get some level of independent testing like Dave showed with his toggle bot.  Maybe you will get some high level historical overview of the design after the fact but I doubt it.   

Personally, I too would have scrapped the boards and pushed on.  Just knowing that a new version is in the works may impede sales of the older model.   

Even on these forums we have read about large companies having to do recalls on their hardware.  Keysight's susceptibility problems for example.  The switch design requiring a shim was a much more telling indicator about UEI's validation process.   Brymen for example has not only told me about how they cycle test their switch designs, they have shown me video clips of their cycle jigs.  If that wasn't good enough, they sent me a meter to repeat my own cycle test on and it held up quite well.   I don't see UEI testing at this level or having the same confidence in their own products. 
Title: Re: EEVBlog 121GW Discussion thread
Post by: Terry01 on December 06, 2018, 12:51:07 pm
If i'd have known there was a newer updated model due out I would have waited rather than buy one a week or two ago!  :(

But there ya go… I suppose!
Title: Re: EEVBlog 121GW Discussion thread
Post by: GeoffreyF on December 06, 2018, 01:15:59 pm
If i'd have known there was a newer updated model due out I would have waited rather than buy one a week or two ago!  :(

But there ya go… I suppose!

It is not a new model.  If you read the fine print in just about any specs including these, it is clearly stated that they may make improvements and tweaks which are within the original specs but somehow improve performance or contain costs.  What you complain of is routine across most products.   Really, go and check.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Brumby on December 06, 2018, 01:26:03 pm
What you complain of is routine across most products.   Really, go and check.

This is very true.

Normally people do not see this stuff happening in real time like we are with Dave's 121GW.  We see it when we ask for spare parts for an appliance or a vehicle and they ask for some very specific identifiers for subtle differences that identify exactly which version of a part is appropriate.... and we don't think twice about this.

As long as you get a product that operates within specification, you don't really have a leg to stand on.  As for any product newly released, there is usually a price for being a first adopter - which usually involves ironing out some kinks.  The switch shim being a perfect example.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Terry01 on December 06, 2018, 05:12:17 pm
I only said if i'd known there was a newer model(version) due out I would have waited.

I tried to measure 89 mA in the mA range last night and the 121GW kept saying "OFL" or whatever it was, my U1273a read it no problems at all.
To be honest i'm not really bothered I will stick it on Ebay and get some of my money back as I have other more reliable meters.

I kinda liked the look and some of the features of the meter but the more I use it the more I find things I don't like about it.

If I had wanted to complain I would have messaged where I bought it but i'm really not that bothered.

A 87v I took a punt on came up so that has nailed the 121GW's coffin shut tight.

It'll be on Ebay soon!  :)
Title: Re: EEVBlog 121GW Discussion thread
Post by: GeoffreyF on December 07, 2018, 01:43:48 am
Right and there isn't a newer version or model.

The same model has received a small improvement.  This happens all the time in all sorts of electronics.  IT IS NOT A NEWER VERSION OR MODEL.   Also, this incremental improvement does not change the published specs.  From the description, it provides the meter with some stray RF noise immunity. This is a good thing but probably makes no difference for many users.   Anyone who works in a development environment can tell you that a particular make/model is always getting tweaked in subsequent manufacturing runs.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Terry01 on December 07, 2018, 08:13:15 am
Right and there isn't a newer version or model.

The same model has received a small improvement.  This happens all the time in all sorts of electronics.  IT IS NOT A NEWER VERSION OR MODEL.   Also, this incremental improvement does not change the published specs.  From the description, it provides the meter with some stray RF noise immunity. This is a good thing but probably makes no difference for many users.   Anyone who works in a development environment can tell you that a particular make/model is always getting tweaked in subsequent manufacturing runs.

Ok, so I would have waited for "the same mode that has received a small improvement" then.

I also saw the "same model has received a small improvement" has a new daughter board and a couple of other updates on it after the 700 boards they have from this run are finished.

That's what I would have waited on. If your spending near £300 you want the best for your money.... unless you are dumb!

Spend today untwisting your knickers man!

Will be interesting to see if the new boards will have a different "V" number.....
Title: Re: EEVBlog 121GW Discussion thread
Post by: GeoffreyF on December 07, 2018, 01:24:43 pm
If you thought about what I wrote (you didn't), you would wait forever.  Not just for test equipment but for cars, microwave ovens, tv sets etc.  EVERYTHING gets tweaked from time to time.   Unless you plan on using your 121GW around intense RF fields, this improvement means nothing.

The 121GW you bought meet specs.  The later ones meet specs. You paid for something that meets specifications.   The addition of the shield is probably to mitigate support questions more than anything.  That's usually the case with this sort of thing.

Do you even know or did you even think about whether the shield would be better for your uses?   Do you even know or think about what you would have to pay for something with the same feature set as what is specified, but also with more accuracy, ruggedness, shielding or whatever?  Every product targets a price point and a perceived need. This one does.  OTOH, if you need something else, you should have bought that one.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on December 07, 2018, 01:51:28 pm
Seeing them change from the single dimple contact to double and now back to single.  Looking at photos of the wear, I'm not convinced the meter will hold up.  Dave did run a life test on some version of it but it seems odd they are changing the design if all is well.     

That "some version of it" was the version with the shim that shipped to everyone.
Of course the "design is changing" to remove the shim, it was never intended to there. That change BTW is just the thickness of the main PCB to go back to what was intended.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on December 07, 2018, 01:58:44 pm
It took also quite some time to acknowledge the mechanical issue with the selector knob.

It takes time to investigate stuff like this.
Fluke took a whole year to investigate and fix the GSM issue for example.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on December 07, 2018, 02:07:50 pm
Right and there isn't a newer version or model.
The same model has received a small improvement.  This happens all the time in all sorts of electronics.  IT IS NOT A NEWER VERSION OR MODEL.

Correct. This is not a new version or model, and there is no new version or model underway. The shim will eventually be removed, and the current mods will be integrated into a new PCB, but there are no plans for other improvements or spec changes. We are more focused on getting the firmware and development system improved, and a new shared version control system is being setup with the intention that we (EEVblog) will now have visibility on firmware changes, and also the ability to eventually make changes and compile/test ourselves.
Title: Re: EEVBlog 121GW Discussion thread
Post by: joeqsmith on December 07, 2018, 02:09:31 pm
If you thought about what I wrote (you didn't), you would wait forever.  Not just for test equipment but for cars, microwave ovens, tv sets etc.  EVERYTHING gets tweaked from time to time.   Unless you plan on using your 121GW around intense RF fields, this improvement means nothing.

The 121GW you bought meet specs.  The later ones meet specs. You paid for something that meets specifications.   The addition of the shield is probably to mitigate support questions more than anything.  That's usually the case with this sort of thing.

Do you even know or did you even think about whether the shield would be better for your uses?   Do you even know or think about what you would have to pay for something with the same feature set as what is specified, but also with more accuracy, ruggedness, shielding or whatever?  Every product targets a price point and a perceived need. This one does.  OTOH, if you need something else, you should have bought that one.

You are suggesting they went to the TI mux and changed the clamp for an RF problem?   Are you suggesting that adding a shield to make the meter less sensitive to the proximity of your hand makes it an RF problem?   

The fact that they have changed the contact design yet again tells me the switch continues to have problems, even with the shim.  We have seen two people post where the meters our of the box with shims did not work.   Granted they were replaced but why spend $300 on a meter that the switch may not hold up?  Manuals are not going to spec the switch life.  I doubt few people buying an expensive meter would consider that something as simple as the switch being a problem.   
Title: Re: EEVBlog 121GW Discussion thread
Post by: Terry01 on December 07, 2018, 03:29:43 pm
If you thought about what I wrote (you didn't), you would wait forever.  Not just for test equipment but for cars, microwave ovens, tv sets etc.  EVERYTHING gets tweaked from time to time.   Unless you plan on using your 121GW around intense RF fields, this improvement means nothing.

The 121GW you bought meet specs.  The later ones meet specs. You paid for something that meets specifications.   The addition of the shield is probably to mitigate support questions more than anything.  That's usually the case with this sort of thing.

Do you even know or did you even think about whether the shield would be better for your uses?   Do you even know or think about what you would have to pay for something with the same feature set as what is specified, but also with more accuracy, ruggedness, shielding or whatever?  Every product targets a price point and a perceived need. This one does.  OTOH, if you need something else, you should have bought that one.

Holy gwackers he's waffling on about cars and microwaves now!  :-DD

If i'd known there was a meter with updates coming I would have waited. THAT'S ALL!!

Do you want me to post you a copy of that in braille or ask Dave or Joe to make you a video up or.....

just go away...pest!

Why does there always have to be that 1 person?
Title: Re: EEVBlog 121GW Discussion thread
Post by: 1anX on December 07, 2018, 09:33:46 pm
Right and there isn't a newer version or model.
The same model has received a small improvement.  This happens all the time in all sorts of electronics.  IT IS NOT A NEWER VERSION OR MODEL.

Correct. This is not a new version or model, and there is no new version or model underway. The shim will eventually be removed, and the current mods will be integrated into a new PCB, but there are no plans for other improvements or spec changes. We are more focused on getting the firmware and development system improved, and a new shared version control system is being setup with the intention that we (EEVblog) will now have visibility on firmware changes, and also the ability to eventually make changes and compile/test ourselves.

Dave, it may not be a complete new model, but it will be a substantial Revision of the current model. The reason I did not buy another 121GW was because UEI and EEVBlog have decided to use up the remaining 700 out of spec PCBs.

While this may make some sort of financial sense to you and UEI it made absolutely no sense to me as a customer as I dont want another prototype meter. I already have my kickstarter meter that I bought because of your involvement with it. I want my test meters to last and the switch and shim solution are at best a temporary fix. Problem is that you and UEI have decided to carry on with it and let your customers carry the risk of early failure.

I wonder how much better the sales of the 121GW would be if you made it clear to customers that the new revision meters had a new PCB with hardware updates and a reliable switch with a stated switch cycle life. I dont think I am alone in deciding that an alternate meter would be a better choice until you and UEI bring this meter up to spec!

Make the responsible decision that is right for the customers and suffer a tiny financial loss on the out of spec PCBs and you will find this meter becoming a best seller. If you do it on the cheap and let your customers carry the risk IMO then you carry the risk of not having any customers.

I have a Brymen BM867s on its way and I would have preferred a properly made 121GW meter instead.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Terry01 on December 07, 2018, 09:47:54 pm
Right and there isn't a newer version or model.
The same model has received a small improvement.  This happens all the time in all sorts of electronics.  IT IS NOT A NEWER VERSION OR MODEL.

Correct. This is not a new version or model, and there is no new version or model underway. The shim will eventually be removed, and the current mods will be integrated into a new PCB, but there are no plans for other improvements or spec changes. We are more focused on getting the firmware and development system improved, and a new shared version control system is being setup with the intention that we (EEVblog) will now have visibility on firmware changes, and also the ability to eventually make changes and compile/test ourselves.

Dave, it may not be a complete new model, but it will be a substantial Revision of the current model. The reason I did not buy another 121GW was because UEI and EEVBlog have decided to use up the remaining 700 out of spec PCBs.

While this may make some sort of financial sense to you and UEI it made absolutely no sense to me as a customer as I dont want another prototype meter. I already have my kickstarter meter that I bought because of your involvement with it. I want my test meters to last and the switch and shim solution are at best a temporary fix. Problem is that you and UEI have decided to carry on with it and let your customers carry the risk of early failure.

I wonder how much better the sales of the 121GW would be if you made it clear to customers that the new revision meters had a new PCB with hardware updates and a reliable switch with a stated switch cycle life. I dont think I am alone in deciding that an alternate meter would be a better choice until you and UEI bring this meter up to spec!

Make the responsible decision that is right for the customers and suffer a tiny financial loss on the out of spec PCBs and you will find this meter becoming a best seller. If you do it on the cheap and let your customers carry the risk IMO then you carry the risk of not having any customers.

I have a Brymen BM867s on its way and I would have preferred a properly made 121GW meter instead.

You won't be disappointed with the 867s. It's an awesome meter! Granted the 121GW has a few extra features but the 867s "does what it says on the tin" and everything it does, it does well!
Title: Re: EEVBlog 121GW Discussion thread
Post by: newbrain on December 07, 2018, 10:02:20 pm
I got side tracked yesterday so didn't get to test the "hysteresis" but I will do it today for sure and post the results.
I don't think you'll get different results from what's already known (https://www.eevblog.com/forum/testgear/eevblog-121gw-discussion-thread/msg1829909/#msg1829909).
In the linked post, for reference, the behaviour of Fluke 87V.

Just to make sure, I quickly retested with FW 1.57, for DC V (5V range) and mA (5mA range): the thresholds are still 40000-55000 counts (-20% + 10% wrt nominal 50000).
Title: Re: EEVBlog 121GW Discussion thread
Post by: Terry01 on December 07, 2018, 10:43:55 pm
I got side tracked yesterday so didn't get to test the "hysteresis" but I will do it today for sure and post the results.
I don't think you'll get different results from what's already known (https://www.eevblog.com/forum/testgear/eevblog-121gw-discussion-thread/msg1829909/#msg1829909).
In the linked post, for reference, the behaviour of Fluke 87V.

Just to make sure, I quickly retested with FW 1.57, for DC V (5V range) and mA (5mA range): the thresholds are still 40000-55000 counts (-20% + 10% wrt nominal 50000).

No prob, I still haven't done it anyways. I will when i'm next at my bench. The difference being I have FW 1.54 installed.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on December 08, 2018, 12:30:18 am
While this may make some sort of financial sense to you and UEI it made absolutely no sense to me as a customer as I dont want another prototype meter. I already have my kickstarter meter that I bought because of your involvement with it. I want my test meters to last and the switch and shim solution are at best a temporary fix. Problem is that you and UEI have decided to carry on with it and let your customers carry the risk of early failure.

We are confident the shim solution will not lead to "early failure".
Title: Re: EEVBlog 121GW Discussion thread
Post by: Terry01 on December 08, 2018, 01:08:51 am
On the rotary switch, I actually was thinking just tonight that it feels very similar to my U1273a. The U1273a is a tiny bit more snappy as it slips into whatever mode but very similar indeed.
Mines came from Welectron with the shim already installed so I don't know what it was like before. I don't mind the rotary switch at all so long as it stays as is. Time will tell.
It is possible to get it to stop in between modes but you have to really try and I doubt very much it would happen by accident in use.

That's just my opinion...
Title: Re: EEVBlog 121GW Discussion thread
Post by: 1anX on December 08, 2018, 05:24:28 am
I was doing some thinking on how many 121GWs have been produced. Taken from Dave's video on the development history, UEI had 4000 PCBs manufactured. That would mean as 700 of these PCBs are still to be used, that approx of 3300 of these meters have been made and sold. Thats a pretty impressive sales figure for a unkown quality meter, in just a little under 12 months.

It also means as there are thousands of these meters now in the wild that UEI and EEVBlog now know the strengths and weaknesses of this meter. My question is to those that may want to comment, what needs to be refined or altered to bring this product up to the next step in its evolution?

Also if we were to condense all our concerns/praise expressed in this thread, what points would we agree on?
Title: Re: EEVBlog 121GW Discussion thread
Post by: ggchab on December 08, 2018, 10:30:39 am
Already said, I think, but in a next version, red texts and symbols should use a lighter color. They would be more visible.

Even big brands do not always make the best colors choices (Ex.: HP Prime calculator : light blue symbol on white keys replaced by dark blue  :-+)
Title: Re: EEVBlog 121GW Discussion thread
Post by: 1anX on December 08, 2018, 09:41:34 pm
While this may make some sort of financial sense to you and UEI it made absolutely no sense to me as a customer as I dont want another prototype meter. I already have my kickstarter meter that I bought because of your involvement with it. I want my test meters to last and the switch and shim solution are at best a temporary fix. Problem is that you and UEI have decided to carry on with it and let your customers carry the risk of early failure.

We are confident the shim solution will not lead to "early failure".

Thats all well and good but I would feel a lot more reassured if that confidence you have in the "shim solution" actually had a long warranty period supporting it!

Looking at the EEVBlog website I could not find and warranty/refund/return policy listed. Can you please provide a link to the warranty information for the meter or for anything that you sell from your eStore?

 
Title: Re: EEVBlog 121GW Discussion thread
Post by: Brumby on December 09, 2018, 12:01:42 am
I hate to point this out (well, not really) but you seem to be making the assumption that the shim solution is less of an engineering decision than the original design.

Let me throw out this purely hypothetical (but not impossible) idea......

It is not inconceivable that the implementation of the shim might actually be a superior solution - something that we may only see after some years of use.

If you want to ask me how, I don't know and I could only speculate.  If I were able to identify a specific engineering case that supports such a scenario, then I think the designers that have been working with this stuff for years might also have been able to have a handle on such an idea.  As it is, I believe that expertise allowed them to come up with the shim as a viable and reliable solution.


Please ... get over this.
Title: Re: EEVBlog 121GW Discussion thread
Post by: 1anX on December 09, 2018, 01:04:15 am
I hate to point this out (well, not really) but you seem to be making the assumption that the shim solution is less of an engineering decision than the original design.

Let me throw out this purely hypothetical (but not impossible) idea......

It is not inconceivable that the implementation of the shim might actually be a superior solution - something that we may only see after some years of use.

If you want to ask me how, I don't know and I could only speculate.  If I were able to identify a specific engineering case that supports such a scenario, then I think the designers that have been working with this stuff for years might also have been able to have a handle on such an idea.  As it is, I believe that expertise allowed them to come up with the shim as a viable and reliable solution.


Please ... get over this.

Ah, its the feral horse back again, and continuously repeating himself with the EEVBlog fanboy mantra!

Now its my turn to repeat myself, have you bought a 121GW meter yet?

The answer is of course NO!!!

This being the case, and you having zero dollars invested in this meter, and having never had hands on experience with it makes you unqualified to comment. What interest do you have in a warranty for a meter you dont own? On what basis of fact are you qualified to pass any comment on this meter that applies to ownership and use of it?

I do however think that are qualified and have a PhD in opinion and BS, but beyond that you are nothing more than a very sad example of a serial pest!

Now back on topic, can anyone provide me with a link to Dave's EEVBlog's warranty/refund policy or let me know if one exists for the products sold on his eStore?
Title: Re: EEVBlog 121GW Discussion thread
Post by: Brumby on December 09, 2018, 04:28:01 am
I WON MY BET with myself!  In fact, I could have taken out a different bet with longer odds and won that, too!

You can't win on the facts of the situation and logical observation - so you have to attack me personally!  Keep going - you haven't insulted me enough to be worried.  I am actually holding it in quite well to stop breaking out in laughter.

But seeing you want to push a button, I'll not disappoint you (this time)..........

NOTHING I have stated is outside the realm of fair and reasonable observation.  I have even invited Dave to shoot me down if I've stepped outside any bounds - but he has offered nothing.  There also seems to be an absolute dearth of other members chiming in decrying my comment.

My interest in this meter is real.  My only constraint in not having purchased one is budgetary.  As part of this interest, I have been following all the threads.

The fact that you have not offered ONE SINGLE CHALLENGE against my arguments demonstrates you cannot and so you resort to attempt to discredit me to maintain your "superiority".  Sorry - but that is a clear marker of someone who lacks objectivity and (IMHO) has self-esteem issues.

SO - the question begs .... When I do get my hands on a 121GW - what will be your basis for dismissing my opinion?  The fact I won't had one for as long as you have?



It is clear you have never sent a product out into the wild.  I have - and so have quite a few others here.  My last such shipment was two units sent to Israel for testing and evaluation.  Even after weeks of my own testing and tweaking, once you send the package on its way, you wonder if you've addressed all the requirements to the customer's satisfaction.  All the communications indicate you have - but until they get the product in their hands and use it, you are always apprehensive.  You also still keep thinking about what can go wrong - of both the things you have thought about and of those you hadn't.  The only practical approach is to get it as right as you can and send it out - then prepare yourself for issues and to address them should they arise.  If you don't do this, then you will never get a product out into the market.

But you don't need to pay any attention to my little example - there are many members here that do much more of this sort of thing than I and they have stories about their experiences which show life isn't perfect.


One parting comment: I would like to point out that ownership is not a pre-requisite for having a valid opinion nor is it the only metric for having an investment in a product.  In fact, I could have purchased one and had it sitting on my desk, still unopened and posted the same comments.  So much for your eligibility criteria.


Please - do yourself a favour and let this go.  You aren't "winning" here in any sense of the word and you are just embarrassing yourself - more and more.


Edit: I know the "let this go" recommendation will fall upon deaf ears - but it still needs to be said ... again.
Title: Re: EEVBlog 121GW Discussion thread
Post by: fboehle on December 09, 2018, 08:12:35 am
Warranty terms are specified in the manual. First pages...

While this may make some sort of financial sense to you and UEI it made absolutely no sense to me as a customer as I dont want another prototype meter. I already have my kickstarter meter that I bought because of your involvement with it. I want my test meters to last and the switch and shim solution are at best a temporary fix. Problem is that you and UEI have decided to carry on with it and let your customers carry the risk of early failure.

We are confident the shim solution will not lead to "early failure".

Thats all well and good but I would feel a lot more reassured if that confidence you have in the "shim solution" actually had a long warranty period supporting it!

Looking at the EEVBlog website I could not find and warranty/refund/return policy listed. Can you please provide a link to the warranty information for the meter or for anything that you sell from your eStore?

Title: Re: EEVBlog 121GW Discussion thread
Post by: 1anX on December 09, 2018, 08:21:03 pm
Joe, I can see the wear grooves between the contacts but cannot see a split in the PCB. Where abouts should I be looking to see the split?
Title: Re: EEVBlog 121GW Discussion thread
Post by: CDaniel on December 09, 2018, 08:49:34 pm
The split is the crack in the red plastic input terminal
Such a switch require tight tolerances , if the shim , pcb , and so on , are not as should be , it will worn very fast . That's why tests should be done . And David did a test .
Title: Re: EEVBlog 121GW Discussion thread
Post by: 1anX on December 09, 2018, 08:52:56 pm
Warranty terms are specified in the manual. First pages...

Ok so EEVBlog does not provide a written warranty only a contact through sales for support. Therefore the "warranty" falls back to the Australian government consumer laws. https://www.accc.gov.au/consumers/consumer-rights-guarantees/repair-replace-refund (https://www.accc.gov.au/consumers/consumer-rights-guarantees/repair-replace-refund)

It would be nice to see a written warranty for 121GW meter, especially as there may be upto 4000 of them with the thin PCBs and shims to correct the selector switch fault that was picked up early after the meter's release.

The meter I have received also has the incorrect springs fitted in the battery box. The springs are too long and even though fully compressed still need to move sideways to enable battery insertion.

It would be nice to see a written warranty supporting EEVBlogs's confidence in this first run of 4000 meters.

I paid $341 for the meter which includes GST and delivery. Assuming EEVBlog have sold approx 3500 of them 3500 x $341 = $1,193,500! Congrats to EEVBlog!


Title: Re: EEVBlog 121GW Discussion thread
Post by: CDaniel on December 09, 2018, 09:25:37 pm
Could you take a picture of the contacts , so we can see how worn they are ?
Title: Re: EEVBlog 121GW Discussion thread
Post by: darik on December 09, 2018, 10:05:28 pm
I paid $341 for the meter which includes GST and delivery. Assuming EEVBlog have sold approx 3500 of them 3500 x $341 = $1,193,500! Congrats to EEVBlog!

Now you just have to subtract the costs of design, production, shipping and support.
Title: Re: EEVBlog 121GW Discussion thread
Post by: joeqsmith on December 09, 2018, 10:38:55 pm
I paid $341 for the meter which includes GST and delivery. Assuming EEVBlog have sold approx 3500 of them 3500 x $341 = $1,193,500! Congrats to EEVBlog!

Now you just have to subtract the costs of design, production, shipping and support.

Never underestimate that one!   :-DD   A friend of mine was having some problems with a little electronic device he had bought.  He brought it over for me to have a look at.  It was an impressive bit of hardware and seemed to work like a champ.   I called the company that produced it and ended up talking with the designer who told me they no longer offer it.    I said why?  This is a great product.  It's small and light weight, very well made, lots of features and seems to be bullet proof.  Cost wasn't bad.   

I proceed to hear the story of how the people that bought them had problems with troubleshooting simple circuits and basic wiring.  Many had problems reading the manual and the device was always to blame.   Many were returned with no problems found and in the end they spent more money in time trying to support it than they were making from sales, so they pulled the plug on it.   
Title: Re: EEVBlog 121GW Discussion thread
Post by: 1anX on December 09, 2018, 10:57:41 pm
I paid $341 for the meter which includes GST and delivery. Assuming EEVBlog have sold approx 3500 of them 3500 x $341 = $1,193,500! Congrats to EEVBlog!

Now you just have to subtract the costs of design, production, shipping and support.

Never underestimate that one!   :-DD   A friend of mine was having some problems with a little electronic device he had bought.  He brought it over for me to have a look at.  It was an impressive bit of hardware and seemed to work like a champ.   I called the company that produced it and ended up talking with the designer who told me they no longer offer it.    I said why?  This is a great product.  It's small and light weight, very well made, lots of features and seems to be bullet proof.  Cost wasn't bad.   

I proceed to hear the story of how the people that bought them had problems with troubleshooting simple circuits and basic wiring.  Many had problems reading the manual and the device was always to blame.   Many were returned with no problems found and in the end they spent more money in time trying to support it than they were making from sales, so they pulled the plug on it.

Yeah, I didn't say the $1,193,500 was all profit, but it is a considerable achievement for dollars generated through their sales  :-+

I guess EEVBlog is no longer just a blog and its now an established retail eSales outlet.

Glad that the warranty page exits and was pointed out to me as being in the manual. I spent a bit of time searching the EEVBlog website and could not find any reference to warranty or support. Maybe I missed that as well?

I see UEI offer a 2 year warranty and Fluke 10 years on some of their meters. The Brymen BM867s have a 3 year warranty label on their box and the EEVBlog 121GW offer 12 months. Fingers crossed we wont be needing to use it and that when we do there will be a Support tab menu item on the EEVBlog website. Its just one of those necessary things that retailers need to have available.
Title: Re: EEVBlog 121GW Discussion thread
Post by: lowimpedance on December 09, 2018, 11:15:00 pm
@Joe
 Your PCB does show some metallic contamination between the switch traces, possibly a combo of the dimple wear and pickup off the PCB gold trace.
Inspection of mine did not appear to have the same 'inter-pad' debris.
 My contact dimples have started to wear, but have not been subjected to anything like the same rotation number that yours have.
I have re posted a pic (that was posted in the firmware thread) as its the most appropriate thread for reference than the other thread.
Also I include the cotton swab with the 'black' stuff cleaned off the PCB.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Terry01 on December 09, 2018, 11:34:59 pm
I paid $341 for the meter which includes GST and delivery. Assuming EEVBlog have sold approx 3500 of them 3500 x $341 = $1,193,500! Congrats to EEVBlog!

Now you just have to subtract the costs of design, production, shipping and support.

Never underestimate that one!   :-DD   A friend of mine was having some problems with a little electronic device he had bought.  He brought it over for me to have a look at.  It was an impressive bit of hardware and seemed to work like a champ.   I called the company that produced it and ended up talking with the designer who told me they no longer offer it.    I said why?  This is a great product.  It's small and light weight, very well made, lots of features and seems to be bullet proof.  Cost wasn't bad.   

I proceed to hear the story of how the people that bought them had problems with troubleshooting simple circuits and basic wiring.  Many had problems reading the manual and the device was always to blame.   Many were returned with no problems found and in the end they spent more money in time trying to support it than they were making from sales, so they pulled the plug on it.

So you had a friend who bought this great little product that that was very well made with loads of features and was bullet proof and worked like a champ but the people who bought it couldn't wire simple circuits or do basic wiring and many couldn't read the manual and blamed the device but the device had no problems and was great so the company pulled the plug? 

Really?  :-DD
Title: Re: EEVBlog 121GW Discussion thread
Post by: Brumby on December 09, 2018, 11:44:53 pm
So you had a friend who bought this great little product that that was very well made with loads of features and was bullet proof and worked like a champ but the people who bought it couldn't wire simple circuits or do basic wiring and many couldn't read the manual and blamed the device but the device had no problems and was great so the company pulled the plug? 

Really?  :-DD

If marketed to the wrong demographic, I could see that happening - though that does reflect badly on the marketing strategy.  Perhaps they aimed too wide and the less technically inclined were the greatest uptake.

It is a strange world - and no matter how good a product may be, if the cost of the business is greater than the revenue, then the only sensible option is to close up shop.
Title: Re: EEVBlog 121GW Discussion thread
Post by: joeqsmith on December 10, 2018, 12:19:25 am
So you had a friend who bought this great little product that that was very well made with loads of features and was bullet proof and worked like a champ but the people who bought it couldn't wire simple circuits or do basic wiring and many couldn't read the manual and blamed the device but the device had no problems and was great so the company pulled the plug? 

Really?  :-DD

If marketed to the wrong demographic, I could see that happening - though that does reflect badly on the marketing strategy.  Perhaps they aimed too wide and the less technically inclined were the greatest uptake.

It is a strange world - and no matter how good a product may be, if the cost of the business is greater than the revenue, then the only sensible option is to close up shop.

The problem in that case is that many of the end users who bought it just didn't have a technical background.  They wanted what the device had to offer and could see other people using it successfully.  The company sold a fair number of them but they never considered the amount of resources it would require to support it.   
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on December 10, 2018, 12:39:45 am
The troll speaks.    Yes, and it shows you can actually read.  I'm impressed.

Please stop the squabbling here, all of you.
Title: Re: EEVBlog 121GW Discussion thread
Post by: GeoffreyF on December 10, 2018, 12:39:53 am
YES!  Really!  I have worked in hardware product companies.   Support is a huge cost. In fact, if you want to assure nobody makes a dime selling you something, call them with your issues.   It REALLY happens all the time that products are cancelled for the support costs.  Evidently this comes as a shock to some but people who manufacture stuff are in it for the money. 

Do you really think someone with the basic skills and knowledge to answer your questions doesn't expect a decent wage?  REALLY?
Title: Re: EEVBlog 121GW Discussion thread
Post by: joeqsmith on December 10, 2018, 02:00:43 am
Zoomed in view of a member's meter.  Notice the wear around the lip of the hole.  With the thinner PCB, I would not have expected there to be any wear in this area.   Actually, with the shim installed  I wouldn't expect the locking tabs to come in contact with the surface of the PCB.  I would expect them to be sitting much higher.   I am sure I am missing something.     
Title: Re: EEVBlog 121GW Discussion thread
Post by: Brumby on December 10, 2018, 02:18:42 am
Notice the wear around the lip of the hole.

I also noticed that this wear is only in that area.  There is no sign of anything that severe at other points.

I'm wondering if it's something as simple as a high point in the switch - perhaps from the molding process.  If so, it could be just a matter of wearing down until it no longer is in contact.

Just a thought - as I don't have a meter I can check.
Title: Re: EEVBlog 121GW Discussion thread
Post by: joeqsmith on December 10, 2018, 02:32:26 am
I assume the switch assembly does not run true (on a light slant) causing it to wear on the one side.   That shim is pretty thick and should have moved these locking fingers far off the board even if it isn't true.   Would have really liked to have seen more data on Dave's life cycle test.  Looks like he made an edited version available. From this we can see he ran the single dimple contacts.   I assume these are the later design after the kickstart.  There is a fair bit of wear around the hole but it is on the switch side rather than the locking tab side.  This is what I would expect.  Also, it does seem to be placing a fair bit of pressure on the switch assembly or we would not see this sort of wear.  It enforces my thought that the switch assembly is very close to the circlip already and the PCB thinkness may not play such a big role.

https://youtu.be/QSmiMlWEpy0?t=333
Title: Re: EEVBlog 121GW Discussion thread
Post by: CDaniel on December 10, 2018, 08:08:04 am
The shim thichness is not relevant because normally there is a empty space between the switch and the case   ... so actually could be a very little push from the shim . My multimeter with the board out of the case is working well if I turn the switch , is not that loose not to make contact without the shim .
So the PCB needs to be just a little thicker . Thats the good solution , because with the shim , all the case tolerances , how the pcb sits on the case  screw mounts play a role ... and you could have in the end too little pressure or to much . If something is not straight the wear will be more in one side .
Title: Re: EEVBlog 121GW Discussion thread
Post by: joeqsmith on December 10, 2018, 06:25:32 pm
I don't disagree with what you have posted but from that last picture I posted, we can see the wear on the locking tab side.  I have mentioned my concern about the hole not being plated.  Its a rough surface.   If the locking tabs are what will be used to hold the tolerances on the spings, I don't see a problem as long as the tabs do not wear.  Sadly, they appear to be. 

I think we can both agree that once they get a handle on the switch and remove the shim, it should be retested.  Hopefully Dave will revamp that cycle testing jig and maybe this time ditch all the sticky notes.   
Title: Re: EEVBlog 121GW Discussion thread
Post by: 1anX on December 11, 2018, 09:50:01 pm
The shim thichness is not relevant because normally there is a empty space between the switch and the case   ... so actually could be a very little push from the shim . My multimeter with the board out of the case is working well if I turn the switch , is not that loose not to make contact without the shim .
So the PCB needs to be just a little thicker . Thats the good solution , because with the shim , all the case tolerances , how the pcb sits on the case  screw mounts play a role ... and you could have in the end too little pressure or to much . If something is not straight the wear will be more in one side .

UEI stated early on, when the first batch of meters were released and the faulty switch reports started coming back, that it was the thin (out of spec) PCB causing the problem. The shim was to correct for the thin board providing insufficient pressure for the switch contacts. At least that was my understanding of what EEVBlog was stating as causing the problem at the time.

Soon enough we will all know if that is the case, as the 4000 out of spec PCBs must now have been fitted into the final batch of meters? That being the case then, if UEI decides to continue the manufacture of the 121GW meter they will be on a correct thickness PCB and the switch will no longer require the shim.

EEVBlog commented earlier that they were unsure of when the next batch of meters produced on the new PCBs and incorporating the updated hardware mods would be produced. It cant be too far away as it seems sales have been strong up to this point. Soon we will have our answers and hopefully photos from the new meter's owners.

Title: Re: EEVBlog 121GW Discussion thread
Post by: beanflying on December 18, 2018, 02:03:22 am
Just by way of contrast to Joe's pictures above I knocked mine down for the first time since I installed the shim today firstly to upgrade the inferior 1.15 firmware that I have been using since it was first released to 1.57, yes I am that lazy when something works.

I got a first production kickstarter meter stickered #137 and the follow up shim kit when first released was installed straight away.

These photos are taken with no clean up of any sort to the board or contacts and no colour or contrast corrections. Just here for comparison not to start a pissing contest. A bit of wear on one side but most of that was there if I recall pre shim.

Title: Re: EEVBlog 121GW Discussion thread
Post by: joeqsmith on December 18, 2018, 04:00:18 am
How did it look on the back side where the locking tabs ride?   
Title: Re: EEVBlog 121GW Discussion thread
Post by: beanflying on December 18, 2018, 04:15:52 am
Looked fine to me. From a strictly engineering point of view I would have liked to see an additional washer, longer barrel and maybe a circlip used instead of the clip but so far the clips are doing their job.

Just a potted theory yours spent more time than most without a shim? (not sure if you got a second meter from Dave?) So is yours indicative of what those of us with shims installed from scratch or fairly early into the life of the meter can expect or is it just what is possible without the shim for period X and then fitting one later?

EDIT: Just trawled my photos from Shim arrival time and none of the meter or PCB
Title: Re: EEVBlog 121GW Discussion thread
Post by: joeqsmith on December 18, 2018, 12:20:22 pm
Looked fine to me. From a strictly engineering point of view I would have liked to see an additional washer, longer barrel and maybe a circlip used instead of the clip but so far the clips are doing their job.

Just a potted theory yours spent more time than most without a shim? (not sure if you got a second meter from Dave?) So is yours indicative of what those of us with shims installed from scratch or fairly early into the life of the meter can expect or is it just what is possible without the shim for period X and then fitting one later?

EDIT: Just trawled my photos from Shim arrival time and none of the meter or PCB

Most of the pictures I posted were taken from what others uploaded.  I am not sure why anyone would attempt to extrapolate anything about switch wear from the prototype.  The pictures I have shown of the prototype are presented only to give some insight into how the design has evolved.   If it is still causing confusion, I can go ahead and scrub this area as well. 

***

I spent a few minutes and cleaned up this area as well.  Hopefully this will avoid further confusion with readers.   
Title: Re: EEVBlog 121GW Discussion thread
Post by: beanflying on December 18, 2018, 01:00:57 pm
Only because I decided to go AWOL from these threads due to the speculators and armchair gurus before most even had meters so I am not in touch with what has gone on and been said or not said was why I asked about your photos. Your much punished prototype deserves a spot on a shelf and retirement as I did watch the torture done to it :)

As the upgrade to the firmware went as it should have and providing the meter test in spec I still will be a happy user. I have some more gear now than when I first got it so a few hours playing across the ranges will be in order but no torture outside of spec ;)
Title: Re: EEVBlog 121GW Discussion thread
Post by: lowimpedance on December 18, 2018, 11:37:55 pm
Just by way of contrast to Joe's pictures above I knocked mine down for the first time since I installed the shim today firstly to upgrade the inferior 1.15 firmware that I have been using since it was first released to 1.57, yes I am that lazy when something works.

I got a first production kickstarter meter stickered #137 and the follow up shim kit when first released was installed straight away.

These photos are taken with no clean up of any sort to the board or contacts and no colour or contrast corrections. Just here for comparison not to start a pissing contest. A bit of wear on one side but most of that was there if I recall pre shim.
Have you had a close up look at the switch spring contact dimples to see if there is any notable wear either even or uneven ...or not !.
My meter which is from the first shipment showed a bit more PCB contamination than yours but after cleaning the PCB was still in excellent condition with no obvious track 'grooving' from the dimples.
The area of wear does appear to be the 'dimples'. Some wear is to be expected, just how much and how fast.... well  :-//.
Photo's from mine are already posted here and in the Firmware thread for comparison.
Title: Re: EEVBlog 121GW Discussion thread
Post by: beanflying on December 19, 2018, 12:03:56 am
Nothing obvious under the microscope even holding them off axis to drop the glare like in the photo. All contacts on all switches wear including the ones in my high end decade boxes have wear. The aim should be to engineer and design within a budget (fact of modern design) the best solution. Maybe the budget in hindsight should have been stretched a bit more.

My thoughts above would be minor in production cost but would require retooling costs to then be recovered across the production. So while the washer, extra plastic and circlip would be in the order of cents the tool for the brush holder would be in the order of four figures even using a composite RIM tool and a lot more in metal for injection molding. The bonus of this sort of solution is it is could be retrofitted to the existing meters. If available I would most likely buy one.
Title: Re: EEVBlog 121GW Discussion thread
Post by: beanflying on December 19, 2018, 03:11:47 am
Capacitance Linearity Tests.

Used Kickstarter V1 Meter running 1.57 firmware. Approximate Temp 23C
HP/Yokagawa Decade Capacitance box. Basic Accuracy 0.25%+3pF (order of magnitude better than the 121GW) Silvered Mica Caps. 0 - 1.2 uF

I used the stock leads with the screw on 4mm adapters as it is a real world device for most of us. Data below for anyone interested.

Small amount of drift generally up on the small capacitance's in the order of generally 10pF or so.

For those not wanting to look at the data it shows well inside spec across a range sliding toward spec at either end which is to be expected.  :-+
Title: Re: EEVBlog 121GW Discussion thread
Post by: beanflying on December 19, 2018, 06:01:22 am
Resistance Linearity Tests.

I did some very quick tests across a limited range of values way back on page 1 of this thread. The Data is included in the spreadsheets below in red. It cross references the Russian decade box to the 121GW to my Agilent 34401A. The Russian Box is at least an order of magnitude better than the 121GW at 0.03 and 0.02% across it's ranges.

Above the 119.99k Limit of the Russian Box I have used my own Vishay 0.1% decade box from 0.1 to 1Meg cross referenced to my 34401A (mainly because I haven't tested it fully before) above that I currently have a limited range. Homebrew box is better than the resistors spec it seems :-+

I have chosen not to test below 0.1 Ohm as it is well outside what I would use for 2W testing generally and not a fair test. The figures for below 1 ohm I would consider fairly good on 2W

Not sure if my meter is better than average but the Resistance readings are way better than the Spec above a few ohms to 50K they are freaky good. I finished up running a check of the same values of the Russian Box on 2W on the 34401a as I also have another few meters to test.  Looks like one of the calibration factors could be tweaked a fraction above 50K but still within spec.

Overall Linearity against a better meter and decent Resistance boxes :-+
Title: Re: EEVBlog 121GW Discussion thread
Post by: nudge on December 19, 2018, 06:49:53 pm
Hey all, I see the 121GW can measure temperatures >1000C in the manual! Just wondering if the thermocouple is safe to put into a conventional oven to test the temperature (multimeter of course outside).

Cheers!
Title: Re: EEVBlog 121GW Discussion thread
Post by: IanB on December 19, 2018, 07:27:04 pm
Hey all, I see the 121GW can measure temperatures >1000C in the manual! Just wondering if the thermocouple is safe to put into a conventional oven to test the temperature (multimeter of course outside).

For most ordinary thermocouples supplied with meters the insulation material around the probe is the limiting factor. It will melt or burn long before reaching the maximum temperature of the thermocouple junction.
Title: Re: EEVBlog 121GW Discussion thread
Post by: GeoffreyF on December 19, 2018, 07:28:53 pm
Hey all, I see the 121GW can measure temperatures >1000C in the manual! Just wondering if the thermocouple is safe to put into a conventional oven to test the temperature (multimeter of course outside).

Cheers!

Yes, I have done exactly that myself.  I don't know if it is safe to put in food itself but probably is. I would check the door just to make sure there are no sharp edges where you run it in.  I assume that by "Conventional" you mean "Gas".  If electrical, just position the probe so it doesn't touch the element directly.  Microwaves would be a bad idea.  I just put the probe end in the oven and closed the door.

I am not sure if the probe itself goes to 1000c but it's within the idea of a baking oven.
Title: Re: EEVBlog 121GW Discussion thread
Post by: beanflying on December 19, 2018, 11:16:52 pm
The limits on the 121GW for Temperature are generally the limits of the 'K type' thermocouple junction used. In practice it goes a little lower than this so there may be hardware or software things going on but if you are south of -200C you won't be using this meter for your readings.

In the photo below is a K type bead termocouple I use for characterising and tuning commercial ovens as it can be poked in through a door seal and looped around a shelf. I haven't run it above 250C but after many years of use the insulation is fine. I would be fairly happy running the 121GW in a similar use but I haven't needed to yet.

A few of the others shown are silicone and teflon coated wires and should be fine in the same region and up toward 400C. The screw in types will easily handle more as only the junction and silica filled barrel are exposed to much heat the metal shield contains just heat resistant braid like the bead ones and is for mechanical strength not heat. Moving into the 1000C+ range they tend to be ceramic carriers for things like kiln etc.

The ones on my baby Coffee Roaster as shown are 6 or 7 years old and working fine at 200-250C.

Just one thing with the Meter is keep it away from as much heat as possible if the internal sensor or board gets hot the readings you will get are likely to be out. If it all goes to poo and you melt it or knick a cable they are cheap and no harm will come to the meter but let us see the carnage  ;)
Title: Re: EEVBlog 121GW Discussion thread
Post by: nudge on December 20, 2018, 08:18:11 am
Very cool info, thanks guys!
Title: Re: EEVBlog 121GW Discussion thread
Post by: jazper on December 20, 2018, 11:23:24 pm
Hey I have seen a lot of negative stuff about the 121GW Multimeter. Lots of people recommending Brymen etc.

I took a chance, I bought the 121GW, and I have to say it's one of the easiest to use and fully featured multimeters I've ever laid my hands on. I'm very happy with the purchase.

I have two minor qualms, one is that the rubber probe holder on one side fits a little too snug, and the other is that the case needs to be purchased separately (and I didn't know that when I bought the meter). That said, it's a lot of bang for not many bucks.

If Dave is reading this - first of all, thankyou! - Second it'd be a really good idea to put an option to add the case on the purchase page of the store, or have a 121GW + Case item on the page.

One very happy customer.
Title: Re: EEVBlog 121GW Discussion thread
Post by: GeoffreyF on December 21, 2018, 12:31:54 am
There are meters which cost 50% more than the 121 GW and still lack features which it has.   Yes, those meters have some other features and I might even buy one of them too *IF* I need those features.  However, I needed those of the 121GW and that's why I bought it.

Not one person with "Issues" actually described a real world task they could not complete and how they might have completed it with something else ... not one.
Title: Re: EEVBlog 121GW Discussion thread
Post by: beanflying on December 22, 2018, 05:26:05 am
Thermal Stability test - sort of but really rough.

Reference is a Fluke 515A portable Calibrator. Switched on for several days now as have the 34401a and Advantest. Overall drift on this gear is way less than the 121GW's ability to resolve it and has been sitting at +- 3LSD regardless of any Temperature variations in the shack over the last day. The Advantest has been out of use for some years and has crept up a fraction.

Not a complete test by any means but just an idea of DC stability in a walk up portable multimeter type test (which is what it is). The GW121 was flicked on and readings taken no more than a minute or two after that. There was 1-2 LSD of drift leaving it on for longer periods of time after that. If I was being serious I would run a graph against Temperature and stuff the whole lot in my chamber but it has other stuff in it held at a stable long term temperature. Any Northerners want to go play in the snow for us to learn more  ;)

The 10M input impedance loads the Fluke a miniscule amount (0.14mV) when connected with the other meters compared to theirs in the GigOhms range. Something to bear in mind when comparing References which may suffer even more with loading than the Fluke. But it is a comparison of stability not a test of 'absolute accuracy'.

There was a post I made way back in January at 42C  :phew: https://www.eevblog.com/forum/testgear/eevblog-121gw-discussion-thread/msg1403277/#msg1403277 (https://www.eevblog.com/forum/testgear/eevblog-121gw-discussion-thread/msg1403277/#msg1403277) Same cheap and cheerful Chinese reference today at 27C is 5.0003V compared to the 4.9998V at 42C. Either could have drifted so draw nothing really from this other than both are fairly decent for general use.

Fluke Comparison Results in the Pics and temperatures on the 121GW.
Title: Re: EEVBlog 121GW Discussion thread
Post by: beanflying on December 22, 2018, 06:04:11 am
How did it look on the back side where the locking tabs ride?

Dropped the back off it again and took a few happy snaps by rotating the knob rather than a tear down. I haven't done any cleanup at all on this area and I don't think I did when I installed the shim either?

Looks fine for another 10 years of use for me at least.  :)
Title: Re: EEVBlog 121GW Discussion thread
Post by: beanflying on December 23, 2018, 06:02:30 am
Mains Frequencies and Voltages

While I have included the 121GW and the data I really wanted to have a proper look at the relative accuracy of a Valhalla 2703 AC Calibrator I have picked up during the year. I have run tests over 50 and 60 hz in the ranges of 100-130V and 220-250V today so this covers the majority of mains used in the world.

Other than spot checks on meters I haven't run a proper series through the Valhalla so time to start and figure out if it is in or out of spec. and look at if it needs a tweak. I will run some higher frequency tests and bigger voltage ranges against the 34401a but unless someone wants anything specifically on the 121GW I won't most likely get any additional data. The 121GW works within spec on limited testing to above 5kHz as claimed as I have done some other testing prior.

Doing this for me was to improve confidence in mains logging I have done from time to time on the 121GW and to get a better idea of the accuracy of the data. Not metrology grade results by any means but to give a reasonable level of confidence.

Valhalla 2703 stated accuracy +- 0.03% reading +0.03 range
Agilent 34401a accuracy +- 0.06 reading +0.03 range (two ranges used <120 and <750)
121GW accuracy +- 0.3 + 10 counts (0.1V in these tests I have manually added it to the errors as parsing data is a PITA)

I have included columns with calculated errors for the readings from the Specifications and while they sit well inside that there appears to be a minor issue with the Valhalla outputting consistently low by circa 0.1V/100V in this sort of frequency range. Voltage Steps of 2V are very consistent against both the meters. If a correction of that 0.1/100V was done the absolute error drops dramatically. Man with two clocks problem but I only have one good clock  :palm:

Call it the 121GW on mains around the world way better than spec regardless :-+
Title: Re: EEVBlog 121GW Discussion thread
Post by: MiroS on December 25, 2018, 01:46:58 pm
One very happy customer.
After watching review of other multimeters on YT of UEI, I was quite sure how it will go . Just look at old review of Dave for UEI multimeter - I think it was 100$ multimers review -  and reflect the same criteria to 121GW.
Title: Re: EEVBlog 121GW Discussion thread
Post by: GeoffreyF on December 27, 2018, 03:59:33 pm
Here is another use for the 121GW.  In keeping with the traditions of obscure complaints, I have a quibble with the migraine inducing high frequency of the "continuity test".  Also, it seems to not "unlatch" quite to my satisfaction as I send dots and dashes at 60wpm.  Finally, it was rather thoughtless that the meter can't receive Morse code to change the configuration.  Wouldn't that be so handy if one is swinging from the rungs of a transmission tower, making measurements, I should not deign to actually touch the meter?  If I paid all this money for Code Practice Oscillator, I think it should be better than $10.00 one that is sold for that purpose.   

KC1KNS
Title: Re: EEVBlog 121GW Discussion thread
Post by: MiroS on December 27, 2018, 05:12:16 pm
Here is another use for the 121GW.  In keeping with the traditions of obscure complaints, I have a quibble with the migraine inducing high frequency of the "continuity test".  Also, it seems to not "unlatch" quite to my satisfaction as I send dots and dashes at 60wpm.  Finally, it was rather thoughtless that the meter can't receive Morse code to change the configuration.  Wouldn't that be so handy if one is swinging from the rungs of a transmission tower, making measurements, I should not deign to actually touch the meter?  If I paid all this money for Code Practice Oscillator, I think it should be better than $10.00 one that is sold for that purpose.   

KC1KNS

Is left side of LCD starting to crack by Morse vibration? 73.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Jon.C on December 29, 2018, 10:31:44 am
@GeoffreyF

 :-DD :-DD
Title: Re: EEVBlog 121GW Discussion thread
Post by: Pat5 on January 07, 2019, 03:57:43 am
Hello,

I would like to ask owners of the 121GW: Would you recommend this meter to be purchased in 2019 ? Are there still any software issues that still need to be resolved ? Are there any missing, unimplemented, features ?

Thank you !
Title: Re: EEVBlog 121GW Discussion thread
Post by: GeoffreyF on January 07, 2019, 12:19:08 pm
Hello,

I would like to ask owners of the 121GW: Would you recommend this meter to be purchased in 2019 ? Are there still any software issues that still need to be resolved ? Are there any missing, unimplemented, features ?

Thank you !

You didn't mention what your needs are.   It meets my needs and does so quite well.  There are other meters which are less expensive but quite sufficient for some purposes.  There are other meters which cost more but are necessary for more advanced applications. There are meters about the same price but which might meet a particular purpose better.  The 121GW meter meets its specifications. I think it is a terrific meter for an advanced hobbyist or for development.  I enjoy using it.   However, many of us who own the 121Gw have other meters to round out our needs. 

So what are your needs?
Title: Re: EEVBlog 121GW Discussion thread
Post by: CDaniel on January 07, 2019, 01:50:05 pm
Hello,

I would like to ask owners of the 121GW: Would you recommend this meter to be purchased in 2019 ? Are there still any software issues that still need to be resolved ? Are there any missing, unimplemented, features ?

Thank you !

Yep , there are issues if you read 121GW threads ...
I don't recomend buying this meter yet , if you are professional or advanced hobbyist , only if you are very patient .
The potential is great , but the firmware quality is not where it should be ...
Title: Re: EEVBlog 121GW Discussion thread
Post by: Pat5 on January 07, 2019, 04:46:13 pm

So what are your needs?

Hello,

I am interested in a device to use in low-voltage electronics work, although i don't see the relevance of this information...
Is this a reliable multimeter which has implemented all of the manufacturer's specified features ? Are all of the issues fixed and can the current firmware (1.57) be considered final ?
Unfortunately i could not reach a conclusion on my own, after going through this thread and the manual.

Thank you.

@CDaniel - Thank you for your feedback !
Title: Re: EEVBlog 121GW Discussion thread
Post by: exe on January 07, 2019, 04:51:12 pm
Unfortunately i could not reach a conclusion on my own

Yep, you have to try it. Esp. because users of this meter have very polar reviews. There is no "final" conclusion possible.

Many small features here and there greatly contribute to user experience, but often not specified. Like boot time, UI responsiveness and usability, etc.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Candid on January 07, 2019, 05:28:20 pm
Would you recommend this meter to be purchased in 2019 ?
Yes I would.

Are there still any software issues that still need to be resolved ? Are there any missing, unimplemented, features ?
Not that I know of or that would keep me from recommending it.

Thank you !
You are welcome.
Title: Re: EEVBlog 121GW Discussion thread
Post by: darik on January 07, 2019, 05:38:22 pm
Hello,

I would like to ask owners of the 121GW: Would you recommend this meter to be purchased in 2019 ? Are there still any software issues that still need to be resolved ? Are there any missing, unimplemented, features ?

Thank you !

I've been using mine as my main meter for hobby stuff since I got it. The only issue that I ever run into is the clumsy ohms autoranging and that is more of a cosmetic problem then a functional one. It's very accurate and works as I expected.
Title: Re: EEVBlog 121GW Discussion thread
Post by: bicycleguy on January 07, 2019, 08:47:17 pm
..
I would like to ask owners of the 121GW: Would you recommend this meter to be purchased in 2019 ? Are there still any software issues that still need to be resolved ? Are there any missing, unimplemented, features ?
..
It was worth it in 2018 and haven't seen any regressions, so yes in 2019 or beyond, it will only get better.

The only real issue IMO is the slow auto-range and showing incorrect results for a second before the real results.  This is currently resolved by manually selecting the range after you set R, V ect.  It won't remember the range after a function switch unfortunately.  I think this will get resolved in one way or the other at some point.

Its my main meter of two.  Though as I look at my stuff while I write this, I can't find the old meter!
Title: Re: EEVBlog 121GW Discussion thread
Post by: Kean on January 07, 2019, 09:24:38 pm
Dave seems to be using the 121GW as his main meter (in his videos at least), and he is working with UEI to get better oversight on the firmware development.  I'm confident there will be further firmware improvements, but there is no rush to get them out as it is now mostly just refinement not fixing the more serious bugs.

I'll admit that I'm not using my 121GW as my main meter, as I still prefer the BM235 for quick measurements.  I have a different meter (or two) on each of my 7 or so workbenches, and I also just got a BM869s for Christmas!

So while the meter isn't perfect, it has the advantage of simple firmware updating.  Many (most?) meters at this price don't support firmware updates at all.

If I could only afford the one (reasonably priced) handheld multimeter I'd want it to be the 121GW.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Kean on January 07, 2019, 10:09:42 pm
Seeing as how I have recently upgraded to 1.57 I've put the 121GW on my main R&D workbench and will see how I find it for day to day use
Title: Re: EEVBlog 121GW Discussion thread
Post by: beanflying on January 07, 2019, 11:19:04 pm
I am interested in a device to use in low-voltage electronics work, although i don't see the relevance of this information...

It is relevant because if you want a meter for pure mains electrical work then you may and probably should make a different selection to the 121GW. With your answer you are on the right track looking at a meter like this with low current/burden capabilities that an Electricians type meter doesn't have for example.

Some of the issues are expectations of perfection not being met too. They have tended to be amplified by constant repetition and searching for failure as a critical mission by some. This meter given the target audience (us bunch of nerds/engineers/tinkerers) has been one of the most publicly scrutinized and discussed meters of the last several years while other meters don't get anywhere near the critique they should (unless your name is Joe Smith  :-DMM).

If you could poll the entire ownership of the meter you would find a more balanced view. As that is unlikely or impossible one source of evidence would be the lack of secondhand ones for sale maybe showing the majority are finding they have a place in their kit.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Seppy on January 08, 2019, 12:07:55 am
..
I would like to ask owners of the 121GW: Would you recommend this meter to be purchased in 2019 ? Are there still any software issues that still need to be resolved ? Are there any missing, unimplemented, features ?
..
It was worth it in 2018 and haven't seen any regressions, so yes in 2019 or beyond, it will only get better.

The only real issue IMO is the slow auto-range and showing incorrect results for a second before the real results.  This is currently resolved by manually selecting the range after you set R, V ect.  It won't remember the range after a function switch unfortunately.  I think this will get resolved in one way or the other at some point.

Its my main meter of two.  Though as I look at my stuff while I write this, I can't find the old meter!

So I looked into the resistance range, its improved somewhat. Instead of scanning down from 50M it scans up from 50R, this way the burden of the slower higher ranges isn't placed on the lower ranges, if you want to try this version of firmware its here, its a beta, I haven't tested everything I wanted to yet:
https://www.eevblog.com/wp-content/plugins/download-attachments/includes/download.php?id=21118 (https://www.eevblog.com/wp-content/plugins/download-attachments/includes/download.php?id=21118)



Title: Re: EEVBlog 121GW Discussion thread
Post by: beanflying on January 08, 2019, 12:51:06 am
So I looked into the resistance range, its improved somewhat. Instead of scanning down from 50M it scans up from 50R, this way the burden of the slower higher ranges isn't placed on the lower ranges, if you want to try this version of firmware its here, its a beta, I haven't tested everything I wanted to yet:
https://www.eevblog.com/wp-content/plugins/download-attachments/includes/download.php?id=21118 (https://www.eevblog.com/wp-content/plugins/download-attachments/includes/download.php?id=21118)

Have you considered testing a firmware with the bargraph disabled and what it might do to the Autorange speed? If there is a reasonable gain then making it switchable? Apart from seeing it go up and down I don't use it in any meaningful way much as others I am sure do.
Title: Re: EEVBlog 121GW Discussion thread
Post by: bicycleguy on January 08, 2019, 12:54:36 am
@Seppy
I didn't try the download yet as the file size is only 60k as opposed to the usual ~130.  Is this ok or is it a zip or something the name was 'EEVBlog1_58.7z'


I see file is compressed with yet another file compression method.  On Mac you will need to search app store for .7z.  Many free apps are available.
Title: Re: EEVBlog 121GW Discussion thread
Post by: CDaniel on January 08, 2019, 01:02:54 am
My quick opinions on the beta firmware for resistance mode ... The new firmware is faster , thats a good thing .
But the hysteresis is the same 55000 counts up and 40000 down , so an 470ohm resistor will autorange wrongly in 5K range , not in 500ohm .
That wrong first value ( something in Mohm range ) is still there .
I know I said the noise problem is resolved ... and it is much better now , but still on some ranges the last 1 or 2 digits fluctuates when you put the hands on the tips . Even in 50ohm range where much of the noise should be shunted by the low test resistor itself . I don't want to be picky but this is the only meter I know with this kind of issue .
And of course for very low resistors <0.1ohm is allmost useless , as the value tend to fluctuate and you don't measure twice the same value ...
Title: Re: EEVBlog 121GW Discussion thread
Post by: darik on January 08, 2019, 01:03:07 am
So I looked into the resistance range, its improved somewhat. Instead of scanning down from 50M it scans up from 50R, this way the burden of the slower higher ranges isn't placed on the lower ranges, if you want to try this version of firmware its here, its a beta, I haven't tested everything I wanted to yet:
https://www.eevblog.com/wp-content/plugins/download-attachments/includes/download.php?id=21118 (https://www.eevblog.com/wp-content/plugins/download-attachments/includes/download.php?id=21118)

I don't know if I'll have time to check the beta but I like the sound of what you are saying. My big beef with the ohms autorange is how it would almost always give a false reading in the 50M range and hold it for a couple seconds, because the sampling rate is so slow in the 50M range. The speed was never as big a problem to me as the meter sitting there with a static, false reading for long enough that I have to tell myself to ignore it and wait for the correct reading to show up.
Title: Re: EEVBlog 121GW Discussion thread
Post by: joeqsmith on January 08, 2019, 01:03:35 am
Hello,

I would like to ask owners of the 121GW: Would you recommend this meter to be purchased in 2019 ? Are there still any software issues that still need to be resolved ? Are there any missing, unimplemented, features ?

Thank you !

I like the idea of the meter.  Low burden, high voltage diode test, wireless, guessing it has decent battery life.   The VA mode could maybe be useful.  I don't see many people posting about it.   

I had planned to buy one last year but am holding out.  I am not too concerned about the firmware.  Overall it's improved a lot and I assume this trend will continue.   My plan is to put one through it's paces and I want to give the meter the best possible chance to shine.   To be frank, while I am glad to hear that they have made a few changes to the circuitry that make effect how the meter performs, I biggest concern is still with that switch.   I just had a cheap UNI-T meter's switch go intermittent from normal use.   This is the third cheap meter (BK and Mastech) where the switches had what I consider a short life.  I am not comfortable with the shim solution.  Yea, I know Dave ran what he called his 50,000 cycle test on it, I watched.   

There was a long standing thread about the high cost of Fluke branded meters and if other lower cost meters would be better.   One of the common things people would post is that we just don't have a lot of data on the lower cost meters compared with Fluke.  They have been in the business a long time.    It's partly why I started testing meters to try and get the fanboyism out of the equation.   
Title: Re: EEVBlog 121GW Discussion thread
Post by: CDaniel on January 08, 2019, 01:15:50 am
We understand your point of view ... your hobby testing how robust a meter is . As a user you dont care that much if the switch won't last only 20K cycles in the future ... but the firmware is buggy now  :-\  and you can't use it as you would like .
Title: Re: EEVBlog 121GW Discussion thread
Post by: Seppy on January 08, 2019, 01:31:04 am
@Seppy
I didn't try the download yet as the file size is only 60k as opposed to the usual ~130.  Is this ok or is it a zip or something the name was 'EEVBlog1_58.7z'


I see file is compressed with yet another file compression method.  On Mac you will need to search app store for .7z.  Many free apps are available.

Whoops, fixed. What do you mean yet another, aren't all the others zips?
https://www.eevblog.com/wp-content/uploads/2017/11/EEVBlog1_58.zip (https://www.eevblog.com/wp-content/uploads/2017/11/EEVBlog1_58.zip)
Title: Re: EEVBlog 121GW Discussion thread
Post by: bicycleguy on January 08, 2019, 01:46:57 am
The 1_58 beta is interesting so far.  Switching from say V to ohms with a 4.7k resistor attached is almost immediate :clap:, thought I had the wrong meter :-DD.  This apparently is my new way of starting a resistance reading.

However, once in resistance mode and you disconnect the resistor it will auto range to the 50meg range.  When you re-attach a resistor it is faster than 1_57 for sure but somewhat randomly still shows a quick flash in the mega ohm range before auto ranging from the bottom.  Definitely an improvement.
Title: Re: EEVBlog 121GW Discussion thread
Post by: joeqsmith on January 08, 2019, 01:59:42 am
We understand your point of view ... your hobby testing how robust a meter is . As a user you dont care that much if the switch won't last only 20K cycles in the future ... but the firmware is buggy now  :-\  and you can't use it as you would like .
I would be pissed if I paid 300+ for a meter and the switch went bad in the first year or two.  The UNI-T was only $30 and really what I expect from a cheap meter with nominal use.  Same for BK and Mastech.  I consider them disposable.  But at $300 it better be built to stand the test of time.   

Same holds true for basic transients.  Last thing I want is a meter like my first brand new Fluke.  Look at it wrong and a $70+ dollar repair bill, that was in the 80s.  Firmware can be fixed but if the hardware is wrong, there is little you are going to do to correct it. 

My normal use of a handheld meter is pretty basic.  That's why I buy cheap, disposable meters for the garage.  The 121GW would be out of place in that environment. 
Title: Re: EEVBlog 121GW Discussion thread
Post by: Seppy on January 08, 2019, 02:25:24 am
The 1_58 beta is interesting so far.  Switching from say V to ohms with a 4.7k resistor attached is almost immediate :clap:, thought I had the wrong meter :-DD.  This apparently is my new way of starting a resistance reading.

However, once in resistance mode and you disconnect the resistor it will auto range to the 50meg range.  When you re-attach a resistor it is faster than 1_57 for sure but somewhat randomly still shows a quick flash in the mega ohm range before auto ranging from the bottom.  Definitely an improvement.

I will try work that out, I'm getting involved with the firmware (previously I could only communicate problems). The reason I suspect is that a filtered reading passed through the 50M range and at that moment post filter the value likely does sit in that range for at most a single or few samples. Low pass a square wave you get the leading edge smudged over all ranges instead of a sudden change, same thing I suspect.

I don't have access to the GIT yet (Internal only GIT), but I have sent them instructions how to get that started.
Title: Re: EEVBlog 121GW Discussion thread
Post by: CDaniel on January 08, 2019, 03:26:39 am
We understand your point of view ... your hobby testing how robust a meter is . As a user you dont care that much if the switch won't last only 20K cycles in the future ... but the firmware is buggy now  :-\  and you can't use it as you would like .
I would be pissed if I paid 300+ for a meter and the switch went bad in the first year or two.  The UNI-T was only $30 and really what I expect from a cheap meter with nominal use.  Same for BK and Mastech.  I consider them disposable.  But at $300 it better be built to stand the test of time.   

Same holds true for basic transients.  Last thing I want is a meter like my first brand new Fluke.  Look at it wrong and a $70+ dollar repair bill, that was in the 80s.  Firmware can be fixed but if the hardware is wrong, there is little you are going to do to correct it. 

My normal use of a handheld meter is pretty basic.  That's why I buy cheap, disposable meters for the garage.  The 121GW would be out of place in that environment.

For potential buyers is important to know the switch longevity , but users can't do anything as you said ( besides beeing pissed  >:()
So we concentrate on what can be changed , the firmware .
And without a mature firmware many switches will last for ever , who would use daily such a multimeter ?
Title: Re: EEVBlog 121GW Discussion thread
Post by: Seppy on January 08, 2019, 05:27:04 am
We understand your point of view ... your hobby testing how robust a meter is . As a user you dont care that much if the switch won't last only 20K cycles in the future ... but the firmware is buggy now  :-\  and you can't use it as you would like .
I would be pissed if I paid 300+ for a meter and the switch went bad in the first year or two.  The UNI-T was only $30 and really what I expect from a cheap meter with nominal use.  Same for BK and Mastech.  I consider them disposable.  But at $300 it better be built to stand the test of time.   

Same holds true for basic transients.  Last thing I want is a meter like my first brand new Fluke.  Look at it wrong and a $70+ dollar repair bill, that was in the 80s.  Firmware can be fixed but if the hardware is wrong, there is little you are going to do to correct it. 

My normal use of a handheld meter is pretty basic.  That's why I buy cheap, disposable meters for the garage.  The 121GW would be out of place in that environment.

For potential buyers is important to know the switch longevity , but users can't do anything as you said ( besides beeing pissed  >:()
So we concentrate on what can be changed , the firmware .
And without a mature firmware many switches will last for ever , who would use daily such a multimeter ?

I don't remember the exact count for our testing of the switch but I believe it was 40000. We did our range switch testing live on youtube.
Title: Re: EEVBlog 121GW Discussion thread
Post by: J-R on January 08, 2019, 06:26:01 am
Hello,

I would like to ask owners of the 121GW: Would you recommend this meter to be purchased in 2019 ? Are there still any software issues that still need to be resolved ? Are there any missing, unimplemented, features ?

Thank you !

Long time lurker, thought I'd chip in a few opinions about the 121GW.

I have about 30 different multimeters going back probably 75+ years (got some from my grandfather) and the 121GW is my most expensive/newest one.  I'm just a casual tinkerer/hobbyist.

What I like about the 121GW is that it is my most modern DMM (Bluetooth/logging/apps), I can update the firmware and there is a very active community for it.  It isn't perfect, nothing is.  I use it regularly, although not for everything. You do want multiple meters since each have their optimal uses and you also will need to check them against each other.

All the issues with the 121GW are basically known at this point and beaten to death.  What impacts me the most personally?  Resistance measurements are painfully slow.  I use my Micronta (22-167) if I need speed.  I recently obtained the DMMCheck Plus and like a kid in the candy store put all my meters through their paces.  The 121GW will take 17 seconds to measure the 4 precision resistors (v1.58 firmware).  The Micronta was 5 seconds (as was the BM235).  It's a manageable problem, but there nonetheless.

My three favorite DMMs right now are the 121GW (workbench), the Amprobe AM-47 (without the rubber case but with the VC3A nylon case, travel/work/backpack), and the UT210D (automotive/house/shop).

Title: Re: EEVBlog 121GW Discussion thread
Post by: Pat5 on January 08, 2019, 07:50:17 am
I would like to thank everyone for the valuable feedback. I was under the impression that resistance measurement was recently improved to around 4.2-4.5 seconds.

The range switch reliability is something which i haven't thought about and is a valid point: No matter how feature-full and accurate, how are you going to use your device if you can't turn it on ?
The above is an extreme example of course, but the idea of joeqsmith (mechanical stress) is well worth taking into consideration.

@exe Personally, I do not believe in objective, non-polarized opinions of people, which is why i'm interested in everyone's opinion. Polarization is the reason that i've chosen this thread to post in.

Again, Thank you !
Title: Re: EEVBlog 121GW Discussion thread
Post by: CDaniel on January 08, 2019, 08:42:24 am
The big step in my opinion would be to make a firmware capable of "normal" autorange hysteresis in all modes - volts , amps , resistance and so on.
Every multimeter has the advertised number of counts 4000 , 6000 , 50000 all the time and switches up and down above this value , lets say at 4400-4100 , 6600-6300 , 55000-52000 ...

Hysteresis is directly corelated with the autorange speed , if a meter could switch ranges instantly  , then there wouldn't be any hysteresis at all needed .

121GW has the biggest hysteresis I ever saw or heard ... 55000-40000 for resistance , 55000-44000 for volts , probably because it is so slow and an autorange loop could form easily if the voltage , resistance is variable up and down .

Title: Re: EEVBlog 121GW Discussion thread
Post by: exe on January 08, 2019, 09:04:32 am
Many (most?) meters at this price don't support firmware updates at all.

Because they don't need it?  >:D
Title: Re: EEVBlog 121GW Discussion thread
Post by: J-R on January 08, 2019, 09:09:28 am
I would like to thank everyone for the valuable feedback. I was under the impression that resistance measurement was recently improved to around 4.2-4.5 seconds.

The range switch reliability is something which i haven't thought about and is a valid point: No matter how feature-full and accurate, how are you going to use your device if you can't turn it on ?
The above is an extreme example of course, but the idea of joeqsmith (mechanical stress) is well worth taking into consideration.

@exe Personally, I do not believe in objective, non-polarized opinions of people, which is why i'm interested in everyone's opinion. Polarization is the reason that i've chosen this thread to post in.

Again, Thank you !

Just to clarify, I mean to test all 4 DMMCheck Plus resistors in a row takes me about about 17 seconds total on the 121GW vs. 5 seconds total on faster meters.  On the BM235, by the time I took my eyes off the probes and looked at the meter, it already had settled on the value.  It's lightning fast.  I have no problems recommending it for quickly checking a pile of random resistors.

Title: Re: EEVBlog 121GW Discussion thread
Post by: beanflying on January 08, 2019, 09:17:30 am
Many (most?) meters at this price don't support firmware updates at all.

Because they don't need it?  >:D


"Just to be clear, I bricked it with own firmware, not with the stock one."



Just to be clear maybe some shouldn't play with it either  ::)
Title: Re: EEVBlog 121GW Discussion thread
Post by: CDaniel on January 08, 2019, 09:33:35 am
You can't play with it so much , it is complicated to reverse engineear the code and maybe doesn't worth the pain ... so it is not hackable , just in theory .
Title: Re: EEVBlog 121GW Discussion thread
Post by: beanflying on January 08, 2019, 09:38:13 am
I would agree not worth the pain. I just upgraded mine February firmware to 1.5x and it has come a long way.

Taking a drive by sling about that firmware upgrade option from someone who broke one with their own was just a bit much. Anyone want to buy a secondhand meter  ::)
Title: Re: EEVBlog 121GW Discussion thread
Post by: FrankBuss on January 08, 2019, 11:36:02 am
You can't play with it so much , it is complicated to reverse engineear the code and maybe doesn't worth the pain ... so it is not hackable , just in theory .

Someone did already reverse engineered the firmware, and modified it for something, without even owning a 121GW, and it works. But there are not many such wizards out there.
Title: Re: EEVBlog 121GW Discussion thread
Post by: CDaniel on January 08, 2019, 11:59:50 am
I'm aware only for that "Hello World" on display , that is not difficult to create if you find in code the text "U-1.57" - the current software version displayed at start-up . You can replace it with everything ... your name maybe .  But to reverse engineer all , without the source code and to understand it , is much harder than to write your own code from scratch . A decompiler will give you something , but is not the original program , much of it must be interpreted and are many ways . That's why it is useless .
Title: Re: EEVBlog 121GW Discussion thread
Post by: Brumby on January 08, 2019, 12:18:56 pm
It's not useless ... just very challenging.

... but then I started out writing application software on mainframes in assembler.
Title: Re: EEVBlog 121GW Discussion thread
Post by: FrankBuss on January 08, 2019, 12:34:04 pm
I'm aware only for that "Hello World" on display , that is not difficult to create if you find in code the text "U-1.57" - the current software version displayed at start-up . You can replace it with everything ... your name maybe .  But to reverse engineer all , without the source code and to understand it , is much harder than to write your own code from scratch . A decompiler will give you something , but is not the original code , much must be interpreted and are many ways . That's why it is useless .

No, he increased the autorange speed, Dave did a video about it, too:

https://www.youtube.com/watch?v=3MD88EYLdQQ (https://www.youtube.com/watch?v=3MD88EYLdQQ)

He has published everything in Github:

https://github.com/tpwrules/121gw-re (https://github.com/tpwrules/121gw-re)

But you are right, probably not useful as the base for a fully open source version. But the circuit diagram is open source, so someone could develop a cleanroom implementation of an open source firmware for it. Shouldn't be too difficult, just a lot of work for all the functions the original firmware has.
Title: Re: EEVBlog 121GW Discussion thread
Post by: joeqsmith on January 08, 2019, 01:16:03 pm
We understand your point of view ... your hobby testing how robust a meter is . As a user you dont care that much if the switch won't last only 20K cycles in the future ... but the firmware is buggy now  :-\  and you can't use it as you would like .
I would be pissed if I paid 300+ for a meter and the switch went bad in the first year or two.  The UNI-T was only $30 and really what I expect from a cheap meter with nominal use.  Same for BK and Mastech.  I consider them disposable.  But at $300 it better be built to stand the test of time.   

Same holds true for basic transients.  Last thing I want is a meter like my first brand new Fluke.  Look at it wrong and a $70+ dollar repair bill, that was in the 80s.  Firmware can be fixed but if the hardware is wrong, there is little you are going to do to correct it. 

My normal use of a handheld meter is pretty basic.  That's why I buy cheap, disposable meters for the garage.  The 121GW would be out of place in that environment.

For potential buyers is important to know the switch longevity , but users can't do anything as you said ( besides beeing pissed  >:()
So we concentrate on what can be changed , the firmware .
And without a mature firmware many switches will last for ever , who would use daily such a multimeter ?

I don't remember the exact count for our testing of the switch but I believe it was 40000. We did our range switch testing live on youtube.

From previous post
Quote
  Yea, I know Dave ran what he called his 50,000 cycle test on it, I watched.   

But again, from pictures people have posted (no my pictures), it appears that the contact has changed.  They had both the single double dimple designs.  I have no idea what is in there today and how it compares with what you tested or why it was changed.   I would like to see you repeat your testing without the yellow sticky notes, with both contact designs and again after the shim has been designed out.  Then again, it's a bit of work.  I've seen switches go bad on enough of these cheap meters that personally, I don't trust it.   Adding the shim last minute didn't build confidence.  That's my feeling. 



No, he increased the autorange speed, Dave did a video about it, too:
...
He has published everything in Github:
...
But you are right, probably not useful as the base for a fully open source version. But the circuit diagram is open source, so someone could develop a cleanroom implementation of an open source firmware for it. Shouldn't be too difficult, just a lot of work for all the functions the original firmware has.
The same person pointed out one of the changes to the code that effected the filter and also found the code that had the logical error for the lead insertion test. 

I suspect that it is more difficult than you think which is why talk surrounding the firmware continues a year after they started shipping. 
Title: 121GW Range Switch Cycle Testing
Post by: Marco1971 on January 08, 2019, 05:20:58 pm
https://www.youtube.com/watch?v=u2-ot2vWLxI (https://www.youtube.com/watch?v=u2-ot2vWLxI)
Title: Re: EEVBlog 121GW Discussion thread
Post by: newbrain on January 10, 2019, 12:28:42 pm
Every multimeter has the advertised number of counts 4000 , 6000 , 50000 all the time and switches up and down above this value , lets say at 4400-4100 , 6600-6300 , 55000-52000 ...
False, neither Fluke 87-V (https://www.eevblog.com/forum/testgear/eevblog-121gw-discussion-thread/msg1829909/#msg1829909) nor (AFAICR) UNI-T 61D do that.
Title: Re: EEVBlog 121GW Discussion thread
Post by: CDaniel on January 10, 2019, 01:55:23 pm
Pretty bad , I hope you don't want 121GW to copy the exceptions or slow meters with the hardware that it has ...

If the hysteresis is very big will eat some resolution because for a 50.000 count meter you can't use a giant up level like 65.000 just to have down level above 50.000 count .
I think  I don't have to explain again that if you adjust a voltage up and down you will experience this loss of resolution .
Anyway the switching should be as seamless as possible , not this huge hysteresis and slowness that now the firmware has ... I don't think any user would want different or wouldn't care
Title: Re: EEVBlog 121GW Discussion thread
Post by: GeoffreyF on January 10, 2019, 06:45:11 pm
Pretty bad , I hope you don't want 121GW to copy the exceptions or slow meters with the hardware that it has ...

If the hysteresis is very big will eat some resolution because for a 50.000 count meter you can't use a giant up level like 65.000 just to have down level above 50.000 count .
I think  I don't have to explain again that if you adjust a voltage up and down you will experience this loss of resolution .
Anyway the switching should be as seamless as possible , not this huge hysteresis and slowness that now the firmware has ... I don't think any user would want different or wouldn't care

I have to wonder what you use meters for.  When I stick my probe in a circuit, I have a pretty good idea what my expectations are because I know how to read a schematic.   If  it turns out my range choice was wrong (that button which says "Range") then I can select another range.   If I really have no idea at all (which is rare) then auto range is quite handy. 

ALL engineering involves compromises which fit around expected use.  So does equipment purchase selection.  In your posts, that concept rarely if ever appears.  The cost of a meter is not that much of an issue if actually using it makes sense.  The 121GW is a good meter for many purposes. Others are good for other things.   This is why people buy different meters.  The 121GW meets the specifications on its tin and always has.   It's great that there are firmware updates.  THAT IS NOT BAD - IT IS GOOD.
Title: Re: EEVBlog 121GW Discussion thread
Post by: newbrain on January 10, 2019, 07:00:10 pm
[...] to copy the exceptions [...]
I'm honestly interested to know which DMMs have a down-range threshold higher than the nominal target range as you have stated.
Can you demonstrably name some?
It looks like an unnatural design decision.

I have provided counter examples to your statement, to which I can add all the Fortune (https://www.ic-fortune.com/upload/Download/FS9721B-DS-17_EN.pdf) chip (https://www.ic-fortune.com/upload/Download/FS9721_LP3-DS-21_EN.pdf) based (https://www.ic-fortune.com/upload/Download/FS9922-DMM4-DS-14_EN.pdf) DMM (https://www.ic-fortune.com/upload/Download/FS9952_LP1-DS-20_EN.pdf) (just check each link).

I can agree (as I did answering your original post) that 121GW thresholds could be somewhat tighter, but please cease this 4 months prolonged cruelty to a deceased ungulate.
 :horse: :horse: :horse: :horse:
Title: Re: EEVBlog 121GW Discussion thread
Post by: CDaniel on January 10, 2019, 08:59:40 pm
Hmm , almost all , if not all , multimeters with the microcontroller imbedded with the measurement chipset , old and new , even the cheapest chinese ones . And the fast multimeters with separate microcontroller ... the extreme hysteresis that needs to go below the nominal counts is a clear indication for slow autoranging .
Title: Re: EEVBlog 121GW Discussion thread
Post by: joeqsmith on January 11, 2019, 01:07:14 am
The big step in my opinion would be to make a firmware capable of "normal" autorange hysteresis in all modes - volts , amps , resistance and so on.
Every multimeter has the advertised number of counts 4000 , 6000 , 50000 all the time and switches up and down above this value , lets say at 4400-4100 , 6600-6300 , 55000-52000 ...

According to your post, which is presented as an absolute statement of fact, EVERY multimeter does this in EVERY function and EVERY range.  If that is true, it would be easy enough to just run DCV for example and sweep it around the first switch point.  There would be no need to check every switch point and every function, correct?   

If the above is correct, I have a few meters that have survived that I could check easy enough.  Then again, you already KNOW the outcome.  So really, there's no point in checking, right? 

Quote
Hmm , almost all , if not all , multimeters with the microcontroller imbedded with the measurement chipset , old and new , even the cheapest chinese ones .
Sorry missed this one.  So it's not for certain EVERY meter as you first state.  It's all or almost all. 

Not being the king of person that would ever listen to what someone has to post on the WWW about meters, I decided to run a few in the DCV mode at the first switch point.  I ran them a few times.

Gossen, M248B, 300K count,  3.07, 2.89      Not off to a real good start for your Almost all, Every statements...
Fluke, 189, 50K, 5.5, 4.89                             2 for 2
Brymen, BM869s, 50K,  5.25,  4.60               Well my favorite meter is at least in with a good group....
Summit, TPI 194II, 50K, 4.99, 4.03               Didn't even make it to 5.0...
UNI-T, UT181A, 60K, 5.9, 5.6                         Again, it didn't make it to 6.0
Brymen, BM839, 20K, 1.93, 1.84                   I am seeing a trend...
Fluke, 87V HR, 20K, 1.99, 1.69                      Yes, there is a trend..
CEM, DT9939, 40K, 4.04, 3.90                       Full disclosure, I actually ran my Extech EX540.  It's just a rebrand of that meter

Well I put in some effort to try and help your case but it seems in doing so, I discovered like so often on the internet, you havn't a clue.   

*****
Mastech, MS8229, 4K, 4.01, 3.60                This meter has some really interesting features. 
Kasuntest, ZT102, 6K, 6.19, 5.74
Fluke, 107, 6K, 5.99, 5.40
AMPROBE, AM530, 4K, 4.028,  3.60

So are you clueless as I think you are, or am I missing the point of your rants?    Feel free to explain your side.  All I have is data.

*****
OWON, B41T+, 22K, 2.257, 2.02               
UNI-T, UT61E, 22K, 2.25, 1.97

Surely you are going to show what we are doing wrong?
Title: Re: EEVBlog 121GW Discussion thread
Post by: GeoffreyF on January 11, 2019, 02:22:46 am
Hmm , almost all , if not all , multimeters with the microcontroller imbedded with the measurement chipset , old and new , even the cheapest chinese ones . And the fast multimeters with separate microcontroller ... the extreme hysteresis that needs to go below the nominal counts is a clear indication for slow autoranging .

Name some meters.  Describe the tests you used to make this benighted determination.  Provide numbers including time and tables of results for these tests you didn't do.  Also, please tell us the accuracy of these meters which you like or think are better in this regard.  - of course you don't even know why I asked you that but you would if you actually read and thought about prior posts.  Name exactly what it is you do with multimeter's that makes your "observations" such a high priority.  Of course you can't do any of this.  You never will.  Nothing you have written is of any actionable use and you obviously have no clue that it isn't.  In all your posts you somehow imagine you will be taken seriously - please consider that a number of people who have never met and don't know each other are simply annoyed with your tedious, redundant, not objective, numerical or measured opinions.  If it's credibility you seek - each post is the opposite of that.   
Title: Re: EEVBlog 121GW Discussion thread
Post by: 2N3055 on January 11, 2019, 07:13:10 am
Metrix 3293, 10.0000 scale :  going up at 9.9999, down at 09.900
Title: Re: EEVBlog 121GW Discussion thread
Post by: GeoffreyF on January 11, 2019, 01:24:49 pm
Metrix 3293, 10.0000 scale :  going up at 9.9999, down at 09.900

And the price? 
Title: Re: EEVBlog 121GW Discussion thread
Post by: 2N3055 on January 11, 2019, 01:54:39 pm
Metrix 3293, 10.0000 scale :  going up at 9.9999, down at 09.900

And the price?
Less than the Gossen mentioned, we're discussing now where different meters switch scales in auto. Not comparing other things..
Title: Re: EEVBlog 121GW Discussion thread
Post by: chronos42 on January 11, 2019, 06:54:04 pm
Metrix 3293, 10.0000 scale :  going up at 9.9999, down at 09.900

Some more data from my handheld meters in the 5V range:

Agilent U1252B, 50000 counts: up 5.2000V, down 4.5000V

Fluke 287, 50000 counts: up 5.5000V, down 4.5000V

Gossen Metrahit Energy, 60000 counts: up 6.1000V, down 5.4000V

Title: Re: EEVBlog 121GW Discussion thread
Post by: Messtechniker on January 12, 2019, 08:54:05 am
VC 940 (UT71E): 4.0 V up 3.8 V down
34465A: 1.2 V up 1.0 V down
Title: Re: EEVBlog 121GW Discussion thread
Post by: newbrain on January 12, 2019, 09:33:22 am
34465A: 1.2 V up 1.0 V down
:scared: Finally we got a winner!  :scared:
The nominal counts for this meter are 1000000, so its hysteresis is not across its range but above!

All the others meters must clearly be exceptions!
 :-DD :palm: :-DD
Title: Re: EEVBlog 121GW Discussion thread
Post by: beanflying on January 12, 2019, 10:06:47 am
You guys are clearly unable to see the immensity of the issue and pushing the manual range button is just so hard  :o

Cruddy Victor 86B 4000 count logging meter up at 4000 and down at 3500.

My couple of bench meters so not perhaps applicable.
Agilent 34401A up at 1200000 and down at 1000000 having to lock ranges measuring 1 & 10V references is destroying my faith in it as it loses resolution :-DD
Advantest 6871E up at 2000000 and down at 1800000 clearly a superior beast for Vref testing at 1 & 10V as the Auto range is 'perfect' for the measurement at hand.

Think you will find the 34465A is 'rated' at 120K 100k + 20% over range as it is 34401a derived.

Want more resolution push a button or buy a better meter?

Quote
From the 34401A manual

Resolution
Resolution is the numeric ratio of the maximum displayed value divided
by the minimum displayed value on a selected range. Resolution is
often expressed in percent, parts-per-million (ppm), counts, or bits.
For example, a 6 1⁄2-digit multimeter with 20% overrange capability can
display a measurement with up to 1,200,000 counts of resolution.
This corresponds to about 0.0001% (1 ppm) of full scale, or 21 bits
including the sign bit. All four specifications are equivalent

edit must wear glasses or use commas typing 000's
Title: Re: EEVBlog 121GW Discussion thread
Post by: joeqsmith on January 12, 2019, 08:29:13 pm
Updated my list again.  The OWON and UT61E are both listed at 22,000 count meters.  Once again, the break points straddle the rated count. 

I am still looking for at least one handheld meter that does what CDaniel claims they do.  Surely they must have seen this at least once in their life to make such a bold claim but I think it would be difficult to locate based on the data we have gathered so far.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Dundarave on January 13, 2019, 04:09:51 am
I'm just about to order up a 121GW for myself, after assimilating the combined wisdom in the various 121GW threads.  The meter appears to offer incredible value, and it will certainly fit my needs, despite any arguable negatives.

But before I placed my order, I did want to confirm that there is no new hardware version imminent, like, shipping the day after I get the current version delivered, lol.

I realize that firmware updates are an ongoing thing, but I would just hate to miss out on hardware version 2.0 or whatever by a few weeks and end up with "old stock" (although I realize that getting in on the first run of any manufacturing version has its risks).

Thanks -  :-DMM
Title: Re: EEVBlog 121GW Discussion thread
Post by: GeoffreyF on January 13, 2019, 02:57:02 pm
I see no reason to believe there is a new hardware version coming out, not at least in the sense that it would be improved or have better specifications.   With any other meter, it would be rather hard to say that because such things are more closed.  With this one, it would be actively discussed here.   That said, there is always the possibility with any manufactured product of minor changes but not ones which appreciably alter the specifications.

There also may be other firms with something in the offing that would be interesting but this particular meter is also a relatively new release itself.   My sense or view of such things is whether the product is the best for your purposes and purse.  If yes, then that's it.  If not, then keep shopping. My sense of where things are going is that there is more specialization for particular trades.  General purpose meters are pretty similar but differ in ruggedness or accuracy - tracking price.   I like my 121 GW a lot.  It's been great.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on January 22, 2019, 11:23:17 am
But before I placed my order, I did want to confirm that there is no new hardware version imminent, like, shipping the day after I get the current version delivered, lol.
I realize that firmware updates are an ongoing thing, but I would just hate to miss out on hardware version 2.0 or whatever by a few weeks and end up with "old stock" (although I realize that getting in on the first run of any manufacturing version has its risks).

Nope, no new v2.0 hardware coming any time soon. There is a new PCB layout to integrate the current mods that has supposedly been done, but I have not even seen a prototype of that yet. I wouldn't really call it a V2 meter.
Get the firmware sorted on Git so we have some control of it is the big thing we want to do.
Title: Re: EEVBlog 121GW Discussion thread
Post by: fboehle on January 22, 2019, 05:05:26 pm
I feel a public bug tracker for the firmware would be also imensly helpful...
But before I placed my order, I did want to confirm that there is no new hardware version imminent, like, shipping the day after I get the current version delivered, lol.
I realize that firmware updates are an ongoing thing, but I would just hate to miss out on hardware version 2.0 or whatever by a few weeks and end up with "old stock" (although I realize that getting in on the first run of any manufacturing version has its risks).

Nope, no new v2.0 hardware coming any time soon. There is a new PCB layout to integrate the current mods that has supposedly been done, but I have not even seen a prototype of that yet. I wouldn't really call it a V2 meter.
Get the firmware sorted on Git so we have some control of it is the big thing we want to do.
Title: Re: EEVBlog 121GW Discussion thread
Post by: beanflying on January 24, 2019, 04:32:35 am
Had a proper play with the autorange resistance switching with V1.58 Beta and had a play with the bluetooth/app I haven't used for a while. Both have improved :-+

Disaster of all disasters it selected 0.4998 k \$\Omega\$ on one occasion instead of the 500.12  \$\Omega\$ it selected on another (34401A 500.034) ::)

Circa 25C data for comparison 500 \$\Omega\$   500.04   121GW      500.017   34401A

Improving the time coding of the bluetooth data recorded straight off the app might be nice 0.5, 1.0, 1.5 ..... :) Currently over 40C in the shack makes it  :popcorn: o'clock.

Quote
Time (s), Temp (°C)
0, 37.8
0.486785, 37.6
1.512485, 37.6
1.999798, 37.6
2.487146, 37.6
2.973385, 37.6
3.460483, 37.6
3.996788, 37.6
4.483994, 37.6
4.971935, 37.6
5.460796, 37.6
........
Title: Re: EEVBlog 121GW Discussion thread
Post by: Seppy on January 29, 2019, 06:11:00 am
Had a proper play with the autorange resistance switching with V1.58 Beta and had a play with the bluetooth/app I haven't used for a while. Both have improved :-+

Disaster of all disasters it selected 0.4998 k \$\Omega\$ on one occasion instead of the 500.12  \$\Omega\$ it selected on another (34401A 500.034) ::)

Circa 25C data for comparison 500 \$\Omega\$   500.04   121GW      500.017   34401A

Improving the time coding of the bluetooth data recorded straight off the app might be nice 0.5, 1.0, 1.5 ..... :) Currently over 40C in the shack makes it  :popcorn: o'clock.

Quote
Time (s), Temp (°C)
0, 37.8
0.486785, 37.6
1.512485, 37.6
1.999798, 37.6
2.487146, 37.6
2.973385, 37.6
3.460483, 37.6
3.996788, 37.6
4.483994, 37.6
4.971935, 37.6
5.460796, 37.6
........

The app timing is as shown above is because the samples are not sent with time information and if a sample is dropped it would result in an incorrect value for time (because it would need to be based on 0.5s increments). For example:

0.5
1.0 <- if this was dropped
1.5 <- this would be 1.0

For this reason you see the jitter (the time fluctuations in the decimal points) in the samples, that jitter is the result of the bluetooth overhead. I will try get this added to the packet.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Kean on January 29, 2019, 06:51:03 am
3 decimal places would probably also be sufficient  >:D
Title: Re: EEVBlog 121GW Discussion thread
Post by: Seppy on January 30, 2019, 05:05:45 am
3 decimal places would probably also be sufficient  >:D
LOL definitely. but I'd prefer leave that up to the end user.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Kean on January 30, 2019, 05:17:20 am
3 decimal places would probably also be sufficient  >:D
LOL definitely. but I'd prefer leave that up to the end user.

Sure - sometimes that is useful.  But here (especially with the BLE latency) the time resolution is probably only accurate to several milliseconds.
ISTR the meter can only report at 5Hz, 200ms intervals.  So what point is there in giving microsecond resolution?  It is just misleading.
If someone actually needed microsecond resolution of the readings, they'd be using a completely different instrument.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on February 08, 2019, 12:28:30 am
A user wrote a new version of the manual which looks much more professional:
http://www.eevblog.com/files/121GW-Manual-v12-proto.pdf (http://www.eevblog.com/files/121GW-Manual-v12-proto.pdf)
Not finished yet, wants a yay or nay to continue to finish it off.
It seems based on an older revision, and it's A4 instead of the A5 we have at the moment.
Feedback welcome.
Title: Re: EEVBlog 121GW Discussion thread
Post by: GeoffreyF on February 08, 2019, 01:49:29 am
I like it. It's much more professional and the diagrams are clearer.  Though the 'gray text' is artistic, it might be a bit not dark / contrasting enough.  How will a printed version do in very strong or very weak lighting? (which is often where multi-meters are used).   There also seem to be a few pages without much on them such as "Back light" and of course a few blanks at the end.

I don't find a need to carry a manual with me. However those who do might like the narrower page format better.  Will the printed version fit neatly in the case?

Suggest formatting for two sided pages.

Side note: If 1.58 beta is complete, tell us and update the description in the store accordingly.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Brumby on February 08, 2019, 02:39:55 am
Just a quick examination, but my thoughts so far....


This is certainly a good effort and I would encourage its further development.  It does seem to have been prepared by someone with an artistic air - and while that can produce aesthetically pleasing results, I feel it can introduce difficulties in what is a document for a working environment where you have to work past the "styling" to get to the facts.

I have to agree with the grey text being harder to read because of reduced contrast.  I would also say that the bulk of this text is also more difficult to read because it is of a fine line style.  When screen reading at text width scale on a FHD monitor, many lines forming the letters are only 1 pixel thick.  I printed a page on a monochrome laser printer and found the same reading difficulty.   Although I, personally, might like another point or two, the font size is acceptable - but the font colour needs to be black and the font line thickness needs to be greater.

The same can essentially be said about the pale blue headings.  They don't jump out the way I would like.  I tried changing the colour of this text to "EEVblog blue" and it was much better.  (I suggest another point or two on the font size would be good.)

I would also suggest an A5 page size.  If the document does get printed, then that is going to be a more portable size.  Also, on screen reading will naturally increase the physical size of the fonts on the monitor.

There are a couple of other comments - but I can see they are the sort of things you get with a work in progress.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Dr. Frank on February 08, 2019, 07:33:59 am
From standpoint of standardization, it's not acceptable to have two different sources or owners of a document. Usually, the intellectual owner of the DMM should also be the owner / author of the document.
'Seppy' seems to represent that role, currently.

If he would hand over the full responsibility and also the latest source code of the document (vers. from 8th Feb. 2019), it would be ok.

The alternative document currently contains a lot of old errors, is partly incomplete, and is in a premature state.

So I decline this document, as nice it may look on the first few pages.

Frank
Title: Re: EEVBlog 121GW Discussion thread
Post by: bitwelder on February 08, 2019, 09:41:16 am
I like the new layout of the manual,
but at least reading it with the built-in PDF reader of Chrome and Firefox on my Linux workstation, one page that included several symbols got messed in rendering (see attachment).
Title: Re: EEVBlog 121GW Discussion thread
Post by: Brumby on February 08, 2019, 10:30:26 am
I got that same misalignment using Acrobat Reader DC.

That's one of the things I put down as a WIP issue.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Octane on February 08, 2019, 01:21:41 pm
From standpoint of standardization, it's not acceptable to have two different sources or owners of a document. Usually, the intellectual owner of the DMM should also be the owner / author of the document.
'Seppy' seems to represent that role, currently.

If he would hand over the full responsibility and also the latest source code of the document (vers. from 8th Feb. 2019), it would be ok.
So you are saying that manual writing cannot be outsourced? Or be done in collaboration?

Quote
The alternative document currently contains a lot of old errors, is partly incomplete, and is in a premature state.
Did you read the full post from EEVBlog? He stated that it is based on an older revision currently and that it is not finished. I assume if there are enough yays, and the design and readability issues are ironed out, that it will be updated to the latest revision and checked and corrected by EEVBlog and Seppy.

Quote
So I decline this document, as nice it may look on the first few pages.
You can keep using the original.

I for my part like the new document very much. Although I agree with many other comments about readability. Grey is suboptimal. The design overall get’s a big plus from me. A professional meter needs a professional looking manual, not one that look’s like it’s made in a copyshop.

BR,
Michael
Title: Re: EEVBlog 121GW Discussion thread
Post by: Andre Gulbis on February 08, 2019, 03:00:04 pm
Hey guys, Andre here - the creator of the 121 Manual/PDF Dave posted.

TLDR Version
Did in Indesign & Illustrator last year over a few months when I got my 121, got busy so couldn't finish, forgot about - remembered today, on whim exported to PDF and sent to Dave - he posted it to this thread!
Thanks for feedback - I am at the communities mercy.  What I have done I consider owned by the EEVBlog community.
Didn't know other work was being done - silly of me not to check.
Slight interloper feelings.
Cheers & ill keep looking at this thread to see what you think.
Andre


Longer Version
Let me give you a little background to this silly incomplete version of the manual.

When I received delivery of my 121GW last year I, of course, wanted to take a look at the manual.
At that time it was the 24 Jan 2018.
Straight away I had a desire to re-do it so it could be as good as maybe a Keysight one.
OCD kicked in.

I didn't contact Dave, didn't look on the forum - I just started.  Bit silly in hindsight.

So the front pic looked like an older version of the meter from when UEI and Dave were refining the design.
So I re-drew it in Illustrator and did it "properly, properly" - used a caliper to measure all dimensions & fonts etc.
I have all that as separate layered Illustrator/vector files.

Then I went through the manual and noticed the descriptions of each position/range etc wasn't 100% consistent.
So if you look through my version properly you will notice it's not just a re-styled version of the 24 Jan version, it a bit re-structured.  The TOC gives you an idea of how its presents.

I tried to get the terms/language consistent  - the rotary switch has 'Positions', containing 1 or more 'Modes'.
And I thought that 'Range' was to be reserved for actual auto/manual change of a range within a mode...
Studied the Keysight/Aglient manuals for U12XXX series a bit, since Ive got one of those.
Anyways, added the Positions and Modes pages 29-31 as a complete overview.
Came up with some new graphics and layouts, like on pages 42, 43, 44.
Also updated the inline button artwork, and the text itself in pages like 50.

So I worked on it for a few months, then got swamped with work, and have been ever since.

I almost forgot about it(!) but used my 121 yesterday and I remembered.
So just on a whim I exported to PDF and sent to Dave.
He got back to me really quick and said that he'd put it on the forum!

As you can tell, much is not finished.
I didn't write it from top to bottom, but was jumping around, so random bits are not done.
And I never did get up to the end sections.

Those large overlapping vector graphics in the TOC I forgot to resize - has to manually be done.
Yeah the text colour is too arty-farty - should be darker.
A5 is no problem....

But it looks like I have thrown a spanner the the works as you guys have been working on another updated version.
And of course people have ownership/are invested in work.
So I am totally open to whatever you guys say.
I can just leave it, or hand it over to other people - make all the vectors available etc.
Or I can redo it to match what you've got, or do a combination of both.

There's also the Illustrator/Indesign thing - so even though that's "Industry Standard" etc it matters not if you guys aren't happy with the format.
Whatever I have done so far belongs to the EEVBlog community.
Feel like a bit of an interloper since I didn't have enough sense to first check the community, and this has kinda just been chucked in the square.

Sorry that was a bit long winded.
Cheers & ill keep reading the posts here to see what ya think.

Andre




Title: Re: EEVBlog 121GW Discussion thread
Post by: Dr. Frank on February 08, 2019, 03:09:44 pm
From standpoint of standardization, it's not acceptable to have two different sources or owners of a document. Usually, the intellectual owner of the DMM should also be the owner / author of the document.
'Seppy' seems to represent that role, currently.

If he would hand over the full responsibility and also the latest source code of the document (vers. from 8th Feb. 2019), it would be ok.
So you are saying that manual writing cannot be outsourced? Or be done in collaboration?

Quote
The alternative document currently contains a lot of old errors, is partly incomplete, and is in a premature state.
Did you read the full post from EEVBlog? He stated that it is based on an older revision currently and that it is not finished. I assume if there are enough yays, and the design and readability issues are ironed out, that it will be updated to the latest revision and checked and corrected by EEVBlog and Seppy.

Quote
So I decline this document, as nice it may look on the first few pages.
You can keep using the original.

I for my part like the new document very much. Although I agree with many other comments about readability. Grey is suboptimal. The design overall get’s a big plus from me. A professional meter needs a professional looking manual, not one that look’s like it’s made in a copyshop.

BR,
Michael


Well, I view the whole story from a professional standardization point of view, inside a big electronics company, so I simply dislike the obvious multiplicity of sources, and fear undirected documentation status.
There is really no indication, that the responsibility for this document should be handed over from Seppy to the alternative author, it's only speculation, what's going on... no sign of collabration, outsourcing, handing over, or whatever. A German saying is: 'Several cooks spoil the meal', and that also goes here..

If the author had the intention to seriously make a working copy, the status of the document could already have been much better; so I needed to emphasize on that retarded status from before about July 2018, (not October!!), despite Daves text, which I of course have read.

A nice design is one thing, but if the author is not able to deliver better content, my future expectations and my opinion about the document is settled, and that's what Dave also asked for.

Btw. the (future) Change Management should also be handled by one person, so I see further ambiguity.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Andre Gulbis on February 08, 2019, 04:24:00 pm
Yeah Dr.Frank I understand.  Accurate info and tracked doco status etc is more important than a fluffy design.
And it looks like you got that system setup for an updated version of the 121 manual already.

(I actually did a stint working for Standards Australia writing and updating Australian Standards - so Ive been well into that. - Back then it was Word 97(?) track changes/templates/macros and Styles mapped to XML with XSTL.)

Dr.F. I am sorry it wasn't prepped and presented better to you guys - it was out of left-field with no introduction or solid grounding, and you knew nothing of me or my intentions.
I didn't know Dave would just throw it straight up on the forum!  But I understand fully why he did.
But that's my fault for being so casual about it and not knowing that others are invested in an updated manual.

So that's where it's at.
Cheers Dr.Frank and I guess we'll see what other say.


PS
I shall indulge in just a little self-defence.
The only part of your last comment I would refute is "not delivering better content".
I'm not sure how much of the PDF you have looked at, but much is new and updated/restructured.
The first pages are more of a face-lift, but the other sections I worked on for some months, working on terms, consistency, readability, cross-references and of course highly accurate artwork.
It's definitely not just a re-style of the original manual.
Cheers mate!
Title: Re: EEVBlog 121GW Discussion thread
Post by: bicycleguy on February 08, 2019, 06:32:52 pm
A user wrote a new version of the manual which looks much more professional:
...Feedback welcome.
6 for original 1/2 dozen for new.  I don't mind who does the manual but really like'd that errors and short comings could be posted in the issues thread and were responded to and incorporated where useful.  Not sure why some of this guys ideas weren't just incorporated but can see why the feedback request.

I see nothing wrong with having more help on the manual as long as all input is reasonably considered as it has been in the past.
Title: Re: EEVBlog 121GW Discussion thread
Post by: jancumps on February 08, 2019, 10:40:41 pm
This is a supporting manual, not a spec or design doc.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Brumby on February 08, 2019, 11:36:42 pm
I feel Dr. Frank's criticisms, while valid, are a bit harsh.

 * The dated origins of the work so far has been explained.
 * The immature state of what has been presented is nothing more than it being a work in progress.  There is a lot of work required to produce this sort of documentation and there is wisdom in offering a sample before uncountable hours are invested in a product that will be rejected - or where recommended changes could mean massive re-work.
 * From what I have read, control of the document is a matter that is up for discussion.

The first two will be addressed in due course, assuming the "go-ahead" is given and defining the means for control of the document isn't an exercise in astrophysics.

If Andre Gulbis wants to continue with his efforts, then there is only one risk - and that is the risk of his efforts being passed by.  If he is OK with that, then I don't see why he can't keep going, if he wants to.

I know I've thrown some ideas for graphics up on this forum - and it has always been on the basis of accepting whatever fate befalls it.  Whether others feel it uninteresting, laughable, liked or adopted for international distribution - I am OK with any of it.
Title: Re: EEVBlog 121GW Discussion thread
Post by: beanflying on February 08, 2019, 11:50:18 pm
One of the realities of manuals in a modern environment is those that come from online sources how many ever get printed out?

Making the manual screen/computer compatible is in some ways more important than printed layout IMO. If I was to print manuals for the Test gear I have it would likely run to well over 1000 pages so unless it came with a manual I am unlikely to print them out much as I have a preference for printed manuals.

While that may seem contradictory to please the majority it needs to be considered when arriving at a layout and page sizing.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Andre Gulbis on February 09, 2019, 10:49:03 am
Hey beanflying yeah I forgot to mention that.

Since it's in Indesign, and completely structured with a hierarchy of styles (It kinda has to be so you can produce the TOCs), you can map those styles to XML tags - and just export to XML/HTML or whatever you want - then just do CSS do XSL/XSTL etc.

I've done that before with other documents a client wanted online - so you get the nice printed version, and at the press of a button you get the fully published XML/HTML version.

So that option is there as well - I can do a demo with the incomplete version if you want.

Of course if you have it in MS Word there are third party products that can map Word Styles >> Intermediate Tag Map >> XML Tag Map.   Ive that before as well, and automatically with Tomcat on a server!  There was some free French authored Java app years ago that did it...

Anyways - yes that can be done.
Cheers!

Andre
Title: Re: EEVBlog 121GW Discussion thread
Post by: joeqsmith on February 10, 2019, 05:54:52 pm
KainkaLabs released a few videos showing the 121GW.  While he mentions they are not a review, he does go into a more details than most.   

https://www.youtube.com/channel/UCd8CdLp2bKP6Uv0jvdLdiRA (https://www.youtube.com/channel/UCd8CdLp2bKP6Uv0jvdLdiRA)
Title: Re: EEVBlog 121GW Discussion thread
Post by: joeqsmith on February 10, 2019, 06:22:52 pm
Looked over the new manual.  I personally like the format.  After watching KainkaLabs Part 3 and reading the manual, I was reminded of a problem I came across when I looked at the prototype 121GW when measuring VA.  Those who caught that video may remember Dave suggesting that I had the meter incorrectly connected.  You may also remember I had been trying to see if the meter handled the burden voltage correctly which it seems like it was not included in the calculation.  Because KainkaLabs is the first person I have seen run this demo, I have asked them to repeat their test, changing the configuration as shown.   

Quote
KainkaLabs  If you make another video, it would be good to see you rerun the VA test as well. When I looked at the prototype meter, there was a problem when using this mode. I think your are the first person to demo it. Basically, how you have connected it is what they show in the manual. However, when I looked at it, it seemed that the firmware did not account for the burden voltage. To get around this, I placed the meter's common point to the low side of the load, Vin to the other side of the load and the current back to the supply. Basically removing the burden from the voltage calculation. After I did this, the numbers would come out correctly. I will post a picture on to the main page I linked if you are not understanding.
Title: Re: EEVBlog 121GW Discussion thread
Post by: joeqsmith on February 10, 2019, 06:32:03 pm
Shown connected with the meters current in the source side of the load.  Again, the meter reading the voltage across the load without the effects of the burden. 
Title: Re: EEVBlog 121GW Discussion thread
Post by: joearkay on February 13, 2019, 09:46:55 am
Beginner question - I've been looking at the current measurement specs of the 121GW. The smallest DC A range is stated as 50uA^5.


What does this notation represent? I'm used to both engineering and scientific notation, but this stumped me a little. Does it literally mean 50^5uA = 312500000? I've never 'deep dived' into DMO specs before so it may be a common practise that I just haven't seen before. Thanks.
Title: Re: EEVBlog 121GW Discussion thread
Post by: ascomm on February 13, 2019, 10:27:29 am
Is it by design that the resistance measurement in auto range is quite slow?
At times it is pretty annoying to wait for the read out.
Title: Re: EEVBlog 121GW Discussion thread
Post by: exe on February 13, 2019, 02:41:30 pm
Could someone please share calibration data? I lost it while messing up with the meter and not all ranges I can calibrate (like I don't have a high-voltage source for AC, for example). I know results won't be perfect, but it's fine :)
Title: Re: EEVBlog 121GW Discussion thread
Post by: Octane on February 13, 2019, 02:54:46 pm
Hi joearkay,

Isn’t the ^5 a footnote? I didn’t check. Just an idea.

BR,
Michael
Title: Re: EEVBlog 121GW Discussion thread
Post by: IanB on February 13, 2019, 03:37:55 pm
Beginner question - I've been looking at the current measurement specs of the 121GW. The smallest DC A range is stated as 50uA^5.


What does this notation represent? I'm used to both engineering and scientific notation, but this stumped me a little. Does it literally mean 50^5uA = 312500000? I've never 'deep dived' into DMO specs before so it may be a common practise that I just haven't seen before. Thanks.

Isn’t the ^5 a footnote? I didn’t check. Just an idea.

Exactly.

Quote
DC A    50 µA5
...
5 This mode will use the x10 amplifier and may have additional offset error that should be REL’d out before measurement.

Title: Re: EEVBlog 121GW Discussion thread
Post by: joeqsmith on February 20, 2019, 12:34:23 pm
Looks like Rodger repeated the test I ran with the VA mode.  It's been almost two years since I posted the original video showing the problems and possible workarounds.  At the time it caused a lot of confusion.   Even Dave seemed lost and when the guy selling the product and testing the prototypes is not following, you have a problem.   Maybe Rodger's testing will be presented in such a way that will be easier to understand. 

https://www.youtube.com/channel/UCd8CdLp2bKP6Uv0jvdLdiRA (https://www.youtube.com/channel/UCd8CdLp2bKP6Uv0jvdLdiRA)
Title: Re: EEVBlog 121GW Discussion thread
Post by: GeoffreyF on February 20, 2019, 01:55:47 pm
Is it by design that the resistance measurement in auto range is quite slow?
At times it is pretty annoying to wait for the read out.

In this or any other meter, I don't use auto range unless I have absolutely no idea what range the expected value is in.   I set the range to what my expectations are.  If it goes out of range, I revert to auto range.   If one is debugging something - there is not such a thing as autorange that is fast enough though some are faster than others.  ALSO - if you are measuring without a really good contact on what you are testing (this is what the sharp plated probes are for) OR there are charges in capacitors or the circuit is energized in some way, then it could autorange forever because the circuit is changing.   That's why oscilloscopes are useful.   Keep in mind that for any number of reasons, the meter might be seeing different values from moment to moment.



Title: Re: EEVBlog 121GW Discussion thread
Post by: CDaniel on February 20, 2019, 03:11:28 pm
Please stop defending this slow firmware , everybody ( including Dave ) knows that it must be improved .
People don't buy a pretty expensive meter to use it in manual range ... this is a bad joke  :-DD . You can use it as you want but keep your precious advices for yourself .
Title: Re: EEVBlog 121GW Discussion thread
Post by: joeqsmith on February 20, 2019, 04:30:44 pm
Please stop defending this slow firmware , everybody ( including Dave ) knows that it must be improved .
People don't buy a pretty expensive meter to use it in manual range ... this is a bad joke  :-DD . You can use it as you want but keep your precious advices for yourself .

You havn't been around for a while.  Now that you have returned, perhaps check out my post #1344 along with others.  We did a fair amount of testing to try and find a meter that behaves as you implied they all do.   Perhaps I misunderstood your original post or you have no clue what you are posting about.   Please take the time to explain your original post. 

Title: Re: EEVBlog 121GW Discussion thread
Post by: gnavigator1007 on February 20, 2019, 06:38:58 pm
Looks like Rodger repeated the test I ran with the VA mode.  It's been almost two years since I posted the original video showing the problems and possible workarounds.  At the time it caused a lot of confusion.   Even Dave seemed lost and when the guy selling the product and testing the prototypes is not following, you have a problem.   Maybe Rodger's testing will be presented in such a way that will be easier to understand. 

https://www.youtube.com/channel/UCd8CdLp2bKP6Uv0jvdLdiRA (https://www.youtube.com/channel/UCd8CdLp2bKP6Uv0jvdLdiRA)

Video is up
https://youtu.be/FNsPr1OEq7c (https://youtu.be/FNsPr1OEq7c)
Title: Re: EEVBlog 121GW Discussion thread
Post by: HKJ on February 20, 2019, 07:34:31 pm
I think this is a bit silly discussion. Of course the meter would have the common input as voltage reference and you have to decide if you want to measure power from the supply or power delivered to the load and connect accordingly.
Title: Re: EEVBlog 121GW Discussion thread
Post by: beanflying on February 20, 2019, 07:41:33 pm
Please stop defending this slow firmware , everybody ( including Dave ) knows that it must be improved .
People don't buy a pretty expensive meter to use it in manual range ... this is a bad joke  :-DD . You can use it as you want but keep your precious advices for yourself .

Wow we all just got just so burned by you throwing that Iced Soy 1/2 shot decaff Latte at us :-DD
Title: Re: EEVBlog 121GW Discussion thread
Post by: chronos42 on February 20, 2019, 08:19:17 pm

Wow we all just got just so burned by you throwing that Iced Soy 1/2 shot decaff Latte at us :-DD

But he is right in this point. There is also no actual progress in the 1.58 beta firmware, Ohm measurements are still a pain with this meter.
Title: Re: EEVBlog 121GW Discussion thread
Post by: beanflying on February 20, 2019, 08:22:04 pm

Wow we all just got just so burned by you throwing that Iced Soy 1/2 shot decaff Latte at us :-DD

But he is right in this point. There is also no actual progress in the 1.58 beta firmware, Ohm measurements are still a pain with this meter.

Not everything can be fixed by firmware!
Title: Re: EEVBlog 121GW Discussion thread
Post by: GeoffreyF on February 21, 2019, 03:34:53 am
Please stop defending this slow firmware , everybody ( including Dave ) knows that it must be improved .
People don't buy a pretty expensive meter to use it in manual range ... this is a bad joke  :-DD . You can use it as you want but keep your precious advices for yourself .

Here is an idea - please stop going on and on making the same point over and over and over - without anything actually useful.   If you stop why would anyone respond to your junk if you are not writing it?  Everybody does not know it must be improved - so don't write what actually is false.   It's not "pretty expensive". It's actually about average.   It's not a bad joke - your posts are.   Practice What you preach except your "advices" are not precious, useful or wanted - so keep them to yourself.
Title: Re: EEVBlog 121GW Discussion thread
Post by: J-R on February 21, 2019, 05:53:06 am
Is it by design that the resistance measurement in auto range is quite slow?
At times it is pretty annoying to wait for the read out.

In this or any other meter, I don't use auto range unless I have absolutely no idea what range the expected value is in.   I set the range to what my expectations are.  If it goes out of range, I revert to auto range.   If one is debugging something - there is not such a thing as autorange that is fast enough though some are faster than others.  ALSO - if you are measuring without a really good contact on what you are testing (this is what the sharp plated probes are for) OR there are charges in capacitors or the circuit is energized in some way, then it could autorange forever because the circuit is changing.   That's why oscilloscopes are useful.   Keep in mind that for any number of reasons, the meter might be seeing different values from moment to moment.

So you're saying if you had a meter that could auto range nearly instantly, you still wouldn't use it that way?  I find that hard to believe.  It's going to be slower to have to constantly cycle through the ranges especially if there is only one button to do so.

You state that the meter could see different values.  Isn't that the entire point of having the auto range feature?  It seems like you are hurting your argument.  Auto ranging was a great advancement along with DMMs.


Please stop defending this slow firmware , everybody ( including Dave ) knows that it must be improved .
People don't buy a pretty expensive meter to use it in manual range ... this is a bad joke  :-DD . You can use it as you want but keep your precious advices for yourself .

Here is an idea - please stop going on and on making the same point over and over and over - without anything actually useful.   If you stop why would anyone respond to your junk if you are not writing it?  Everybody does not know it must be improved - so don't write what actually is false.   It's not "pretty expensive". It's actually about average.   It's not a bad joke - your posts are.   Practice What you preach except your "advices" are not precious, useful or wanted - so keep them to yourself.

I don't condone his constant pointing out of the slowness either, because we can watch any number of Youtube videos and see some other meters that are "slow" as well.  But when you suggest that we use manual ranges as a fix I can see why it would get a reaction.   I just ran a test in manual range of a 6800uF capacitor and the 121GW takes 9 seconds to display the value, the ESR70 was 5.5 seconds, the BM235 was 5 seconds and a capacitance meter my grandfather (rest in peace) designed and built from scratch 30 years ago can do it in under 1.5 seconds, and that includes powering it on.

I'm going to assume that after all this time if the speed of the 121GW could be drastically improved, they would have done it already.  There are hints of this being the case in some other forum posts I found.  Maybe someone could make an official statement and clear the air...
Title: Re: EEVBlog 121GW Discussion thread
Post by: IanB on February 21, 2019, 06:10:29 am
I'm going to assume that after all this time if the speed of the 121GW could be drastically improved, they would have done it already.  There are hints of this being the case in some other forum posts I found.  Maybe someone could make an official statement and clear the air...

I have a problem that when attempts were made to speed up the resistance range the auto-ranging become less reliable. Therefore if fast and reliable is not to be achieved, I prefer slow and reliable over fast and unreliable.

I would rather the developers ignore the shouts of "Faster! Faster!" and try to make the thing actually work...
Title: Re: EEVBlog 121GW Discussion thread
Post by: J-R on February 21, 2019, 06:15:44 am
I'm going to assume that after all this time if the speed of the 121GW could be drastically improved, they would have done it already.  There are hints of this being the case in some other forum posts I found.  Maybe someone could make an official statement and clear the air...

I have a problem that when attempts were made to speed up the resistance range the auto-ranging become less reliable. Therefore if fast and reliable is not to be achieved, I prefer slow and reliable over fast and unreliable.

I would rather the developers ignore the shouts of "Faster! Faster!" and try to make the thing actually work...

The ideal solution would be to have an option for the end user to make the choice himself if those goals are mutually exclusive.
Title: Re: EEVBlog 121GW Discussion thread
Post by: GeoffreyF on February 21, 2019, 03:45:26 pm


So you're saying if you had a meter that could auto range nearly instantly, you still wouldn't use it that way?  I find that hard to believe.  It's going to be slower to have to constantly cycle through the ranges especially if there is only one button to do so.

You state that the meter could see different values.  Isn't that the entire point of having the auto range feature?  It seems like you are hurting your argument.  Auto ranging was a great advancement along with DMMs.


No I am not "saying" or writing that.  If I was even thinking it, I would have written it and I didn't. So why did you speculate?   Do you know of an "instant auto ranging meter" with the price and other features?  - I don't.  If you did, you would have commented.  So why don't you explain why an "instant auto range" meter would have range selection?   Also, since you think you can read minds, or speculate, explain how "Instant autorange" would work with an accurate wide ranging meter.   Next time you try to speculate on what another said or write - TAKE THE TIME TO CONSIDER IF YOU ARE BEING SILLY. (you  were, as I outlined quite specifically).
Title: Re: EEVBlog 121GW Discussion thread
Post by: chronos42 on February 21, 2019, 07:15:59 pm
Thanks for showing the video from Kainka Labs and also joeqsmith for his suggestion how to connect the 121GW in VA mode to avoid the problem of wrong VA readings.

Just for fun I did the same test with the Gossen Metrahit Energy. Same setup as in the video, 1V source, resistor 22 Ohm. The Gossen is connected as it should, gnd to gnd, voltage input to the +1V output of the source and the current input is connected to the resistor, the resistor is connected to 1V source.

The result is shown at picture 1   :-+

Then I changed GND and current input at the Gossen. Result is picture 2.  8)

That means that the Gossen meter uses the same wiring in the power mode which joeqsmith suggested for the 121GW.
Title: Re: EEVBlog 121GW Discussion thread
Post by: IanB on February 21, 2019, 07:40:55 pm
I did some experiments on power measurement with the 121GW and I observed the "correct" way to connect it to measure power consumed by a load resulted in a negative display value for the power.

At first I didn't like this, but actually you could argue that power consumed is negative and power produced is positive. So perhaps it is just a matter of human perspective rather than any technical limitation of the system?
Title: Re: EEVBlog 121GW Discussion thread
Post by: chronos42 on February 21, 2019, 08:13:46 pm
Think in "drain" and "source". Source is positive, drain is negative and than it fits.... :)
Title: Re: EEVBlog 121GW Discussion thread
Post by: joeqsmith on February 21, 2019, 10:11:38 pm
Thanks for showing the video from Kainka Labs and also joeqsmith for his suggestion how to connect the 121GW in VA mode to avoid the problem of wrong VA readings.

Just for fun I did the same test with the Gossen Metrahit Energy. Same setup as in the video, 1V source, resistor 22 Ohm. The Gossen is connected as it should, gnd to gnd, voltage input to the +1V output of the source and the current input is connected to the resistor, the resistor is connected to 1V source.

The result is shown at picture 1   :-+

Then I changed GND and current input at the Gossen. Result is picture 2.  8)

That means that the Gossen meter uses the same wiring in the power mode which joeqsmith suggested for the 121GW.

Thanks for the post.  I had not thought about the Gossen Energy.   
Title: Re: EEVBlog 121GW Discussion thread
Post by: darik on February 21, 2019, 10:15:28 pm
I did some experiments on power measurement with the 121GW and I observed the "correct" way to connect it to measure power consumed by a load resulted in a negative display value for the power.

At first I didn't like this, but actually you could argue that power consumed is negative and power produced is positive. So perhaps it is just a matter of human perspective rather than any technical limitation of the system?

Understanding how it works, I'm okay with this implementation. But I'm sure glad I don't have to write the documentation to explain it to someone else.
Title: Re: EEVBlog 121GW Discussion thread
Post by: 2N3055 on February 21, 2019, 10:32:43 pm
Metrix MTX3293 actually shows negative VA in secondary VA mode... For instance it will show 5V, -100mA and -500mVA..
But it will be correct.
Title: Re: EEVBlog 121GW Discussion thread
Post by: joeqsmith on February 22, 2019, 01:25:11 am
Metrix MTX3293 actually shows negative VA in secondary VA mode... For instance it will show 5V, -100mA and -500mVA..
But it will be correct.

I just DLed the manual for this meter.  Interesting enough, they don't provide many details for the VxA mode.  There are no recommendations on how to connect it that I saw and there was no mention about the burden voltage when using this mode.   I then looked for a video showing it but I only found one.  The guy really doesn't provide any details other than to say how nice he thought it was.      Is there an application note or better manual available for this meter?

https://youtu.be/BtlWO8TIkO8
Title: Re: EEVBlog 121GW Discussion thread
Post by: 2N3055 on February 22, 2019, 07:40:36 am

I just DLed the manual for this meter.  Interesting enough, they don't provide many details for the VxA mode.  There are no recommendations on how to connect it that I saw and there was no mention about the burden voltage when using this mode.   I then looked for a video showing it but I only found one.  The guy really doesn't provide any details other than to say how nice he thought it was.      Is there an application note or better manual available for this meter?

Hi Joe!
Yes, not much data about that instrument in general. You are correct, no explanation in manual for connection. There are only two ways to connect it though, and only one that gives correct reading, and I 'we been using it like that since day one, not giving it much thought about it. Apparently it is not that obvious... And as I said, instrument shows power drain with correct sign.
Anyways, i shot an E-mail to support at Chauvin Arnoux to clarify connections and a suggestion to add it the manual. We'll see if and how they will respond.

Regards,
Siniša
Title: Re: EEVBlog 121GW Discussion thread
Post by: beanflying on March 02, 2019, 03:30:30 am
Playing with my new (to me) Fluke 335D DC Calibrator and I decided to grab the 121GW out and hook it up as I haven't done any high voltage DC testing with it (100V max in the past).

Also just for interest I used both the Android and the Windoze Apps via Blutooth to record the information. Phone was handheld maybe 1m away and the PC is more like 3m away and uses a dirt cheap evilbay dongle. Both hooked up fine but the phone at one stage failed to connect until I power cycled the meter after being on the PC. Not an issue just noted if you are swapping connections.

As per previous testing on DC in particular my meter is well inside spec (0.05%+5 counts) I couldn't get it outside 2 counts of my Agilent from 100-600Vdc. Yes it is around 38C in my shack today but it is cooler than yesterday :phew:

At 100V it was reading 99.98V (worst % accuracy measured) against the Agilent which is 0.02% + 0 counts so a factor of 10 better than spec  :-+ Also clearly the Temp Co claimed for the meter is WRONG Complain Complain Complain .......  ::)

Beer time  :popcorn:
Title: Re: EEVBlog 121GW Discussion thread
Post by: joeqsmith on March 16, 2019, 04:55:17 pm
Dave,

I just watched the latest mailbag.  You mention a new version of the 121GW and working towards getting your rotary switch life cycle tester working again.   I plan to do a full review of this meter which would include cycling the switch.  If you are interested, I would be be willing to buy a couple of these meters now (assuming you are happy with the other changes to the hardware) and run the test for you.   

It would be the 50K full cycle test like I have been running.   It would be non-stop unless something were to go wrong and I decided to abort the test.   


https://youtu.be/7iXwRlGDLmI?t=903
Title: Re: EEVBlog 121GW Discussion thread
Post by: Cliff Matthews on March 16, 2019, 05:11:57 pm
That switch has been a nagging thing keeping me from buying.
Title: Re: EEVBlog 121GW Discussion thread
Post by: GeoffreyF on March 16, 2019, 08:34:58 pm
That switch has been a nagging thing keeping me from buying.

Have you compared the test results to your use and that of other meters?  What is true for them all is that switching modes while connected to a device you are testing, especially where there are higher voltages present, can blow a meter.

Meters in this price class are not considered to be forever investments either. If you really are using it, it will pay for itself in a few months. If you use it occasionally and without switching modes hot, you probably won't have a problem with the switch on this or any other meter in its class.
Title: Re: EEVBlog 121GW Discussion thread
Post by: joeqsmith on March 17, 2019, 12:21:15 am
That switch has been a nagging thing keeping me from buying.

If they did address the problems with the switch and rolled in the other changes, I think it's good enough to give it another go.  It will be interesting to see if their changes to the mux and clamps improves it's ability to survive my low energy transients. 

When I was running all of these drift, noise, BT tests and developing the Labview interface for the prototype, I took it apart to tack a few wires to the PCB.  I noticed a fair amount of metallic debris around the contacts.  I had cleaned the meter early on but it appears to continue to wear.  Looking forward to seeing the improved version.
Title: Re: EEVBlog 121GW Discussion thread
Post by: joeqsmith on March 20, 2019, 12:28:42 pm
Dave,

I just watched the latest mailbag.  You mention a new version of the 121GW and working towards getting your rotary switch life cycle tester working again.   I plan to do a full review of this meter which would include cycling the switch.  If you are interested, I would be be willing to buy a couple of these meters now (assuming you are happy with the other changes to the hardware) and run the test for you.   

It would be the 50K full cycle test like I have been running.   It would be non-stop unless something were to go wrong and I decided to abort the test.   

I assume the lack of a response means it's not yet ready for prime time.  I'm in no rush.  Please let me know when they are available and the old stock has been flushed.  I don't see any reason to run the old version and want to make sure I get the latest hardware.   That's assuming that the shim was actually addressed.
Title: Re: EEVBlog 121GW Discussion thread
Post by: DavidWC on March 20, 2019, 12:52:47 pm
Hi everyone,

I'm a fellow 121GW owner and EEVBlog fan.  I'm also a programmer, and I'm trying to develop a mobile app that will work with a variety of BLE multimeters. 

For obvious reasons, I've started with the 121GW.  The name of the app is "Meteor", and I've released an early (beta) version to the iOS App Store:

https://itunes.apple.com/us/app/meteor-for-121gw/id1452124710?ls=1&mt=8

Here are the main differences in the v0.1 Meteor app vs. the EEVBlog 121GW app:

+ Control buttons available in landscape mode
+ Option for spoken measurements
+ Option for continuity buzzer
+ Dark mode option
+ Connect/disconnect button and disconnect-status labels
- Does not yet support multiple meters or math mode
- No in-app capture of samples (yet)

I wrote this initial version to look as much like the EEVBlog app as possible, so that it would be familiar to users and would allow me to compare its functionality to the first-party app.  It will, however, diverge in appearance as development continues.

The app is free, and I welcome feedback and suggestions.  As a v0.1 release, there are probably bugs and flaws.  Please report any bugs or issues to support@westerncomputational.com.

Regards,
David Lavo
david@westerncomputational.com
Title: Re: EEVBlog 121GW Discussion thread
Post by: Cliff Matthews on April 03, 2019, 02:31:02 pm
KainkaLabs posted this YT vid today. For 10pF he'd be better off using an adapter rather than long gripper leads.
https://www.youtube.com/watch?v=cWHzHzsWT28 (https://www.youtube.com/watch?v=cWHzHzsWT28)
Title: Re: EEVBlog 121GW Discussion thread
Post by: bitwelder on April 08, 2019, 07:58:56 pm
What's the max safe temperature for the K-type temperature probe provided with the meter?
Manual says 1350 C, but that's about the probe itself.
What about the coating of the probe wiring?
Title: Re: EEVBlog 121GW Discussion thread
Post by: beanflying on April 08, 2019, 09:37:28 pm
What's the max safe temperature for the K-type temperature probe provided with the meter?
Manual says 1350 C, but that's about the probe itself.
What about the coating of the probe wiring?

I wouldn't go above 250-300C in particular if the cable is resting on a hot surface. I used mine recently in the well of my Temperature Calibrator at 400C and the outer sheath was getting sticky. https://www.eevblog.com/forum/testgear/sika-18600e-dryblock-temperature-calibrator-teardown-pictures-testing/msg2249781/#msg2249781 (https://www.eevblog.com/forum/testgear/sika-18600e-dryblock-temperature-calibrator-teardown-pictures-testing/msg2249781/#msg2249781)

(https://www.eevblog.com/forum/testgear/sika-18600e-dryblock-temperature-calibrator-teardown-pictures-testing/?action=dlattach;attach=670062;image)
Title: Re: EEVBlog 121GW Discussion thread
Post by: rthorntn on May 04, 2019, 01:00:13 am
Hi All,

Sorry if I missed this but is the voltage and current for continuity test listed somewhere?

Someone is telling me that an STM32 can be damaged by DMM continuity checks...

Thanks.

Richard
Title: Re: EEVBlog 121GW Discussion thread
Post by: FrankBuss on May 04, 2019, 01:10:45 pm
Sorry if I missed this but is the voltage and current for continuity test listed somewhere?

Someone is telling me that an STM32 can be damaged by DMM continuity checks...

I don't know a full list, but here are some examples:

https://www.eevblog.com/forum/testgear/multimeter-with-low-continuity-test-voltage/ (https://www.eevblog.com/forum/testgear/multimeter-with-low-continuity-test-voltage/)

It can go up to 7.3 V for some multimeters like the Fluke 87V, but only 1 mA, so maybe not dangerous for the STM32.
Title: Re: EEVBlog 121GW Discussion thread
Post by: FrankBuss on May 04, 2019, 01:15:00 pm
For the 121GW I couldn't find it in the manual, but see this page:

https://lygte-info.dk/review/DMMEEVBlog%20121GW%20UK.html

2.1 V open and 0.57 mA shorted.
Title: Re: EEVBlog 121GW Discussion thread
Post by: J-R on May 05, 2019, 08:03:54 am
For the 121GW I couldn't find it in the manual, but see this page:

https://lygte-info.dk/review/DMMEEVBlog%20121GW%20UK.html

2.1 V open and 0.57 mA shorted.

I tested this with a pile of meters and can confirm those numbers: 2.111V - 2.115V and 0.571mA - 0.578mA.  There was a very large grouping around 2.111V, which I find interesting.
Title: Re: EEVBlog 121GW Discussion thread
Post by: ggchab on May 08, 2019, 07:43:38 am
I bought the 121GW because it looked promising (and it is) but also because of some other points:
- heavily supported by Dave
- upgradable/hackable
- Dave's enthusiasm

Now, it seems that the "soufflé est retombé" as we say in French. I would like to be proven the opposite, but except a few apparitions of the multi-meter in some videos, enthusiasm seems to be gone, upgrades are no longer available, no more reaction from any Dave.

Available resources have probably moved to the micro supply ... until the next project ? May a small team support several projects and keep enthusiasm for all of them?

No offense at all, only my feeling... Buying the GW121 was my own decision, it's working, I use it and I don't regret it. I was just hoping a bit more.
Title: Re: EEVBlog 121GW Discussion thread
Post by: rthorntn on May 08, 2019, 09:23:31 am
I'm hoping the eevblog team are on holidays, I broke a probe tip 12 days ago, emailed them that same day and I haven't heard back from the team on how to replace it, fingers crossed they will come back rested and send me a response.
Title: Re: EEVBlog 121GW Discussion thread
Post by: beanflying on May 08, 2019, 09:33:58 am
I'm hoping the eevblog team are on holidays, I broke a probe tip 12 days ago, emailed them that same day and I haven't heard back from the team on how to replace it, fingers crossed they will come back rested and send me a response.

It was New South Wales School Holidays until the 29th of April so you might be MIA in a block of Emails while Dave was doing Dad stuff. Worth a resend maybe?

I bought the 121GW because it looked promising (and it is) but also because of some other points:
- heavily supported by Dave
- upgradable/hackable
- Dave's enthusiasm

Now, it seems that the "soufflé est retombé" as we say in French. I would like to be proven the opposite, but except a few apparitions of the multi-meter in some videos, enthusiasm seems to be gone, upgrades are no longer available, no more reaction from any Dave.

Available resources have probably moved to the micro supply ... until the next project ? May a small team support several projects and keep enthusiasm for all of them?

No offense at all, only my feeling... Buying the GW121 was my own decision, it's working, I use it and I don't regret it. I was just hoping a bit more.

The Firmware was never going to be open sourced but the Bluetooth is this was known before the kickstarter closed and maybe before? Seems there is a new Firmware available making it maybe the third?? (haven't checked) upgrade since the start of the year? I am sure it will be available sooner rather than later like all the others.

What were you expecting? Personally I feel the firmware is likely approaching the limits of the hardware so incremental change will naturally slow and be minor in nature.
Title: Re: EEVBlog 121GW Discussion thread
Post by: ggchab on May 08, 2019, 09:59:59 am
Quote
What were you expecting? Personally I feel the firmware is likely approaching the limits of the hardware so incremental change will naturally slow and be minor in nature.

May be a bit more responsiveness. We know for more than a week that version 1.61 is available and I haven't read anything from Dave (may be, it's somewhere but I haven't seen it). So my question: where is the enthusiasm of the beginning gone ? May be a subjective feeling.

But as I said, the multi-meter is doing its job, I use it and don't regret it.
Title: Re: EEVBlog 121GW Discussion thread
Post by: dcac on May 08, 2019, 12:45:20 pm
All we can do is wait, I’m pretty sure the moment Dave receives new FW he will let us know.

I seem to remember it has happened before that more recently bought 121gw’s had newer FW than what was available at eevblog.com. Perhaps just the way the communication goes - it might not be the same person who sends new FW to the factory who also sends it to Dave.

Title: Re: EEVBlog 121GW Discussion thread
Post by: Brumby on May 08, 2019, 12:48:47 pm
So my question: where is the enthusiasm of the beginning gone ? May be a subjective feeling.
At the beginning, there was an air of excitement, interest and critical assessment of various aspects of a new meter.  Much of that has now produced a more refined product which does not have as many "issues".  As a more mature product, it will - like every other - slide down people's scale of enthusiasm and settle into a typically mundane "workhorse" status. 

That's not to say it's a perfect meter and it will likely have some FW revisions further down the track, but the bigger issues seem to have been addressed and the limitations understood, so such revisions will come at some later date.

Also - please be aware that there are many things that still go on without advertising each mini step, especially when there may be several things being tried out.  I'd rather someone spend time working on the FW than telling me of all the little things they've done.  If you want that level of involvement, then get a job on the development team.

Nevertheless, I met with Dave and David a couple of weeks ago and the 121GW FW came into the discussion.  I won't go into that because it's not my place to say (not that it was particularly dramatic) - but it did show me that the 121GW was definitely NOT a forgotten project.

Quote
But as I said, the multi-meter is doing its job, I use it and don't regret it.
That's where this meter's evolution sits right now for a great many owners.  The boring, everyday workhorse.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Brumby on May 08, 2019, 12:56:04 pm
I seem to remember it has happened before that more recently bought 121gw’s had newer FW than what was available at eevblog.com. Perhaps just the way the communication goes - it might not be the same person who sends new FW to the factory who also sends it to Dave.
The official FW is produced by the factory.  They have "secret sauce" routines which they are coy about sharing.  Dave would get it after the factory has released it.

Other versions of the FW you may have seen around could have come from enterprising members who got into the hex code and made their own tweaks.
Title: Re: EEVBlog 121GW Discussion thread
Post by: joeqsmith on May 08, 2019, 04:56:15 pm
I bought the 121GW because it looked promising (and it is) but also because of some other points:
...
Now, it seems that the "soufflé est retombé" as we say in French. I would like to be proven the opposite, but except a few apparitions of the multi-meter in some videos, enthusiasm seems to be gone, upgrades are no longer available, no more reaction from any Dave.

Available resources have probably moved to the micro supply ... until the next project ? May a small team support several projects and keep enthusiasm for all of them?

No offense at all, only my feeling... Buying the GW121 was my own decision, it's working, I use it and I don't regret it. I was just hoping a bit more.

After Dave's comments about reviving the toggle bot to repeat the switch life cycle testing, I offered to buy a couple of the new meters and run that test for them but no response and I have not heard anything else.   

I wonder if the new meters people are buying still have the shim and old PCB. 
Title: Re: EEVBlog 121GW Discussion thread
Post by: exe on May 09, 2019, 08:13:55 am
I received a letter with title "EEVblog 121GW Stock Clearance!". Initially I thought this may mean the dmm is approaching EOL, but I don't want to speculate. Anyway, for those who interested, check this out: "Use the coupon code fluxcapacitor in the checkout for 20% off the meter, and if you like, the carry case as well."
Title: Re: EEVBlog 121GW Discussion thread
Post by: 1anX on May 09, 2019, 08:53:28 am
I received a letter with title "EEVblog 121GW Stock Clearance!". Initially I thought this may mean the dmm is approaching EOL, but I don't want to speculate. Anyway, for those who interested, check this out: "Use the coupon code fluxcapacitor in the checkout for 20% off the meter, and if you like, the carry case as well."

Yeah, I got the same email about 20% off stock clearance!
I'm guessing a revised 121GW is about to be released or its all over for the meter which has had extremely short shelf life if thats the case.
Hopefully its a revision of the meter and one that fulfills its initial promise of being a fast responding and unique electronics focused meter.
I get the feeling all will be revealed soon!
Title: Re: EEVBlog 121GW Discussion thread
Post by: Brumby on May 09, 2019, 10:42:45 am
My guess is that Dave has stock on his shelves that needs to be turned into cash.  Stock on the shelf doesn't do anything but tie up capital.  It needs to be sold and new stock ordered for any business to survive.

My suspicion is that people have been hanging back, waiting for all the "problems" to be ironed out and that's taken the edge off the interest in this meter.  From what I've read, it seems that a lot has been sorted out, so there's no real reason for people with an interest to wait any longer.

A promotion with a discount is a pretty common way to attract sales - so if anyone was hesitating, I'd say now is a good time to pull the trigger.
Title: Re: EEVBlog 121GW Discussion thread
Post by: hammy on May 09, 2019, 11:55:35 am
To get the shelf empty it would help to put firmware version 1.61 onto the download page.
Title: Re: EEVBlog 121GW Discussion thread
Post by: JayHattler on May 09, 2019, 01:06:04 pm
Yes, I am one of those who are waiting on a new model. I like the meter and want it, but am in no hurry. I read enough to realize that it makes no sense to buy a version with a shim when a new one is approaching. So, patiently waiting. Perhaps the clearance sale will entice others and empty the inventory so that we can move on.
Title: Re: EEVBlog 121GW Discussion thread
Post by: GeoffreyF on May 09, 2019, 01:50:35 pm
People who wait clearly don't have much need for a multi-meter.  People who quibble over the price obviously have not been paid much for their "Skill" in using one.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Towger on May 09, 2019, 03:01:44 pm
People who wait may also have more multimeters than they can possibly require in a lifetime.  This is the EEVBlog home of many TEA addicts!
Title: Re: EEVBlog 121GW Discussion thread
Post by: e0ne199 on May 09, 2019, 07:07:03 pm
hello everyone, i recently have just bought 121GW multimeter from eevblog store...i heard that there is an issue related with VA mode in both DC and AC measurement, is it already resolved now?
Title: Re: EEVBlog 121GW Discussion thread
Post by: J-R on May 09, 2019, 07:53:00 pm
They raised the price from $300 to $315 for the sale, still no case included?  It's only $23 US cheaper than my purchase last summer with a carrying case.  Not enough for me to be interested in buying another as a spare or a gift, especially with some minor annoyances still present and the lack of information about future firmware updates.  I'm not bashing it, just saying those are factors that are preventing me from buying another.
Title: Re: EEVBlog 121GW Discussion thread
Post by: kelemvor on May 09, 2019, 08:19:17 pm
I received a letter with title "EEVblog 121GW Stock Clearance!". Initially I thought this may mean the dmm is approaching EOL, but I don't want to speculate. Anyway, for those who interested, check this out: "Use the coupon code fluxcapacitor in the checkout for 20% off the meter, and if you like, the carry case as well."

Ugh that smarts.  I just got my 121gw about a week ago.  If it wasn't shipping to/from Australia, I'd consider returning it and re-purchasing for $60 off.

Also, I didn't bother looking at the included firmware and flashed it right away.   Guess now I miss out on the new fw for now.
Title: Re: EEVBlog 121GW Discussion thread
Post by: kelemvor on May 09, 2019, 08:30:05 pm
Does anyone know if there's a way to have the meter default to turning on the Back-light and the Bluetooth?

I really like both features. I tend to use the app to take screenshots of measurements since I'm learning and taking notes... and the backlight just makes the screen far easier to read indoors.
Title: Re: EEVBlog 121GW Discussion thread
Post by: oliv3r on May 09, 2019, 08:39:37 pm
To get the shelf empty it would help to put firmware version 1.61 onto the download page.

I'm surprised nobody has managed to pull it of the microSD card :) *hint* *hint*

I received a letter with title "EEVblog 121GW Stock Clearance!". Initially I thought this may mean the dmm is approaching EOL, but I don't want to speculate. Anyway, for those who interested, check this out: "Use the coupon code fluxcapacitor in the checkout for 20% off the meter, and if you like, the carry case as well."

Yeah, I got the same email about 20% off stock clearance!
I'm guessing a revised 121GW is about to be released or its all over for the meter which has had extremely short shelf life if thats the case.
Hopefully its a revision of the meter and one that fulfills its initial promise of being a fast responding and unique electronics focused meter.
I get the feeling all will be revealed soon!

As an owner, I hope the changes are minimal and can optionally be reworked into the current model ;)
Title: Re: EEVBlog 121GW Discussion thread
Post by: Mr.B on May 09, 2019, 08:54:04 pm
I'm surprised nobody has managed to pull it of the microSD card :) *hint* *hint*

AFAIK, It is not on the SD card in the *as shipped* condition - brand new.
Certainly was not on mine.
Title: Re: EEVBlog 121GW Discussion thread
Post by: oliv3r on May 09, 2019, 09:56:10 pm
I'm surprised nobody has managed to pull it of the microSD card :) *hint* *hint*

AFAIK, It is not on the SD card in the *as shipped* condition - brand new.
Certainly was not on mine.

I just upgraded mine from the shipped 1.01 to the beta 1.58 and on the sd card, was low and behold, the bin. But I would not be supprised that they 'stilink' program the firmware normally, and if an update is still needed just before shipping; they'll do it the 'manual' way.
Title: Re: EEVBlog 121GW Discussion thread
Post by: maxcp on May 09, 2019, 09:56:53 pm
Hi!

I was so happy when I was able to order a 121GW on 26.07.2018 early in the morning, but had not much luck with the shipping. It was probably due to the german customs, which are really slow and had no website at that point in time. It was the 15.09.2018 when I wrote you my first mail and asked for my shipment. I received a mail, that I should be patient and that the multimeter would probably be held back by the german customs. I was patient and waited until the tracking number disappeared from the DHL tracking website. Then I wrote you my next mail on 01.11.2018. A few days later I received another answer, that the shipment could not be delivered (failed delivery attempt) and was returned. I was offered to get either a refund or another delivery attempt.

Here comes the mistake: For some reasons I answered that mail several month later. It was the 17.02.2019 and I never received an answer. I have also checked my paypal account, but could not find any refund. I have written another mail on 16.04.2019 and have again not received an answer. Of cause you can now argue on how stupid I am, that I have waited so long. But the drama is: Every time I am watching the eevblog I am virtually seeing my multimeter being used with a tear in one eye for my stupidity and on top of that I cannot really justify to buy another one of such from a german vendor before I have received any refund. I need a decision. I now want a decision. Is there still anything I can do or hope for or do I really have to live with that situation now?
Title: Re: EEVBlog 121GW Discussion thread
Post by: 1anX on May 10, 2019, 01:22:45 am
My guess is that Dave has stock on his shelves that needs to be turned into cash.  Stock on the shelf doesn't do anything but tie up capital.  It needs to be sold and new stock ordered for any business to survive.

My suspicion is that people have been hanging back, waiting for all the "problems" to be ironed out and that's taken the edge off the interest in this meter.  From what I've read, it seems that a lot has been sorted out, so there's no real reason for people with an interest to wait any longer.

A promotion with a discount is a pretty common way to attract sales - so if anyone was hesitating, I'd say now is a good time to pull the trigger.

I guess you'll finally be buying one these then Brumby!!!!!!!!!
Perhaps not? As you seem to know all Dave's intentions for this meter, both present and future, if you resist this bargain 20% off deal then maybe your holding off for a revised model?
Title: Re: EEVBlog 121GW Discussion thread
Post by: beanflying on May 10, 2019, 04:04:26 am
To get the shelf empty it would help to put firmware version 1.61 onto the download page.

That is just DUMB and Illogical. If as has been reported new ones are already coming with 1.61 how is your statement going to magically help boost sales?

Even if someone scores one with an earlier version it remains a trivial thing to upgrade later. Mine ran for nearly a year on 1.0x before I added 1.4x firmware.

1.61 will not be Magic and life altering just a progression.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on May 10, 2019, 05:19:30 am
I received a letter with title "EEVblog 121GW Stock Clearance!". Initially I thought this may mean the dmm is approaching EOL, but I don't want to speculate.

It's not EOL, I'll be selling this meter for many more years to come.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on May 10, 2019, 05:24:09 am
My guess is that Dave has stock on his shelves that needs to be turned into cash.  Stock on the shelf doesn't do anything but tie up capital.  It needs to be sold and new stock ordered for any business to survive.

Correct. I talked about this on the Amp hour the other month. I have to buy a lot of meters in one hit, and it's a huge amount of money, the last lot (plus other things) practically wiped out the companies cash reserve. So much so that I had to stop paying myself wages.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on May 10, 2019, 06:03:16 am
Now, it seems that the "soufflé est retombé" as we say in French. I would like to be proven the opposite, but except a few apparitions of the multi-meter in some videos, enthusiasm seems to be gone, upgrades are no longer available, no more reaction from any Dave.

What "enthusiasm" do you want?
Want me to include an outro in every video plugging the meter?
It's just a meter, there was some excitement because it was a kickstarter, but now it's a year and half later and it's now just another product in my store. That was inevitable.
Fixes are still coming. I'm using 2.00 firmware at present and UEI have said we can release it, so expect it soon. Improvements are better and faster resistance and capacitance autoranging.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on May 10, 2019, 06:09:19 am
After Dave's comments about reviving the toggle bot to repeat the switch life cycle testing, I offered to buy a couple of the new meters and run that test for them but no response and I have not heard anything else.

If I had a spare new thicker PCB meter to send you, I would.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Brumby on May 10, 2019, 07:52:44 am
I guess you'll finally be buying one these then Brumby!!!!!!!!!
Perhaps not? As you seem to know all Dave's intentions for this meter, both present and future, if you resist this bargain 20% off deal then maybe your holding off for a revised model?

Gee - you like riding me, don't you?

As for "knowing Dave's intentions", there's nothing I have said that anyone could not deduce - but because there are a lot of people who don't make that effort, I'll do it for them - you included, it seems.

As for my purchasing the 121GW or not, that has nothing to do with revisions.  It has everything to do with 2 quite specific reasons.  The first is that I do not have a specific need for the functions the 121GW offers.  My EEVblog BM235 and the other meters I have currently serve me more than well enough.  The second is that I do not have sufficient funds for such a discretionary purchase at this time.  However, should I find myself with such funds available, then I will go shopping.


There is one thing that should be understood .... I've been following the development of the 121GW from the moment Dave gave the first hints of such a project.  Excuse me if I've picked up a few details and have an opinion on some things.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Brumby on May 10, 2019, 08:03:03 am
My guess is that Dave has stock on his shelves that needs to be turned into cash.  Stock on the shelf doesn't do anything but tie up capital.  It needs to be sold and new stock ordered for any business to survive.

Correct. I talked about this on the Amp hour the other month. I have to buy a lot of meters in one hit, and it's a huge amount of money, the last lot (plus other things) practically wiped out the companies cash reserve. So much so that I had to stop paying myself wages.

Not surprising to anyone with half an idea of how small business is challenged on a daily basis.  I don't have any secret communications, just common sense (sometimes  :D ).
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on May 10, 2019, 08:09:14 am
Not surprising to anyone with half an idea of how small business is challenged on a daily basis.  I don't have any secret communications, just common sense (sometimes  :D ).

Or people could just listen to The Amp Hour  ;D
Title: Re: EEVBlog 121GW Discussion thread
Post by: ggchab on May 10, 2019, 08:45:53 am
It's just a meter, there was some excitement because it was a kickstarter, but now it's a year and half later and it's now just another product in my store. That was inevitable.

To be totally honest, I would add "and because it was Dave's meter"  ;)
Thank you for the clarification. I was hoping this would take more time but I understand.

A simple message like
Quote
I'm using 2.00 firmware at present and UEI have said we can release it, so expect it soon."
is good news  :)
Title: Re: EEVBlog 121GW Discussion thread
Post by: thinkfat on May 10, 2019, 09:15:48 am
I'm using the 1.54 software version, no problems with it. If 2.00 improves it even further - that will be brilliant!
Title: Re: EEVBlog 121GW Discussion thread
Post by: Brumby on May 10, 2019, 09:22:21 am
Fixes are still coming. I'm using 2.00 firmware at present and UEI have said we can release it, so expect it soon. Improvements are better and faster resistance and capacitance autoranging.

Well, that explains why there was no comment about the V1.61 FW some people had encountered.  No need to waste time with that when the new release was imminent.  (We just have an alert user base that picked up on that a week or two too early.)
Title: Re: EEVBlog 121GW Discussion thread
Post by: oliv3r on May 10, 2019, 08:15:03 pm
Could someone please share calibration data? I lost it while messing up with the meter and not all ranges I can calibrate (like I don't have a high-voltage source for AC, for example). I know results won't be perfect, but it's fine :)

Check your PM for:
$ md5sum CAL.BIN
ca2b85fe5be9863f3b96db3cc925d419  /media/oliver/121GW/CAL.BIN

Since I can PM files, I'm sure you don't mind that it's base64 encoded :)
Title: Re: EEVBlog 121GW Discussion thread
Post by: joeqsmith on May 11, 2019, 12:24:53 am
After Dave's comments about reviving the toggle bot to repeat the switch life cycle testing, I offered to buy a couple of the new meters and run that test for them but no response and I have not heard anything else.

If I had a spare new thicker PCB meter to send you, I would.
I'm in no rush.   

Not surprising to anyone with half an idea of how small business is challenged on a daily basis.  I don't have any secret communications, just common sense (sometimes  :D ).

Or people could just listen to The Amp Hour  ;D

If you pay attention, there are normally a few gold nuggets in those shows. 
Title: Re: EEVBlog 121GW Discussion thread
Post by: rthorntn on May 13, 2019, 10:28:28 am
Does anyone have any idea on how to source replacement probes?
Title: Re: EEVBlog 121GW Discussion thread
Post by: jancumps on May 13, 2019, 10:33:46 am
Does anyone have any idea on how to source replacement probes?

This is the model: Silicone test leads BL21S2-T4SC Brymen
Title: Re: EEVBlog 121GW Discussion thread
Post by: J-R on May 14, 2019, 05:16:04 pm
Now, it seems that the "soufflé est retombé" as we say in French. I would like to be proven the opposite, but except a few apparitions of the multi-meter in some videos, enthusiasm seems to be gone, upgrades are no longer available, no more reaction from any Dave.

What "enthusiasm" do you want?
Want me to include an outro in every video plugging the meter?
It's just a meter, there was some excitement because it was a kickstarter, but now it's a year and half later and it's now just another product in my store. That was inevitable.
Fixes are still coming. I'm using 2.00 firmware at present and UEI have said we can release it, so expect it soon. Improvements are better and faster resistance and capacitance autoranging.

That's the biggest announcement about the 121GW I've heard since I bought it a year ago.  I'm enthusiastic about getting my hands on the new firmware.
Title: Re: EEVBlog 121GW Discussion thread
Post by: BrianG61UK on May 14, 2019, 05:25:45 pm
I just received my 121GW.

I don't understand the reasoning behind "Low Z".

Having an optional internal load on a voltage range makes sense, but why fixed on a high voltage range and not auto ranging? And why AC only?

I just don't get it.
Title: Re: EEVBlog 121GW Discussion thread
Post by: 0xdeadbeef on May 14, 2019, 05:31:21 pm
"Low Z"  is typically meant for "ghost voltage" on mains.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Cnoob on May 14, 2019, 05:40:44 pm
https://www.ebay.co.uk/itm/Brymen-Silicone-Gold-Plated-Test-Leads-Probes-for-Multimeters-CAT-IV-1000V/171162377470?hash=item27da129cfe:g:uSQAAOxyTjNShpch&frcectupt=true (https://www.ebay.co.uk/itm/Brymen-Silicone-Gold-Plated-Test-Leads-Probes-for-Multimeters-CAT-IV-1000V/171162377470?hash=item27da129cfe:g:uSQAAOxyTjNShpch&frcectupt=true)

I get my Brymen Probes from here plus other test leads all good quality and quick and reliable delivery.
Title: Re: EEVBlog 121GW Discussion thread
Post by: BrianG61UK on May 14, 2019, 06:06:39 pm
"Low Z"  is typically meant for "ghost voltage" on mains.
But wouldn't it make sense to allow it to be used for other things like testing batteries?

In most high impedance "ghost" mains voltage cases isn't one more interested in measuring the current anyway (measure with a few kohm R in series so no chance you blow a fuse somewhere)?

In the low impedance case (eg two earths/grounds that have a voltage between them) you can just use normal voltage range.
 
Title: Re: EEVBlog 121GW Discussion thread
Post by: 0xdeadbeef on May 14, 2019, 11:10:14 pm
But wouldn't it make sense to allow it to be used for other things like testing batteries?
Theoretically yes, but the current would be still pretty low for a battery. E.g. the Fluke 117 has ~3kOhm resitance in LoZ mode, so a 1.5V cell would cause a current of 500µA. That's probably not enough to be useful for battery testing.


In most high impedance "ghost" mains voltage cases isn't one more interested in measuring the current anyway (measure with a few kohm R in series so no chance you blow a fuse somewhere)?
just use normal voltage range.
Ghost voltages are created by capacitive coupling (no current flowing). With the typical multi MOhm resistance, you can measure voltages like e.g. 75V that seem to be dangerous. When measuring in LoZ mode, the current over the e.g. 3kOhm resistor is enough for the ghost voltage to disappear.
Title: Re: EEVBlog 121GW Discussion thread
Post by: BrianG61UK on May 14, 2019, 11:46:21 pm
But wouldn't it make sense to allow it to be used for other things like testing batteries?
Theoretically yes, but the current would be still pretty low for a battery. E.g. the Fluke 117 has ~3kOhm resitance in LoZ mode, so a 1.5V cell would cause a current of 500µA. That's probably not enough to be useful for battery testing.


In most high impedance "ghost" mains voltage cases isn't one more interested in measuring the current anyway (measure with a few kohm R in series so no chance you blow a fuse somewhere)?
just use normal voltage range.
Ghost voltages are created by capacitive coupling (no current flowing). With the typical multi MOhm resistance, you can measure voltages like e.g. 75V that seem to be dangerous. When measuring in LoZ mode, the current over the e.g. 3kOhm resistor is enough for the ghost voltage to disappear.
You think that if you put AC across a capacitor no current flows?

I thought we were all engineers in here.


Sent from my SM-N9005 using Tapatalk

Title: Re: EEVBlog 121GW Discussion thread
Post by: 0xdeadbeef on May 14, 2019, 11:55:55 pm
You think that if you put AC across a capacitor no current flows?
Let's not start nitpicking. It's quite obvious that I intended to explain that ghost voltages are not caused by inductive coupling (i.e. through a current) but by capacitive coupling.

I thought we were all engineers in here.
I thought we were here to help each other, not to be smarty-pants.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Brumby on May 15, 2019, 03:21:32 am
You think that if you put AC across a capacitor no current flows?

You seem to be missing some basics here...

For the ghost voltage situation, putting a DMM with a 10M (or higher) input impedance across it is not going to load the voltage down a lot.  You could easily measure 100VAC which might prompt you to start chasing down a fault that simply does not exist.  The simple answer is to put an appropriate load across the measured points and then read off the voltage.  Know your load and know your voltage means you know your current.

What is of most interest here is not the actual current that flows but the voltage you read when the circuit is under this load.  Because the capacitance that allow these voltages to exist is so low, the loading provided by a meter with a Lo-Z range often drops the voltage measurements down to zero - or close to.  When this happens, your confidence that the circuit measured does not have dangerous power behind it rises dramatically.

Of course, if you still measure 100VAC (or whatever) on a Lo-Z range, then you do have something to chase down.



I thought we were all engineers in here.
This is not helpful.

Most of us here have, what I call, "engineering minds".  Some are qualified, some have experience, some have the drive and some, the ambition - but we all try and keep ourselves grounded in the way things work in the real world.  You seem to be resting on the pedant pedestal a tad.

So, let me ask you this question...
Say you measure 100VAC in the normal high impedance mode of a DMM - and then measure zero when you switch to the Lo-Z mode?  How much current is flowing?  Ohm's law gives a clear answer.

Of course, theoretically we know there must be some current flowing - but it's going to be one poofteenth of a gnat's wing - and as far as the real world is concerned, that is negligible (unless you're playing with atomic force microscopy or somesuch).

As a practical consideration, sometimes the theoretical needs to be properly understood - and put to one side.
Title: Re: EEVBlog 121GW Discussion thread
Post by: CDaniel on May 15, 2019, 10:22:19 am
LoZ is for AC and DC . When "engineering minds" work in real world will find many situations when a voltage in a circuit looks OK with a tipical high impedance multimeter , but it's not actually , because there is a fault and the circuit is just capacitive coupled or there is some high resistance conductive dirt somewhere ... For this is LoZ .
For example in a car circuit , you should check with LoZ or a light bulb if the fuses are OK , if not , a blown fuse can leave some conductive traces and you would be fooled with a normal multimeter .
Title: Re: EEVBlog 121GW Discussion thread
Post by: BrianG61UK on May 15, 2019, 10:48:33 am
LoZ is for AC and DC . When "engineering minds" work in real world will find many situations when a voltage in a circuit looks OK with a tipical high impedance multimeter , but it's not actually , because there is a fault and the circuit is just capacitive coupled or there is some high resistance conductive dirt somewhere ... For this is LoZ .
For example in a car circuit , you should check with LoZ or a light bulb if the fuses are OK , if not , a blown fuse can leave some conductive traces and you would be fooled with a normal multimeter .

Yes.
So why is it AC only on the 121GW ?
Title: Re: EEVBlog 121GW Discussion thread
Post by: BrianG61UK on May 15, 2019, 10:55:59 am
You think that if you put AC across a capacitor no current flows?

You seem to be missing some basics here...

For the ghost voltage situation, putting a DMM with a 10M (or higher) input impedance across it is not going to load the voltage down a lot.  You could easily measure 100VAC which might prompt you to start chasing down a fault that simply does not exist.  The simple answer is to put an appropriate load across the measured points and then read off the voltage.  Know your load and know your voltage means you know your current.

What is of most interest here is not the actual current that flows but the voltage you read when the circuit is under this load.

Most interest? Why?  The rules and regulations about how much leakage is safe quote currents not voltages across some vaguely defined non linear load.
Title: Re: EEVBlog 121GW Discussion thread
Post by: HKJ on May 15, 2019, 11:16:14 am

So why is it AC only on the 121GW ?

Why do you believe it is AC only?
My 121GW have no problems showing DC voltage in LowZ mode.
Title: Re: EEVBlog 121GW Discussion thread
Post by: HKJ on May 15, 2019, 11:21:44 am
Most interest? Why?  The rules and regulations about how much leakage is safe quote currents not voltages across some vaguely defined non linear load.

You need both voltage and current before it is dangerous and I am not sure LowZ is designed to show dangerous voltage, but more to show if there is power available.
Title: Re: EEVBlog 121GW Discussion thread
Post by: BrianG61UK on May 15, 2019, 12:00:06 pm

So why is it AC only on the 121GW ?

Why do you believe it is AC only?
My 121GW have no problems showing DC voltage in LowZ mode.
That's odd. Mine showed nothing on a 6V battery.

Sent from my SM-N9005 using Tapatalk

Title: Re: EEVBlog 121GW Discussion thread
Post by: HKJ on May 15, 2019, 12:02:47 pm

Why do you believe it is AC only?
My 121GW have no problems showing DC voltage in LowZ mode.
That's odd. Mine showed nothing on a 6V battery.


You need about 12VDC before the meter will show anything (In my opinion this is a silly detail).
Title: Re: EEVBlog 121GW Discussion thread
Post by: CDaniel on May 15, 2019, 12:08:01 pm
LoZ is for finding faults in circuits not for leakage or some fancy "engineer" stuff ...
Of course in 121GW LoZ is both AC and DC . But only above 12V . You should read the manual . Mine is working from 10V
Title: Re: EEVBlog 121GW Discussion thread
Post by: BrianG61UK on May 15, 2019, 12:17:16 pm

Why do you believe it is AC only?
My 121GW have no problems showing DC voltage in LowZ mode.
That's odd. Mine showed nothing on a 6V battery.


You need about 12VDC before the meter will show anything (In my opinion this is a silly detail).
It's totally bizarre.

Sent from my SM-N9005 using Tapatalk

Title: Re: EEVBlog 121GW Discussion thread
Post by: Brumby on May 15, 2019, 05:48:25 pm
It doesn't seem particularly bizarre to me.

The 121GW is a tool that has features designed to perform certain functions.  That tool has specifications and instructions, which define what it can do and how to achieve that.  It, like every other multimeter, is not capable of every type of measurement that can be imagined - but does what it was intended to do.

The Lo-Z range and the characteristics of its operation seem to me to be quite reasonable and suitable for the purpose for which it was designed - including the low voltage threshold.

But that's just me.
Title: Re: EEVBlog 121GW Discussion thread
Post by: 0xdeadbeef on May 15, 2019, 06:33:25 pm
For the record: my "travel" DMM is a Fluke 117 which has an "Auto-V LoZ" mode. This actually works for single NiMh cells but there's not much of a difference compared to the high ohmic mode - which (as stated before) is not really to be expected with a ~500µA load current. Actually, the value displayed is e.g. 1.4V in LoZ mode vs. 1.412V in DC Volt mode but the "difference" is most probably mainly due to the lower resolution (0.1V) in "Auto-V" mode.
Title: Re: EEVBlog 121GW Discussion thread
Post by: exe on May 15, 2019, 08:46:31 pm
This actually works for single NiMh cells but there's not much of a difference compared to the high ohmic mode - which (as stated before) is not really to be expected with a ~500µA load current.

Fine with me, this means impedance of ~3KOhm (comprate 10MOhm). Afaik it uses PTC, so, connected to mains, impedance will be higher.
Title: Re: EEVBlog 121GW Discussion thread
Post by: chronos42 on May 15, 2019, 10:30:41 pm
I use the lowZ mode of multimeters mostly for discharging capacitors, for this purpose the lowZ DC range of the 121GW should be lower than 12V to see if the capacitor is really completely discharged. But I assume this cannot be easily done by firmware.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on May 16, 2019, 05:21:02 am
121GW Currently on sale for AU$260 ($179US), this won't last.
https://www.eevblog.com/product/121gw/ (https://www.eevblog.com/product/121gw/)
Even cheaper if you pay with crypto!
Title: Re: EEVBlog 121GW Discussion thread
Post by: Jon.C on May 16, 2019, 10:42:32 am
Hi Dave

when will you publish firmware 2.0?

Thank you
Title: Re: EEVBlog 121GW Discussion thread
Post by: bitwelder on May 16, 2019, 11:09:02 am
Even cheaper if you pay with crypto!
How is the price with cryptocoins?
Conversion from price in AUD using the rate at time of purchase?
Title: Re: EEVBlog 121GW Discussion thread
Post by: btspce on May 16, 2019, 01:10:56 pm
Just got this below from Welectron here in Europe so maybe Dave should make a note of the serial range on the firmware page if he publishes the newer firmware.

Quote
Dear Sir or Madam,

We have been informed by Kane Test that some of the shipped EVBlog 121GW multimeters have an issue. This can result in a loss of calibration data after a firmware update. Unfortunately, this issue cannot be resolved by the customer.

Please check if your 121GW has a serial number in the range of 190106323 .. 190106450.
If this is the case:
- Do NOT attempt to update the firmware on your 121GW.
- Do NOT yet send the device back to us. We will arrange an exchange once we receive new stock from Kane Test in about 3-4 weeks.
- Please let us know the serial number of your device, and if you agree in exchanging your affected 121GW with a new device.

If your 121GW is not in the noted serial number range, you do not need to worry and can ignore this e-mail.

Thank you for your cooperation!

Best regards,
Your Welectron Team
Title: Re: EEVBlog 121GW Discussion thread
Post by: exe on May 16, 2019, 03:44:49 pm
Quote
Please check if your 121GW has a serial number in the range of 190106323 .. 190106450.

Interesting, I wonder why. Or was it because these multimeters use a different format/location of calibration data? May be that's an issue with unpublished firmware.
Title: Re: EEVBlog 121GW Discussion thread
Post by: joeqsmith on May 17, 2019, 01:43:58 am
When I changed the firmware on the prototype Dave sent, it had to be realigned.  I assume it was because they changed the format (locations, size, types....).    What's a bit odd is I have since installed many of the versions that were available and never had a problem.   Maybe these were some of the very first meters and they shipped with pre 1.0. 

Maybe if the owners wanted to keep their SNs, they could have then realigned by an outside house.   
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on May 17, 2019, 02:13:26 am
Even cheaper if you pay with crypto!
How is the price with cryptocoins?
Conversion from price in AUD using the rate at time of purchase?

Try the checkout and find out  ;D
Yes, conversion is at the time of purchase based on CoinPayments/net rate whereever they get that from.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on May 17, 2019, 09:07:22 am
Just got this below from Welectron here in Europe so maybe Dave should make a note of the serial range on the firmware page if he publishes the newer firmware.

Quote
Dear Sir or Madam,

We have been informed by Kane Test that some of the shipped EVBlog 121GW multimeters have an issue. This can result in a loss of calibration data after a firmware update. Unfortunately, this issue cannot be resolved by the customer.

Please check if your 121GW has a serial number in the range of 190106323 .. 190106450.
If this is the case:
- Do NOT attempt to update the firmware on your 121GW.
- Do NOT yet send the device back to us. We will arrange an exchange once we receive new stock from Kane Test in about 3-4 weeks.
- Please let us know the serial number of your device, and if you agree in exchanging your affected 121GW with a new device.

If your 121GW is not in the noted serial number range, you do not need to worry and can ignore this e-mail.

Thank you for your cooperation!

Best regards,
Your Welectron Team

This only affected 21 units, and only units shipped by Welectron.
UEi did a new version of firmware and shipped that with units to Welectron (who direct order from UEi, they don't buy from me), unfortunately there was a calibration goof of some sort and those units had to be recalled and units replaced (or re-calibrated, but quicker to replace in this instance for those customers).
Everything is fixed now and all new units from Welectron will ship with the latest 2.00 firmware and problem solved.
So there should not be any meters left in the wild that cannot be upgraded in future, so no need for any advice on the firmware page.
My stock is not affected.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on May 17, 2019, 09:08:10 am
When I changed the firmware on the prototype Dave sent, it had to be realigned.  I assume it was because they changed the format (locations, size, types....). 

Yes, your unit was pre-production and a lot changed from your version to release.
Title: Re: EEVBlog 121GW Discussion thread
Post by: e0ne199 on May 19, 2019, 02:10:31 pm
hello everyone  :) :D
Title: Re: EEVBlog 121GW Discussion thread
Post by: BrianG61UK on May 23, 2019, 01:53:13 pm

Why do you believe it is AC only?
My 121GW have no problems showing DC voltage in LowZ mode.
That's odd. Mine showed nothing on a 6V battery.


You need about 12VDC before the meter will show anything (In my opinion this is a silly detail).
It's totally bizarre.

Sent from my SM-N9005 using Tapatalk

I tried two 9V batteries in series. Over 19V.

It takes a long time to register considering that no auto ranging is happening.

2 or 3 seconds.
 :(
Title: Re: EEVBlog 121GW Discussion thread
Post by: 286sx on May 23, 2019, 07:41:15 pm
Super nice multimeter..
compared with Fluke 87V , Fluke 87, Fluke 287, Fluke 289, Fluke 867b, 187, 189, Metrix, Keysight, Brymen...  (i compared only with high level handheld multimeters)
This multimeter is absolutely accurate. Nice features like low burden measurement, bluetooth, sd card (i like it for fw upgrade), crisply lcd display and build quality is just awesome.
I'm sure Dave will improve the SW side.

I compared specially Fluke 189/289 vs 121GW, they have similar specs. (I used ir3000FC bluetooth adapter on fluke's)
121GW software (android) is better
121GW has more features
integrated bluetooth
same accuracy
open source
and you can buy 4 121GW instead one fluke.. :)

Thank you Dave ! specially for the color :)
Title: Re: EEVBlog 121GW Discussion thread
Post by: hammy on May 27, 2019, 02:33:32 pm
Fixes are still coming. I'm using 2.00 firmware at present and UEI have said we can release it, so expect it soon. Improvements are better and faster resistance and capacitance autoranging.

Any news about the new 2.0 firmware?
Title: Re: EEVBlog 121GW Discussion thread
Post by: 1anX on May 29, 2019, 07:43:16 am
Fixes are still coming. I'm using 2.00 firmware at present and UEI have said we can release it, so expect it soon. Improvements are better and faster resistance and capacitance autoranging.

Any news about the new 2.0 firmware?
My guess is that there is a problem with V2.0 otherwise it would be released!
Why withhold an improvement that would benefit users? Can only be a problem was found and its pointless releasing a buggy version. 
Title: Re: EEVBlog 121GW Discussion thread
Post by: HKJ on May 29, 2019, 07:50:20 am
My guess is that there is a problem with V2.0 otherwise it would be released!
Why withhold an improvement that would benefit users? Can only be a problem was found and its pointless releasing a buggy version.

That is a very doubtful explanation, new meters has for some time been delivered with newer software than is available on the website.
Title: Re: EEVBlog 121GW Discussion thread
Post by: ggchab on May 29, 2019, 10:07:08 am
It's just a meter, there was some excitement because it was a kickstarter, but now it's a year and half later and it's now just another product in my store. That was inevitable.

There is no more hurry to publish improvements ?
UEI does not send the new firmware and Dave does not ask ?
Something else ?

The new firmware will come one day or another  :)
Title: Re: EEVBlog 121GW Discussion thread
Post by: 1anX on May 29, 2019, 10:18:55 am
The new firmware will come one day or another  :)

It will probably arrive along with revised hardware in the form of a new version of the meter.
Dave will probably regain his interest in a new meter, as its required to promote sales.
Title: Re: EEVBlog 121GW Discussion thread
Post by: lowimpedance on May 29, 2019, 10:26:37 am
My guess is that there is a problem with V2.0 otherwise it would be released!
Why withhold an improvement that would benefit users? Can only be a problem was found and its pointless releasing a buggy version.

That is a very doubtful explanation, new meters has for some time been delivered with newer software than is available on the website.

 That being so, then wouldn't the other meters 'out there' also benefit from having access to the same firmware revision ?.
Title: Re: EEVBlog 121GW Discussion thread
Post by: e0ne199 on May 31, 2019, 05:07:50 am
so that means the hardware i have bought yesterday is buggy???  |O
it was expensive for my budget though, i bought it for 300AUD  :horse:
Title: Re: EEVBlog 121GW Discussion thread
Post by: Brumby on May 31, 2019, 05:47:40 am
Don't panic.

The first consideration is just what might be affected by the version of firmware supplied.  From what I can glean here, it seems to be working fairly well for most users.

Check the firmware version it has when you get it.  Also, this meter has the ability to update the firmware - so you're ahead with that feature!
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on May 31, 2019, 06:50:03 am
Sorry I thought David had put v2.00 on the website, I've just added it now.
Improvements include improved resistance autoranging speed, and update speed on higher resistance ranges. Plus various capacitance range improvements.
Title: Re: EEVBlog 121GW Discussion thread
Post by: darik on May 31, 2019, 07:01:50 am
Wow, the improvement in ohms autorange is _huge_.
Title: Re: EEVBlog 121GW Discussion thread
Post by: J-R on May 31, 2019, 08:15:10 am
I ran some resistance tests on 1.58 and 2.00 and my opinion is that the new firmware has improved speeds.  My informal test process used to take ~15 seconds on 1.58 (if I moved crazy fast it sometimes was as low as ~10 seconds), but now is ~9 seconds on 2.00 (normal pace).  Unfortunately for the 121GW, the same test is only ~5 seconds on the BM235 and many of my other meters.
Title: Re: EEVBlog 121GW Discussion thread
Post by: chronos42 on May 31, 2019, 08:15:44 am
Hi,
the ohm autorange is faster now, still not my fastest multimeter, but it is ok.
The "low capacitance bug" seems still present, a 220pF NP0 ceramic capacitor is shown as 0.160nF at the first time, then as 0.180nF after that as 0.200nF... The more often I switch the meter off and on, the closer the reading comes to the actual value. Also if I first use a small capacity, then a bigger one (e.g. several hundred nF) and then again the small capacity, the 121GW every time shows a different reading. I am not able to get a steady reading of small capacities with the 121GW. Can other users reproduce this behavior?  This is really odd.  For higher capacitances the meter shows correct values and the autorange speed seems also faster in capacitance mode now.
Title: Re: EEVBlog 121GW Discussion thread
Post by: bitwelder on May 31, 2019, 09:29:56 am
Sorry I thought David had put v2.00 on the website, I've just added it now.
Improvements include improved resistance autoranging speed, and update speed on higher resistance ranges. Plus various capacitance range improvements.
Thanks!
Hopefully also the manual changelog will be soon updated with the recent f/w history changes.
Title: Re: EEVBlog 121GW Discussion thread
Post by: CDaniel on May 31, 2019, 02:39:58 pm
Hi,
the ohm autorange is faster now, still not my fastest multimeter, but it is ok.
The "low capacitance bug" seems still present, a 220pF NP0 ceramic capacitor is shown as 0.160nF at the first time, then as 0.180nF after that as 0.200nF... The more often I switch the meter off and on, the closer the reading comes to the actual value. Also if I first read the small capacity, then a bigger one (e.g. several hundred nF) and then again the small capacity, the 121GW every time shows a different reading. I am not able to get a steady reading of small capacities with the 121GW. Can other users reproduce this behavior?  This is really odd.  For higher capacitances the meter shows correct values and the autorange speed seems also faster in capacitance mode now.

We talked about this issue and was confirmed , but ...  probably they don't care or can't fix it .
It seems to me that only the comunity will solve all the issues ... when someone pissed off will write a better firmware .
Title: Re: EEVBlog 121GW Discussion thread
Post by: 1anX on May 31, 2019, 09:11:22 pm
Anyone wondering if they should bother to update firmware to V2.0?
My advice for what its worth is to do it! The update certainly speeds up the meter's responsiveness for resistance and gives it a faster feel all round.
Title: Re: EEVBlog 121GW Discussion thread
Post by: BrianG61UK on May 31, 2019, 10:05:02 pm
Anyone wondering if they should bother to update firmware to V2.0?
My advice for what its worth is to do it! The update certainly speeds up the meter's responsiveness for resistance and gives it a faster feel all round.
Indeed. I agree.
Title: Re: EEVBlog 121GW Discussion thread
Post by: GeoffreyF on June 01, 2019, 04:16:33 pm
I did it successfully but there is a "Gotcha" in this.  The .bin file is named EEVBlog2_00.bin.  That name will not upload into the meter.  Rename it to EEVBlog.bin, as it has been in the past and the upload will work.   I will also remind people that the Analog bar will show the progress of the upload.   If it does not move, it's not doing anything.

I can also confirm (though do not recommend) that after a couple minutes, of "Douun" ... turning the meter off caused no harm.  If you are sitting there and the download to the meter is not working, despite cautions in the instructions, I did turn if off (and did this twice) without ill effect.  Then I just renamed the file name as explained above and all was well.

EEVBlog folks may wish to repost the 2.0  zip with the .bin file name modified to avoid confusion and match past releases.  Suggestion for 2.0+ is to not display "Douun" if the meter could not find a file to load, either because it was not the correct name (as here) or some other reason.  It should post something like "Err" and then restart after a few seconds.
Title: Re: EEVBlog 121GW Discussion thread
Post by: CDaniel on June 01, 2019, 06:02:28 pm
Now the ranges for voltage switch at 55000 counts up and 50000 counts down ( before was at 45000 down) , this is fairly normal and the switching is faster ... so it could be done , why took so long it's a interesting question .
Title: Re: EEVBlog 121GW Discussion thread
Post by: Brumby on June 02, 2019, 01:46:18 am
I did it successfully but there is a "Gotcha" in this.  The .bin file is named EEVBlog2_00.bin.  That name will not upload into the meter.  Rename it to EEVBlog.bin, as it has been in the past and the upload will work.   

I wouldn't call this a "Gotcha".  This has been a requirement from the very beginning.

I would strongly suggest that you always keep the firmware showing the version number in the filename and ONLY change it when copied to the card for uploading.

My recommendation: NEVER, EVER, EVER put up a file named EEVBlog.bin here or anywhere else - because you won't know what version it is.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Brumby on June 02, 2019, 01:50:22 am
EEVBlog folks may wish to repost the 2.0  zip with the .bin file name modified to avoid confusion and match past releases.
Please, no.

Quote
  Suggestion for 2.0+ is to not display "Douun" if the meter could not find a file to load, either because it was not the correct name (as here) or some other reason.  It should post something like "Err" and then restart after a few seconds.
That's not a bad idea.
Title: Re: EEVBlog 121GW Discussion thread
Post by: BrianG61UK on June 02, 2019, 02:01:51 am


I did it successfully but there is a "Gotcha" in this.  The .bin file is named EEVBlog2_00.bin.  That name will not upload into the meter.  Rename it to EEVBlog.bin, as it has been in the past and the upload will work.   

I wouldn't call this a "Gotcha".  This has been a requirement from the very beginning.

I would strongly suggest that you always keep the firmware showing the version number in the filename and ONLY change it when copied to the card for uploading.

My recommendation: NEVER, EVER, EVER put up a file named EEVBlog.bin here or anywhere else - because you won't know what version it is.

No. Keep it in the zip file where it's protected from accidental corruption until you need it. The zip file can have the version number in the name but the bin file inside should be the correct name to just extract it on to the microSD without any messing about renaming it.

Sent from my SM-N9005 using Tapatalk

Title: Re: EEVBlog 121GW Discussion thread
Post by: Brumby on June 02, 2019, 02:06:14 am
That's not unreasonable, but it does put a greater risk of getting it wrong when the firmware is zipped by Dave/David.

I'm happier with the fail safe method currently in use.  When things go wrong now - no damage is done and is fixed by a simple rename.
Title: Re: EEVBlog 121GW Discussion thread
Post by: BrianG61UK on June 02, 2019, 02:20:35 am
That's not unreasonable, but it does put a greater risk of getting it wrong when the firmware is zipped by Dave/David.

I'm happier with the fail safe method currently in use.  When things go wrong now - no damage is done and is fixed by a simple rename.

Whoever zips the firmware is welcome to call it whatever they want until they zip it. (Hopefully it's arriving from UEI already in a zip file and not just as an unprotected email attachment)
But please after zipping it in an appropriately named zip file rename it so it's ready to use when I extract it to the microSD card.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Brumby on June 02, 2019, 02:58:47 am
I still don't like the idea.

I can see why you are asking - but is a simple rename too much to ask?

Edit: I say this because after more years than I care to remember in the software development game, version control is extremely important and easily stuffed up.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on June 02, 2019, 03:21:58 am
Quote
  Suggestion for 2.0+ is to not display "Douun" if the meter could not find a file to load, either because it was not the correct name (as here) or some other reason.  It should post something like "Err" and then restart after a few seconds.
That's not a bad idea.

I don't think that change is possible, as that code would be in the fixed protected bootloader code.
Title: Re: EEVBlog 121GW Discussion thread
Post by: joeqsmith on June 02, 2019, 03:25:37 am
They have no way to reprogram the boot loader?   Even if they create an application to reprogram the boot?  Seem odd they wouldn't have considered that. 
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on June 02, 2019, 03:39:25 am
They have no way to reprogram the boot loader?

Of course there is, but it requires a programmer and a special cable. Not something you'd ordinarily instruct or encourage customers to do unless the circumstances were dire.
Countless products follow this exact principle.
The factory can certainly update the bootloader for new units shipped.
BTW, I don't know how they actually do it at the factory, but they could buy the ARM chips pre-programmed with the bootloader and so wouldn't ordinarily program the bootloader at the factory.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Muttley Snickers on June 02, 2019, 06:18:25 am
It would be good if somebody could do another side by side comparison video to show how much better this meter performs now with the new firmware.

Title: Re: EEVBlog 121GW Discussion thread
Post by: e0ne199 on June 02, 2019, 06:52:42 am
Hi,
the ohm autorange is faster now, still not my fastest multimeter, but it is ok.
The "low capacitance bug" seems still present, a 220pF NP0 ceramic capacitor is shown as 0.160nF at the first time, then as 0.180nF after that as 0.200nF... The more often I switch the meter off and on, the closer the reading comes to the actual value. Also if I first use a small capacity, then a bigger one (e.g. several hundred nF) and then again the small capacity, the 121GW every time shows a different reading. I am not able to get a steady reading of small capacities with the 121GW. Can other users reproduce this behavior?  This is really odd.  For higher capacitances the meter shows correct values and the autorange speed seems also faster in capacitance mode now.

does anyone care about this problem?
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on June 02, 2019, 07:29:37 am
It would be good if somebody could do another side by side comparison video to show how much better this meter performs now with the new firmware.

https://www.youtube.com/watch?v=q4gXnpFPFzQ (https://www.youtube.com/watch?v=q4gXnpFPFzQ)
Title: Re: EEVBlog 121GW Discussion thread
Post by: Muttley Snickers on June 02, 2019, 07:44:09 am
Thanks, I will have a look at that video shortly.   :)

I just found this video on Youtube where someone has created a splendid addition to the tilt stand on the 121GW meter.   :-/O   

https://www.thingiverse.com/thing:3666409 (https://www.thingiverse.com/thing:3666409)        :-+

https://www.youtube.com/watch?v=vZ2xE71g_xw (https://www.youtube.com/watch?v=vZ2xE71g_xw)
Title: Re: EEVBlog 121GW Discussion thread
Post by: IanB on June 02, 2019, 09:19:07 am
https://www.youtube.com/watch?v=q4gXnpFPFzQ (https://www.youtube.com/watch?v=q4gXnpFPFzQ)

This video clearly shows the "ghost" reading in resistance mode, for example at the 0:28 mark and at the 3:24 mark. If you have auto-hold turned on will it capture these ghost readings instead of the final correct reading? I would prefer that the display is suppressed until it settles on a final reading.
Title: Re: EEVBlog 121GW Discussion thread
Post by: CDaniel on June 02, 2019, 09:47:11 am
Some resistance ranges are still affected by noise , probably where the ADC is at the maximum sensitivity . Overall the measurement current is too small on all ranges if you compare it with a known brand multimeter and this force the ADC to be very sensitive and easily capturing any noise from the hands holding the probes . It would be fantastic if in real world we would measure resistors like in the video , without holding the probes .
Title: Re: EEVBlog 121GW Discussion thread
Post by: beanflying on June 02, 2019, 10:02:36 am
Some resistance ranges are still affected by noise , probably where the ADC is at the maximum sensitivity . Overall the measurement current is too small on all ranges if you compare it with a known brand multimeter and this force the ADC to be very sensitive and easily capturing any noise from the hands holding the probes . It would be fantastic if in real world we would measure resistors like in the video , without holding the probes .

So you are claiming the Meter is faulty because of being used with poor technique with no evidence I have seen to back it up? Seriously what a load of  :bullshit:
Title: Re: EEVBlog 121GW Discussion thread
Post by: CDaniel on June 02, 2019, 10:06:50 am
I just say that some people would use it working on something  ;D not just for show .
Now it is much better than it was with some old firmware , but still in some ranges last 2 digits will fluctuate .
Sorry if I spoil somebody sensation that this is the perfect meter .
Title: Re: EEVBlog 121GW Discussion thread
Post by: joeqsmith on June 02, 2019, 04:52:21 pm
High res video of old man hands.   :-DD :-DD

Looks much better (firmware, not your hands). 

I did pick up both programming adapters for this meter.  I reprogrammed the BLE controller on the prototype meter but have decided to hold off doing anything with the firmware.   
I was thinking they could reprogram the boot from some other means  but I agree most of the time, you would never do this on a handheld (or any product).  Normally true for the  application as well. 
Title: Re: EEVBlog 121GW Discussion thread
Post by: joeqsmith on June 02, 2019, 05:01:06 pm
Thanks, I will have a look at that video shortly.   :)

I just found this video on Youtube where someone has created a splendid addition to the tilt stand on the 121GW meter.   :-/O     

Too bad the stand just wasn't wider at the base.  I wonder thy they didn't print a whole new stand that would step out from the boot and then lay flat across the back rather than to snap in this extension.   Seems like even adding even 5mm to to both sides would really help. 
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on June 02, 2019, 11:31:20 pm
I was thinking they could reprogram the boot from some other means

No, and that's the whole point, so that the bootloaded is fully protected from idiot users.
In theory there should be no way you can crash the firmware upload and brick your meter, i.e. taking out the card during programming, or power interruption, or corrupted code etc.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Smafe on June 02, 2019, 11:40:15 pm
I think I may have bricked my meter. I downloaded the V2 firmware, extracted the file, renamed it, transferred it on to a different Micro SD card that I'd formatted in Windows 10, then put it in the meter and tried to update it. It's been sitting at IAP- douun for over half an hour now. Help!
Title: Re: EEVBlog 121GW Discussion thread
Post by: BrianG61UK on June 02, 2019, 11:51:22 pm
I think I may have bricked my meter. I downloaded the V2 firmware, extracted the file, renamed it, transferred it on to a different Micro SD card that I'd formatted in Windows 10, then put it in the meter and tried to update it. It's been sitting at IAP- douun for over half an hour now. Help!
It should only take about 5 seconds.
Say a prayer and switch off and on again.

Later:
I recommend this: https://www.sdcard.org/downloads/formatter/ (https://www.sdcard.org/downloads/formatter/) for formatting SD cards using Windows. Windows itself tends to format them in nonstandard ways that can confuse some devices.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Smafe on June 03, 2019, 12:22:53 am
Two hours after starting the upgrade it hadn't moved, so I took a deep breath turned it off and tried putting the new firmware on the original Micro SD. I put it in and tried uploading it and it worked, like you said - in less than 5 seconds. When I turn the meter on the backlight flashes briefly but it's done that since I upgraded to 1.57. I'll test the meter out later and hope like hell that I haven't shagged it. I was just trying to use a faster Micro SD. Oh well, we live and learn, and make dicks of ourselves.
Title: Re: EEVBlog 121GW Discussion thread
Post by: BrianG61UK on June 03, 2019, 12:35:36 am
Two hours after starting the upgrade it hadn't moved, so I took a deep breath turned it off and tried putting the new firmware on the original Micro SD. I put it in and tried uploading it and it worked, like you said - in less than 5 seconds. When I turn the meter on the backlight flashes briefly but it's done that since I upgraded to 1.57. I'll test the meter out later and hope like hell that I haven't shagged it. I was just trying to use a faster Micro SD. Oh well, we live and learn, and make dicks of ourselves.
That all sounds normal again.
That backlight flicks on for a moment on mine too.
Even when they work right firmware updates are scary, especially if you have no real idea how much thought has gone into making the process failure proof.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Dino KL0S on June 03, 2019, 01:27:23 am
I had the same problem earlier today. Turns out you need to rename the file from EEVBlog2_00.bin to EEVBlog.bin; that did the trick and it updated to V2 in only a few seconds. Had the same "oh crap" thought when the "down" display just sat there...took a chance and cycled the power and fortunately the boot loader didn't have a problem!   :phew:
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on June 03, 2019, 01:46:07 am
I had the same problem earlier today. Turns out you need to rename the file from EEVBlog2_00.bin to EEVBlog.bin

You just like it tell you to do right above the very link you download it from?

(https://i.imgur.com/ScwnxxF.png)
Title: Re: EEVBlog 121GW Discussion thread
Post by: joeqsmith on June 03, 2019, 04:06:55 am
I was thinking they could reprogram the boot from some other means

No, and that's the whole point, so that the bootloaded is fully protected from idiot users.
In theory there should be no way you can crash the firmware upload and brick your meter, i.e. taking out the card during programming, or power interruption, or corrupted code etc.

Perhaps your customers are just a bit overzealous causing them to experiment more than they should.  After all, isn't that the jist of Don't Turn it on,  Take it apart.   
Title: Re: EEVBlog 121GW Discussion thread
Post by: beanflying on June 03, 2019, 04:12:28 am
I just say that some people would use it working on something  ;D not just for show .
Now it is much better than it was with some old firmware , but still in some ranges last 2 digits will fluctuate .
Sorry if I spoil somebody sensation that this is the perfect meter .

It is my everyday driver in my toolbag and works fine. It is you who has the problem, sell your meter and stop being a sook.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on June 03, 2019, 04:18:52 am
I just say that some people would use it working on something  ;D not just for show .
Now it is much better than it was with some old firmware , but still in some ranges last 2 digits will fluctuate .
Sorry if I spoil somebody sensation that this is the perfect meter .

I just compared it to the Brymen BM869 and Keysight U1272A and they have exactly the same fluctuation when handling the leads, even worse perhaps, using the same 30M resistor with the same leads.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on June 03, 2019, 04:20:23 am
I was thinking they could reprogram the boot from some other means

No, and that's the whole point, so that the bootloaded is fully protected from idiot users.
In theory there should be no way you can crash the firmware upload and brick your meter, i.e. taking out the card during programming, or power interruption, or corrupted code etc.

Perhaps your customers are just a bit overzealous causing them to experiment more than they should.  After all, isn't that the jist of Don't Turn it on,  Take it apart.

All the more reason for me not to encourage anyone to experiment with the bootloader, let alone provide them instructions to do so.
Title: Re: EEVBlog 121GW Discussion thread
Post by: 1anX on June 03, 2019, 04:21:36 am
I just say that some people would use it working on something  ;D not just for show .
Now it is much better than it was with some old firmware , but still in some ranges last 2 digits will fluctuate .
Sorry if I spoil somebody sensation that this is the perfect meter .

It is my everyday driver in my toolbag and works fine. It is you who has the problem, sell your meter and stop being a sook.

Hey BeanFlying, I believe CDaniel is entitled to share his opinion just as you and I am!
You like the meter and its in your tool bag thats cool.
CDaniel wants to criticize certain functions of the meter and how it operates thats cool too!
We even have one person in this thread who shares his opinion on this meter and he doesn't even own or have one. Thats amazingly cool as well!
No need to get your knickers in a knot over opinionated people because as we all know, everyone has one (IMO)  :-+

Title: Re: EEVBlog 121GW Discussion thread
Post by: beanflying on June 03, 2019, 04:24:37 am
I just say that some people would use it working on something  ;D not just for show .
Now it is much better than it was with some old firmware , but still in some ranges last 2 digits will fluctuate .
Sorry if I spoil somebody sensation that this is the perfect meter .

It is my everyday driver in my toolbag and works fine. It is you who has the problem, sell your meter and stop being a sook.

Hey BeanFlying, I believe CDaniel is entitled to share his opinion just as you and I am!
You like the meter and its in your tool bag thats cool.
CDaniel wants to criticize certain functions of the meter and how it operates thats cool too!
We even have one person in this thread who shares his opinion on this meter and he doesn't even own or have one. Thats amazingly cool as well!
No need to get your knickers in a knot over opinionated people because as we all know, everyone has one (IMO)  :-+

He had a first dig and as such I WILL REPLY if I think it warranted. Which I have done in this case. I will not be told by you or anyone that I shouldn't reply.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on June 03, 2019, 04:28:06 am
I had the same problem earlier today. Turns out you need to rename the file from EEVBlog2_00.bin to EEVBlog.bin; that did the trick and it updated to V2 in only a few seconds. Had the same "oh crap" thought when the "down" display just sat there...took a chance and cycled the power and fortunately the boot loader didn't have a problem!   :phew:

For those having a whinge about, i've fixed the ZIP file.
I'll await the whinge when someone mistakes the eevblog.bin for an older eevblog.bin
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on June 03, 2019, 04:32:11 am
I just say that some people would use it working on something  ;D not just for show .
Now it is much better than it was with some old firmware , but still in some ranges last 2 digits will fluctuate .
Sorry if I spoil somebody sensation that this is the perfect meter .

I just compared it to the Brymen BM869 and Keysight U1272A and they have exactly the same fluctuation when handling the leads, even worse perhaps, using the same 30M resistor with the same leads.

Also the BM235, and the Fluke 17B have exactly the same fluctuation.
Shall I keep going  ;D
Title: Re: EEVBlog 121GW Discussion thread
Post by: CDaniel on June 03, 2019, 04:52:06 am
I didn't say it's the highest range ... the reading fluctuate in 5K range for example when you hold the probes .
Just don't ask for proofs , I don't make videos for something that everyone with 2 hands and willingness to use them can replicate easily  ;D...
Perhaps it is just a lack of filtration at the ADC input . Before firmware 1.57 was much worse , so something can be done .
It is at least silly to design a meter and not check if is stable when holding the probes ...
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on June 03, 2019, 05:06:44 am
I didn't say it's the highest range ... the reading fluctuate in 5K range for example when you hold the probes .

Nope, doesn't do it for me. 5k resistor only varies +/-1LSD, maybe 2LSD at a pinch with cable handing.
And that's either touching cables (i.e. capacitive coupling) or touching either probe, and even rubbing my shoes on the carpet to generate some ESD.
No worse than a Keysight U1272A.
Are you using yours in high V/m field or something?
Title: Re: EEVBlog 121GW Discussion thread
Post by: CDaniel on June 03, 2019, 05:21:43 am
OK , a video with a 47K , even with no touching  hands , just the bench noise . If I move the meter away from the table it is stable , but obviously something is not right

https://streamable.com/giz9s
Title: Re: EEVBlog 121GW Discussion thread
Post by: darik on June 03, 2019, 05:26:51 am
OK , a video with a 47K , even with no touching  hands , just the bench noise . If I move the meter away from the table it is stable , but obviously something is not right

https://streamable.com/giz9s

 :-DD
Title: Re: EEVBlog 121GW Discussion thread
Post by: beanflying on June 03, 2019, 05:28:17 am
OK , a video with a 47K , even with no touching  hands , just the bench noise . If I move the meter away from the table it is stable , but obviously something is not right

https://streamable.com/giz9s

You have a switchmode supply within 50mm of it and you want to be taken seriously? Please tell us that it and other nearby SMP's are not near the leads  :palm:
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on June 03, 2019, 05:32:42 am
OK , a video with a 47K , even with no touching  hands , just the bench noise . If I move the meter away from the table it is stable , but obviously something is not right

All multimeters have a tolerance for electric fields, some even specify a V/m field strength for the the accuracy. Looks like you are in a potentially horrible environment there, evidenced by the problem going away when you move it away from your bench.
Title: Re: EEVBlog 121GW Discussion thread
Post by: CDaniel on June 03, 2019, 05:34:34 am
That power outlet with USB power supply in it has a switch and wasn't turn on  ;D
Nothing was turned on on the bench , just the normal electrical noise from the wires
Title: Re: EEVBlog 121GW Discussion thread
Post by: Smafe on June 03, 2019, 06:51:48 am
Hi Dave, I wasn't having a whinge (apart from the back light flashing briefly when the meter turns on). I'm grateful for all the help you've given me over the past couple of years. I did rename the file, but I put it on a different Micro SD card. It was the card out of my phone and I wasn't sure which way to format it, so tried formatting in Windows 10. That must have been the problem as when I put the bin file on the original card and booted it from there it worked. I was worried as I couldn't remember whether to rename the zip or extract the bin file. It sounds stupid now, but I've only updated the firmware once before and that was when I first received the meter and updated straight to V1.57. I love the 121GW. I've got both your meters, cases, lots of fuses, and even brought a BM235 for a friend! I'm still a beginner and try my best, and am sorry for the annoyance.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on June 03, 2019, 07:12:40 am
Hi Dave, I wasn't having a whinge (apart from the back light flashing briefly when the meter turns on).

I'm not sure why people hate this so much, I like to think it's a little exercise of the battery and the backlight every time.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Smafe on June 03, 2019, 09:23:48 am
Maybe, like me, people worry that it means something is wrong? If its nothing to worry about, then I won't give it another thought. I'm loving the faster response time. Thank you.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Uncle Bob on June 03, 2019, 09:54:32 am
Hi Dave, I wasn't having a whinge (apart from the back light flashing briefly when the meter turns on).

I'm not sure why people hate this so much, I like to think it's a little exercise of the battery and the backlight every time.

I thought it was the flux capacitor that was leaking.   :phew:

 ;D
Title: Re: EEVBlog 121GW Discussion thread
Post by: BrianG61UK on June 03, 2019, 10:43:20 am
Hi Dave, I wasn't having a whinge (apart from the back light flashing briefly when the meter turns on).

I'm not sure why people hate this so much, I like to think it's a little exercise of the battery and the backlight every time.

Well it's exactly the right length, at exactly the right moment, to make one wonder if something might be wrong in the rotary switch, contacts making in the wrong order or something. If it were a deliberate self test type thing one would expect it to be a little longer and perhaps synchronized with a beep. But it's fine once you know it's okay.
Title: Re: EEVBlog 121GW Discussion thread
Post by: CDaniel on June 03, 2019, 11:10:38 am
Hate is too much but that flash of light at start-up looks like a lack of programming finesse ... I doubt it is intentionally there . But if the rest of the firmware would be perfect I doubt peaple would "hate" it .
Title: Re: EEVBlog 121GW Discussion thread
Post by: joeqsmith on June 03, 2019, 12:03:52 pm
OK , a video with a 47K , even with no touching  hands , just the bench noise . If I move the meter away from the table it is stable , but obviously something is not right

https://streamable.com/giz9s

That power outlet with USB power supply in it has a switch and wasn't turn on  ;D
Nothing was turned on on the bench , just the normal electrical noise from the wires

The prototype Dave provided is pretty sensitive to low frequency changing magnetic fields.  Eventually, I will have a look at the released version.  It may be interesting to repeat the testing with the 121GW along side the shielded Gossen in the chamber and see how it does against my Fluke 189 and the Brymen BM869s (as a reference).   Was hoping the dust would settle in a year after the kick start, but no word yet on the thicker PCB.  Hopefully it will be available yet this year.   

https://youtu.be/_u_34E5ZUOI?t=144
Title: Re: EEVBlog 121GW Discussion thread
Post by: CDaniel on June 03, 2019, 12:40:48 pm
In some internet videos , including David's videos , if you look carefully you can see abnormal changes in readings when touching or moving the hands near the probes .
This should be measurable by injecting some AC 50/60Hz voltage in resistance mode . I think the firmware is not using enough low pass filtering at the ADC input . HY3131 has a switchable capacitor and some resistors for this .
Title: Re: EEVBlog 121GW Discussion thread
Post by: 286sx on June 03, 2019, 07:04:14 pm
2.0 released !

tested... much more faster on resistance and capacitor measurement.
Title: Re: EEVBlog 121GW Discussion thread
Post by: 636steve on June 06, 2019, 01:33:54 pm
I have just upgraded to v2 software and everything seems fine except I can't turn the backlight on anymore. is anyone else seeing this. Admittedly I have not used the backlight for a while so might not have been working before I upgraded the firmware.
Title: Re: EEVBlog 121GW Discussion thread
Post by: chronos42 on June 06, 2019, 04:37:27 pm
I have just upgraded to v2 software and everything seems fine except I can't turn the backlight on anymore. is anyone else seeing this. Admittedly I have not used the backlight for a while so might not have been working before I upgraded the firmware.

I have no problems with the backlight and v2.
Title: Re: EEVBlog 121GW Discussion thread
Post by: jancumps on June 06, 2019, 04:48:04 pm
Same here. Worked before and after the update.
Title: Re: EEVBlog 121GW Discussion thread
Post by: bicycleguy on June 06, 2019, 09:14:04 pm
@chronos42
Mine works ok.  Just curious, do you get the light flash when first turning on?
Title: Re: EEVBlog 121GW Discussion thread
Post by: PoLoMoTo on June 07, 2019, 12:21:42 am
This may be a silly question or already answered but I was wondering what this slot on the back of the rubber case is for, picture attached.  Wasn't sure what to search to figure it out.
Title: Re: EEVBlog 121GW Discussion thread
Post by: beanflying on June 07, 2019, 12:28:16 am
This may be a silly question or already answered but I was wondering what this slot on the back of the rubber case is for, picture attached.  Wasn't sure what to search to figure it out.

Use the slot for something like this eBay auction: #132926318720 or I have been going to do something with 3D Printing and a good magnet but as I don't do much work is metal cabinets it isn't that important to me.

(https://i.ebayimg.com/images/g/7SwAAOSwRZlcRoA9/s-l1600.jpg)
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on June 07, 2019, 05:26:50 am
This may be a silly question or already answered but I was wondering what this slot on the back of the rubber case is for, picture attached.  Wasn't sure what to search to figure it out.

It fits UEI's magnetic hanger, but I don't actually sell that.
Title: Re: EEVBlog 121GW Discussion thread
Post by: wilfred on June 07, 2019, 01:35:07 pm


Use the slot for something like this eBay auction: #132926318720 or I have been going to do something with 3D Printing and a good magnet but as I don't do much work is metal cabinets it isn't that important to me.


Use the magnet to hold screws so you don't lose them.
Title: Re: EEVBlog 121GW Discussion thread
Post by: chronos42 on June 07, 2019, 01:43:59 pm
@chronos42
Mine works ok.  Just curious, do you get the light flash when first turning on?
Yes, I still get the light flash. Not sure if this is a intended feature or a short undefined state after power on, but I do not have any problem with this behaviour.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Roelof on June 07, 2019, 04:23:43 pm
It fits UEI's magnetic hanger, but I don't actually sell that.

This one, I assume:
https://www.ueitest.com/products/accessories/amh1 (https://www.ueitest.com/products/accessories/amh1)
Title: Re: EEVBlog 121GW Discussion thread
Post by: e0ne199 on June 09, 2019, 12:11:25 pm
hello i have a question...
does 121GW multimeter have differential probe for measuring current? i want to measure current around more than 10 Amps on my device anyway
answer is really appreciated, thx before
Title: Re: EEVBlog 121GW Discussion thread
Post by: dadler on June 11, 2019, 05:29:52 am
hello i have a question...
does 121GW multimeter have differential probe for measuring current? i want to measure current around more than 10 Amps on my device anyway
answer is really appreciated, thx before

A differential probe for... current? What is your use case?

Without more information or your requirements (AC or DC? Contactless or resistive current measurement? Are the sources isolated?), the following methods may work.

Multiple 121GW meters can connect to an Android device or Windows PC via Bluetooth, and math functions can be performed against the connected meters. You could simply take the subtraction of the readings between two connected meters.

Resistive:
Contactless:

It may be more cost-effective (and offer greater insight) to use a cheap oscilloscope such as a Rigol DS1054Z than multiple 121GW meters. Depending on your requirements, you could also build a circuit to do this, and measure it with a single 121GW (or any other meter or oscilloscope).

But answer the specifically asked question: no, the 121GW doesn't have any differential probes.
Title: Re: EEVBlog 121GW Discussion thread
Post by: exe on June 11, 2019, 11:30:36 am
Afaik all DMMs are "differential" in a sense they are not referenced to ground.

As of measuring larger current, just use an external shunt.
Title: Re: EEVBlog 121GW Discussion thread
Post by: beanflying on June 11, 2019, 12:38:15 pm
So the TV options sucked tonight. On the printer but I am off to bed at 10.30pm so we will see what the morning brings. I may have made the press section to strong to push in so it might take a tweak yet.

Printed heavy and on it's side with supports to get the layer orientation correct for strength. If it looks ok I will swing 4 or 5kg extra on mine to test before releasing the final design. Add your own magnet, webbing or a lump of old rope....



Title: Re: EEVBlog 121GW Discussion thread
Post by: beanflying on June 12, 2019, 01:50:40 am
Overall size is nicely snug so the tongue will be gripped by the bumper on all sides. The Push release with PLA isn't and is to stiff. Printed in PETG would be more flexible and tougher but I am aiming for a PLA printable with 0.2mm layers so all 3D printers can manage it. Also need to reduce the release length and round it's corners to suit the bumper. It fits in the zip up case installed so even if the release is hard to use not that much of an issue I guess and it can just stay locked in.

Coffee First then CAD
Title: Re: EEVBlog 121GW Discussion thread
Post by: beanflying on June 12, 2019, 05:10:33 am
Tweakage finished unless anyone who makes it finds an issue and I will see if it can be improved.

Hollowed out the release so it now has more flex, fattened up the front bar for more strength and short of hanging your toolbag on it shouldn't ever be a problem. Also increased the web at the rear of the release for more strength when being pressed. The release as it is here in PLA can be deflected down by about 3mm without any risk of breaking it and the urethane section of the bumper can easily be flipped over it then to release the hanger. Still recommend PETG if you have it (I will try one next time I have some loaded).

Print settings 6 layers all round 40% infill so basically solid at 0.2mm layers. Printed on edge with bed supports only, could fully support it but the one shown in this post wasn't. STL is in the Zip file attached here.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on June 12, 2019, 06:26:40 am
It fits UEI's magnetic hanger, but I don't actually sell that.

This one, I assume:
https://www.ueitest.com/products/accessories/amh1 (https://www.ueitest.com/products/accessories/amh1)

Yep, I think that's the one.
Could probably make a little slide in adapter that took some sort of standard size magnet (say 10mm dia) and allowed it to fit snug inside.
Title: Re: EEVBlog 121GW Discussion thread
Post by: beanflying on June 12, 2019, 07:18:39 am
It fits UEI's magnetic hanger, but I don't actually sell that.

This one, I assume:
https://www.ueitest.com/products/accessories/amh1 (https://www.ueitest.com/products/accessories/amh1)

Yep, I think that's the one.
Could probably make a little slide in adapter that took some sort of standard size magnet (say 10mm dia) and allowed it to fit snug inside.

Very rough 5 minute hack up to take a 20x10mm 5mm c/sunk magnet. It needs to be this tall to clear the rubber bumper.
Title: Re: EEVBlog 121GW Discussion thread
Post by: beanflying on June 12, 2019, 08:17:47 am
And here is a nicer one.

Designed to take a 20x10 5mm Magnet (Order away I have already  ;) ) eBay auction: #183364882157
Countersunk 5mm screw or bolt to suit and the recess will take a Nyloc nut for depth but a standard one and lock washer would do too.

I haven't printed this one but using the settings above should print fine. STL is in the Zip.

Title: Re: EEVBlog 121GW Discussion thread
Post by: e0ne199 on June 12, 2019, 12:50:59 pm
hello i have a question...
does 121GW multimeter have differential probe for measuring current? i want to measure current around more than 10 Amps on my device anyway
answer is really appreciated, thx before

A differential probe for... current? What is your use case?

Without more information or your requirements (AC or DC? Contactless or resistive current measurement? Are the sources isolated?), the following methods may work.

Multiple 121GW meters can connect to an Android device or Windows PC via Bluetooth, and math functions can be performed against the connected meters. You could simply take the subtraction of the readings between two connected meters.

Resistive:
  • 2x 121GW meters (or any oscilloscope with simple math functions + some milliohm-scale power resistors)
  • An Android device or Windows PC (if using the 121GW)
Contactless:
  • 2x 121GW meters (or any oscilloscope with simple math functions)
  • 2x hall-effect current sensors, such as the PDI CA-60 (https://smile.amazon.com/gp/product/B00X3GDVWM/)
  • An Android device or Windows PC (if using the 121GW)

It may be more cost-effective (and offer greater insight) to use a cheap oscilloscope such as a Rigol DS1054Z than multiple 121GW meters. Depending on your requirements, you could also build a circuit to do this, and measure it with a single 121GW (or any other meter or oscilloscope).

But answer the specifically asked question: no, the 121GW doesn't have any differential probes.

haha i asked a wrong question i think...i mean external current probe clamp for 121GW that can measure current more than 10 amps, i am sorry i thought when i mentioned differential probe that would mean external current probe clamp  ;D

maybe i need to repeat the question again..does 121GW have external current probe clamp for measuring high current (more than 10 amps)?
Title: Re: EEVBlog 121GW Discussion thread
Post by: lowimpedance on June 17, 2019, 06:22:18 am
Tweakage finished unless anyone who makes it finds an issue and I will see if it can be improved.

Hollowed out the release so it now has more flex, fattened up the front bar for more strength and short of hanging your toolbag on it shouldn't ever be a problem. Also increased the web at the rear of the release for more strength when being pressed. The release as it is here in PLA can be deflected down by about 3mm without any risk of breaking it and the urethane section of the bumper can easily be flipped over it then to release the hanger. Still recommend PETG if you have it (I will try one next time I have some loaded).

Print settings 6 layers all round 40% infill so basically solid at 0.2mm layers. Printed on edge with bed supports only, could fully support it but the one shown in this post wasn't. STL is in the Zip file attached here.

 I have printed your design using ABS, and it was completely successful with no issues so far. As printed the hanger snaps confidently into the slot on the bumper, (support material removed of course!).
The locking tab works perfectly and can be easily depressed for removal from the meter, no structural problems observed after many test operations.
See attached photos using a FLUKE hanger  :D.
 Thanks again for the effort.
Title: Re: EEVBlog 121GW Discussion thread
Post by: frankmhowell on July 04, 2019, 02:22:43 pm
But what is the metric of the Time field? Is it in interval units (e.g., seconds, etc.) relative to the start time stamp? As successfully received via Bluetooth?
Title: New version of manual online: EEVBlog 121GW Discussion thread
Post by: Dr. Frank on August 08, 2019, 01:41:30 pm
Hello,

an updated version (8th of August 2019)  of the manual is online

Frank

Goto: https://www.eevblog.com/product/121gw/ (https://www.eevblog.com/product/121gw/)    => documentation

Title: Re: EEVBlog 121GW Discussion thread
Post by: mattbrockuk on August 16, 2019, 06:20:41 am
Very slow on this i'm sure, but just clicked about this products model number lol... back to the future rules!   :D
Title: Re: New version of manual online: EEVBlog 121GW Discussion thread
Post by: jchw4 on August 19, 2019, 03:08:13 am
Hello,

an updated version (8th of August 2019)  of the manual is online

Frank

Goto: https://www.eevblog.com/product/121gw/ (https://www.eevblog.com/product/121gw/)    => documentation

The difference is pretty minimal: https://www.diffchecker.com/bQNsVKdS (https://www.diffchecker.com/bQNsVKdS)

Added to the document changelog:
Quote
08/08/2019
Added battery voltage check to the firmware update pro-
cedure.

Added v2.00 firmware version changelog:
Quote
2.00
Improved the Auto-ranging reading speed in both ca-
pacitance and resistance ranges.

Added requirement to check battery voltage prior to updating firmware:
Quote
1. Ensure the low battery indicator is not present.
See Battery Voltage, Page 60.

It all looks to be a response to https://www.eevblog.com/forum/testgear/eevblog-121gw-multimeter-issues/msg2570484/#msg2570484 (https://www.eevblog.com/forum/testgear/eevblog-121gw-multimeter-issues/msg2570484/#msg2570484) .
Title: Re: EEVBlog 121GW Discussion thread
Post by: Bobo666 on September 12, 2019, 02:13:28 am
Looking at purchasing this. Mainly interested in the logging feature.

Have most of the known bugs been taken care of?

Do all the new meters come with the upgraded dial?

Anyone using it for logging (either BLE or card) and how do you find it?

Thanks
Title: Re: EEVBlog 121GW Discussion thread
Post by: dr.diesel on September 12, 2019, 10:24:29 am
Looking at purchasing this. Mainly interested in the logging feature.

BLE logging is still very broken.
Title: Re: EEVBlog 121GW Discussion thread
Post by: tautech on September 12, 2019, 11:07:11 am
Looking at purchasing this. Mainly interested in the logging feature.

BLE logging is still very broken.
And you still have that signature ?  :-//
Title: Re: EEVBlog 121GW Discussion thread
Post by: Bobo666 on September 13, 2019, 03:21:50 am
Looking at purchasing this. Mainly interested in the logging feature.

BLE logging is still very broken.

That is unfortunate, especially after so many firmware updates.
Title: Re: EEVBlog 121GW Discussion thread
Post by: beanflying on September 13, 2019, 04:14:32 am
Broken isn't the right term but buggy is closer with the bluetooth. It has improved over the release version but would still benefit from more work on the app.

I am still running V1.58 firmware as I haven't got around to an upgrade yet. Pulled it out of my site bag, turned it on hooked straight up to my Galaxy 7 and starting logging the mains in the shack. This data in the spread sheets below is off the App to the phone then emailed off the app.

I hadn't installed thew windoze app on my new box so I did that and it hooked up too. Screen caps below. So not broken :-//

The hits to voltage are from my 3500W espresso machine kicking in and out. The logging data isn't where it should be as the 'precise timing' from the meter is bs and still needs fixing to something meaningful or sensible preferably at the meter end in firmware.
Title: Re: EEVBlog 121GW Discussion thread
Post by: CDaniel on September 13, 2019, 06:44:03 am
OK , is somewhat working , not completely dead  ;) , but if is not reliable as many have said , sometimes recording false values , no time stamps , and so on , I would say it's like a broken toy  . Or simply a toy for beginers in electronics , just to see something on the screen .
This is not to be espected from a quality brand multimeter .
Title: Re: EEVBlog 121GW Discussion thread
Post by: beanflying on September 13, 2019, 06:46:16 am
And continuing to be an ASSHAT and adding zero to the discussion again  :palm:
Title: Re: EEVBlog 121GW Discussion thread
Post by: Bobo666 on September 13, 2019, 09:57:34 am
Broken isn't the right term but buggy is closer with the bluetooth. It has improved over the release version but would still benefit from more work on the app.

The logging data isn't where it should be as the 'precise timing' from the meter is bs and still needs fixing to something meaningful or sensible preferably at the meter end in firmware.

Thank you for the pics and data. I'm not so much interested in the apps as I intended to stream the data straight to Node Red (perhaps others have already done the same?), but your second comment doesn't inspire with confidence achieving this as the data needs to be fairly precise coming from the meter itself.

Need to give it some more thought. Thanks again. And also thanks for the additional "banter"  ;)
Title: Re: EEVBlog 121GW Discussion thread
Post by: beanflying on September 15, 2019, 02:11:06 am
Precision, Accuracy etc are a matter of reference. You need to specify it to have a frame of reference. My biggest beef with the software/meter for logging is the BS timebase used not the 'accuracy' of the meter. The timebase can be post edited in a spreadsheet with a little maths but it shouldn't have to be.

Against my recently calibrated Keysight 34461A snd I haven't looked at recalibrating it against this and my in cal 34401A but it is well within the combined error margin of both.

Rough setup and plenty of possibilities for stray noise to play with the BT but looking for dropped results and NOPE.

30 minutes of logging with a rough setup as shown and lets look at the 'false recordings' and other random unsubstantiated claims of the Troll boy in chief - NOPE :palm:



Title: Re: EEVBlog 121GW Discussion thread
Post by: J-R on September 15, 2019, 03:08:01 am
I feel sorry for someone trying to research this meter for purchase. There is too much back and forth and these threads are ridiculous for trying to find the current status of the meter.  I suppose an official page with all the firmware versions and known and fixed "concerns" listed out would be too much to ask for???  There really should be one page that lists out everything a 121GW owner (or potential owner) needs to know.  For example, there are different hardware versions/updates, a recall of specific serial numbers, troubleshooting suggestions, etc....

How about a new pinned thread with strict rules on new posts?
Title: Re: EEVBlog 121GW Discussion thread
Post by: 2N3055 on September 15, 2019, 08:03:19 am
Precision, Accuracy etc are a matter of reference. You need to specify it to have a frame of reference. My biggest beef with the software/meter for logging is the BS timebase used not the 'accuracy' of the meter. The timebase can be post edited in a spreadsheet with a little maths but it shouldn't have to be.

Against my recently calibrated Keysight 34461A snd I haven't looked at recalibrating it against this and my in cal 34401A but it is well within the combined error margin of both.

Rough setup and plenty of possibilities for stray noise to play with the BT but looking for dropped results and NOPE.

30 minutes of logging with a rough setup as shown and lets look at the 'false recordings' and other random unsubstantiated claims of the Troll boy in chief - NOPE :palm:

Thanks for the test. Real experiment and real data is only important thing.


If you're willing to make another one let me suggest parameters that would be more relevant to dispense with all of the fluff once and for all.

Logging time should be at least 24h. Use case would be leaving meter to monitor battery state, or monitor charge/discharge cycle.

I see you have very nice SDG 2000X. Any AWG should do, actually.
Siggen should be set to create low frequency sine wave. Something like 20 second cycle ( 50 mHz ). Make it nice 4.8 V P-P.
Set meter to DC, 5V range manual.
Make a logging to a SD card and BT.

For 24 hours. Why 24 hours? Because that is what logging is for. 30 minutes is not proof.
Those who reported problems said meter can sometimes log for hours at a time without problems.
Why sine wave? Because of its nature, it is easy to detect any discontinuities, missed points, nonlinearities...

Post original data file here.

Can anybody make this 2 tests? To experimentally prove one or the other.
If it's working OK, great news. If there are problems, it will be quality data for manufacturer to fix the problem.

Regards,
Title: Re: EEVBlog 121GW Discussion thread
Post by: Bobo666 on September 15, 2019, 09:50:35 am
I feel sorry for someone trying to research this meter for purchase. There is too much back and forth and these threads are ridiculous for trying to find the current status of the meter.  I suppose an official page with all the firmware versions and known and fixed "concerns" listed out would be too much to ask for???

I have to say that I was a bit surprised at the official support for this meter when I came looking. Dave being Dave, I assumed that he would've been fairly thorough in providing this (official updates, notifications etc). There isn't even a readme file attached to the firmware zip.

Also I just discovered that there is hardware (pcb?) upgrade to fix (I assume) the rotary dial issue? Has this change been rolled out to for sale units?

Anyhow perhaps I'm being a bit too critical as I don't know the history behind the meter. 
Title: Re: EEVBlog 121GW Discussion thread
Post by: amspire on September 15, 2019, 09:58:45 am

I have to say that I was a bit surprised at the official support for this meter when I came looking. Dave being Dave, I assumed that he would've been fairly thorough in providing this (official updates, notifications etc). There isn't even a readme file attached to the firmware zip.
The manual has instructions for the firmware. The most recent manual is on the Meter's page on EEVBlog.com (https://www.eevblog.com/wp-content/plugins/download-attachments/includes/download.php?id=30207 (https://www.eevblog.com/wp-content/plugins/download-attachments/includes/download.php?id=30207))
Quote


Also I just discovered that there is hardware (pcb?) upgrade to fix (I assume) the rotary dial issue? Has this change been rolled out to for sale units?

Anyhow perhaps I'm being a bit too critical as I don't know the history behind the meter.
Dave did send out the updated rotary switch hardware to people who had received the original dial. If you need it and did not receive it, I guess you need to contact EEVBlog.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Bobo666 on September 15, 2019, 10:06:43 am
Ok, so the firmware changes are explained in the manual. What about existing bugs? I don't think it is unreasonable to have a list of those. And I mean a concise list on the product page, not 50 pages of threads with people saying "I can't get this to work" ...

I realise that a fix was released but I understood there was also a pcb upgrade as well?

I don't own a meter (yet), hence the questions.
Title: Re: EEVBlog 121GW Discussion thread
Post by: amspire on September 15, 2019, 10:28:51 am
Ok, so the firmware changes are explained in the manual. What about existing bugs? I don't think it is unreasonable to have a list of those. And I mean a concise list on the product page, not 50 pages of threads with people saying "I can't get this to work" ...

I realise that a fix was released but I understood there was also a pcb upgrade as well?

I don't own a meter (yet), hence the questions.
If you do not own a meter, then you may not realize that it is actually a very good meter. It had some unique features such as a very low burden voltage for the current ranges.

The Bluetooth capability was added late in the design, I believe. It was not one of the primary design goals. It works, but not as robustly as some people would like. I have not used the logging myself yet - I use it as an accurate multimeter for the purpose of talking live readings. For me, it works great.

Lots of test hardware has bugs when you dig deep enough. You will see it all the time in Dave's reviews of new test and lab instruments.

What you have to understand with Dave's multimeter is it is not a multimeter made in the millions with a massive R&D budget. The reality is it would be totally amazing if Dave's meters would be totally flawless. If you want a meter that is totally flawless - good luck. I do not know how you are going to find one even from the biggest manufacturers. I never expected absolute perfection from Dave's meter.

Richard
Title: Re: EEVBlog 121GW Discussion thread
Post by: Bobo666 on September 15, 2019, 10:44:30 am

The Bluetooth capability was added late in the design, I believe. It was not one of the primary design goals. It works, but not as robustly as some people would like. I have not used the logging myself yet - I use it as an accurate multimeter for the purpose of talking live readings. For me, it works great.

Lots of test hardware has bugs when you dig deep enough. You will see it all the time in Dave's reviews of new test and lab instruments.

What you have to understand with Dave's multimeter is it is not a multimeter made in the millions with a massive R&D budget.

Richard

It is the BLE feature that got me very interested in this device to begin with.

You seem to think I am berating the product for having bugs. I can assure you I am not. But that doesn't mean to say I don't care what they are. In fact the whole point of me posting is to try to find out, but that is proving quite a challenge.

And while I know the history of EEVBlog I don't know the history of the meter. Dave has surely raised the bar with this product, but unfortunately that also means raising the expectations too.
Title: Re: EEVBlog 121GW Discussion thread
Post by: amspire on September 15, 2019, 11:00:08 am

It is the BLE feature that got me very interested in this device to begin with.

It is just exceptionally boring to hear disappointment at the BLE endlessly. Dave and the meter company put a design together with BLE hardware as a late addition, and it turns out it doesn't work as well as some people want. It is not possible for Dave to wave a magic wand and have the BLE magically turned into a non-BLE Bluetooth interface.

As with all hardware, it is what it is. Just accept it. If it is not good enough for you, find another meter. If the primary feature you want from a meter is its data logging capability, buy a meter that is designed primarily for data logging.
Title: Re: EEVBlog 121GW Discussion thread
Post by: CDaniel on September 15, 2019, 12:18:08 pm
For people to find another meter we must tell here its fauts and bugs , so you are contradicting yourself like a fanboy .
After all we don't care how and when the logging was added , just if it is working like it supose or not .
Of course there are another bugs , just the discusion is now shifted to logging .
Title: Re: EEVBlog 121GW Discussion thread
Post by: amspire on September 15, 2019, 12:39:00 pm
For people to find another meter we must tell here the meter fauts and bugs , so you are contradicting yourself like a fanboy .
After all we don't care how and when the logging was added , just if it is working like it supose or not .
Of course there are another bugs , just the discusion is now shifted to logging .
Name calling is a great way to end a conversation.
Title: Re: EEVBlog 121GW Discussion thread
Post by: beanflying on September 15, 2019, 01:05:48 pm
For people to find another meter we must tell here its fauts and bugs , so you are contradicting yourself like a fanboy .
After all we don't care how and when the logging was added , just if it is working like it supose or not .
Of course there are another bugs , just the discusion is now shifted to logging .

YAWN another WOFTAM post from trollboy. Show us some DATA and EVIDENCE to back your persistent sledging and bitching about unspecific ambit claims!  :palm:
Title: Re: EEVBlog 121GW Discussion thread
Post by: CDaniel on September 15, 2019, 03:55:36 pm
Is posted enough evidence not to trust in logging , of course for fanboys never will be suficient . He made a 30min , one time logging ( I supose his only logging ever with this meter ) , and he thinks is "proving " that is ok  ;D ;D ;D
Title: Re: EEVBlog 121GW Discussion thread
Post by: beanflying on September 15, 2019, 05:32:20 pm
Is posted enough evidence not to trust in logging , of course for fanboys never will be suficient . He made a 30min , one time logging ( I supose his only logging ever with this meter ) , and he thinks is "proving " that is ok  ;D ;D ;D

Refer to post #11, 12, 24 and others numbnuts and there is even a youtube video using the BT logging on software 1.02 about the same time. You are not so much smart as a smart ass!
Title: Re: EEVBlog 121GW Discussion thread
Post by: J-R on September 16, 2019, 12:12:57 am
I need to call out some of you for not being precise about the topics being discussed:

- Bluetooth connection difficulties between the meter and your device

- Logging via Bluetooth to the Android or Windows application

- Logging to the SD card


User reports:

- Android app needs the location permission.

- Logging using SD card and Bluetooth does not generate consistent timestamp intervals or absolute timestamps.

- Logging to SD card sometimes stalls and generates the same value over and over.


My comments:

- Wireless logging inherently has the potential to be unstable since you are subject to changing conditions (latency, re-transmissions, etc.).

- There are no logging settings in the Android/Windows apps (time interval, absolute time stamps, etc.)

- SD card logging is currently not practical for regular daily use because you must remove the outer case, back cover and SD card to download the data.

- Long term logging is not practical for continual use because this is a battery powered device.
Title: Re: EEVBlog 121GW Discussion thread
Post by: tautech on September 16, 2019, 02:04:12 am
I feel sorry for someone trying to research this meter for purchase. There is too much back and forth and these threads are ridiculous for trying to find the current status of the meter.  I suppose an official page with all the firmware versions and known and fixed "concerns" listed out would be too much to ask for???  There really should be one page that lists out everything a 121GW owner (or potential owner) needs to know.  For example, there are different hardware versions/updates, a recall of specific serial numbers, troubleshooting suggestions, etc....
Yep, 121GW threads could be much better managed which should be a breeze as Dave and Seppy are administrators.
Quote
How about a new pinned thread with strict rules on new posts?
Nope, they just need to clean up existing threads and lock one in which to make announcements and post links to all resources for 121GW.
This would be a good one in which to do this with just an edit of the title and a bit of a cleanup dropping OT posts into one of the other threads:
https://www.eevblog.com/forum/testgear/eevblog-121gw-multimeter-firmware-details/ (https://www.eevblog.com/forum/testgear/eevblog-121gw-multimeter-firmware-details/)

And while at it even setup 121GW daughter/Child board to the TE board for all 121GW threads and stick this one there too:
https://www.eevblog.com/forum/testgear/re-eevblog-121gw-discussion-thread/ (https://www.eevblog.com/forum/testgear/re-eevblog-121gw-discussion-thread/)

Title: Re: EEVBlog 121GW Discussion thread
Post by: Bobo666 on September 16, 2019, 02:47:39 am

It is just exceptionally boring to hear disappointment at the BLE endlessly.
As with all hardware, it is what it is. Just accept it. If it is not good enough for you, find another meter.

Well, if you find it exceptionally boring, can't you do what any other normal person would do, and just not read/reply?

And I find your stating the bleeding obvious quite puerile. I am trying to determine whether the meter will fit my needs by asking questions about the product, otherwise YES, I will find another meter.

Thank you for your contribution.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on September 16, 2019, 04:35:44 am
It is just exceptionally boring to hear disappointment at the BLE endlessly. Dave and the meter company put a design together with BLE hardware as a late addition, and it turns out it doesn't work as well as some people want. It is not possible for Dave to wave a magic wand and have the BLE magically turned into a non-BLE Bluetooth interface.

Correct. BLE was with hindsight a troublesome choice for some things. Full bluetooth would have been better, but unfortunately we are stuck with BLE and have to make do with the capabilities of that.
Title: Re: EEVBlog 121GW Discussion thread
Post by: hammy on September 16, 2019, 10:32:02 am
... and have to make do with the capabilities of that.

@Dave: There are sometimes reports from other buyers about newer firmware versions. Do you get the newest firmware in parallel from the manufacturer after they send it out? Why is there a gap between the shipped version and the download version on your homepage?

Title: Re: EEVBlog 121GW Discussion thread
Post by: joeqsmith on September 16, 2019, 11:14:59 am
It is just exceptionally boring to hear disappointment at the BLE endlessly. Dave and the meter company put a design together with BLE hardware as a late addition, and it turns out it doesn't work as well as some people want. It is not possible for Dave to wave a magic wand and have the BLE magically turned into a non-BLE Bluetooth interface.

Correct. BLE was with hindsight a troublesome choice for some things. Full bluetooth would have been better, but unfortunately we are stuck with BLE and have to make do with the capabilities of that.

I ran fair number of tests using the proto's BLE interface with LabView.  While the radio seems a bit weaker than the other two BLE meters I have looked at, it seemed to work alright with the firmware I was using.   It doesn't seem to be a bad choice for hardware.  Maybe if they remove that 1-Byte packet and leverage the hardware's built-in error checking/correction it may help improve it.   
Title: Re: EEVBlog 121GW Discussion thread
Post by: Bobo666 on September 17, 2019, 01:23:44 am

I ran fair number of tests using the proto's BLE interface with LabView.  While the radio seems a bit weaker than the other two BLE meters I have looked at, it seemed to work alright with the firmware I was using.     

Which I assume is v2.00?
Title: Re: EEVBlog 121GW Discussion thread
Post by: joeqsmith on September 17, 2019, 03:11:57 am

I ran fair number of tests using the proto's BLE interface with LabView.  While the radio seems a bit weaker than the other two BLE meters I have looked at, it seemed to work alright with the firmware I was using.     

Which I assume is v2.00?
I am not sure if I did much testing beyond 1.26, if at all.  They were making changes to the filters during that time and I was running tests to evaluate them.  The BLE interface wasn't working originally on the prototype meter, so I was using the card to log the data.  Using the firmware supplied (pre 1.0 really early stuff), logging to the card would hang but once I had 1.0 loaded, it seemed fine.    When I first started working with the BLE, I had some problems but discovered this was with my code, not the 121. 

I had several posts in the Issues area documenting my findings but it seems it was getting a bit too cluttered for Dave so I cleaned them out to help them with their bug tracking.   These were fairly long tests I was running and I don't recall having problems outside the range being less than expected.     

I didn't want to invest more time until at least the hardware had settled.  Dave had mentioned some of the changes they were making beyond addressing the shim.  It seemed like they were moving in the right direction.   It's been a while since I have seen him post any more about it.  Maybe next year... 

If you do have problems and decide to roll the firmware back, just keep in mind the changes to the filter I mentioned.  You can see from the attached plot how they were playing with the roll off.   
Title: Re: EEVBlog 121GW Discussion thread
Post by: beanflying on September 17, 2019, 11:47:54 am
I had given this magnet up for dead but it turned up yesterday packed well inside styrofoam so it wouldn't stick to all and sundry but seriously 3 months since ordered  :wtf: :horse: eBay auction: #183364882157 Apparently Chinese but shipped from Singapore so who knows.

That said printed the file as per last page in this thread and the 20x10 has plenty of stick plus some to spare. Just pick another source for the magnet. https://www.eevblog.com/forum/testgear/eevblog-121gw-discussion-thread/msg2479518/#msg2479518 (https://www.eevblog.com/forum/testgear/eevblog-121gw-discussion-thread/msg2479518/#msg2479518)

edit just added an extra side on photo. Sits level on the probe holders and magnet to help grip on shiny surfaces and pushing buttons or range changing.

Title: Re: EEVBlog 121GW Discussion thread
Post by: Blue_Alien on September 20, 2019, 04:00:06 pm
I just ran into a bug with the Max hold function not displaying the correct range. Meter was displaying A, but the units were displaying as mA. I had to change the mode from DC -> AC -> DC to get it to resolve the problem.
Title: Re: EEVBlog 121GW Discussion thread
Post by: 1anX on September 21, 2019, 10:15:43 am
I just ran into a bug with the Max hold function not displaying the correct range. Meter was displaying A, but the units were displaying as mA. I had to change the mode from DC -> AC -> DC to get it to resolve the problem.
Probably best to copy this over to the EEVBLog 121GW Issues thread as its an issue worth reporting!
Title: Re: EEVBlog 121GW Discussion thread
Post by: 1anX on September 28, 2019, 07:10:09 am
I see firmware V2.02 is available from Dave's website https://www.eevblog.com/product/121gw/ (https://www.eevblog.com/product/121gw/)
Title: Re: EEVBlog 121GW Discussion thread
Post by: e0ne199 on September 28, 2019, 02:09:50 pm
anyone has tested this new firmware?? what are the changes after installing it?
Title: Re: EEVBlog 121GW Discussion thread
Post by: beanflying on September 28, 2019, 02:29:44 pm
At the risk of LMGTFY  ;) From the revised manual just a bug fix over 2.01 by the looks of it.

[attachimg=1]
Title: FW 2.02
Post by: Dr. Frank on October 02, 2019, 01:29:20 pm
FW 2.02 solves the 550..600 Vdc unsteady ranging problem.
Instead, the 1000 Vdc range does not down-range any more  @ Uin < 500 V, but stays in this 1000 V range until Uin < 60.0 V, i.e. @ 59.9 V

Frank

As it's a new error, again, I will post this also in the Multimeter Issues thread
Title: Re: EEVBlog 121GW Discussion thread
Post by: 1anX on November 07, 2019, 12:22:06 am
Joe Smith has got a youtube vid up with 2 new meters he just bought from the EEVBlog shop being put through their paces.

 https://www.youtube.com/watch?v=wR1dHQsFBeM (https://www.youtube.com/watch?v=wR1dHQsFBeM)


Title: Re: EEVBlog 121GW Discussion thread
Post by: CDaniel on November 08, 2019, 08:32:16 pm
The resistance settling time is definitly not caused by debris  ;D , its the firmware . Every firmware is somewhat different . Of course this is just a part of the problem ...
Those 2 meters are very bad refusing to measure 150pF and 1nF showing less ... at least mine is just drifting about 50pF as we discused some time ago . Maybe this a hardware issue after all , not firmware  :-//
Title: Re: EEVBlog 121GW Discussion thread
Post by: chronos42 on November 08, 2019, 09:13:19 pm
I wrote this before several month:

"A 220pF NP0 ceramic capacitor is shown as 0.160nF at the first time, after switching off and on again as 0.180nF, after another power cycling as 0.200nF... The more often I switch the meter off and on, the closer the reading comes to the actual value. Also if I first use a small capacity, then a bigger one (e.g. several hundred nF) and then again the small capacity, the 121GW every time shows a different reading. I am not able to get a steady reading of small capacities with the 121GW."
This is one of the most weird issue I have ever seen with a multimeter. The fact that Joe's prototype seems not affected from this issue shows that this probably can't be fixed with a firmware update and is hardware related.
Title: Re: EEVBlog 121GW Discussion thread
Post by: CDaniel on November 08, 2019, 09:56:47 pm
The prototipe is affected too , Joe confirmed later .

My meter is behaving like yours , but if you leave it on you should also see the value drifting slowly .
Title: Re: EEVBlog 121GW Discussion thread
Post by: 1anX on November 08, 2019, 10:28:06 pm
I think Joe will reveal the real issues with this meter once and for all. He has planned a number of vids and will be running one on firmware version differences. Facts and data are always appreciated along with his unbiased assessment.
Might put an end to the fanboy and troll comments this meter seems to attract?
Title: Re: EEVBlog 121GW Discussion thread
Post by: joeqsmith on November 09, 2019, 07:50:35 pm
I think Joe will reveal the real issues with this meter once and for all. He has planned a number of vids and will be running one on firmware version differences. Facts and data are always appreciated along with his unbiased assessment.
Might put an end to the fanboy and troll comments this meter seems to attract?

That's a tall order!!   :-DD :-DD 

I wouldn't read too much into the unboxing video beyond that it does appear that the mechanical stack up between the prototype and production meters appears the same (except for the added preload caused by the shim).   Not being able to read the 150pF was a bit of a surprise but I am sure I could add enough capacitance to the fixture to get the meter to read something, then null it out and try again.  It's not like we have not seen this with other meters but I wouldn't have expected the 121 to be this far out.   

I don't recall the prototype ever having problems reading a 1M resistor.   Actually, I don't think I have seen ANY meter exhibiting a problem like this.   After cycling the switch a few times, the readings continued to get tighter and I never saw the meter hunt like that again.    It can be difficult to track down problems like this that are not reproducible. 

Obviously the settling time has been a hot topic.  I'm sure a few of you remember me posting a fair amount of data on the firmware changes to the filters which I expect was an attempt to get the meter to settle faster.  I removed most of that data to help clean up the "issues" area.   Personally, I will take slow, accurate measurements any day over fast inaccurate ones.   While I had installed 1.57 in the prototype, I don't appear to have any notes about testing it.  I suspect the upgrade was part of sorting out the BLE / LabView interface.   

My plan is to dedicate one full segment just to the firmware.   I plan to repeat my previous noise testing on the production meter which will include all the same firmware plus the latest versions.   For now I will stay focused on the hardware differences between the current production meters and the prototype. 
Title: Re: EEVBlog 121GW Discussion thread
Post by: bicycleguy on November 10, 2019, 02:21:30 am
Joe
The rotary switch contact holder has a 3 split shaft with little tangs that grab the back of the PCB.  The height of these tabs minus the PCB thickness was probably what determined the compression of the contacts in the original design.  I think the idea of the shim was to provide more compression without having to remold the plastic contact holder.  You didn't measure the height of the tabs, but since the shim is still present one can conclude that the new meters are same as old except with shim pre-installed.

The shim is not necessarily a bad idea, although a tolerance analysis of the resulting stack-up would surely prove otherwise, but maybe proper height tabs caused too much friction and subsequent debris or since the contact load is in a straight line perhaps the assembly would cock off axis which the shim would prevent.

Title: Re: EEVBlog 121GW Discussion thread
Post by: joeqsmith on November 10, 2019, 03:08:27 am
Joe
The rotary switch contact holder has a 3 split shaft with little tangs that grab the back of the PCB.  The height of these tabs minus the PCB thickness was probably what determined the compression of the contacts in the original design. 

I agree and stated that in the video. 

I think the idea of the shim was to provide more compression without having to remold the plastic contact holder.

Per Dave, they want to use a thicker PCB.   Personally, I don't think they have a clear understanding of the root problem.  The original prototype had some major wear problems so when they added a shim after the release, I wasn't all that surprised to hear they were still fighting a mechanical problem.

You didn't measure the height of the tabs, but since the shim is still present one can conclude that the new meters ae same as old except with shim pre-installed.

I measure the PCB thickness and the height of the contact holder to the bottom of the PCB.  I also measured the resting height of the contacts dimple to the bottom of the contact holder.  None of these have changed.   From a mechanical standpoint in regards to the switch, the contacts are now plated, the contacts now use a single dimple rather than two and there is an addition of a shim. 

The shim is not necessarily a bad idea, although a tolerance analysis of the resulting stack-up would surely prove otherwise, but maybe proper height tabs caused too much friction and subsequent debris or since the contact load is in a straight line perhaps the assembly would cock off axis which the shim would prevent.

On most meters I have looked at where they use a hole in the PCB as part of a bearing surface, they have it plated.  In the case of the prototype without the shim, the debris was not from this area but from the contacts and pads.   Until I run it, it's just a guess on how it will hold up to the 50,000 cycle test.   I understand what you are saying about it going off axis.  The center of the plastic contact holder is locked in place by the hex shaft.  Of course that could go off axis as well.     

As far as the shim idea, having looked at the prototype and seeing the wear first hand, I have been concerned about the switch design ever since.   After hearing they added this shim as a last minute fix did nothing to improve my confidence.   I openly stated that the reason I did not buy a production meter was in hope that they would address the problems that caused them to add the shim.   Per Dave, a thicker PCB.  I think the last time I saw an update on this was during one of the Amp Hour shows.  That's been several months ago.    I felt allowing them two years to sort out these problems was more than fair enough.   So, what happens when I try some simple tests to check out the meter?  As you saw, it appears as though the shimmed switch is still having problems. 

I wouldn't be at all surprised to hear about a new revision once I finish this series.
Title: Re: EEVBlog 121GW Discussion thread
Post by: CDaniel on November 10, 2019, 11:25:53 am
The materials and the optimal contact preasure for long life shouldn't be "rocket sience" if you are in the industry , but ... when we see how difficult it is for them to do a decent firmware the trust is not very high .
Title: Re: EEVBlog 121GW Discussion thread
Post by: joeqsmith on November 10, 2019, 04:12:31 pm
The materials and the optimal contact preasure for long life shouldn't be "rocket sience" if you are in the industry , but ... when we see how difficult it is for them to do a decent firmware the trust is not very high .

When we have looked at low cost meters like the ANENGs, we can see that designing a reliable switch is not in everyone's wheelhouse.  Even Keysight seems to have problems designing a reliable detent spring.  We know Brymen tests their products as part of the design process.  We have seen their test setups.   I suspect Fluke does something similar as their meters have done very well in this test as well. 

I also didn't think designing an electrically robust meter would be rocket science for those skilled in the art. 

Two topics that firmware is never going to address.  It's the main reason I am more interested in how the hardware has changed from the prototype to the production release. 
Title: Re: EEVBlog 121GW Discussion thread
Post by: e0ne199 on November 11, 2019, 04:36:58 am
I wrote this before several month:

"A 220pF NP0 ceramic capacitor is shown as 0.160nF at the first time, after switching off and on again as 0.180nF, after another power cycling as 0.200nF... The more often I switch the meter off and on, the closer the reading comes to the actual value. Also if I first use a small capacity, then a bigger one (e.g. several hundred nF) and then again the small capacity, the 121GW every time shows a different reading. I am not able to get a steady reading of small capacities with the 121GW."
This is one of the most weird issue I have ever seen with a multimeter. The fact that Joe's prototype seems not affected from this issue shows that this probably can't be fixed with a firmware update and is hardware related.

what type of batteries are you using?
Title: Re: EEVBlog 121GW Discussion thread
Post by: e0ne199 on November 11, 2019, 05:38:02 am
I think Joe will reveal the real issues with this meter once and for all. He has planned a number of vids and will be running one on firmware version differences. Facts and data are always appreciated along with his unbiased assessment.
Might put an end to the fanboy and troll comments this meter seems to attract?

That's a tall order!!   :-DD :-DD 

I wouldn't read too much into the unboxing video beyond that it does appear that the mechanical stack up between the prototype and production meters appears the same (except for the added preload caused by the shim).   Not being able to read the 150pF was a bit of a surprise but I am sure I could add enough capacitance to the fixture to get the meter to read something, then null it out and try again.  It's not like we have not seen this with other meters but I wouldn't have expected the 121 to be this far out.   

I don't recall the prototype ever having problems reading a 1M resistor.   Actually, I don't think I have seen ANY meter exhibiting a problem like this.   After cycling the switch a few times, the readings continued to get tighter and I never saw the meter hunt like that again.    It can be difficult to track down problems like this that are not reproducible. 

Obviously the settling time has been a hot topic.  I'm sure a few of you remember me posting a fair amount of data on the firmware changes to the filters which I expect was an attempt to get the meter to settle faster.  I removed most of that data to help clean up the "issues" area.   Personally, I will take slow, accurate measurements any day over fast inaccurate ones.   While I had installed 1.57 in the prototype, I don't appear to have any notes about testing it.  I suspect the upgrade was part of sorting out the BLE / LabView interface.   

My plan is to dedicate one full segment just to the firmware.   I plan to repeat my previous noise testing on the production meter which will include all the same firmware plus the latest versions.   For now I will stay focused on the hardware differences between the current production meters and the prototype.
if it cannot measure pF then it will be useless for me... and if firmware update cannot fix this issue then looks like i need to sell my 121GW...seeing that even chinese cheap crap multimeters can measure pF range accurately really makes 121GW look like a stupid purchase
Title: Re: EEVBlog 121GW Discussion thread
Post by: beanflying on November 11, 2019, 06:07:26 am

if it cannot measure pF then it will be useless for me... and if firmware update cannot fix this issue then looks like i need to sell my 121GW...seeing that even chinese cheap crap multimeters can measure pF range accurately really makes 121GW look like a stupid purchase

Not sure about the current firmware or if it is an issue but I ran a fairly broad range test against my HP/Yokagowa Capacitance Decade box a while ago https://www.eevblog.com/forum/testgear/eevblog-121gw-discussion-thread/msg2051194/#msg2051194 (https://www.eevblog.com/forum/testgear/eevblog-121gw-discussion-thread/msg2051194/#msg2051194)

No smoke no trolling bs from the peanut gallery just what I found.

Low end range is 10 nF 0.01 nF ±2.5%+5counts if you want lower or better accuracy then you may need something else.
Title: Re: EEVBlog 121GW Discussion thread
Post by: tautech on November 11, 2019, 06:36:07 am
See a recent post from Joe and watch the vid linked for further info on low capacitance measurements:
https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg2778872/#msg2778872 (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg2778872/#msg2778872)
Title: Re: EEVBlog 121GW Discussion thread
Post by: 1anX on November 11, 2019, 09:45:34 pm
It seems the two 121GW meters Joe's just purchased from the EEVBlog store are not the latest revision!
Looks like the meter has been revised and some people have them but not Joe Smith who is about to put the meters under a complete range of tests.
I imagine he is pretty pissed  :palm:

Maybe Dave can advise us all on what the current revision is for the meters and if he plans to sell a revised PCB to those who already have the meter?
A discounted replacement PCB for early adopters would be much appreciated! (Providing its actually an improvement of course).
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on November 11, 2019, 11:17:25 pm
Maybe Dave can advise us all on what the current revision is for the meters and if he plans to sell a revised PCB to those who already have the meter?
A discounted replacement PCB for early adopters would be much appreciated! (Providing its actually an improvement of course).

No plans for replacement boards to be made available, there is no functional difference, it's just a normal process of refining the design over time, happens regularly to all meters. Existing customers are not missing out on anything.
Title: Re: EEVBlog 121GW Discussion thread
Post by: J-R on November 11, 2019, 11:30:08 pm
Random 68pF cap:
121GW - 68-70pF (drifted upward over a 10 second period)
Homebuilt cap meter - 66.2pF
Roman Black Kit- 71.10pF

If I let the 121GW sit overnight, it displays ~25pF at power on.  Using REL makes it spot on.

Bought my unit about a year ago, running v2.00 firmware.


The homebuilt unit was made by my grandfather about 35 years ago and can measure 0.1pf up to 9.99F within 1 second.  So naturally I use it 99% of the time with an occasional check on other meters for sanity.

More history, my grandfather worked for the Air Force and his primary job was checking test equipment.  I remember some of his stories about the National Bureau of Standards (of course now called NIST) and how the various test processes worked.  My primary take-away was for sure never trust a single piece of equipment...  Just to clarify, I don't mean any disrespect to the 121GW, it's just a good idea to verify measurements!
Title: Re: EEVBlog 121GW Discussion thread
Post by: 1anX on November 12, 2019, 08:22:52 pm
Maybe Dave can advise us all on what the current revision is for the meters and if he plans to sell a revised PCB to those who already have the meter?
A discounted replacement PCB for early adopters would be much appreciated! (Providing its actually an improvement of course).

No plans for replacement boards to be made available, there is no functional difference, it's just a normal process of refining the design over time, happens regularly to all meters. Existing customers are not missing out on anything.

Hey Dave it would be nice if you could provide an update on what hardware revisions the "most current" version of the 121GW has had installed.
It would also be appreciated to know what the revised hardware has been fitted to achieve in the meter's function or protection.

It seems the EEVBLog store is selling older versions of the 121GW meter as Joe Smith found with his latest purchase of 2 new meters from your store. Can you supply from your store the current version meter? Will you discount the old meters or continue to sell old revision meters at full price?

How about sending Joe Smith 2 current version meters so we can see the results of comprehensive and unbiased testing of the current 121GW meter!!!!!!!!!!!!!!!!!!!
Title: Re: EEVBlog 121GW Discussion thread
Post by: Terry01 on November 13, 2019, 07:41:48 am
I brought this up when I bought my 121 GW and was steam rolled by the same people moaning now that the meter was great and upgrades meant nothing and the meter I got was the same as the revised ones  so no different. In fact it wasn't new so it was no different yada yada yada....!

Too funny  ;D
Title: Re: EEVBlog 121GW Discussion thread
Post by: joeqsmith on November 13, 2019, 12:46:41 pm
I brought this up when I bought my 121 GW and was steam rolled by the same people moaning now that the meter was great and upgrades meant nothing and the meter I got was the same as the revised ones  so no different. In fact it wasn't new so it was no different yada yada yada....!

Too funny  ;D

Link?
Title: Re: EEVBlog 121GW Discussion thread
Post by: joeqsmith on November 13, 2019, 01:10:19 pm
Maybe Dave can advise us all on what the current revision is for the meters and if he plans to sell a revised PCB to those who already have the meter?
A discounted replacement PCB for early adopters would be much appreciated! (Providing its actually an improvement of course).

No plans for replacement boards to be made available, there is no functional difference, it's just a normal process of refining the design over time, happens regularly to all meters. Existing customers are not missing out on anything.

Hey Dave it would be nice if you could provide an update on what hardware revisions the "most current" version of the 121GW has had installed.
It would also be appreciated to know what the revised hardware has been fitted to achieve in the meter's function or protection.

It seems the EEVBLog store is selling older versions of the 121GW meter as Joe Smith found with his latest purchase of 2 new meters from your store. Can you supply from your store the current version meter? Will you discount the old meters or continue to sell old revision meters at full price?

How about sending Joe Smith 2 current version meters so we can see the results of comprehensive and unbiased testing of the current 121GW meter!!!!!!!!!!!!!!!!!!!

I assumed buying the meters from Dave's store of all places would yield the latest hardware.  If he had both new and old stock, I would have just paid the difference for the latest.   If Germany has been selling the new one for months prior to me placing an order, I wonder if this is part of the EU approval.  Maybe the revisions are tied to that.  If the changes make no difference, they are stupid for making them in the first place.  Your just pissing money away at that point.     

Someone had suggested I just cut my losses and sell the meters.  After cycling the switches the readings have improved but seeing that one brand new, out of the box unit hunt the way it did,  to be honest, I wouldn't give them away.   I have no confidence in them and I see them is more a novelty than anything.   CEM quality with an EEVBLOG name on it.  I don't know many people who want to play with firmware loads.   
Title: Re: EEVBlog 121GW Discussion thread
Post by: daveyk on November 13, 2019, 08:43:30 pm
"Someone had suggested I just cut my losses and sell the meters.  After cycling the switches the readings have improved but seeing that one brand new, out of the box unit hunt the way it did,  to be honest, I wouldn't give them away.   I have no confidence in them and I see them is more a novelty than anything.   CEM quality with an EEVBLOG name on it.  I don't know many people who want to play with firmware loads."

Quite honestly I was expecting a super meter, better than anything I have ever used before.  The resistance function on the free harbor freight meters work better.  Putting the two leads together on the `121GE still takes 2-2.5 seconds to come up with a reading less than zero and then that reading fluctuates so much that it make the REL function irrelevant.  Readings voltages has been fine.  When I am trouble-shooting, I use my scope to read voltages and my DVM to read resistance and the 121GW, with 2.02 code is still not usable for resistance measurement.  Yes, you have the range switch, but I can not tell what range I am putting it in, nor when I cycled through all the ranges.

I think the 121GW is a cool piece of hardware, and it may be very accurate in numerous modes, but it is a very difficult device to use for trouble-shooting.  Perhaps my 121GW isn't good, but I wouldn't know how to tell.  I do need to purchase a new Fluke 87 or something for trouble-shooting.

I hope it doesn't end up in my storage closet with other useless test equipment such as that Siglent scope I bought last year.
Title: Re: EEVBlog 121GW Discussion thread
Post by: CDaniel on November 13, 2019, 10:23:20 pm
All the meters are like yours with slow resistance autorange . The 50ohm range  is not stable because they design it with very low measurement current and insanely high ADC gain .  This can't be fixed in firmware .
Title: Re: EEVBlog 121GW Discussion thread
Post by: exe on November 14, 2019, 07:56:47 am
Is it possible to modify that diode clamp so it doesn't disturb resistance measurements? I'm actually willing to sacrifice meter's survivability if it improves usability and doesn't degrade my safety.
Title: Re: EEVBlog 121GW Discussion thread
Post by: J-R on November 14, 2019, 10:43:27 am
Dug up some resistors to test with my 121GW using the UEI leads:
0.1 - 0.094 (two in series was 0.208)
2 - 1.918
10 - 9.985
27 - 27.743

Values from a sub-$50 meter:
0.10
2.01
10.3
28.5


Also revisited capacitance, with four 68pF caps in parallel (individually, they measure between approximately 60pF and 70pF, as mentioned previously)
121GW - 244pF
BM235 - 260pF (0.26nF)
Home built - 270pf
Roman Black - 284.18pF


The 121GW performed these measurements reasonably well.  Keep in the mind the published accuracy for this meter.

For accurately measuring small pF caps I believe I would primarily use the Roman Black unit as it is accurate to within 0.01pF and designed specifically for this.

Title: Re: EEVBlog 121GW Discussion thread
Post by: CDaniel on November 14, 2019, 11:10:29 am
You should read carefully what are the issues , use the meter some time and then tell us the conclusion .
I doubt your pF measurement is consistent and not drifting ...
The problem with the 50ohm range are the last 2 digits or so , for small resistors ... even when you short the leads the reading is very inconsistent .
Title: Re: EEVBlog 121GW Discussion thread
Post by: beanflying on November 14, 2019, 01:11:48 pm
You should read carefully what are the issues , use the meter some time and then tell us the conclusion .
I doubt your pF measurement is consistent and not drifting ...
The problem with the 50ohm range are the last 2 digits or so , for small resistors ... even when you short the leads the reading is very inconsistent .

So you start with knowing the issues, use the meter and then reach a conclusion based on what exactly? :palm: Your non scientific method is truly amazing and a wonder to behold :o

What J-R should maybe look at FIRST is what are the accuracy or tolerance of the Caps he is playing with and do his meters confirm that the combined accuracy is in the correct ballpark. You can test with as many meters as you like but without a 'known' starting point or some sort of reference all the readings are just relative to each other. Stating meter X is better than Y is  :bullshit: without a reference or known standard to compare against. The best you can do is really give a best guess yeah or nay as to accuracy at the extremes of spec.

The drift is another matter and as per the post I linked to I found that to be the case on small Caps nearly a year ago https://www.eevblog.com/forum/testgear/eevblog-121gw-discussion-thread/msg2051194/#msg2051194 (https://www.eevblog.com/forum/testgear/eevblog-121gw-discussion-thread/msg2051194/#msg2051194) If you want to go there and be stable best look elsewhere for a meter. This you can make observations about drift or non shorted readings compared to shorted ones before readings as they are just comparative rather than a finite number. Buy an LCR meter and do it properly if you NEED these readings to be accurate otherwise it is just NOISE.

Want to measure small resistances accurately buy a Millohm meter or certainly one with four wire measurement. It is 'sensible' to use a low current on a battery powered meter as a compromise so stop exaggerating and making overstated claims. My Milliohmmeter for example kicks the butt of my 34401A and 34461A as it pumps up to 1A on the lower ranges as a test current.
Title: Re: EEVBlog 121GW Discussion thread
Post by: CDaniel on November 14, 2019, 03:08:40 pm
For fanboys ... Fluke 289  multimeter use 10mA for 50ohm range , of course you have to be Fluke to realize this ...  ;D

In capacitance mode , when something drifts , the reading is not consistent +-50pF or so , it's shitty accuracy all day long . It can't be trusted .
And please don't tell me what to buy , if you don't know how a good design meter should behave  :-X  ,  although probably even a chinese crap meter doesn't have this capacitance issue .
 


Title: Re: EEVBlog 121GW Discussion thread
Post by: daveyk on November 15, 2019, 03:11:17 pm
All the meters are like yours with slow resistance autorange . The 50ohm range  is not stable because they design it with very low measurement current and insanely high ADC gain .  This can't be fixed in firmware .

So CDDaniel, you are basically telling me the Resistance mode of the 121GW is just plain bad?  It does work okay, in manual resistance range.  I just can't tell watch range I am in or when I cycle back to auto when pushing the range switch.  It would be nice for some sort of easier to view enumerator was on the display.  There is the "AUTO", but when range is pushed that goes away and I have no idea what range I am in, and NO, I am not reading the manual to know what ranges it toggles through.  Why should I have to do that?  Any other meter displays what range it is on! Okay maybe that bottom analog scale might show it?... It is hard to read.  Why not put something where the AUTO is? So I press range one time and I am on the 50 ohm range? Leads together read 0.000 ohms. Push range again, and it stays on 50 ohms , but reads 0.50, no .204, just slowly drifts up. Push range again, and I am on 500 ohm range? Put leads together and it reads 0.00, after a few seconds of braiding down to 0.00. Push range again and it changes from 500 ohm to 5 ohm range? 0.0000 K ohms with leads together. Range again: 50 ohm range, again. Range again, stays on 500 ohm range, Leads together, it takes about 3 seconds to read 0.00.   I could go on, it is just difficult to figure this thing out.  It may be fantastic but it is not natural to use.  I push Range many times and it does not go back to auto.  Maybe it's cycling through the various ranged, but it so hard to tell when to stop.  That could be fixed in Firmware.

Dave
Title: Re: EEVBlog 121GW Discussion thread
Post by: CDaniel on November 15, 2019, 04:51:18 pm
The issues I see with resistance mode
1 - slow autorange , this is improving with every firmware update
2 - in 50ohm range the last 2 digits are pretty useless . Every time you short the leads you get different reading and fluctuating .
3 - any range is more or less affected by mains noise , if you touch the probes . Of course this is subjective as some people have "quiet" labs , so for them is ok .
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on November 15, 2019, 11:55:27 pm
So CDDaniel, you are basically telling me the Resistance mode of the 121GW is just plain bad?  It does work okay, in manual resistance range.  I just can't tell watch range I am in or when I cycle back to auto when pushing the range switch.  It would be nice for some sort of easier to view enumerator was on the display.  There is the "AUTO", but when range is pushed that goes away and I have no idea what range I am in, and NO, I am not reading the manual to know what ranges it toggles through.  Why should I have to do that?  Any other meter displays what range it is on! Okay maybe that bottom analog scale might show it?... It is hard to read.  Why not put something where the AUTO is?
\

Seriously?
The 121GW works like every other auto ranging meter in existence. Press Range and the fixed range annunciators are clearly displayed on the right hand side.

Quote
I push Range many times and it does not go back to auto.

You hold down the Range switch for a few second to go back into Auto mode.
Title: Re: EEVBlog 121GW Discussion thread
Post by: J-R on November 16, 2019, 07:46:16 am
The issues I see with resistance mode
1 - slow autorange , this is improving with every firmware update
2 - in 50ohm range the last 2 digits are pretty useless . Every time you short the leads you get different reading and fluctuating .
3 - any range is more or less affected by mains noise , if you touch the probes . Of course this is subjective as some people have "quiet" labs , so for them is ok .

1 - Agreed, "slow" is a valid term to use.  I typically grab another meter for rapid resistance tasks, but I trust the 121GW to give me an accurate reading if necessary.

2 - In the 50 Ohm range, the accuracy at best is within 20 counts in either direction, so the last digit IS useless and the second to the last digit is effectively useless.  So I don't think your point is valid.

3 - Why would you be touching the probes if you care about accuracy?  I think this point is also invalid.

Title: Re: EEVBlog 121GW Discussion thread
Post by: J-R on November 16, 2019, 08:42:07 am
What J-R should maybe look at FIRST is what are the accuracy or tolerance of the Caps he is playing with and do his meters confirm that the combined accuracy is in the correct ballpark. You can test with as many meters as you like but without a 'known' starting point or some sort of reference all the readings are just relative to each other. Stating meter X is better than Y is  :bullshit: without a reference or known standard to compare against. The best you can do is really give a best guess yeah or nay as to accuracy at the extremes of spec.

I suppose what you are saying is technically valid, but we can also consider probabilities, statistics, logic, reason, etc.  If I'm standing outside my house and my GPS says I'm 2,300' under sea level, I can just look left and right and know that my GPS is faulty no matter what calibration certificate is stuck to it, unless we all live in The Matrix and nothing is real.

So if I buy a few random capacitors from various suppliers, measure each one individually using multiple devices to check their claimed values, then add them together in parallel and the values are still reasonable, then the probability of everything being completely wrong is tiny to the point of being nearly impossible.  Or I'm living in the Matrix and nothing is real.  I know what I'm going with...
Title: Re: EEVBlog 121GW Discussion thread
Post by: J-R on November 16, 2019, 10:32:51 am

So CDDaniel, you are basically telling me the Resistance mode of the 121GW is just plain bad?  It does work okay, in manual resistance range.  I just can't tell watch range I am in or when I cycle back to auto when pushing the range switch.  It would be nice for some sort of easier to view enumerator was on the display.

The operational characteristics of the 121GW are probably more hen-pecked than any other device out there and you can search the forums for specific tasks you might want to perform to get more information.


If the meter is in Auto Range mode, then pressing the Range button once will disable Auto Range and the meter will STAY in the current range.  So if you short the leads in Auto mode, it will end up in the 50 Ohm range and pressing the Range button once will set it there.  Similarly, if the leads are OPEN, then it will end up in the 50M Ohm range and pressing the Range button once sets it there.

Subsequent Range button presses cycles through the ranges, in order, as listed in the manual (page 19).

If a value is displayed on the meter, you can observe the decimal point and the "M" or "k" to immediately see the resistance value.  If OFL is displayed, you can reference the small number on the bottom right of the display as it cycles between 5, 50 and 500 along with the units display (M, k, etc.) to determine what range you are in.

Title: Re: EEVBlog 121GW Discussion thread
Post by: 1anX on November 16, 2019, 08:48:09 pm
Hey Dave, or anyone from the EEVBlog Store!
Can you please make clear what version of the meter is currently in stock and being sold from EEVBlog Store.
Dave, how about a technical run down on what the latest hardware revision of the meter does and how the meter has changed over the period of time since it first went on sale!
It seems you provided heaps of great info on this meter initially, (pre-sales) and I for one found it interesting and informative.
The meter has a few problems and didn't live upto initial expectations, but I'm still interested as an owner and as an early adopter/supporter of your collaborative effort with UEI.
My wish is that you would come forward and update the buyers of this meter on just what progress has been made!
The worst thing IMHO is that you have become silent on the technical progress of this meter. Your silence and not keeping the community around this meter informed is damaging your reputation as an advocate for honest unbiased technical reviews.
Looking forward to hearing from you with an updated EEVBlog on the current state of play with the 121GW meter!
Title: Re: EEVBlog 121GW Discussion thread
Post by: joeqsmith on November 17, 2019, 12:34:00 am
I wrote Dave today after he suggested that I "... should have asked first!" that it's really up to him to communicate with his customers, not the other way around.   

In my case, the entire drama could have very easily been avoided with a simple note in the ad.   Again, to be clear, I was never looking for special treatment.  I want the meters that any one else placing an order would get.   What I was not expecting was to find out that a newer major revision of the meter was available a few months before I bought mine and I received the old hardware, without notification.    This is just bad business practice and pointing the finger at the customer is certainly not a step in the right direction.   They are certainly free to handle their affairs as they see fit, but as a past customer it won't happen again.     

I suggest major revision as the PCB revision had changed and the shim had been removed, along with other changes.  Any changes to that switch design IMO is major. 

While we are off to a rocky start with this review, you can be assured I will remain unbiased.  These tests are data driven, not drama driven. 
Title: Re: EEVBlog 121GW Discussion thread
Post by: ornea on November 17, 2019, 02:21:23 am
I think statistically there is value in using many meters to compare.

I was in a metrology lab (same one dave visited) one day and  asked how the calibrate their top level equipment (The exact equipment may have been measuring time, I cant remember). They said they compare and reference against same level of tier of equipment around the world and if they agree then its calibrated.
Title: Re: EEVBlog 121GW Discussion thread
Post by: e0ne199 on November 17, 2019, 03:25:59 am
Hey Dave, or anyone from the EEVBlog Store!
Can you please make clear what version of the meter is currently in stock and being sold from EEVBlog Store.
Dave, how about a technical run down on what the latest hardware revision of the meter does and how the meter has changed over the period of time since it first went on sale!
It seems you provided heaps of great info on this meter initially, (pre-sales) and I for one found it interesting and informative.
The meter has a few problems and didn't live upto initial expectations, but I'm still interested as an owner and as an early adopter/supporter of your collaborative effort with UEI.
My wish is that you would come forward and update the buyers of this meter on just what progress has been made!
The worst thing IMHO is that you have become silent on the technical progress of this meter. Your silence and not keeping the community around this meter informed is damaging your reputation as an advocate for honest unbiased technical reviews.
Looking forward to hearing from you with an updated EEVBlog on the current state of play with the 121GW meter!

i agree with this..i honestly see that this meter actually has so many potentials to be one of the great meters but somehow it is constantly plagued with so many major bugs and it takes too much time for a fix...i really hope so much that the problem is not related with hardware...i hope that people who made this meter should try fix every bugs that exist in this meter and if they aren't able to do it anymore (or probably unable to do it) then just release its source code to the public so that everyone can work together to fix the problem of this meter...
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on November 17, 2019, 07:54:23 am
I wrote Dave today after he suggested that I "... should have asked first!" that it's really up to him to communicate with his customers, not the other way around.   
In my case, the entire drama could have very easily been avoided with a simple note in the ad.   

When you placed your order I had not received the new meters and still had a couple of boxes of old meters, so your order was shipped as standard.
In terms of getting the latest build your order was a simple case of terrible timing, that once again could have been avoided if you simply had asked. You seemed very upset and angry that you got an older version and I offered to replace them but you refused, and that's fine, I have no problem with it, your choice. I'm not sure how many times I'm going to have to repeat saying this.

To be very clear, there are no specification changes, no operational changes, and no rating change between meters. Most customers would not care about every minute detail you care about, to them it's the same spec meter with the same performance, the same features, and the same warranty. They are fully independently tested by ETL.

Quote
I suggest major revision as the PCB revision had changed and the shim had been removed, along with other changes.  Any changes to that switch design IMO is major. 

This change has been know about since almost day one. There were 4000 assembled PCB's from the first Kickstarter batch, and I stated publicly at the time that all those 4000 boards would be used up until stock was exhausted and then the next production run would use the correct 1.6mm PCB that would not require the shim.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on November 17, 2019, 08:07:09 am
Hey Dave, or anyone from the EEVBlog Store!
Can you please make clear what version of the meter is currently in stock and being sold from EEVBlog Store.

I have I think a box and half of the original stock left.
I just got in a shipment of the latest build, that AFAIK Welectron do not have yet. FYI, I have no no visibility in what stock Welectron have or when they got it, they order direct from UEi as required, but I'm fairly sure they don't have the new 1.6mm PCB. So once the box and half or whatever is gone I'll start selling the new build.

This new build (v.02 -1910 PCB) is the first run after the 4000 Kickstarter boards were assembled, changes are (IIRC):
1) Correct 1.6mm PCB as intended (the KS PCB was unknowingly thinner from the manufacturer, hence the shim)
2) Plated hole on the knob
3) The protection transistors that were fitted onto small daughter boards are now integrated into the PCB.
4) Battery terminals are now smaller
5) Supplied with UEi silicone probes now instead of Brymen.

[attachimg=1]
Title: Re: EEVBlog 121GW Discussion thread
Post by: thinkfat on November 17, 2019, 09:34:50 am
In my case, the entire drama could have very easily been avoided with a simple note in the ad.   Again, to be clear, I was never looking for special treatment.  I want the meters that any one else placing an order would get.   What I was not expecting was to find out that a newer major revision of the meter was available a few months before I bought mine and I received the old hardware, without notification.    This is just bad business practice and pointing the finger at the customer is certainly not a step in the right direction.   They are certainly free to handle their affairs as they see fit, but as a past customer it won't happen again.     

If I order some device, be it directly from the OEM or through a distributor, I won't know either whether I have the very latest revision of the device. Unless I specifically ask for a specific revision I have no leverage anyway, it will be from whatever stock is in the warehouse at the time. If I look at listings at Distrelec or Batronix or wherever, they don't even mention specific revisions. They will assume, rightfully, that all gear the receive from the OEM are meeting advertised specifications. If not, there would be a update notification or even a recall option.

Dave says there was no update to the published spec, so I don't quite see what's the ruckus...
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on November 17, 2019, 09:51:52 am
Dave says there was no update to the published spec, so I don't quite see what's the ruckus...

There was no ruckus with the BM235 which underwent a couple of hardware revisions and half a dozen (non-upgradeable) software updates
Title: Re: EEVBlog 121GW Discussion thread
Post by: ggchab on November 17, 2019, 09:53:49 am
If a production meter is a production meter and specifications have not changed, tests results should be the same whether it's the latest hardware version or not. Or am I missing something ?

On the other hand, I am wondering why spending time and money to change something that already meets specifications ? (except thickness of the PCB to avoid the patch)

So, it would be interesting if Dave could simply send another 121GW with the latest hardware to Joe Smith so that he could make real comparisons. But I don't think this will ever happen  ???

Also, as Joe already said, I don't see why he would deserve a better service than other users ? He bought his meters the same way we all did. May we swap our 121GW with one having the latest changes ?
Title: Re: EEVBlog 121GW Discussion thread
Post by: CDaniel on November 17, 2019, 12:48:51 pm
But who said that newer meters behave better ? As far I can see my meter always could measure 150pF and Joe's newer version out of the box couldn't .
I'm wondering how is working now , has recovered itself ? In the latest video 1nF was close with the other meters , not 1nF - 150pF
Title: Re: EEVBlog 121GW Discussion thread
Post by: jancumps on November 17, 2019, 01:49:48 pm
...

On the other hand, I am wondering why spending time and money to change something that already meets specifications ? (except thickness of the PCB to avoid the patch)
...

These are answered a few posts above: move protection transistors from separate little PCB to main PCB, thickness of PCB, the hole for the knob plated, smaller springs for the batteries.
Costs are saved because no daughter board and shim needed, while specs stay the same.
Title: Re: EEVBlog 121GW Discussion thread
Post by: joeqsmith on November 17, 2019, 02:59:14 pm
But who said that newer meters behave better ? As far I can see my meter always could measure 150pF and Joe's newer version out of the box couldn't .
I'm wondering how is working now , has recovered itself ? In the latest video 1nF was close with the other meters , not 1nF - 150pF

I suspect there is both a software and hardware problem when measuring small capacitor values,  which is what I was showing in the last segment.   No the meter has not magically healed itself.   The new hardware could very well correct one of the problems.
Title: Re: EEVBlog 121GW Discussion thread
Post by: daveyk on November 17, 2019, 03:09:05 pm
Hello Joe,  I found your videos on YouTube; nice.  Is the older board the reason, they were on sale on the EEVBLOG store verses getting them from another source with the newer board?  Is there anything other than the board, switch and shielding?
Title: Re: EEVBlog 121GW Discussion thread
Post by: joeqsmith on November 17, 2019, 03:21:07 pm
This new build (v.02 -1910 PCB) is the first run after the 4000 Kickstarter boards were assembled, changes are (IIRC):
1) Correct 1.6mm PCB as intended (the KS PCB was unknowingly thinner from the manufacturer, hence the shim)
2) Plated hole on the knob
3) The protection transistors that were fitted onto small daughter boards are now integrated into the PCB.
4) Battery terminals are now smaller
5) Supplied with UEi silicone probes now instead of Brymen.


We know there was a least one meter sold without a shim using PCB revision V.02-1905.   Like my old hardware, these also appear not to have a plated hole for the knob.  Both clamps in question are using different components than seen on my old hardware and are located on mezzanine boards.   

According the the person who supplied the picture, this hardware was available at least two months prior to me placing an order. 

We have shimmless to shim and back to shimless.   No shield to shield.   Then we have  diodes to TVS to small transistor mezzanine to a large transistor mezzanine onto large transistor integrated clamps.      They were changing the switch contacts as well.   At some point they have some sort of hybrid using both double single dimples.  My old hardware is all single dimple.  No idea what's in there now.

I think the difference is Brymen seems to do a decent job with their testing.  They make small corrections once a problem has been identified, not major reckless changes.  From what I have seen so far, there is no comparison in the quality.
Title: Re: EEVBlog 121GW Discussion thread
Post by: joeqsmith on November 17, 2019, 03:31:09 pm
Hello Joe,  I found your videos on YouTube; nice.  Is the older board the reason, they were on sale on the EEVBLOG store verses getting them from another source with the newer board?  Is there anything other than the board, switch and shielding?
Thanks. 

Your first question is for Dave.  You can check the store  https://www.eevblog.com/product/121gw/ (https://www.eevblog.com/product/121gw/)    and see if they have changed the ad to include details about the revisions and what you are buying.   If something goes on sale, I wouldn't normally jump to the conclusion it is old stock.   Normally this would be part of the ad.   

Your second question is difficult for me to answer as it's relative to what?  I don't have one of the original kick start meters to compare it with.  They don't maintain the public documentation (schematics).   Read my last post which includes some of the things I have noticed from what other's have posted. 
Title: Re: EEVBlog 121GW Discussion thread
Post by: 1anX on November 18, 2019, 11:05:10 pm
Dave has a new video up on auto-ranging speed!

https://www.youtube.com/watch?v=izCDWjK_pV4&t=60s (https://www.youtube.com/watch?v=izCDWjK_pV4&t=60s)
Title: Re: EEVBlog 121GW Discussion thread
Post by: Terry01 on November 20, 2019, 11:31:38 am
Seems it's right in the middle of the stack when compared with other decent meters. 1 second either way isn't a big deal really.  :-+
Title: Re: EEVBlog 121GW Discussion thread
Post by: daveyk on November 20, 2019, 03:38:01 pm
Shorting the leads together, then it taking 2.5 seconds to show something <0 ohms and then that reading <0 floating around and slowly raising to maybe .200 or .260 ohms over several more seconds is an issue if you are trying to trouble-shoot circuits that are low in resistance to begin with.  The inability for the meter to settle down with shorted leads, make the REL button not applicable.

The manual mode does not have this issue, but my complaint with the manual mode, is that unless you spend mental energy on the meter verses the circuit you are working on, trying to figure out what range you are on is difficult, at least for me.  I think a good fix would be to better enumerate the display to show what manual range you are on.  There is one manual range (I think the second press of the range button), that floats around too.  Most manual ranges are fast and stable, I just have a hard time figuring out what range I am on.  Is it not a dot matrix display?  Can not the firmware display whatever it needs to?  Kindly rework the ohms display to make it easier to tell what manual range I am on, and I think the problem is fixed.
Title: Re: EEVBlog 121GW Discussion thread
Post by: joeqsmith on November 20, 2019, 04:32:08 pm
Shorting the leads together, then it taking 2.5 seconds to show something <0 ohms and then that reading <0 floating around and slowly raising to maybe .200 or .260 ohms over several more seconds is an issue if you are trying to trouble-shoot circuits that are low in resistance to begin with.  The inability for the meter to settle down with shorted leads, make the REL button not applicable.

The manual mode does not have this issue, but my complaint with the manual mode, is that unless you spend mental energy on the meter verses the circuit you are working on, trying to figure out what range you are on is difficult, at least for me.  I think a good fix would be to better enumerate the display to show what manual range you are on.  There is one manual range (I think the second press of the range button), that floats around too.  Most manual ranges are fast and stable, I just have a hard time figuring out what range I am on.  Is it not a dot matrix display?  Can not the firmware display whatever it needs to?  Kindly rework the ohms display to make it easier to tell what manual range I am on, and I think the problem is fixed.

When Dave ran this test, he suggested the drift was due to finger pressure on the button.  The same you may see when probing a circuit.  So I removed the mechanical switch and repeated the test....


I have included my attempt to reproduce Dave's speed test in Part 4.   Dave does claim the "...I checked, the Keysight "drifts" in a similar way,.... "
https://youtu.be/-eUkSufMK5A?t=460
I overlaid Dave's two meters to better show how the 121 compares with the Keysight meter.    I also included more information about my test.   
Title: Re: EEVBlog 121GW Discussion thread
Post by: ElectricPower on November 22, 2019, 02:40:41 pm

I am quite new here in the forum, but have read some in the multimeter thread regarding 121GW here and it seems there is a lot of error with it?

I wonder if I should order one, but became skeptical when I read the thread.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Brumby on November 23, 2019, 02:17:44 am

I am quite new here in the forum, but have read some in the multimeter thread regarding 121GW here and it seems there is a lot of error with it?

I wonder if I should order one, but became skeptical when I read the thread.

This thread provides a rather unusual connection between those who purchase a product and those involved in its development and production.  As such, all the personal preferences and minutae that any given owner may have can be aired directly - with the idea of influencing the development to suit them.  This is not something I have ever seen with ANY other commercial product.

As such, the voices here express a point that they feel is worth addressing - and while this may be a widespread concern, we can only be certain that it is a concern for those who have voiced it here.  One or two squeaky wheels here may not represent the concerns of the thousands who own and use this meter - who tend to just quietly work with the meter as supplied.

I would suggest you read the "issues" carefully and decide if anything mentioned would really affect you.  This is your homework.  You might normally have to go trawling around the net to find this information for any other product - but you have it encapsulated here.


Disclosure: I do not own a 121GW - not because of any the reports, but because I do not have the need.  My current equipment line-up covers more than I require at this time.

... but I AM interested.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Doom-the-Squirrel on November 23, 2019, 02:58:45 am
Sorry if this has been asked before, but would the 121GW be a good choice for automotive electrical and electronics?

Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on November 23, 2019, 06:30:32 am
Sorry if this has been asked before, but would the 121GW be a good choice for automotive electrical and electronics?

Not really.
A simpler less precise meter would be a better choice, like a BM235 or an Automotive variant of that:
https://brymen.eu/shop/bm319s/
Title: Re: EEVBlog 121GW Discussion thread
Post by: firewalker on November 23, 2019, 10:19:51 am
I teach electronics to automotive technicians. They are in a stage that they can use a DMM to measure sensors etc with ease. I gave them 121GW to use for a change. After 5 minutes the wanted to break it.  :D :D :D

Alexander.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on November 23, 2019, 10:22:22 am
I teach electronics to automotive technicians. They are in a stage that they can use a DMM to measure sensors etc with ease. I gave them 121GW to use for a change. After 5 minutes the wanted to break it.  :D :D :D

Yes, the more rugged BM235 is more suited to field and automotive use IMO.
And if you need the features of an automotive meters like tacho/dwell then you need a specific automotive model.
Best to start a new thread asking for the best automotive meter.
Title: Re: EEVBlog 121GW Discussion thread
Post by: in06khattab on November 24, 2019, 02:20:18 am
Is it possible to silence the beep in continuity mode and use the screen flashing as an indicator?
Title: Re: EEVBlog 121GW Discussion thread
Post by: jancumps on November 24, 2019, 12:59:00 pm
Is it possible to silence the beep in continuity mode and use the screen flashing as an indicator?

No. You can switch the beeper on or off, but for continuity, it will always beep. The screen does not flash.
Title: Re: EEVBlog 121GW Discussion thread
Post by: dr.diesel on November 24, 2019, 01:15:57 pm
Is it possible to silence the beep in continuity mode and use the screen flashing as an indicator?

This would be a great feature!

How about a config file on the SD card as well for custom options:

continuityflash=1
autopoweroff=45
ble=1
defaultDCVrange=2

etc
Title: Re: EEVBlog 121GW Discussion thread
Post by: in06khattab on November 24, 2019, 04:28:48 pm
Surely, that is a simple software update?
This can be enabled in the setup menu.
Then if the buzzer sounds, flash the screen.

If the firmware was available, this is very easy to add (without the setup menu).
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on November 26, 2019, 02:09:01 am
17 units of the old kickstarter build stock left, 20% discount off the already sale price on the EEVblog website, coupon code fluxcapacitor
https://www.eevblog.com/product/121gw/ (https://www.eevblog.com/product/121gw/)
Title: Re: EEVBlog 121GW Discussion thread
Post by: Brumby on November 26, 2019, 03:43:42 am
Geez....  Now you're really tempting me - but I have to take care of the Christmas budget first.


(Not to mention the reaction I will get if I bring another multimeter into the house  ;D )
Title: Re: EEVBlog 121GW Discussion thread
Post by: BrianG61UK on December 02, 2019, 03:49:37 am
17 units of the old kickstarter build stock left, 20% discount off the already sale price on the EEVblog website, coupon code fluxcapacitor
https://www.eevblog.com/product/121gw/ (https://www.eevblog.com/product/121gw/)
What improvements are we missing out on if we choose to save by getting one of these old build 121GWs?
Title: Re: EEVBlog 121GW Discussion thread
Post by: BVH on December 08, 2019, 12:37:33 am
Is there a new 20% off for Christmas coupon code available?
Title: Re: EEVBlog 121GW Discussion thread
Post by: popol on December 11, 2019, 01:18:42 pm
Hi,

I'm busy looking at the 121GW schematic, and I have some questions.

On the set "Burden", what is the component FB2 BEAD ??
See link :

(https://i.ibb.co/QP8hLns/Burden-value.png) (https://ibb.co/m9vdktQ)

It's a capacitor? or another type of room? If anyone knows what it is,

Witch value have this component ?

thanks for the answer.

Title: Re: EEVBlog 121GW Discussion thread
Post by: Grandchuck on December 11, 2019, 02:23:40 pm
A ferrite bead?
Title: Re: EEVBlog 121GW Discussion thread
Post by: gdewitte on December 11, 2019, 02:52:38 pm
Ferrite bead (another one at FB3). https://www.analog.com/en/analog-dialogue/articles/ferrite-beads-demystified.html# (https://www.analog.com/en/analog-dialogue/articles/ferrite-beads-demystified.html#)
Title: Re: EEVBlog 121GW Discussion thread
Post by: popol on December 11, 2019, 03:56:56 pm
Ok, thank-you for your response. But witch are caracteristics of this component ( uH, pF, Ohms ? )

Title: Re: EEVBlog 121GW Discussion thread
Post by: CDaniel on December 11, 2019, 05:09:05 pm
I don't think inductance is very important like in a normal LC filter , after all is just a very short wire , but the ferrite is made "lossy" ( hysteresis losses ) so high frequency is "consumed" inside .
Title: Re: EEVBlog 121GW Discussion thread
Post by: ejeffrey on December 11, 2019, 09:22:13 pm
The document gdewitte linked to shows some typical impedance vs. frequency curves, but a typical ferrite bead has very low impedance at low frequency -- basically just a short wire, and then cuts on with a very low Q inductance (i.e., mostly resistive) at higher frequency, typically several MHz to several hundred MHz.  Far above anything a multimeter cares about.  Their purpose is to limit EMI pickup from external sources (like FM radio) and also to prevent emissions of internally generated high frequencies such as from digital electronics and switching power supplies.  If chosen at all appropriately they have negligible effect on the actual desired signal.
Title: Re: EEVBlog 121GW Discussion thread
Post by: popol on December 13, 2019, 04:54:03 pm
Ok, its clear now, thank-you for your response. 8)
Title: Re: EEVBlog 121GW Discussion thread
Post by: npelov on January 18, 2020, 06:30:43 am
Yesterday I gave up on logging onto the SD card and tried the android app - it worked fine for a while - I could save the data in csv. But then after about one hour the save button did not work any more. If I press save nothing happens.
The last time I was able to save something was at the 50 minute mark. I pressed the save button and because nothing happened in a second or two I pressed it again. Then the usual share dialog appeared, but when I saved the file another share dialog appeared - I guess it was just taking it's time.

And it's a separate thing I can't save the csv file on the phone itself - I can only put it in an email, google drive and other things that usually popup in "share file".

Is there any way to log data with this DMM in a stable way?

You would think that a DMM advertised as "logging" would be able to log and after an year and a half the major bugs would be fixed. I'm sorry Dave but you are nip-picking other products for much smaller flows. I know you are not directly responsible for the firmware, but you should be more pressing. Your name is on the meter.

BTW the 500mA range is unstable. Sometimes I get quite a bit of noise. I'll be back later with numbers, because I forgot how much it was jumping around. I think I was in fixed 500mA range measuring 10mA. I think it's not like that all the time, but I'm not sure. I'll try to investigate more. The low burden is pushing the limits a bit but I think there is more to it, because sometimes it's relatively stable.
Title: Re: EEVBlog 121GW Discussion thread
Post by: joeqsmith on January 18, 2020, 05:54:13 pm
Is there any way to log data with this DMM in a stable way?

When I tried their Windows 10 software, it wasn't very smooth to use.    Maybe it works better now and would allow you to make longer logs.   The last test I ran with the meter I was logging for about a day and a half using 2.02 firmware.  This is using LabView, not their software.    However, after seeing the problems with the SD card, I wonder if the BLE would have the same problem.  Most of the tests I have ran using the 121, I was looking at drift, noise... so the input was stable.     

https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg2839508/#msg2839508 (https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg2839508/#msg2839508)

Title: Re: EEVBlog 121GW Discussion thread
Post by: npelov on January 19, 2020, 11:31:06 pm
The BLE reflects the display. The display was fine when the SD card log showed non sense. Also BLE sends at a rate independent of SD cart log interval. I feel like the bug is just in the SD card write routines. I selected 10 seconds  for the last try - logging both SD card and android app. I logged for a few hours and the DMM froze. Just before freezing it looked like this:
[attach=1][attach=3]

The second display shows 5dE04 ... while it was still recording. It should be showing the record number. The last record number in the SD log is 1140. Last voltage 10.345V (you can see on the android app 10.190V), last power 17.03VA, note that it's 16.74 on the display.  So the log stopped a while ago. I was measuring 12V/9Ah battery discharge on a 20W car bulb, so the power gets lower with the voltage.

Then it frose like this and only turn off fixed it:
[attach=2]
The SD card log was good this time, but it was for just few hours at 10 second interval.

The android app save button didn't work. I guess it has too many records.
Title: Re: EEVBlog 121GW Discussion thread
Post by: joeqsmith on January 20, 2020, 12:45:28 am
I am not that tech savy where I need one of those cell phone things, so I can't replicate what you are seeing with the Android.   

If you had a Windows tablet with BLE, you could give that a try.   You could also try using the BLE without the SD card and see if it hangs the same way. 

Personally, if I were needing to run long tests like this and couldn't trust the equipment, I would start looking for something better. 
Title: Re: EEVBlog 121GW Discussion thread
Post by: npelov on January 20, 2020, 07:23:39 am
The hanging part has nothing to do with using the SD card and BLE at the same time. It happened before, but I don't remember the circumstances. I think it was again on VA, but I'm not sure.

You are right about the logging equipment, but the whole idea of buying this DMM is using it for it's special features - BT, SD logging, low burden voltage, and they all don't work reliably.
Title: Re: EEVBlog 121GW Discussion thread
Post by: joeqsmith on January 20, 2020, 01:09:59 pm
The hanging part has nothing to do with using the SD card and BLE at the same time. It happened before, but I don't remember the circumstances. I think it was again on VA, but I'm not sure.

You are right about the logging equipment, but the whole idea of buying this DMM is using it for it's special features - BT, SD logging, low burden voltage, and they all don't work reliably.

On the lock up, I would have to take your word for it as I have not ran any tests like this. 

Beyond the EEVBLOG brand, I didn't see a reason to buy one.  There have been a couple of years of posts about the problems with the meter,  several in regards to logging.    There have been countless firmware releases.   I'm not sure why anyone today would have confidence in the product.   

There is virtually no support outside of the people who own them.  Even simple questions seem to go unanswered.   

Think of the years it took to build the EEVBLOG brand.   I think it was sold cheap and damaged from making this deal.  My advice is for you to learn from this.   You could waste a lot of time playing around with this meter, or you could get something that fits your needs and spend your time working on your projects.   

Outside of offering to run a similar test using a full blown PC to log the data using custom software,  I am not sure what else I can do for you.   Again, this seems to be reliable but until a few months ago, I assumed they has the SD card storage sorted out.   

You should be aware that there are some major problems with the VA mode.  This was seen with the prototype and 2+ years later has yet to be addressed.   :palm:

https://www.youtube.com/watch?v=FNsPr1OEq7c (https://www.youtube.com/watch?v=FNsPr1OEq7c) 
Title: Re: EEVBlog 121GW Discussion thread
Post by: 1anX on January 20, 2020, 09:20:27 pm
Fair call Joe!

I bought one of the meters simply because it was EEVBlog branded and wanted to support Dave in his quest. I enjoy Dave's blog and forums, but I wont be buying another one of his products as the meter has not been supported in any meaningful way to rectify its numerous issues. Probably because it needs hardware revisions and re-manufacturing.

The meter does a few things well, but is not the reliable meter I turn to use for my electronics projects. The meter as you point out has not evolved much at all over the time it has been available and the firmware has not fixed the issues.

I cant call the meter a "lemon" because it does function, just not in the way I expected. The meter IMO just did not deliver on Dave's pre-production hype and the manufacturing faults did not help build confidence. I rate the EEVBlog 121GW the "lime" award, as its left a sour, lemon like taste in my mouth.

Would I buy a revised and re-manufactured version of the 121GW? I'm afraid not, as once bitten twice shy, applies for me and this product.

I would like to thank Joe Smith for all his testing of this meter and providing an unbiased data set for any potential 121GW meter buyer to use as a reference outside of the manufactures specs.


Title: Re: EEVBlog 121GW Discussion thread
Post by: npelov on January 21, 2020, 01:05:30 am
You should be aware that there are some major problems with the VA mode.  This was seen with the prototype and 2+ years later has yet to be addressed.   :palm:

If you are talking about the adding of burden voltage  - that's not a problem. Also it's only a problem if you want to measure load power. I am measuring power supply (in my case battery) power. Every measuring instrument has imperfections and as long as you know about them - you can workaround them. The problem however when it starts freezing - that's not a normal DMM flow, it's a bug.

But yes, I agree that reversing the current probes in VA mode should be in the manual - it's a nice idea how to measure load power better (not power out of the supply).
Title: Re: EEVBlog 121GW Discussion thread
Post by: CDaniel on January 21, 2020, 01:05:52 am
As I said before they underestimated the firmware complexity ... anyway for +2 years  it's impossible that more than 2 guys worked at this  ;D , or maybe one just stood and watched the other  :--
Title: Re: EEVBlog 121GW Discussion thread
Post by: joeqsmith on January 21, 2020, 02:05:35 am
You should be aware that there are some major problems with the VA mode.  This was seen with the prototype and 2+ years later has yet to be addressed.   :palm:

If you are talking about the adding of burden voltage  - that's not a problem. Also it's only a problem if you want to measure load power. I am measuring power supply (in my case battery) power. Every measuring instrument has imperfections and as long as you know about them - you can workaround them. The problem however when it starts freezing - that's not a normal DMM flow, it's a bug.

But yes, I agree that reversing the current probes in VA mode should be in the manual - it's a nice idea how to measure load power better (not power out of the supply).

If this were true, you would not be posting here for help.   I'm not aware of any other workarounds beyond the one I mentioned.  You could wait for the next firmware, or the one after that, or after that.......   Looking at the release dates, it seems they are winding down.    With David2 now out of the picture, I doubt you will see much effort being put into the application side.    Good luck.
Title: Re: EEVBlog 121GW Discussion thread
Post by: joeqsmith on January 21, 2020, 02:33:19 am
As I said before they underestimated the firmware complexity ... anyway for +2 years  it's impossible that more than 2 guys worked at this  ;D , or maybe one just stood and watched the other  :--

It's not just the firmware.   The meter is less robust now than it was with the original front end design.  Sadly, I think a few of us were aware of that before I even ran the test.  Maybe they finally have a handle on the switch but honestly, I doubt it.    These are basic things that I would expect the designers to have sorted out before the first meter was ever produced.   
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on January 21, 2020, 04:19:38 am
With David2 now out of the picture, I doubt you will see much effort being put into the application side.

That was never the plan. We got the app to a good refined working point and released it as fully open source software. If people want to improve upon it and add features they can, but we never had any plans to extend it ourselves beyond what it already is.
Title: Re: EEVBlog 121GW Discussion thread
Post by: joeqsmith on January 21, 2020, 05:18:00 am
With David2 now out of the picture, I doubt you will see much effort being put into the application side.

That was never the plan. We got the app to a good refined working point and released it as fully open source software. If people want to improve upon it and add features they can, but we never had any plans to extend it ourselves beyond what it already is.

From your comment, it seems as the development had stopped prior to David2 leaving.  The MS store shows a release date of 2/28/2018.  When I made that video showing how poorly it worked with my touchscreen tablet, I had the latest software.    At least I now know not to expect any further improvements.   
Title: Re: EEVBlog 121GW Discussion thread
Post by: Brumby on January 21, 2020, 05:54:08 am
Why criticise the original plan?  It's not as if Dave kept it secret.  Besides, as Dave has stated, software isn't his forte.

All we need is for others who are better equipped to develop the App to take up the challenge.  Then things can improve.
Title: Re: EEVBlog 121GW Discussion thread
Post by: npelov on January 21, 2020, 11:17:31 am
The app is not the biggest deal. If the firmware is working fine there will be someone to develop an app. If the firmware is not working there is no point of developing an app.


If this were true, you would not be posting here for help.

I'm not posting here for help. I'm reporting bugs. I payed for the DMM because I think it's a great idea. I still want it, so I'm doing what I can to help fixing the bugs. It doesn't help that they didn't open source the firmware. The problem is that the more bugs, the less Dave sells the DMM -> the less interest the Korean guys have in fixing the bugs.

Here is my observations on the 500mA current offset:
When I noticed the offset it was quite big - 0.65mA and it was slowly drifting down. It took about 2-3 minutes to drop down to 0. Now here is the strange part. When I move the probe to mA/uA socket the decimal place moves, but the offset stays in the same place on the screen - 0.65mA becomes 0.0065mA (that's the 5mA range I guess). And while it was drifting down I moved the probe between the A and mA/uA socket - the last two digits were almost the same and drifting down with the same speed - when it was 0.20 mA it became 0.0020mA on the other socket. It looks like this offset is closer to the ADC (or the firmware) rather than the front end.
The problem is that it eventually dropped down to zero and no matter what I did I couldn't make it rise (including turning off, switching ranges etc.).

One strange thing was that I moved the probes to A while it was still on 12V battery (switched to volts). Because the beep takes a second to start it took me 2-3 seconds to remove it. So I thought the fuse is gone. I guess there is some mosfet switching going on because the fuse if fine (Like Dave explained in the low burden video). Like I said this dmm was a great idea, but I think the wrong company manufactured it.
Title: Re: EEVBlog 121GW Discussion thread
Post by: joeqsmith on January 21, 2020, 01:20:29 pm
Why criticise the original plan?  It's not as if Dave kept it secret.  Besides, as Dave has stated, software isn't his forte.

All we need is for others who are better equipped to develop the App to take up the challenge.  Then things can improve.

All I am saying is that a little feedback goes a long way.  If the software was the final release and there wasn't going to be any further updates, change your MS store to reflect that.  If you're selling old revision of the meter when newer ones have been released, change your store to make a note of it.   


The app is not the biggest deal. If the firmware is working fine there will be someone to develop an app. If the firmware is not working there is no point of developing an app.

Does this mean if the hardware is not working, there is no point of developing firmware?


If this were true, you would not be posting here for help.

I'm not posting here for help. I'm reporting bugs.

I thought in your first post,
Quote
Is there any way to log data with this DMM in a stable way?
you were asking for help.   My bad.  There is a thread to report bugs. 


Title: Re: EEVBlog 121GW Discussion thread
Post by: e0ne199 on January 21, 2020, 03:37:33 pm
i am starting to think that every new firmware released depends on how many 121GW are sold to the customers...i always believe that 121GW is actually a very good product... the real problem lies only in the firmware which is still not open source...if the source code is given to this forum members i believe that 99% of the bugs will be fixed asap

anyway i also have the logging problem, either using android app or using SD card....for android, when i use the logging feature for about 30 mins through bluetooth the app suddenly freezes and stops logging the data although the 121GW still runs with no problems.... as for logging using SD card, the problem is the same as what several forum members here mentioned before
Title: Re: EEVBlog 121GW Discussion thread
Post by: dcac on January 21, 2020, 04:38:04 pm
https://www.eevblog.com/forum/blog/eevblog-1157-transistor-zener-clamp-circuit/msg2043871/#msg2043871 (https://www.eevblog.com/forum/blog/eevblog-1157-transistor-zener-clamp-circuit/msg2043871/#msg2043871)
https://www.eevblog.com/forum/blog/eevblog-1157-transistor-zener-clamp-circuit/msg2037994/#msg2037994 (https://www.eevblog.com/forum/blog/eevblog-1157-transistor-zener-clamp-circuit/msg2037994/#msg2037994)

Here are Dr Franks’s posts he made just after Dave released his video discussing the advantage of the double transistor zener type clamp, and that this now would be implemented in 121gw.

Now there’s nothing wrong with Dave’s video as such, I think he does a great job presenting it. But it’s very hard to see how Dr Frank could have made it any clearer that this clamp solution would not work as transients at +/- 25V now could reach U9 the HEF4053. Although it of course depends on exactly how you implemented this new clamp, U9 would have a very hard time handling these voltages. There were also quite a few other members in that thread voicing their concerns.

Still the clamp change went ahead and new HW revision of 121gw released, and it seems it‘s this revision Joe received with the two production meters he recently bought. And anyone following Joe’s videos knows exactly how well this new clamp worked.

Anyway, I guess this also is an example of the (broken) “information age” we now live in, but still it’s things like this that's really frustrating as a 121gw owner, seeing perfectly valid and detailed feedback not really be taking into account.

Title: Re: EEVBlog 121GW Discussion thread
Post by: Dr. Frank on January 21, 2020, 05:32:40 pm
https://www.eevblog.com/forum/blog/eevblog-1157-transistor-zener-clamp-circuit/msg2043871/#msg2043871 (https://www.eevblog.com/forum/blog/eevblog-1157-transistor-zener-clamp-circuit/msg2043871/#msg2043871)
https://www.eevblog.com/forum/blog/eevblog-1157-transistor-zener-clamp-circuit/msg2037994/#msg2037994 (https://www.eevblog.com/forum/blog/eevblog-1157-transistor-zener-clamp-circuit/msg2037994/#msg2037994)

Here are Dr Franks’s posts he made just after Dave released his video discussing the advantage of the double transistor zener type clamp, and that this now would be implemented in 121gw.

Now there’s nothing wrong with Dave’s video as such, I think he does a great job presenting it. But it’s very hard to see how Dr Frank could have made it any clearer that this clamp solution would not work as transients at +/- 25V now could reach U9 the HEF4053. Although it of course depends on exactly how you implemented this new clamp, U9 would have a very hard time handling these voltages. There were also quite a few other members in that thread voicing their concerns.

Still the clamp change went ahead and new HW revision of 121gw released, and it seems it‘s this revision Joe received with the two production meters he recently bought. And anyone following Joe’s videos knows exactly how well this new clamp worked.

Anyway, I guess this also is an example of the (broken) “information age” we now live in, but still it’s things like this that's really frustrating as a 121gw owner, seeing perfectly valid and detailed feedback not really be taking into account.

In case that Dave really has implemented the FLUKE clamp as described in his videos, it's quite obvious, that this would fail.. and I also think that I have explained it reasonably well...but no feedback from Dave so far.

On the other hand, I would have expected that Joe might have re-engineered and analysed the actual protection circuit, either for confirmation or disproof of my findings .. instead he just did his brute-force / destructive tests on the 121GW.
Again, I'm no real friend of these tests, as they do not really comply to the usual test standards, therefore I also do not share his totally negative conclusions in full depth.

His findings about the faulty over-voltage / HV warning indication I fully support.

When I participated on the Kickstarter campaign, I was never expecting to get a fully professional and perfect DMM, so I'm not disappointed at this point in time at all.
I simply call it my 'Dave-O-Meter', so I have to admit that I also bought it, because it's from Dave and it's got the eevblog logo on it.

But in daily use, it's got several very practical and very well working features, like data logging via BT and on battery operation, which the other of my much higher grade DMMs don't have, so I'm really appreciating this instrument. 

I've found and reported many bugs on this instrument, so please don't call me a fan-boy, like I also found many bugs as well in the past on professional equipment like the 3458A or the 344465A.
Maybe some guys here shouldn't be too super-critical, because they simply had too high expectancy upfront.

Frank
Title: Re: EEVBlog 121GW Discussion thread
Post by: joeqsmith on January 21, 2020, 06:17:05 pm
Maybe some guys here shouldn't be too super-critical, because they simply had too high expectancy upfront.

The feedback I often receive is something to the effect:

We been watching Dave's videos for years.  He is very critical of every meter he looks at, depending on the brand.  We are expecting his meter to not have the problems he rants about in his videos.   

Of course the problem with this is that they see what he has released and I think the question is, why is it now alright to sell a product that you would normally not spend the time to review. 

Quote
On the other hand, I would have expected that Joe might have re-engineered and analysed the actual protection circuit, either for confirmation or disproof of my findings .. instead he just did his brute-force / destructive tests on the 121GW.
I had invested a fair amount of time looking at the prototype.  It seems that most of what I pointed out was ignored.  It really made no sense to revisit how to improve it yet again as based on past history, I already knew what the end result would be. 

https://www.youtube.com/watch?v=lb_M7rCRoW4 (https://www.youtube.com/watch?v=lb_M7rCRoW4)
Title: Re: EEVBlog 121GW Discussion thread
Post by: dcac on January 21, 2020, 09:00:48 pm
But Dave did change things, after it became clear that using 4007 clamp diodes with leakage in uA range wasn’t a good idea if you want to measure resistance using 20nA as reference and you don’t want the measurement to drift too much with temperature changes.

Title: Re: EEVBlog 121GW Discussion thread
Post by: joeqsmith on January 22, 2020, 01:14:07 pm
If you looked at those last couple of posts of that UL listed TPI meter I showed, there are no MOVs and the meter was easily damaged.   I assume they don't need all the MOVs and fluff for UL be cause the meter does not need to be robust.  It needs to be safe.    This is the difference between what Frank is mentioning with following the standards.   There are no robustness standards so rather than follow the safety standards, I branched out on my own to look at their robustness.     

In the 121, it's anyone's guess what their goals were for robustness.  I am guessing something along the lines of UNI-Tish was good enough.  But they include the MOVs and basic parts.   

So while they did make a change, they didn't consider the impact it would have on how robust the meter was.  Or maybe they did and that was a very low priority.  Your guess is as good as mine.  One thing is certain is that it's now on par with many UNI-T products I have looked at. 
Title: Re: EEVBlog 121GW Discussion thread
Post by: CDaniel on January 22, 2020, 04:56:43 pm
For 50 ohm range I thought that thermistors are the cause for the last 2 digits drift ... if I heated with my finger  ...  then I replace them with wires and surprise , the drift was the same . At the ridiculous low current for measurement and hi-gain , every solder joint in the signal path is generating enough thermovoltage .
I don't say it's the same for mV range but could be .
Title: Re: EEVBlog 121GW Discussion thread
Post by: dcac on January 22, 2020, 06:57:55 pm
If you looked at those last couple of posts of that UL listed TPI meter I showed, there are no MOVs and the meter was easily damaged.   I assume they don't need all the MOVs and fluff for UL be cause the meter does not need to be robust.  It needs to be safe.    This is the difference between what Frank is mentioning with following the standards.   There are no robustness standards so rather than follow the safety standards, I branched out on my own to look at their robustness.     

In the 121, it's anyone's guess what their goals were for robustness.  I am guessing something along the lines of UNI-Tish was good enough.  But they include the MOVs and basic parts.   

So while they did make a change, they didn't consider the impact it would have on how robust the meter was.  Or maybe they did and that was a very low priority.  Your guess is as good as mine.  One thing is certain is that it's now on par with many UNI-T products I have looked at.

As we know UEi already changed the design again, now using transistors with a VEB0 at about 16V and that will clamp close to this voltage instead of 25V as your production 1-2 probably had. And as manufactures usually aren't changing their design just for the fun of it, they at least seems to be trying for some level of ‘robustness’.

Title: Re: EEVBlog 121GW Discussion thread
Post by: joeqsmith on January 23, 2020, 12:52:52 am
If you looked at those last couple of posts of that UL listed TPI meter I showed, there are no MOVs and the meter was easily damaged.   I assume they don't need all the MOVs and fluff for UL be cause the meter does not need to be robust.  It needs to be safe.    This is the difference between what Frank is mentioning with following the standards.   There are no robustness standards so rather than follow the safety standards, I branched out on my own to look at their robustness.     

In the 121, it's anyone's guess what their goals were for robustness.  I am guessing something along the lines of UNI-Tish was good enough.  But they include the MOVs and basic parts.   

So while they did make a change, they didn't consider the impact it would have on how robust the meter was.  Or maybe they did and that was a very low priority.  Your guess is as good as mine.  One thing is certain is that it's now on par with many UNI-T products I have looked at.
As we know UEi already changed the design again, now using transistors with a VEB0 at about 16V and that will clamp close to this voltage instead of 25V as your production 1-2 probably had. And as manufactures usually aren't changing their design just for the fun of it, they at least seems to be trying for some level of ‘robustness’.

I did offer to run one of the new designs.   I have a feeling there is not a lot of confidence and honestly, I think for good reason.   I test both +/-.   Clamps are not a stead fast number.   Again, the reason I went to the mux they have in there today.   The margins are very tight but it could be protected if that were a goal.   
Title: Re: EEVBlog 121GW Discussion thread
Post by: dcac on January 24, 2020, 03:16:27 pm
A basic robustness test I’ve seen Dave use a couple of times is to put mains 240VAC into whatever mode the mode switch can be placed in, perhaps for a couple of seconds or so. I do my damndest trying to avoid doing a “mistake” like that. But still not an unreasonable test to do and see if the meter survives. So in this scenario the meters clamps, PTC’s and other input series resistors have to cope with the stress resulting from about 340V peak to peak, there can of course be some nasty overlayed transients on top of that but unless you’re monitoring the VAC with a scope you have no clue if this is the case.

Anyway, I can’t really remember if Dave also did this test on the 121gw, but I think so, in its original configuration anyway with the 4007‘s. But has he also done it with the new clamp configuration i.e. to show that it’s just as robust as it was before. If it isn't perhaps mentioning this in the next user manual revision is a good idea.

Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on January 25, 2020, 12:20:30 am
A basic robustness test I’ve seen Dave use a couple of times is to put mains 240VAC into whatever mode the mode switch can be placed in, perhaps for a couple of seconds or so. I do my damndest trying to avoid doing a “mistake” like that. But still not an unreasonable test to do and see if the meter survives. So in this scenario the meters clamps, PTC’s and other input series resistors have to cope with the stress resulting from about 340V peak to peak, there can of course be some nasty overlayed transients on top of that but unless you’re monitoring the VAC with a scope you have no clue if this is the case.
Anyway, I can’t really remember if Dave also did this test on the 121gw, but I think so, in its original configuration anyway with the 4007‘s. But has he also done it with the new clamp configuration i.e. to show that it’s just as robust as it was before. If it isn't perhaps mentioning this in the next user manual revision is a good idea.

Yes, done that (245VAC) countless times on every design variant.
I also do +/-1100V DC and 1100V AC as well, but both of my high voltage supplies will go into current limit mode when the meter is on the ohms range.
Survives all this just fine.
Title: Re: EEVBlog 121GW Discussion thread
Post by: dcac on January 25, 2020, 03:59:22 pm
A basic robustness test I’ve seen Dave use a couple of times is to put mains 240VAC into whatever mode the mode switch can be placed in, perhaps for a couple of seconds or so. I do my damndest trying to avoid doing a “mistake” like that. But still not an unreasonable test to do and see if the meter survives. So in this scenario the meters clamps, PTC’s and other input series resistors have to cope with the stress resulting from about 340V peak to peak, there can of course be some nasty overlayed transients on top of that but unless you’re monitoring the VAC with a scope you have no clue if this is the case.
Anyway, I can’t really remember if Dave also did this test on the 121gw, but I think so, in its original configuration anyway with the 4007‘s. But has he also done it with the new clamp configuration i.e. to show that it’s just as robust as it was before. If it isn't perhaps mentioning this in the next user manual revision is a good idea.

Yes, done that (245VAC) countless times on every design variant.
I also do +/-1100V DC and 1100V AC as well, but both of my high voltage supplies will go into current limit mode when the meter is on the ohms range.
Survives all this just fine.

[attachimg=1]

There are many manufactures of the 4053 type mux, all with slightly different spec. but they all seem to quote this +/- 10mA as absolute maximum input current.

As I understand it, in the original 121gw with 4007's diode clamps, this would have limited the current to just around those 10mA as you'd have about 1V over the diodes and then R82 100 ohms resistor in series with the mux input.

But with the transistor type clamps that i.e. Joe’s production 1-2 had, the current into the mux can be as much as 250mA, so way over the suggested limit by the manufactures.

So it seems even if the mux ‘survives’ an over current event, you have no idea if it will do so the next time or if it perhaps has degraded its performance in other aspects.

I my experience integrated type diode clamps, like the ones in the 4053 mux are very rarely precisely specified as to what current they really can withstand or for how long. I think you’re actually not even to regard them as 'clamping’ diodes.

Title: Re: EEVBlog 121GW Discussion thread
Post by: joeqsmith on January 25, 2020, 05:37:01 pm
Someone's digging in...

Something to keep this in mind is there are other difference between what Dave sold me and the last schematics besides removing the two diodes and changing to the transistor clamp.   Off the top of my head, I know the 10ohm was removed.    I was hoping they would supply an up to date schematic.   

Because they have even newer hardware, there really wasn't much point in reversing what I purchased as the new may have other changes beyond the clamp. 
Title: Re: EEVBlog 121GW Discussion thread
Post by: dcac on January 25, 2020, 07:37:31 pm
No not really...

I’m just perplexed, like I think many 121gw owners are. Mostly perhaps as you mentioned by the lack of information.

And just to be clear I’m not trying to put any blame on Dave, I’ve no idea what deal he has with UEi, but I got a feeling he’s not really in a position to put any pressure on them or is free to release information as he pleases. And this seems to leave quite a gap between 121gw users and the manufacture.

But I am interested in what clamping solution can be used instead of the leaky 4007's. Perhaps specially selected TVS diodes could be an option after all.
Title: Re: EEVBlog 121GW Discussion thread
Post by: joeqsmith on January 25, 2020, 08:05:03 pm
For the prototype,  I clamped it on the other side of R82.    The resistor limits the current to the mux.  I did have a TVS across the mux's supply but again, my goal wasn't to achieve anything outside of seeing what the next failure point would be.  In other words, protect that mux at all cost.   

Again, that prototype has some different circuits.   U9 used to be supplied for VDD through D9, or through R81 when U10 was active.   I noticed R81 was missing and assumed they power it another way.  I would see if you can get your hands on the version they are now selling and reverse engineer the design.  Then you could take look at how to protect  it based on your personal goals. 
Title: Re: EEVBlog 121GW Discussion thread
Post by: e0ne199 on January 26, 2020, 12:11:33 am
No not really...

I’m just perplexed, like I think many 121gw owners are. Mostly perhaps as you mentioned by the lack of information.

And just to be clear I’m not trying to put any blame on Dave, I’ve no idea what deal he has with UEi, but I got a feeling he’s not really in a position to put any pressure on them or is free to release information as he pleases. And this seems to leave quite a gap between 121gw users and the manufacture.

But I am interested in what clamping solution can be used instead of the leaky 4007's. Perhaps specially selected TVS diodes could be an option after all.

probably dave cannot control that meter development at all and after all it is just a UEi meter with EEVBLOG logo sticking on it to make people belive that it is dave who designed it.. cmiiw
Title: Re: EEVBlog 121GW Discussion thread
Post by: jancumps on January 26, 2020, 12:19:48 am
There are several videos discussing design decision between UEi and Dave.
Title: Re: EEVBlog 121GW Discussion thread
Post by: dcac on January 26, 2020, 01:32:54 am
No not really...

I’m just perplexed, like I think many 121gw owners are. Mostly perhaps as you mentioned by the lack of information.

And just to be clear I’m not trying to put any blame on Dave, I’ve no idea what deal he has with UEi, but I got a feeling he’s not really in a position to put any pressure on them or is free to release information as he pleases. And this seems to leave quite a gap between 121gw users and the manufacture.

But I am interested in what clamping solution can be used instead of the leaky 4007's. Perhaps specially selected TVS diodes could be an option after all.

probably dave cannot control that meter development at all and after all it is just a UEi meter with EEVBLOG logo sticking on it to make people belive that it is dave who designed it.. cmiiw

I know you're joking, but.

Just to be even clearer, I don't think Dave is in a position to put pressure on UEi to fix things, that is i.e. to make them fix problems with the meter's basic functionality. Like this logging issues people are having, or the worrisome high voltage ranging and warning issue. Just to name a couple (lol).

Title: Re: EEVBlog 121GW Discussion thread
Post by: joeqsmith on January 26, 2020, 02:01:42 am
I had looked up the Intertek cert.  Looks like more than UEi are involved. 
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on January 26, 2020, 08:25:52 am
I had looked up the Intertek cert.  Looks like more than UEi are involved.

Kane own UEi and Finest.
The meter was designed and is manufactured by Finest in South Korea. UEi is basically the US brand they bought in 1992, and Finest is the Asian brand they recently acquired.
Title: Re: EEVBlog 121GW Discussion thread
Post by: joeqsmith on January 26, 2020, 04:13:37 pm
I tried to look up the IN address.    Maybe a rented office of sorts.
Title: Re: EEVBlog 121GW Discussion thread
Post by: joeqsmith on January 26, 2020, 04:24:17 pm
UEi also appears to have a brand in IN.  It's at a different address than what was listed.  Maybe a warehouse?   

Dave had mentioned about working with someone in the USA to design it.  Maybe the design house is in Portland.
Title: Re: EEVBlog 121GW Discussion thread
Post by: joeqsmith on January 26, 2020, 04:31:13 pm
Looking at the address Dave provided,  maybe the shipping and receiving warehouses.
Title: Re: EEVBlog 121GW Discussion thread
Post by: joeqsmith on January 26, 2020, 04:37:38 pm
Maybe Fine Instruments Corp is not the same as Finest.   Looks like an apartment building rather than a manufacturing house. 

Makes me wonder where the meters were produced.  Judging by some of the soldering, maybe they were made in an apartment. 
Title: Re: EEVBlog 121GW Discussion thread
Post by: dcac on January 26, 2020, 07:37:23 pm
My KS #924 121gw meter is reasonable well built, just had to clean up some flux residues. So perhaps it was manufactured before they moved to the apartment.

I’ve also removed the pre-installed shim as Joe’s videos seemed to show this actually could cause more problems than it solved. When I removed it I also wanted to clean the PCB switch area as I noticed how incredible tight the switch holder hub was rotating in the PCB hole. it had even started to grind of some fiberglass dust that had contaminated the switch area. And my meter has not been used much at all, in fact mostly used for testing and hacking the FW as I feel the problems with this is simply making the meter too unreliable. But anyway, the switch was easy enough to clean up and I also gave the PCB hole a slight polish with a fine sandpaper to make it rotate more freely.

The switch now feels and sounds much better than before. And as long as it doesn’t get contaminated by more of this dust I think the contact pressure will be just fine.
Title: Re: EEVBlog 121GW Discussion thread
Post by: dcac on January 26, 2020, 11:36:23 pm
I had looked up the Intertek cert.  Looks like more than UEi are involved.

Kane own UEi and Finest.
The meter was designed and is manufactured by Finest in South Korea. UEi is basically the US brand they bought in 1992, and Finest is the Asian brand they recently acquired.

I’ve seen a few Finest and UEi branded multimeters and noticed the resemblance.

(https://img.yumpu.com/50633897/1/500x640/model-816-ev-amp-hev-automotive-dmm-fine-instruments-corp.jpg)
(https://img.yumpu.com/27456964/1/500x640/manual-uei-automotive.jpg)


But with the 121gw and how it was presented I always got the impression UEi was the actual manufacture and responsible for the FW updates. But of course doesn’t really matter. But it would be interesting to know if the KS meters and the 121gw that's being sold now were manufactured in the same factories.

Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on January 27, 2020, 07:15:00 am
But with the 121gw and how it was presented I always got the impression UEi was the actual manufacture and responsible for the FW updates. But of course doesn’t really matter. But it would be interesting to know if the KS meters and the 121gw that's being sold now were manufactured in the same factories.

Yes, same factory.
I'm not sure why the fuss over this. Companies in this sort of industry often have lots of complex relationships with part ownerships and branding etc.
I can assure you that the design and manufacturing has always been and is still done in South Korea by (formally) Finest (Fine Instrument Co) who is now wholly owned by Kane Test. They don't really use the finest brand any more that I am aware of, legally it's "Kane Asia" and that's who my purchase orders go to.
http://kanetest.co.kr/contact/ (http://kanetest.co.kr/contact/)
My point of contact for the design is the former CEO of Finest Instruments who now works for Kane Asia.
UEi are also another brand of Kane Test, and that is the brand they wanted associated with publicly for the project from day one, but that's the extent of "UEi" involvement with this project.
A lot of UEi stuff used Finest as the OEM, while other UEi stuff is designed and made in the USA.
If you want to go deeper down the rabbit whole, Klein Tools owned (or did own?) 50% of UEi, and that's actually how this whole thing started, I was talking to the head designer at Klein tools and down the rabbit whole it went to eventually Finest. They are all intertwined.
Title: Re: EEVBlog 121GW Discussion thread
Post by: dcac on January 27, 2020, 04:13:33 pm
But with the 121gw and how it was presented I always got the impression UEi was the actual manufacture and responsible for the FW updates. But of course doesn’t really matter. But it would be interesting to know if the KS meters and the 121gw that's being sold now were manufactured in the same factories.

Yes, same factory.
I'm not sure why the fuss over this. Companies in this sort of industry often have lots of complex relationships with part ownerships and branding etc.
I can assure you that the design and manufacturing has always been and is still done in South Korea by (formally) Finest (Fine Instrument Co) who is now wholly owned by Kane Test. They don't really use the finest brand any more that I am aware of, legally it's "Kane Asia" and that's who my purchase orders go to.
http://kanetest.co.kr/contact/ (http://kanetest.co.kr/contact/)
My point of contact for the design is the former CEO of Finest Instruments who now works for Kane Asia.
UEi are also another brand of Kane Test, and that is the brand they wanted associated with publicly for the project from day one, but that's the extent of "UEi" involvement with this project.
A lot of UEi stuff used Finest as the OEM, while other UEi stuff is designed and made in the USA.
If you want to go deeper down the rabbit whole, Klein Tools owned (or did own?) 50% of UEi, and that's actually how this whole thing started, I was talking to the head designer at Klein tools and down the rabbit whole it went to eventually Finest. They are all intertwined.

Thanks for the information Dave. it was just there’s been all this talk of UEi and now this Finest name suddenly was mentioned. So again thanks for clearing that up, how that name relates to the 121gw. And that the factory who’s actually making the 121gw is still the same.
Title: Re: EEVBlog 121GW Discussion thread
Post by: joeqsmith on January 28, 2020, 01:11:47 pm
No fuss.  Just curious what their factory looked like to see what sort of capabilities they have.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on January 28, 2020, 09:59:24 pm
No fuss.  Just curious what their factory looked like to see what sort of capabilities they have.

I don't think I have any photos inside.
Kane Asia is somewhere in here:
Title: Re: EEVBlog 121GW Discussion thread
Post by: DavidWC on March 07, 2020, 10:33:10 am
To anyone interested:

I've written an independent, third-party Android app for the 121GW called "Meteor".  It is a free app and you can get it from the Google Play Store:

https://play.google.com/store/apps/details?id=com.westerncomputational.meteor

It was designed to look and function much like the official EEVBlog app, with a few additions:

* Control buttons in landscape mode
* Long-press on control buttons to get alternate functions
* Option for spoken measurements (using Android voice synthesizer)
* Option for continuity tone and/or vibration
* Dark mode option
* Connect/disconnect button and connection-status label

There are a couple of features that the EEVBlog app has that Meteor doesn't (yet):

- Does not support two connected meters or math mode
- Does not capture or log measurements

As with all Android BLE apps, there is no guarantee that Meteor will work with your particular phone.  Try it out and see, especially if you've had trouble connecting with the EEVBlog app.  If you don't see your meter in the scan list, make sure it's not already connected to another phone or computer.   Turning the meter's BLE off and back on (with the 1ms button) can help, as can turning your phone's BLE off and back on again (in the Android Settings app).  Note that you will also have to grant Meteor location permissions on your phone, since Android requires this to scan for nearby BLE devices.

I've also written and released an iOS version, which I recently updated to v0.2:

https://apps.apple.com/us/app/meteor-for-121gw/id1452124710

This version adds automatic, continuous datalogging, so now any measurement you receive while connected with the app is automatically recorded for later export.  You can limit the number of samples recorded, or turn off logging, using the Settings page.  This version also adds some display options and fixes some bugs in some of the VA meter modes.

Both of these apps are still under development and should be considered beta quality.  Meteor is something of a testbed for my development on other BLE projects, so bug reports and feature suggestions are always welcome: support@westerncomputational.com.

Regards,
David Lavo
david@westerncomputational.com
Title: Re: EEVBlog 121GW Discussion thread
Post by: pppopol on March 07, 2020, 04:50:06 pm
Hi DavidWC,

Thank you for this development of APPS which seems interesting.
But I have a problem.
The APP works 1/2 second, and closes immediately?
My Bluethoot is activated, as is my location.
I have firmware V2.02 on my 121GW.
Do you have any idea how to fix this problem?

Regards
Title: Re: EEVBlog 121GW Discussion thread
Post by: bateau020 on March 07, 2020, 07:48:01 pm
@DavidWC also any chance you'd be able to create a MacOS app for logging?
Or anyone else, does that kind of app exist?

My reasons:

I would like to have logging to a desktop device. Don't need anything else like interaction with the meter or graphical stuff. Command line suffices, as long as it writes in a structured format.
So in all, I now have to dig up a "real" windows machine to get the logging to a desktop device.

Not ideal.
Title: Re: EEVBlog 121GW Discussion thread
Post by: DavidWC on March 07, 2020, 11:21:48 pm
The APP works 1/2 second, and closes immediately?
This sounds like a crash, and definitely should not happen.  Which version is this - the iOS or the Android version?
Title: Re: EEVBlog 121GW Discussion thread
Post by: beanflying on March 07, 2020, 11:25:12 pm
Downloaded to my S7 from the store. Turned on the 121GW enabled BT, started the software and it happily found hooked up and ran  :-+

The ability to capture Logs is a must in your no doubt vast quantities of 'spare time'  ;)

Also important will be the ability to clear the data from the log or trigger a start of logging. Not sure what is possible but maybe even optional logging against the devices clock instead of the meters?

The pinch zoom vertically works fairly well but having the option or being able to show from the start of logging stay on screen would be great too rather than continual scrolling. That is assuming I didn't find a pinch zoom for that option that already exists?

 :-+ :-+ from me so far
Title: Re: EEVBlog 121GW Discussion thread
Post by: DavidWC on March 08, 2020, 01:29:52 am
@DavidWC also any chance you'd be able to create a MacOS app for logging?

A native Mac app (from scratch) would probably be a lot of work, but I can look into a "Catalyst" port, which is supposed to allow you to (relatively) quickly port an iPhone/iPad app to MacOS.  But you'd have to be running the latest version of MacOS, which is Catalina.

If you have a relatively-recent Mac and can run Meteor on an iPhone, capturing the data in the app and then using AirDrop to send them to the Mac is only one extra step and relatively painless.  That's how I do it now for my own data.

The ability to capture Logs is a must in your no doubt vast quantities of 'spare time'  ;)

Also important will be the ability to clear the data from the log or trigger a start of logging. Not sure what is possible but maybe even optional logging against the devices clock instead of the meters?

The pinch zoom vertically works fairly well but having the option or being able to show from the start of logging stay on screen would be great too rather than continual scrolling. That is assuming I didn't find a pinch zoom for that option that already exists?

Adding logging to the Android app is next on my list.  You can look at the iPhone version (or screenshots in the App Store) to see how it's implemented.  Not everybody will love this approach, since it logs every measurement the app receives, and creates a new data set for every new mode you switch to on the meter.  This can cause some clutter in the Data view, but I wanted it to be thorough.  I'll take your advice and add a "clear" button at the top, along with a "pause" button for people who want to turn logging on and off at will.

Regarding the graphing, I'm using an open-source third-party library called "Charts" (on iOS) and "MPAndroidChart" (on Android).  I'm using both pretty much out-of-the-box, except for axis labeling, but there are a lot of options for formatting and interaction.  I agree that there should be an easy way to "reset" the graph to show all data points, either a double tap or a two-finger tap or similar.  I will look into this for the next version.

Thanks for all the suggestions!
Title: Re: EEVBlog 121GW Discussion thread
Post by: pppopol on March 08, 2020, 10:14:25 am
Hi DavidWC,

I'm on Android 9, and GSM is a Samsung Galaxy S8 ( SM-G950F )

Regards
Title: Re: EEVBlog 121GW Discussion thread
Post by: DavidWC on March 08, 2020, 11:30:31 am
Hi DavidWC,

I'm on Android 9, and GSM is a Samsung Galaxy S8 ( SM-G950F )

Ok,

If this is a crash caused by a bug (or mis-configuration) in Meteor, then if you have "Share usage & diagnostic data" (usually in Privacy Settings) turned on in your phone then I will eventually get a crash report from Google.  This can take a few days, however, so in the meantime you can try:

1. Restart your phone by holding the power button and choosing either "Restart" or "Power Off" (and then power back on).  After the phone restarts, try Meteor again and see if you get the same result.  The idea here is to clear out state and any memory-exhaustion issues.

2. If that doesn't work, uninstall Meteor from your phone, either in Settings, Apps & Notifications, or by tapping and holding on the icon and choosing "Uninstall" (or drag to trashcan icon).

3. Restart your phone again, if you have the patience for it.

4. Check to see if the "Share usage & diagnostic data" is turned on in Settings.  Also, while you're in Settings, check the Storage section to make sure your phone has at least a few MB free.  Meteor doesn't use much space, but Android will kill new apps if it feels constrained.

5. Go to the Google Play Store and download and re-install Meteor again.  Cross your fingers and try running the app again.  If it crashes, then eventually I should get a crash report and be able to debug the problem.

Anyway, I'm sorry to hear that you're experiencing problems running the app.  I'd be happy to continue trying to help you out, and I'd like to figure out what the problem is, but I don't want to pollute this message board with too much diagnostics.  If you want to keep working on it, please send me an email at support@westerncomputational.com (or david@westerncomputational.com) and I'll try to think of something else to try.
Title: Re: EEVBlog 121GW Discussion thread
Post by: DavidWC on March 09, 2020, 04:48:43 am
So I had another Android Meteor tester report a strange launch issue, where upon first launch the app displayed a mostly-blank splash screen with a message like "Hello World" or "Welcome to Android".  This is definitely not the intended behavior, and that screen (and text) don't appear anywhere in my code.

The only explanation I can think of for this bizarre behavior is that I was using "App Bundling" from the Google Play Store, where the app is actually not built until a user downloads it.  Perhaps this process had a problem building in my desired splash screen and instead substituted a generic replacement?

Anyway, I've jettisoned the App Bundle idea and gone back to building and submitting a traditional APK to the Play Store.  To pppopol and anybody else who experienced strange behavior on launch, please visit the Play Store and get the update (version 0.1.1) and try it out.

The intended behavior on launch should be a blue splash screen with the Meteor logo and text.  Then, you should get a request to grant location permission for scanning for nearby 121GW meters.  If granted, you should then see the device-scan screen, and if a meter is on and nearby (with BT on) you should see that meter listed.  The whole sequence is demonstrated with screenshots below.

I apologize if you've had trouble trying out the app, but please report any issues - and send any suggestions - to support@westerncomputational.com.  Thanks for trying this out, despite the teething pains ....

[attachimg=1]
Title: Re: EEVBlog 121GW Discussion thread
Post by: bateau020 on March 09, 2020, 04:09:18 pm
If you have a relatively-recent Mac and can run Meteor on an iPhone, capturing the data in the app and then using AirDrop to send them to the Mac is only one extra step and relatively painless.  That's how I do it now for my own data.

Understood. I just bit the bullet and whipped together a small command line MacOS app capable of logging the 121GW data (and nothing more). Translating the stream was the hardest, as the documentation is not really great. Might put that on github if people want to see it.
Title: Re: EEVBlog 121GW Discussion thread
Post by: VK5RC on March 10, 2020, 11:38:43 am
Works a treat for me! Samsung s9, android v 10. Quick Bluetooth recognition, connected reasonably well. I really appreciate your work, thanks. Rob
Title: Re: EEVBlog 121GW Discussion thread
Post by: pppopol on March 11, 2020, 04:51:18 pm
That's work for me too, on French Androïd and after technical support by David imself.

Thank-you for this apps David !
Title: Re: EEVBlog 121GW Discussion thread
Post by: CkeKchy on March 17, 2020, 05:03:48 am
With David2 now out of the picture, I doubt you will see much effort being put into the application side.

That was never the plan. We got the app to a good refined working point and released it as fully open source software. If people want to improve upon it and add features they can, but we never had any plans to extend it ourselves beyond what it already is.

At  https://sigrok.org/wiki/EEVBlog_121GW   "The meter is announced as having "hackable firmware" but its source code is not available and probably never will. Alternative OpenSource firmware is possible but would have to start at square one. There are connector pads to program the MCU and the BLE module. "   

Pardon, if I missed the source code availability, somewhere that my search failed to shows;  I am certainly would be very appreciative if someone would kindly point me to the finding -- I wonder -Why the source code not available?
Title: Re: EEVBlog 121GW Discussion thread
Post by: Brumby on March 17, 2020, 05:46:40 am
This question has been asked several times - but it comes down to this:  UEI have used some proprietary routines - "secret sauce" as Dave puts it.

I have no doubt these routines represent a significant investment and have proven to be of great competitive value.  As such, it would be quite easy to understand why they might not prepared to make these available.
Title: Re: EEVBlog 121GW Discussion thread
Post by: CDaniel on March 17, 2020, 01:09:11 pm
So far I don't see that great value  ;D , just sloppy coding with bugs after numerous updates that someone ( 1 guy ) could do it far better ... of course there is little incentive to waste time for this .
After all is just a microcontroller , not FPGA or something more complex .
Title: Re: EEVBlog 121GW Discussion thread
Post by: ggchab on March 17, 2020, 01:28:15 pm
Unfortunately, after so many releases, this is also my feeling: not very well written/tested firmware. How could you have no doubt that
Quote
these routines represent a significant investment and have proven to be of great competitive value
Did you have any chance to see the code or speak with some UEi developers ? It would be interesting to know  :)
Title: Re: EEVBlog 121GW Discussion thread
Post by: jancumps on March 17, 2020, 01:42:43 pm
It may be the most engineer-tested firmware around. We're all on it and report any issue.
I think it's an interesting situation to be able to have a meter around where so many engineers have a poke at, comment on, critique on. It's all in the open (except the code  :) ).

I enjoy using the meter. All the public scrutiny, reviews, videos make it the most alive piece of test equipment on the desk.
And the fact that all the shortcomings are out in the open. Almost like my own life ;)

Title: Re: EEVBlog 121GW Discussion thread
Post by: Brumby on March 18, 2020, 12:09:11 am
Unfortunately, after so many releases, this is also my feeling: not very well written/tested firmware. How could you have no doubt that
Quote
these routines represent a significant investment and have proven to be of great competitive value
Did you have any chance to see the code or speak with some UEi developers ? It would be interesting to know  :)
1. I am just passing on information that Dave has made public in the past
2. The routines I refer to are the sort of standard subroutines that UEI would have written long before the 121GW came across their desk and are completely separate to the specific code written for the 121GW hardware.
3. Why else would UEI want to keep their routines secret if they did not have competitive value?

(If you really want to program the 121GW from scratch, then you can simply put on your machine code hat and write the binary straight up, using one of the versions of FW already available as a guide.  We've had a couple of people tweak things through editing a binary.)
Title: Re: EEVBlog 121GW Discussion thread
Post by: CkeKchy on March 18, 2020, 05:52:20 pm

Do we know who made and claimed this part of the DMM product making:  "fully open source software" ?     What sort of work ethic is it if no owners who supported the 121GW have NO access to the "fully open source software"?
Title: Re: EEVBlog 121GW Discussion thread
Post by: darrellg on March 18, 2020, 06:03:05 pm
Do we know who made and claimed this part of the DMM product making:  "fully open source software" ?     What sort of work ethic is it if no owners who supported the 121GW have NO access to the "fully open source software"?

If you look at the Kickstarter page (https://www.kickstarter.com/projects/eevblog/eevblog-121gw-multimeter/description (https://www.kickstarter.com/projects/eevblog/eevblog-121gw-multimeter/description)), it doesn't say the meter software is open source. It says the application software is open source.
Title: Re: EEVBlog 121GW Discussion thread
Post by: e0ne199 on March 18, 2020, 06:44:09 pm
It may be the most engineer-tested firmware around. We're all on it and report any issue.
I think it's an interesting situation to be able to have a meter around where so many engineers have a poke at, comment on, critique on. It's all in the open (except the code  :) ).

I enjoy using the meter. All the public scrutiny, reviews, videos make it the most alive piece of test equipment on the desk.
And the fact that all the shortcomings are out in the open. Almost like my own life ;)

and the slowest response for firmware fix available although the error is right before your eyes... you must make several people angry first in order to create the fix  ::)

anyway VA mode fix is still not available, i am still waiting for it  ::)
Title: Re: EEVBlog 121GW Discussion thread
Post by: knapik on March 26, 2020, 10:22:13 am
I had to use a microSD card, and well the only one around was in the 121GW :-X
I'm trying to update the firmware, but the process doesn't work anymore. I believe that it may be a formatting issue, I've tried fat32 & exfat but still doesn't update. What exactly should I be formatting the microSD card to
Title: Re: EEVBlog 121GW Discussion thread
Post by: beanflying on March 26, 2020, 10:24:49 am
I had to use a microSD card, and well the only one around was in the 121GW :-X
I'm trying to update the firmware, but the process doesn't work anymore. I believe that it may be a formatting issue, I've tried fat32 & exfat but still doesn't update. What exactly should I be formatting the microSD card to

What did you rename the firmware file to? https://www.eevblog.com/forum/testgear/eevblog-121gw-multimeter-issues/msg2952134/#msg2952134 (https://www.eevblog.com/forum/testgear/eevblog-121gw-multimeter-issues/msg2952134/#msg2952134)
Title: Re: EEVBlog 121GW Discussion thread
Post by: knapik on March 26, 2020, 10:32:30 am
What did you rename the firmware file to? https://www.eevblog.com/forum/testgear/eevblog-121gw-multimeter-issues/msg2952134/#msg2952134 (https://www.eevblog.com/forum/testgear/eevblog-121gw-multimeter-issues/msg2952134/#msg2952134)

EEVBlog.bin. Trying to upgrade from 1.26 to 2.02, but it just gets stuck on the down screen and never moves from there.
Title: Re: EEVBlog 121GW Discussion thread
Post by: beanflying on March 26, 2020, 10:35:19 am
EEVblog.bin not EEVBlog.bin likely case will matter?
Title: Re: EEVBlog 121GW Discussion thread
Post by: knapik on March 26, 2020, 10:45:55 am
EEVblog.bin not EEVBlog.bin likely case will matter?

Tried both, but same issue, so  :-//
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on March 26, 2020, 10:52:12 am
Do we know who made and claimed this part of the DMM product making:  "fully open source software" ?     What sort of work ethic is it if no owners who supported the 121GW have NO access to the "fully open source software"?

There was never a claim that the source code is open source. I think many people have confused the meter firmware with the app software which is and has always been advertised as fully open source.
There was a hope way back at day 1 of development that the firmware could be open source, but that never eventuated and was never advertised.
Because I did not pay for the development of this meter or the firmware, I do not have a say in whether it is made open source or not, I do not own it.
I did however pay for the app development, so I own that, and that is why it's fully open source.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on March 26, 2020, 10:53:05 am
EEVblog.bin not EEVBlog.bin likely case will matter?
Tried both, but same issue, so  :-//

Some people have reported firmware update issues if their batteries are low.
Title: Re: EEVBlog 121GW Discussion thread
Post by: knapik on March 26, 2020, 11:08:04 am
Some people have reported firmware update issues if their batteries are low.

Don't worry I got it now  :-+
it was most likely an issue because I had it named EEVBlog.bin, not EEVblog.bin & that the SD card was formatted as exfat rather than fat32.
Title: Re: EEVBlog 121GW Discussion thread
Post by: swgertsch on April 16, 2020, 09:38:53 pm
Regarding getting logged data off the internal MicroSD card... why not make it possible to do a File Transfer over BT? This should address users physical accessibility issues. Tried a BT file transfer from Windows 10 PC but the 121GW ignores the "Receive a File" request. Is it an issue the software stack to implement this feature is beyond the hardware's capability?

Recently I wanted to log temperature measurements every 5 seconds and thought I could easily do this with my Android phone using the 121GW app. While the app is capable of "Saving" data sent from the 121GW, there does not appear to be a way set/control the interval time (sampling rate). The interval time appears to be around 300ms which is about as fast the 121GW can log readings to the internal MicroSD card. I would have thought the interval time would be used to control the rate data is sent over BT to the app.

I also noticed the file formats for data saved from the app versus logged to the internal MicroSD card are quite different. The format used for the MicroSD card is more complete. The file formats should be consistent.

I guess I would like to see the app to be more of a remote control than a remote display for the device.
Title: Re: EEVBlog 121GW Discussion thread
Post by: cowasaki on April 27, 2020, 09:47:11 pm
I've tried searching but does the 121GW no longer come with a case?  Just bought a new one from the official distributer over here and there wasn't one in the box, the meter was just wrapped in bubble wrap.......
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on April 28, 2020, 03:32:04 am
I've tried searching but does the 121GW no longer come with a case?  Just bought a new one from the official distributer over here and there wasn't one in the box, the meter was just wrapped in bubble wrap.......

The meter has never come standard with a case.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on April 28, 2020, 03:33:54 am
Regarding getting logged data off the internal MicroSD card... why not make it possible to do a File Transfer over BT? This should address users physical accessibility issues. Tried a BT file transfer from Windows 10 PC but the 121GW ignores the "Receive a File" request. Is it an issue the software stack to implement this feature is beyond the hardware's capability?

It was considered very early on back in the development but it was deemed to be too hard. IIRC it needed added support in the bootloader code, so I don't think it's even possible with just a firmware update.
Title: Re: EEVBlog 121GW Discussion thread
Post by: cowasaki on April 28, 2020, 07:05:55 am
I've tried searching but does the 121GW no longer come with a case?  Just bought a new one from the official distributer over here and there wasn't one in the box, the meter was just wrapped in bubble wrap.......

The meter has never come standard with a case.

No worries.  I'm so far impressed
Title: Re: EEVBlog 121GW Discussion thread
Post by: J-R on April 28, 2020, 07:49:15 pm
Regarding getting logged data off the internal MicroSD card... why not make it possible to do a File Transfer over BT? This should address users physical accessibility issues. Tried a BT file transfer from Windows 10 PC but the 121GW ignores the "Receive a File" request. Is it an issue the software stack to implement this feature is beyond the hardware's capability?

It was considered very early on back in the development but it was deemed to be too hard. IIRC it needed added support in the bootloader code, so I don't think it's even possible with just a firmware update.

What if you could "play back" the logged data on the display so the app could read it?
Title: Re: EEVBlog 121GW Discussion thread
Post by: moore on May 02, 2020, 05:33:21 pm

Is this meter still available for sale in the US?  I only found a couple of used ebay listings.  Amazon says no stock. 

Is there any issue with ordering directly from the site - customs holds etc.?
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on May 03, 2020, 08:38:53 am
Is this meter still available for sale in the US?  I only found a couple of used ebay listings.  Amazon says no stock. 
Is there any issue with ordering directly from the site - customs holds etc.?

No customs issues for the US. It ships via DHL express courier from my site.
I do not have enough stock at present to restock Amazon.
Title: Re: EEVBlog 121GW Discussion thread
Post by: cowasaki on May 30, 2020, 08:55:48 am
About a month ago I bought three more multimeters, two £40  ones with bluetooth so I can monitor two voltages and display the values on the iPad and a 121GW as an accurate decent quality one on the bench.  I have a Keithley 2100 and two Philips bench meters but sometimes it's easier just use a hand held meter.  My first impressions are good and I like the probes.  The possible issue I have with the 121GW is reading small values of resistance.  I have built a bench adjustable load 2/4/8/16 ohms and the new meters and bench meters all work with it but the 121GW just reads that there is no connection.  I can read larger values and the accuracy matches up very well with the keighley but small values are not working.  I have ended up switching leads and using the cheap ones which seems silly

Any ideas? 
Title: Re: EEVBlog 121GW Discussion thread
Post by: CDaniel on May 30, 2020, 08:58:49 am
But what is showing when shorting leads ?
Title: Re: EEVBlog 121GW Discussion thread
Post by: cowasaki on May 30, 2020, 12:09:26 pm
But what is showing when shorting leads ?

0.046 ohms

I've just checked it now and it read the resistance of a transformer correctly.

I'm going to have to work out the context of it doing this and repost
Title: Re: EEVBlog 121GW Discussion thread
Post by: cowasaki on June 04, 2020, 06:57:29 pm
Ok it's not working again....

Unless I'm missing something obvious.

I have a 56K resistor with probes attached either side.  First I'm measuring with a brilliant cheap multimeter the Owen B35T+. It measures the resistor at 56K5 which is confirmed using using Keithley 2100.  Then I haven't changed anything at all but simply moved the probes from the Owen to the 121GW.  The 121GW measures the value as...... well it doesn't even recognise there is a value.  I then put the probes back into the Owen and it is measuring the same.  All I get out of the 121GW is OF.L. Not good for a meter costing 10-15 times the amount. 

[attachimg=1]

[attachimg=2]
Title: Re: EEVBlog 121GW Discussion thread
Post by: cowasaki on June 04, 2020, 07:02:03 pm
And I've just plugged it in again and it seems to be working.  I'm been having these issues from day 1 but as I have over ten meters I've not got round to doing anything with it.......
Title: Re: EEVBlog 121GW Discussion thread
Post by: dcac on June 04, 2020, 08:35:48 pm
You seem to have the 121gw in Continuity mode and not in Ohms mode - Continuity can only measure up to 500.00 ohms.
 
Title: Re: EEVBlog 121GW Discussion thread
Post by: cowasaki on June 04, 2020, 09:23:05 pm
You seem to have the 121gw in Continuity mode and not in Ohms mode - Continuity can only measure up to 500.00 ohms.

? I switch to ohms and it was the only resistance mode that came up.  Do I have to change something else?  That doesn't seem very intuitive.  What tells you it's in continuity mode?
Title: Re: EEVBlog 121GW Discussion thread
Post by: darrellg on June 04, 2020, 09:40:00 pm
You seem to have the 121gw in Continuity mode and not in Ohms mode - Continuity can only measure up to 500.00 ohms.

? I switch to ohms and it was the only resistance mode that came up.  Do I have to change something else?  That doesn't seem very intuitive.  What tells you it's in continuity mode?

Press the Mode button until is says AUTO in the top left and the Ohms symbol appears on the right.
Title: Re: EEVBlog 121GW Discussion thread
Post by: cowasaki on June 04, 2020, 09:41:37 pm
You seem to have the 121gw in Continuity mode and not in Ohms mode - Continuity can only measure up to 500.00 ohms.

? I switch to ohms and it was the only resistance mode that came up.  Do I have to change something else?  That doesn't seem very intuitive.  What tells you it's in continuity mode?

Press the Mode button until is says AUTO in the top left and the Ohms symbol appears on the right.

Does it remember it next time?
Title: Re: EEVBlog 121GW Discussion thread
Post by: dcac on June 04, 2020, 09:46:35 pm
Yes last mode selected with red button is remembered - even after power of I think.

Continuity mode is shown by symbol in red circle.
[attachimg=1]
Title: Re: EEVBlog 121GW Discussion thread
Post by: ve2mrx on June 23, 2020, 09:24:19 pm
Hi everyone,

I got a 121GW last month from the EEVblog website, and I have one question:
What is the difference between the currently-sold 121GW "pre-Kickstarter" model sold by EEVblog's website and the "normal" production one?
My PCB looks like it's 2019-09 dated...

Quote
NOTE: The current stock meter from this website is the latest pre-Kickstarter build that has the new PCB (doesn’t require the shim) and larger protection transistors fitted. It also comes with the UEi test leads instead of the Brymen test leads. These leads do not have banana tip adapters like the Brymen leads

I'm OK with the different leads or cosmetics. I'm really wondering about performance/quality differences.

Hi Dave,
Thanks everyone!

73's de Martin VE2MRX
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on June 23, 2020, 11:14:43 pm
Hi everyone,

I got a 121GW last month from the EEVblog website, and I have one question:
What is the difference between the currently-sold 121GW "pre-Kickstarter" model sold by EEVblog's website and the "normal" production one?
My PCB looks like it's 2019-09 dated...

Quote
NOTE: The current stock meter from this website is the latest pre-Kickstarter build that has the new PCB (doesn’t require the shim) and larger protection transistors fitted. It also comes with the UEi test leads instead of the Brymen test leads. These leads do not have banana tip adapters like the Brymen leads

Oops, that should read "post-Kickstarter"!
My store has had the latest hardware build for many months now.
Title: Re: EEVBlog 121GW Discussion thread
Post by: ve2mrx on June 24, 2020, 02:07:32 am
Hi Dave!

Thanks for the explanation!

Indeed, I found it odd that the PCB was 2019-09 and it was supposed to be "pre-Kickstarter"... I figured all that was "Pre-Kickstarter" was the meter's shell and boot, meticulously upgraded with the new guts :P

Well, your comment explains everything!

Thanks!
Martin
near Montreal, Quebec, Canada
Title: Re: EEVBlog 121GW Discussion thread
Post by: cowasaki on June 25, 2020, 12:01:47 pm
To be honest I am less than impressed with the 121gw. An experienced engineer should not not to resort to the manual every time he wants to do something that is basically simple. I’m just trying to work out the wiring in a speaker cab. The difference between the resistances is small but the leads I’m using are showing as 1.5 ohms. Now that probably because I’m going through several adapters but I don’t have five arms so it’s the only way I can manage with what I have with me. Simple just zero the probes and it’s not a problem!!!!

Err no. How do I zero the probes? On my Keighley there is a nice zero button. On the 121gw? No I can’t work it out. This is the second time I’ve had issues with this DMM and it’s the second time I’ve used it. The first first it wouldn’t read certain resistances at all because it was in some mode.

Any clues?  If it had been a £10 DDM I would have chucked it out of the window by now
Title: Re: EEVBlog 121GW Discussion thread
Post by: newbrain on June 25, 2020, 12:15:13 pm
Err no. How do I zero the probes? On my Keighley there is a nice zero button. On the 121gw?
The's a nice REL-Δ button.

Exactly the same as on my Fluke 87V, and FWIW, the UNI-T 61-D I previously had...
Or did I misunderstand something? :-//
Title: Re: EEVBlog 121GW Discussion thread
Post by: beanflying on June 25, 2020, 12:20:10 pm
To be honest I am less than impressed with the 121gw. An experienced engineer should not not to resort to the manual every time he wants to do something that is basically simple. I .... Snip

 :o Rel, Zero, Null ........ all in common use so  :-//
Title: Re: EEVBlog 121GW Discussion thread
Post by: cowasaki on June 25, 2020, 12:26:12 pm
That was the first thing I tried REL doesn’t do anything at all.
Title: Re: EEVBlog 121GW Discussion thread
Post by: cowasaki on June 25, 2020, 12:29:10 pm
Ok I’ve pressed it and wobbled it and pressed it harder then suddenly it zeros. I think I might have a slightly dodgy button. That would explain things....  will have a proper mess later I need to get this cab back together.
Title: Re: EEVBlog 121GW Discussion thread
Post by: firewalker on June 25, 2020, 12:44:15 pm
Ok it's not working again....

Unless I'm missing something obvious.

I have a 56K resistor with probes attached either side.  First I'm measuring with a brilliant cheap multimeter the Owen B35T+. It measures the resistor at 56K5 which is confirmed using using Keithley 2100.  Then I haven't changed anything at all but simply moved the probes from the Owen to the 121GW.  The 121GW measures the value as...... well it doesn't even recognise there is a value.  I then put the probes back into the Owen and it is measuring the same.  All I get out of the 121GW is OF.L. Not good for a meter costing 10-15 times the amount. 


I have a similar issue on Ohms range. In my case is the rotary switch. If it is not centered exactly, it doesn't behave correctly.

Alexander.
Title: Re: EEVBlog 121GW Discussion thread
Post by: cowasaki on June 25, 2020, 12:45:06 pm
Yes after it worked that first time it now works every time (I will have to start using it more to make sure it doesn’t happen again before the warranty is up) I bought this 2-3 months ago but as I have a couple of Philips/fluke and a Keighley bench meter on my bench it doesn’t get used much (twice). I’m currently scrabbling around on the floor trying to rewire a cab with speakers that don’t belong in it! I was getting more and more annoyed :-) it’s working now and I can get back to my nice soothing valve amplifiers.......
Title: Re: EEVBlog 121GW Discussion thread
Post by: cowasaki on June 25, 2020, 12:50:00 pm
Fire walker,

I think it was just that the button was stiff from new or not seated right. It’s working fine now and all the other buttons SEEM to be fine. I’ve only used it once before. I can’t use it as my main DDM as I build valve amplifiers and I’m messing with voltages higher than 500v which it didn’t want to measure (no doubt there will be a way to measure them and I’ll have to check the destruction book to see). I’ve not spent any real time with it. I bought it on a whim when I got a refund for a camera for my bench scope.
Title: Re: EEVBlog 121GW Discussion thread
Post by: ornea on June 25, 2020, 08:50:18 pm
Not my go to meter as it makes me work hard to get results but I can report it spent a night in torrential rain and after a drying session appears to be fine.
Title: Re: EEVBlog 121GW Discussion thread
Post by: van0014 on July 01, 2020, 11:42:56 am
I've been using mine often as an auto electrician, but I don't work flat out so it's not used every day. The voltage accuracy is brilliant.

It happily measures micro volts (after the decimal), so when power is flowing across a fuse, I can approximate the current draw from the voltage drop. Fuses act like a current shunt, but the reading is very small and changes for each fuse size.
Hoping for a chance to use bluetooth or logging on a job. It works well, given it uses BLE to save energy. That gives it a refresh rate slower than the LCD, but it's fast enough for many things.
I get slightly different diode voltage readings between 3v and 15v. For example, an IR diode reads 1.038v (3v) or 1.131v (15v). To be fair, accuracy isn't specified for diodes. Maybe the PTC affects the reading too much.

I'm glad that this meter has worked well for me. With firmware v2.04, it's given me no problems and I like it as my main meter
Title: Re: EEVBlog 121GW Discussion thread
Post by: dcac on July 25, 2020, 12:15:52 pm
What's happened to the "EEVblog 121GW Multimeter Issues" thread?

https://www.eevblog.com/forum/testgear/eevblog-121gw-multimeter-issues (https://www.eevblog.com/forum/testgear/eevblog-121gw-multimeter-issues)

I get 404 error trying to access it.
Title: Re: EEVBlog 121GW Discussion thread
Post by: jack-daniels on July 25, 2020, 12:38:45 pm
What's happened to the "EEVblog 121GW Multimeter Issues" thread?

https://www.eevblog.com/forum/testgear/eevblog-121gw-multimeter-issues (https://www.eevblog.com/forum/testgear/eevblog-121gw-multimeter-issues)

I get 404 error trying to access it.

I received this notification by email

"Topic removed: EEVblog 121GW Multimeter Issues

EEVblog Electronics Community Forum <do_not_reply@eevblog.com>
To:jack_daniels
Sat, Jul 25 at 7:53 AM
A topic you are watching has been removed by Simon.

Regards,
The EEVblog Electronics Community Forum Team."

Title: Re: EEVBlog 121GW Discussion thread
Post by: firewalker on July 25, 2020, 12:53:10 pm
I guess there were no more issues. :P :P :P

Alexander.
Title: Re: EEVBlog 121GW Discussion thread
Post by: dcac on July 25, 2020, 01:06:28 pm
lol, yep fix all problems by burning the error report.

have it actually ever happened before here on eevblog a whole thread being nuked.

Title: Re: EEVBlog 121GW Discussion thread
Post by: joeqsmith on July 25, 2020, 03:21:51 pm
What's happened to the "EEVblog 121GW Multimeter Issues" thread?

https://www.eevblog.com/forum/testgear/eevblog-121gw-multimeter-issues (https://www.eevblog.com/forum/testgear/eevblog-121gw-multimeter-issues)

I get 404 error trying to access it.

I received this notification by email

"Topic removed: EEVblog 121GW Multimeter Issues

EEVblog Electronics Community Forum <do_not_reply@eevblog.com>
To:jack_daniels
Sat, Jul 25 at 7:53 AM
A topic you are watching has been removed by Simon.

Regards,
The EEVblog Electronics Community Forum Team."

That's really strange.   Is the plan to merge those posts into this thread or is the idea to try and erase the history? 
Title: Re: EEVBlog 121GW Discussion thread
Post by: dcac on July 25, 2020, 06:00:31 pm
That wouldn't make any sense -  this thread (EEVBlog 121GW Discussion thread) was started after the KS meters had been delivered - and is more or less a continuation of this old thread: https://www.eevblog.com/forum/testgear/new-eevblog-branded-multimeter-coming/ (https://www.eevblog.com/forum/testgear/new-eevblog-branded-multimeter-coming/).

The now missing issues thread was intended for reporting specific issues - sure there was some overlapping between the threads - but for the most part they served their purpose - and a possibility to report issues with less chance of it drowning in the general discussion around the meter.

Title: Re: EEVBlog 121GW Discussion thread
Post by: dcac on July 25, 2020, 06:07:48 pm
I could also just have said - if someone thought there were to be too many 121gw threads - then just lock the one(s) deemed redundant.

Title: Re: EEVBlog 121GW Discussion thread
Post by: joeqsmith on July 25, 2020, 10:08:46 pm
That wouldn't make any sense - this thread (EEVBlog 121GW Discussion thread) was started after the KS meters had been delivered - and is more or less a continuation of this old thread: https://www.eevblog.com/forum/testgear/new-eevblog-branded-multimeter-coming/ (https://www.eevblog.com/forum/testgear/new-eevblog-branded-multimeter-coming/).

The now missing issues thread was intended for reporting specific issues - sure there was some overlapping between the threads - but for the most part they served their purpose - and a possibility to report issues with less chance of it drowning in the general discussion around the meter.

I don't think there was any confusion about the purpose of the thread.  Deleting it makes little sense to me.   
Title: Re: EEVBlog 121GW Discussion thread
Post by: dcac on July 25, 2020, 11:44:32 pm
It doesn't look like Dave or Simon been online since the thread disappeared. When they get back hopefully they can provide some info on wtf happened.
Title: Re: EEVBlog 121GW Discussion thread
Post by: 1anX on July 26, 2020, 07:42:28 am
IMHO the 121GW never lived up to the pre KickStarter hype or the potential of the design. Major hardware problems with the selector switch and then auto-ranging times, etc, with the firmware, set the scene for a troubled launch.

I bought into the KickStater event knowing full well the V1.0 could be a lemon, but love EEVBlog and supported Dave in the venture. Well the meter is usuable and a good size for limited bench space, so for basic multimeter functions it gets used. I'm surprised Dave is closing off forum discussion on the meter's issues and would like very much to hear Dave's reasons for doing it.

I personally would not buy another test instrument from Dave for the simple reason that I think customer support is not at a professional level and many other wholesaler/retailers do a much better job. Stick with what you do well is always a good mantra to follow.

Dave is really good at critically and objectively evaluating test instruments and EEVBlog teardowns and forums are the best in class.

Title: Re: EEVBlog 121GW Discussion thread
Post by: Brumby on July 26, 2020, 08:55:33 am
I'm surprised Dave is closing off forum discussion on the meter's issues ...
That is not certain.

All we know is that the thread is no longer available.  There could be other reasons.

I would like to have a specific response before venturing any further down that path.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on July 26, 2020, 09:02:20 am
What's happened to the "EEVblog 121GW Multimeter Issues" thread?
https://www.eevblog.com/forum/testgear/eevblog-121gw-multimeter-issues (https://www.eevblog.com/forum/testgear/eevblog-121gw-multimeter-issues)
I get 404 error trying to access it.

 :o  :scared:
I did delete a new thread the other day that someone started that was a duplicate of a post in the Isssues thread, but that was it, I did not deliberate remove the Issues thread.
It's possible I deleted the wrong thing  :palm: , I need to investigate....
Title: Re: EEVBlog 121GW Discussion thread
Post by: Brumby on July 26, 2020, 09:32:05 am
Ah....

Will the lynch mob please stand down.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on July 26, 2020, 09:40:37 am
Yep, it was deleted  :(
I can see the entire thread in the deleted posts section but the Restore Topic function doesn't seem to be working, I have no idea why. It spins the wheels for a few second and goes back the list as if it worked, but it's still in the deleted section.
So I'm currently at a loss as to how to get this back  >:(
Title: Re: EEVBlog 121GW Discussion thread
Post by: firewalker on July 26, 2020, 10:15:30 am
Maybe you and another moderator saw the new similar post. One deleted the correct and the other the wrong one...

Alexander.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on July 26, 2020, 10:37:26 am
Maybe you and another moderator saw the new similar post. One deleted the correct and the other the wrong one...

Yep, I suspect that's what happened.
Normally not a problem, just hit Restore Topic and it's fixed.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Brumby on July 26, 2020, 12:12:35 pm
Well, the data is still around then.  It's just going to be a matter of getting links and pointers and whatever other elements of the structure back to normal - but doing this manually requires a full understanding of how SMF does this.  These details can become convoluted, especially on software that's been around for a while and has had lots of revisions.

I won't pretend to know SMF this well, but unless an SMF process can be found, I can see Gnif possibly getting involved.

It might be an easy fix - or it might not.  Be patient people.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on July 26, 2020, 01:27:30 pm
Apparently it's a bug in SMF when threads get too long, they can't be restored.
But Gnif worked his magic on the database and it's back!  :clap:
Title: Re: EEVBlog 121GW Discussion thread
Post by: Brumby on July 26, 2020, 01:41:24 pm
Somehow I had a feeling Gnif might have known his way around the database.   :-+
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on July 26, 2020, 01:43:40 pm
Somehow I had a feeling Gnif might have known his way around the database.   :-+

Manually tweaking the database is his preferred method for everything, he's a nerd  ;D
Title: Re: EEVBlog 121GW Discussion thread
Post by: Brumby on July 26, 2020, 01:45:16 pm
Somehow I had a feeling Gnif might have known his way around the database.   :-+

Manually tweaking the database is his preferred method for everything, he's a nerd  ;D
I like his approach.   ;D  :-+ :-+
Title: Re: EEVBlog 121GW Discussion thread
Post by: dcac on July 26, 2020, 01:47:39 pm
Thanks for the update - it wasn’t really anything urgent I needed to search for in that thread. So I'll just wait until it gets back online.

Title: Re: EEVBlog 121GW Discussion thread
Post by: dcac on July 26, 2020, 01:54:00 pm
I see you guys are working on it as we speak - just a note the restored thread does not have the 'pinned' status (yet).

Title: Re: EEVBlog 121GW Discussion thread
Post by: coromonadalix on July 28, 2020, 01:40:00 am
now pinned 
Title: Re: EEVBlog 121GW Discussion thread
Post by: oliv3r on August 09, 2020, 08:32:05 am
Hey all,

I seem to be stuck on the IAP- 'down' screen for some 20 minutes now, trying to update from 1.58 (beta) to 2.04. Any reason why? or should I just restart it ...
Title: Re: EEVBlog 121GW Discussion thread
Post by: Scottjd on August 09, 2020, 09:00:18 am
https://www.eevblog.com/forum/testgear/eevblog-121gw-multimeter-firmware-details/msg2828400/#msg2828400 (https://www.eevblog.com/forum/testgear/eevblog-121gw-multimeter-firmware-details/msg2828400/#msg2828400)

If you downloaded the firmware and its in a zip package, you have to unzip/uncompress the file first.
Its important to make sure the new firmware file on the SD card is named “EEVBlog.bin” with no spaces in the file name or the meter might hang and just display down.
If the batteries are old then you might want to make sure you have a fresh set of batteries installed before running the firmware update. I think I’ve read the newer firmware will check the battery level first, but i’m not sure about that.

1. Turn the meter off then hold down MEM and HOLD while turning on the meter.  You will see IAP on the display.
2. Press the “SETUP” button and it will display “DOWN / DOUUN” and after 5 seconds the meter bar should start rising from the left to right.
3. Once the bar hits the end the meter will restart displaying the new version of firmware installed.
This whole process after it displays “DOWN / DOUUN” shouldn’t take more then 15 seconds.

Someday, maybe someday they will add a timeout to the firmware update menu so it will error out after say 3 to 5 minutes????
Title: Re: EEVBlog 121GW Discussion thread
Post by: oliv3r on August 11, 2020, 01:56:48 pm
https://www.eevblog.com/forum/testgear/eevblog-121gw-multimeter-firmware-details/msg2828400/#msg2828400 (https://www.eevblog.com/forum/testgear/eevblog-121gw-multimeter-firmware-details/msg2828400/#msg2828400)

If you downloaded the firmware and its in a zip package, you have to unzip/uncompress the file first.
...
Thanks for that, (of course) I did all that, but the problem was far simpler. I forgot to move the SD card into the meter :D

Someday, maybe someday they will add a timeout to the firmware update menu so it will error out after say 3 to 5 minutes????
Which would have been super helpful in my case. But I think this is the built-in IAP code, so bootloader change, and remotely (via SD) not update-able? (update-able fine with st-link of course)
Title: Re: EEVBlog 121GW Discussion thread
Post by: Brumby on October 03, 2020, 06:05:57 am
If I were Dave, I'd be rather interested to see what the actual cause of the failure was.......


Looks like the post was removed.
Yes, it has been.
Title: Re: EEVBlog 121GW Discussion thread
Post by: J-R on February 10, 2021, 09:06:49 am
Is there a discussion about the fact the 121GW is 99,999 count when in calibration mode?
Title: Re: EEVBlog 121GW Discussion thread
Post by: dcac on February 10, 2021, 04:34:01 pm
Is there a discussion about the fact the 121GW is 99,999 count when in calibration mode?

Not that I can recall - other than it’s been mentioned Agilent U1282 which is a 60,000 count meter also uses the HY3131.

And then there's this: https://reference.digilentinc.com/reference/add-ons/dmm-shield/reference-manual (https://reference.digilentinc.com/reference/add-ons/dmm-shield/reference-manual) which is also based on HY3131 and claims to be a 5 1/2 digit meter.

But HY3131 is only rated for 50,000 count at a specified sample rate, accuracy and linearity in the datasheet. But it is in fact a 24bit ADC so theoretically you could get 2^23 or 8388608 count - in a perfect world that is.

But I noticed that too with 121gw in calibration mode that many modes/ranges acts as a 99,999 count meter. But I think the 5M and 50M ohms ranges only reaches 67,000 or something like that.
Title: Re: EEVBlog 121GW Discussion thread
Post by: J-R on February 11, 2021, 06:25:03 am
Ran a bunch of tests and was surprised that specifically all the DCV & DCmV ranges were quite accurate all the way up, for example 9.87654V on the calibrated supply was 9.8764V on the 121GW.  Past about 2 9's on the display and things were a bit off, however.

mA and A gained the extra headroom but the accuracy wasn't quite worth it.  Capacitance and resistance were spotty as well.  Some useful information could possibly be found under certain conditions.

Pushed 990V through it for about a minute with no issues.  It still beeped constantly despite happily displaying the correct voltage...
Title: Re: EEVBlog 121GW Discussion thread
Post by: skysurf76 on February 12, 2021, 08:18:56 pm
Anyone have any idea how often Dave gets shipments of 121GWs?  I'm wanting to pick up another but they are currently out of stock.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Brumby on February 12, 2021, 09:55:47 pm
From what Dave has said recently, I don't think even he can answer that at the moment.  It appears there are supply issues with some of the components - which would make it difficult for even the manufacturer to give a date.
Title: Re: EEVBlog 121GW Discussion thread
Post by: skysurf76 on February 12, 2021, 10:54:44 pm
I figured that might be the case. Thanks Brumby.
Title: Re: EEVBlog 121GW Discussion thread
Post by: J-R on March 08, 2021, 11:03:48 pm
Welectron has some in stock now.
Title: Re: EEVBlog 121GW Discussion thread
Post by: DeuxVis on March 17, 2021, 04:50:42 pm
I got a 121GW off the kickstarter campaign, Johnny B. Goode level

I never received a shim, is that because not all the kickstarter meters are affected by the pcb thickness problem ?

My range switch is behaving as expected by the way, just wondered.

Sorry I couldn't find the information in that very long thread, it's probably hiden somewhere inhere...


Thanks.
Title: Re: EEVBlog 121GW Discussion thread
Post by: J-R on March 17, 2021, 06:10:24 pm
Bought one a couple years back, removed the shim right away and have had no issues.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on March 18, 2021, 12:03:15 am
From what Dave has said recently, I don't think even he can answer that at the moment.  It appears there are supply issues with some of the components - which would make it difficult for even the manufacturer to give a date.

They are now saying April 30th. But I'm getting the feeling that's still based on a promise from component suppliers, I don't think they actually have all the parts in had at the moment.
FYI, Brymen are having production delays too due to component shortages.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Keyview on March 18, 2021, 08:56:15 pm
I have a question on the specifications in the user manual of the 121GW.

In most cases, the specifications of a multimeter are valid only for a certain part of the range, e.g. from 10% to 100% of a range.
This becomes relevant in particular in the lowest range.

As an example, the AC 50 mV range accuracy of the Fluke 289 is specified for 5% to 100% of range. Below 5% of range, extra 20 digits need to be added to accuracy. 
But for the 121GW, e.g. for AC V, no such restrictions apply.
It is simply stated for the 50 mV range as 1.2%+15 digits (for 45-400 Hz) without a lower bound.

So, I wonder whether the given specifications of the 121 GW are valid down to 0% of range.

Thank you!
Title: Re: EEVBlog 121GW Discussion thread
Post by: dcac on March 19, 2021, 05:52:23 pm
@Keyview

There might be a typo in the 121GW manual - the footnote (3) for 50mV DC probably also should apply to 50mV AC but here it refers to footnote (2)? which is not to be found.

(https://www.eevblog.com/forum/testgear/eevblog-121gw-discussion-thread/?action=dlattach;attach=1197526;image)   
Title: Re: EEVBlog 121GW Discussion thread
Post by: Keyview on March 19, 2021, 11:53:27 pm
There might be a typo in the 121GW manual - the footnote (3) for 50mV DC probably also should apply to 50mV AC but here it refers to footnote (2)? which is not to be found.
Thank you for sharing your observation on the potential typo.

I now checked with the Fluke 289 manual: The requirement for rel mode and zeroing for 50 mV DC is mentioned there, too, but no requirement for rel mode for 50 mV AC.
So, the footnote 2 on page 17 of the 121GW manual is maybe not to be read as footnote 3.

I consider to purchase the 121GW for low V AC measurements because it has a better accuracy than the Fluke 289 in this low area.
For example, measuring 1 mV AC with the Fluke 289 has an accuracy of 0.42 dB (65 Hz - 10 kHz). Whereas for the 121 GW it is 0.23 dB (45-400 Hz) and 0.34 dB (400 Hz - 5 kHz).

But maybe I should wait with the purchase until the footnote for the 50 mV AC range is clarified.
Title: Re: EEVBlog 121GW Discussion thread
Post by: J-R on March 20, 2021, 05:42:15 am
Accuracy specifications can be a poor metric in my opinion.  You have some equipment that just barely squeaks by and other equipment that exceeds the spec by a factor of 10 in some cases.

Got a bit carried away and tested a pile of my DMMs with a 3312A signal generator.  100.0000mV sine wave at 1KHz fed through a Gertsch RT-5 ratio transformer for a final output of 1mV.  (I picked those values because I have recent calibration data for the 34401A which states 100.0000mV is 99.9932mV at 1KHz.)

34401A -- 0.994mV
Fluke 287 -- 1.002mV
121GW #1 -- 0.989mV
121GW #2 -- 0.985mV
Fluke 87V -- 0.99mV
Fluke 88V -- 0.86mV
BM869s -- 0.99mV
BM789 -- 0.84mV
Agilent U1461A -- 1.010mV

I did not use relative mode on any of these.  All devices were powered up for a couple hours at 67F and allowed to settle before taking a reading.

After some further tinkering, I did notice the Fluke 287 drops to 0 around 0.150mV and the 34401A drops to 0.100mV at 0.300mV and to 0 around 0.200mV.
Both 121GW units had no trouble showing something meaningful down that low, so 0.100mV was 0.085mV and 0.050mV was 0.033mV for example...

I also ran the same tests at 200Hz and found the results to be virtually identical.

If my calculations are correct, the Fluke 287 was 0.02dB high, and the worst 121GW was 0.13dB low.

Title: Re: EEVBlog 121GW Discussion thread
Post by: dcac on March 20, 2021, 08:12:06 am
There might be a typo in the 121GW manual - the footnote (3) for 50mV DC probably also should apply to 50mV AC but here it refers to footnote (2)? which is not to be found.
Thank you for sharing your observation on the potential typo.

I now checked with the Fluke 289 manual: The requirement for rel mode and zeroing for 50 mV DC is mentioned there, too, but no requirement for rel mode for 50 mV AC.
So, the footnote 2 on page 17 of the 121GW manual is maybe not to be read as footnote 3.


Yes perhaps - the signal path for AC mV is quite different from DC mV and so is any possible offset that needs to be canceled out. I wonder what footnote (2) is about though. I found an older manual from 2017 that is different and with no footnote for AC mV.

(https://www.eevblog.com/forum/testgear/eevblog-121gw-discussion-thread/?action=dlattach;attach=1198004;image)

Title: Re: EEVBlog 121GW Discussion thread
Post by: Keyview on March 20, 2021, 12:50:33 pm
Got a bit carried away and tested a pile of my DMMs [...]
Thank you very much for your excellent analysis!
This convices me to order the 121GW.

If this performance is typical for a 121GW then it might be worth to explicitly add in the user manual that the specifications are valid down to 0% of range - for V AC and the other measurements.
Otherwise one might wonder whether stating a lower bound for the specifications has been forgotten.

Thank you for your and dcac's swift and competent feedback!
Title: Re: EEVBlog 121GW Discussion thread
Post by: J-R on March 21, 2021, 06:44:53 am
The mV relative mode statements in the manual makes no sense to me.  If the zero calibration point is off far enough that you need to REL the meter before taking a measurement, then the final reading will be off as well.  If you REL out noise/interference, same issue.

I think the larger issue here is that you need a way to verify your readings.  Don't blindly trust one DMM.  Using the function generator and the ratio transformer, I can easily make any of my DMMs display garbage values where they really shouldn't.  But frequently one DMM pulls through where another falls flat.  The inability of the 34401A and the 287 to display very low mV AC values surprised me a bit.  But they also both destroy the 121GW and Brymens with DCV accuracy all day long...
Title: Re: EEVBlog 121GW Discussion thread
Post by: Keyview on March 21, 2021, 12:36:17 pm
Don't blindly trust one DMM.
This is a key point. If I had (besides budget) more room, I would get a Keysight 34465 bench meter and a good handheld DMM, say Fluke 287/289.
(Btw, the Flukes are here in Europe twice the price of the US market prices.)

I am interested in low voltage AC (down to a few mV) for some audio connected measurements.
Ideally, I would find a handheld DMM with the accuracy of the 34465, but this does not exist.
I would also like to simply trust the product specifications to avoid having several quality devices that can measure (by specification) quite accurately down to 1 mV AC.
Not sure, if it is smart to fully trust the specifications. Maybe this is indeed blind trust.

The inability of the 34401A and the 287 to display very low mV AC values surprised me a bit.
Actually, the 287 does not meet its specifications with your observation that 0.150 mV 1 kHz is displayed as 0.
The accuracy as stated by Fluke should be 0.4% + 45 digits (0.001 mV) in this case.
Title: Re: EEVBlog 121GW Discussion thread
Post by: dcac on March 21, 2021, 01:26:07 pm
The mV relative mode statements in the manual makes no sense to me.  If the zero calibration point is off far enough that you need to REL the meter before taking a measurement, then the final reading will be off as well.  If you REL out noise/interference, same issue.

I believe the reason for using REL in the lowest mV range is to compensate for any temporary offset drift (usually) caused by temperature variations. In DC mV mode the signal passes through PTCs which can exhibit thermocouple behavior - then there’s i.e. also possible drift in the pre-amp and ADC.

In AC mV mode the signal has more or less the same path as DC but is then AC coupled right before the AD8436 RMS converter - so here it’s really only if the converter exhibits any drift you’d want to use the REL to cancel it out.

This description is for the 121GW but many other DMMs has much the same problem.
Title: Re: EEVBlog 121GW Discussion thread
Post by: dcac on March 21, 2021, 01:48:01 pm
Don't blindly trust one DMM.
This is a key point. If I had (besides budget) more room, I would get a Keysight 34465 bench meter and a good handheld DMM, say Fluke 287/289.
(Btw, the Flukes are here in Europe twice the price of the US market prices.)

I am interested in low voltage AC (down to a few mV) for some audio connected measurements.
Ideally, I would find a handheld DMM with the accuracy of the 34465, but this does not exist.


Perhaps a dedicated AC mV meter would be a better option - I don’t really have any specific to suggest though.

When I needed to measure sub mV Audio signals I built an external AC amplifier based on the OP37 opamp. Placed it in a battery powered small shielded box I could attach directly to a handheld DMM. I could set the amplification to 10, 100 or 200X and here the frequency response was perfectly flat 20Hz - 20KHz and a bit beyond. I don’t know if any such device exists ready to buy though.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Keyview on March 22, 2021, 11:29:28 am
When I needed to measure sub mV Audio signals I built an external AC amplifier based on the OP37 opamp. [...] I don’t know if any such device exists ready to buy though.
I have never soldered before, so I would have to buy it - if it is for sale.
Your approach sounds somewhat similar to the eevblog uCurrent, but I am not sure if it measures uV AC.
Besides, the uCurrent is out of stock everywhere.

Please let me know if anyone has an idea where to get a (reasonably priced) AC amplifier to use with a DMM.
Title: 400mA fuse replacement
Post by: skyjumper on March 22, 2021, 03:26:56 pm
Hi All, this weekend I blew the 400mA 600V fuse. I'm in the US, and Dave's fuse pack would take some time to get here. I see lots of 600V 500mA fuses available, not so much with the 400mA. Could I safely use a 500mA fuse instead?
Title: Re: EEVBlog 121GW Discussion thread
Post by: Wytnucls on March 22, 2021, 05:41:26 pm
The range is 500mA, so the 500mA 600V fuse is fine, if it has a FF rating (Fast) and a high breaking capacity (10kA).
6x32mm, rated for AC/DC (UL248-1)
Title: Re: EEVBlog 121GW Discussion thread
Post by: skyjumper on March 22, 2021, 08:28:31 pm
Thanks very much, I thought as much but this makes me wonder why there is a 400mA fuse to begin with? Although I did end up finding some 400mA @ 600V, are these acceptable:

https://www.amazon.com/gp/product/B0891P5XMM/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1 (https://www.amazon.com/gp/product/B0891P5XMM/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1)
Title: Re: EEVBlog 121GW Discussion thread
Post by: Wytnucls on March 22, 2021, 09:15:23 pm
Stick to good brands, like Littelfuse, Cooper Bussmann or Siba if you can, otherwise examine the datasheet carefully for compliance.
The manual recommends  cryptically ASTM HV610.0.4 400 mA (600V) or HV620.0.4(1000V) A/500 mA current input fuse (sic)
Title: Re: EEVBlog 121GW Discussion thread
Post by: skyjumper on March 22, 2021, 09:18:00 pm
Stick to good brands, like Littelfuse, Cooper Bussmann or Siba if you can, otherwise examine the datasheet carefully for compliance.
The manual recommends  cryptically ASTM HV610.0.4 400 mA (600V) or HV620.0.4(1000V) A/500 mA current input fuse (sic)

Ah okay, well if 1000V fuse is acceptable then there are many 500mA to choose from. Thanks.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Brumby on March 22, 2021, 11:53:00 pm
This:
Stick to good brands
Title: Re: EEVBlog 121GW Discussion thread
Post by: AVGresponding on March 23, 2021, 09:49:29 am
This:
Stick to good brands

And make sure the spelling is correct! Poor spelling invariably indicates counterfeits that have no sand inside to quench the fault arc, something I'm seeing more of in the UK with BS1362 fuses.
They can and do explode under fault loading.
Title: Re: EEVBlog 121GW Discussion thread
Post by: skyjumper on March 23, 2021, 04:24:38 pm
I have Dave's fuse pack on order, but that will take 15 days and I can't wait that long to get this back into service. I should have stocked up on fuses for it, but it never occurred to me they would be hard to find on short notice. In the meantime I'll use the one I ordered and be super careful not to screw up again. Maybe the international postal Gods will smile on me :-)
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on March 24, 2021, 07:40:13 am
Stick to good brands, like Littelfuse, Cooper Bussmann or Siba if you can, otherwise examine the datasheet carefully for compliance.

Beware of fakes on ebay and other places. Because of the very high potential margins on these, the market is awash with fakes.
Title: Re: EEVBlog 121GW Discussion thread
Post by: tmcks on April 21, 2021, 02:04:39 am
Hi all,

I received my 121GW today. I went to check the firmware and I see v2.04 is the highest listed on the 121GW firmware page, but the start screen on the DMM shows v2.05. Is this an error and I should flash 2.04, or is 2.05 real and just not listed yet?

Thanks.
Title: Re: EEVBlog 121GW Discussion thread
Post by: firewalker on April 21, 2021, 09:43:31 am
Hi all,

I received my 121GW today. I went to check the firmware and I see v2.04 is the highest listed on the 121GW firmware page, but the start screen on the DMM shows v2.05. Is this an error and I should flash 2.04, or is 2.05 real and just not listed yet?

Thanks.

Probably not listed yet. Check the contents of the microSD card. If you see a file named EEVBlog.bin, share it with us.  :D :D :D

Alexander.
Title: Re: EEVBlog 121GW Discussion thread
Post by: tmcks on April 21, 2021, 01:59:17 pm

Probably not listed yet. Check the contents of the microSD card. If you see a file named EEVBlog.bin, share it with us.  :D :D :D

Alexander.

Sorry, but the SD card seems to be empty.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on April 22, 2021, 01:35:01 am
Hi all,
I received my 121GW today. I went to check the firmware and I see v2.04 is the highest listed on the 121GW firmware page, but the start screen on the DMM shows v2.05. Is this an error and I should flash 2.04, or is 2.05 real and just not listed yet?
Thanks.

I don't have have 2.05, have asked Kane what the deal is.
I have new stock on the way soon, don't know what version they will have. I can only presume that you bought it from Welectron and they somehow have a newer version firmware.
Title: Re: EEVBlog 121GW Discussion thread
Post by: tmcks on April 22, 2021, 02:31:41 am
Hi all,
I received my 121GW today. I went to check the firmware and I see v2.04 is the highest listed on the 121GW firmware page, but the start screen on the DMM shows v2.05. Is this an error and I should flash 2.04, or is 2.05 real and just not listed yet?
Thanks.

I don't have have 2.05, have asked Kane what the deal is.
I have new stock on the way soon, don't know what version they will have. I can only presume that you bought it from Welectron and they somehow have a newer version firmware.

Yes, it is from Welectron.

Thank you.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on April 22, 2021, 02:56:09 am
I now have v2.05
They changed the low pass filter curve to better match the performance of the Fluke 289, which I guess they are using as a sort of reference.
And yes, this version was shipped to Welectron.
Title: Re: EEVBlog 121GW Discussion thread
Post by: J-R on April 22, 2021, 05:03:59 am
Flashed without incident.
Title: Re: EEVBlog 121GW Discussion thread
Post by: e0ne199 on April 27, 2021, 06:09:50 pm
I now have v2.05
They changed the low pass filter curve to better match the performance of the Fluke 289, which I guess they are using as a sort of reference.
And yes, this version was shipped to Welectron.

is that the only update??
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on April 28, 2021, 12:55:40 am
I now have v2.05
They changed the low pass filter curve to better match the performance of the Fluke 289, which I guess they are using as a sort of reference.
And yes, this version was shipped to Welectron.
is that the only update??

Yes. That is the only change they said was made.
Title: Re: EEVBlog 121GW Discussion thread
Post by: commandlinehool on May 28, 2021, 01:21:31 pm
Also got mine from electron today with 2.05. Also the yellow shim have been removed?

Does it always comes without probes? I thought it’s either Brymen or UEI probes.

Cheers
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on May 29, 2021, 10:26:12 am
Also got mine from electron today with 2.05. Also the yellow shim have been removed?

Yes, the shim was only for the first several thousand PCB's that had the wrong thickness.

Quote
Does it always comes without probes? I thought it’s either Brymen or UEI probes.

I don't have control over what Welectron sell, but Kane's standard FOB quote is without probes. If the distributor wants probes then they have to order them as a separate line item.
Title: Re: EEVBlog 121GW Discussion thread
Post by: J-R on May 30, 2021, 01:13:04 am
By default Welectron checks the box to include the probes when you hit the 121GW page, but you can uncheck it.

I have two 121GW units that came with shims.  I removed it from both and have had zero issues.  Perhaps after things wear it might be needed.
Title: Re: EEVBlog 121GW Discussion thread
Post by: commandlinehool on June 01, 2021, 11:50:17 am
Also got mine from electron today with 2.05. Also the yellow shim have been removed?

Yes, the shim was only for the first several thousand PCB's that had the wrong thickness.

Quote
Does it always comes without probes? I thought it’s either Brymen or UEI probes.

I don't have control over what Welectron sell, but Kane's standard FOB quote is without probes. If the distributor wants probes then they have to order them as a separate line item.

Thx for the reply. I didn't know they aren't stock included. :)

By default Welectron checks the box to include the probes when you hit the 121GW page, but you can uncheck it.

I have two 121GW units that came with shims.  I removed it from both and have had zero issues.  Perhaps after things wear it might be needed.

Yeah, I thought there were some included, so I unchecked it  ;D.  Got myself some Fluke Probes now, maybe have to shorten the banana plugs a bit but otherwise they work fine.

Yeah, I wanted to remove them to avoid issues and found out they aren't there anymore. :)
Title: Re: EEVBlog 121GW Discussion thread
Post by: Timz on June 03, 2021, 09:01:54 pm
Yeah, just received 121GW 2 days ago, and the firmware reads 2.05,  no idea if that's actually from Welectron, but I ordered it directly from EEVBlog shop online.  Delivered to UK by DHL courier and it originated from Australia.

Happy with this product so far.  Thank you so much.

Title: Re: EEVBlog 121GW Discussion thread
Post by: dzenbo on June 04, 2021, 02:25:41 pm
Hi, I have not read all thread trough so maybe this note will be not a new. But in my opinion AutoHold mod is slightly raw, especially in resistance measurement - it takes all my time to get value of a single res. In the same time in a basic mode I see that the value jumps in a least significant digit only. And it is very disapoint that I cant check 5% resistors over the board as fast as I have expected  :P
I understand that design and consumer satisfaction it is all about trade-offs. But my vision of this process is to give user freedom to select between A) more digits, sometimes more noise and more time to get a value, and B) less digits - faster response.

We have a "1 kHz" mode which enables filter. So maybe it is reasonable to make it available for other modes?

One more. Looks that the AutoHold mode does not depends of Auto range or particular range is selected. I thought the overall time to get hold the value is a sum of the time required to find the range and the time required to ensure that the value is stable. But looks that it is not. Very strange

If required I will make a video report later.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on June 07, 2021, 05:38:05 am
Yeah, just received 121GW 2 days ago, and the firmware reads 2.05,  no idea if that's actually from Welectron, but I ordered it directly from EEVBlog shop online.  Delivered to UK by DHL courier and it originated from Australia.

Correct, all my units in stock are the latest 2.05. Welectron were just the first to get it.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Timz on June 07, 2021, 08:28:12 pm
Thanks Dave for your reply.  Can I ask what is the changelog for 2.05, please?

Title: Re: EEVBlog 121GW Discussion thread
Post by: firewalker on June 09, 2021, 10:31:15 am
Thanks Dave for your reply.  Can I ask what is the changelog for 2.05, please?

From Dave.

I now have v2.05
They changed the low pass filter curve to better match the performance of the Fluke 289, which I guess they are using as a sort of reference.
Title: Re: EEVBlog 121GW Discussion thread
Post by: SeoulBigChris on June 12, 2021, 10:04:28 am
Got my 121 finally, on a circuitous path through a buddy in New Zealand because they can’t shop from Australia to South Korea for some reason.

Been working great! I was testing a board where I can program resistance (like a digipot) and I had the 121 connected for some time. A few times during the day I heard this loud alarm beep. The first couple of times I thought it was some alert from my aircon or electric fan. On the third time I finally realized it was the 121 telling me that it was about to auto-shutdown. That’s one loud beeper!
Title: Re: EEVBlog 121GW Discussion thread
Post by: Neo2199 on June 25, 2021, 10:59:31 pm
Yeah, this multimeter is great. I have upgraded my leads to Pomona, good stuff :)
Title: Re: EEVBlog 121GW Discussion thread
Post by: sirtet on July 22, 2021, 11:21:02 am
Hi all. I have two questions:

Firmware 2.05:
Where is it? on
https://www.eevblog.com/product/121gw/ (https://www.eevblog.com/product/121gw/)
i still see 2.04 as the latest...

Shim:
I don't know the full Story with the shim that some revisions needed because of a wrong pcb thickness, so:
Do i have to check if my meter needs the shim, or were no meters sold without that fix?

PS:
@dave, there's an issue with reporting an issue (not that i had one, just saw this:)
(https://i.imgur.com/q7EHxpO.png)
Title: Re: EEVBlog 121GW Discussion thread
Post by: J-R on July 23, 2021, 03:07:20 am
Dave posted the 2.05 firmware one page back.  Here's a link to it: https://www.eevblog.com/forum/testgear/eevblog-121gw-discussion-thread/?action=dlattach;attach=1213626 (https://www.eevblog.com/forum/testgear/eevblog-121gw-discussion-thread/?action=dlattach;attach=1213626)

I'm sure there are units out there where they are "supposed" to have the shim but don't.  Personally I think the shim is not always needed.  I have two that came with the shim but removed it because I thought the switch felt better without it.  Zero issues so far.  If I need it after the contacts wear, I'll re-install.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on July 23, 2021, 03:46:59 am
I don't know the full Story with the shim that some revisions needed because of a wrong pcb thickness, so:
Do i have to check if my meter needs the shim, or were no meters sold without that fix?

IIRC no meters were sold without the shim. It was limited to the Kickstarter shipped units.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Ecogeek on July 27, 2021, 08:09:21 pm
Stick to good brands, like Littelfuse, Cooper Bussmann or Siba if you can, otherwise examine the datasheet carefully for compliance.

Beware of fakes on ebay and other places. Because of the very high potential margins on these, the market is awash with fakes.
Yes I ordered a pack of "Bussman" fuses from China, strangely arrived same day as my order from EEVBlog Australian shop, the labels were identical to the blown 11A fuse Busman fuse I removed, but the fuse end caps did not have "Bussman" stamped and the cap crimping was not the same. The cap plating was also slightly dull and difficult to get a good low resistance contact with my meter leads, when I did a low ohms resistance check they all measured higher resistance than the fuses supply by the EEVBlog shop. 
Thanks Dave for the much cheaper quality fuses. :)
Title: Re: EEVBlog 121GW Discussion thread
Post by: AVGresponding on July 28, 2021, 05:18:46 am
Stick to good brands, like Littelfuse, Cooper Bussmann or Siba if you can, otherwise examine the datasheet carefully for compliance.

Beware of fakes on ebay and other places. Because of the very high potential margins on these, the market is awash with fakes.
Yes I ordered a pack of "Bussman" fuses from China, strangely arrived same day as my order from EEVBlog Australian shop, the labels were identical to the blown 11A fuse Busman fuse I removed, but the fuse end caps did not have "Bussman" stamped and the cap crimping was not the same. The cap plating was also slightly dull and difficult to get a good low resistance contact with my meter leads, when I did a low ohms resistance check they all measured higher resistance than the fuses supply by the EEVBlog shop. 
Thanks Dave for the much cheaper quality fuses. :)

Did you weigh them to see if they are lighter? (no sand inside) Or smash one open to see if it had any?
Title: Re: EEVBlog 121GW Discussion thread
Post by: Ecogeek on July 29, 2021, 02:40:49 am
Further information on Bussman DMM-B-11A and ASTM 11A fuses.[attachimg=1]
As you can see by the photo the plating is duller, the fuses do appear to be OEM (the labels were identical) but possibly old stock or at least different end cap assembly with no OEM cap branding to the Bussman I removed from my meter.

I did some 4 wire resistance measurements (as opposed to multimeter ohms with test probes) with 1A of current flowing.
Results of resistance measurements of six Bussman fuses from Alibaba in mohms.
Bussman DMM-B-11A; 7.446,6.997,7.636,7.298,7.132, 7.306     Average 7.302mohm
weighed in at about 8 grams (on my kitchen scales)

ASTM HV110;  9.255mohm
weighed in at 9 grams

Little Fuse FLU-11A; 8.265mohm

I also did the 4wire resistance measurements of three mulitmeters 10A shunt including fuses (at meter terminals);
Fluke 87  with ASTM HV110 fuse              25.6mohm   (fuse 36% of total)
Agilent U1233A with ASTM HV110 fuse     22.06 mohm (fuse 42% of total)
EEVBlog 121GW with Little Fuse FLU-11A  32.3mohm   (fuse 25.6% of  total)

Conclusion: The spread of 11A fuse resistances was close to 2mohms with the Bussman DMM-B-11A being the lowest, ASTM HV110 the highest with the Little fuse in the middle. The Bussman fuses do appear to be OEM but of unknown age.

PS When I was doing the multimeter 10A resistance measurements I noticed the fluke was "unstable" i.e. seemed to vary which the other two meters did not.  Long story short; the soldering of the fuse holders was causing the problem, the fuse holders only had the fuse tabs soldered and after close to two decades the solder connections were failing. I removed and resoldered including the full base of the fuse holders this time and also replaced the input jack assembly while I was doing the repair work. Hopefully good for another couple of decades.
Title: Re: EEVBlog 121GW Discussion thread
Post by: J-R on July 29, 2021, 09:53:33 am
Did a quick run through on some of my fuses and got 9.1mOhm and 9.2mOhm on two of Dave's ASTMs and 8.4mOhm on my only loose Bussmann labelled with C17 and made in Mexico.  I bought it from Welectron in late 2019 with a DMM.  Weight was 8.1 grams.

Found one document from 2018 that says B04 is 4th week of 2018, but C wasn't specifically listed.  I'm quite confident C17 is 17th week of 2019 though.

https://www.eaton.com/content/dam/eaton/products/electrical-circuit-protection/fuses/solution-center/bus-ele-faq-10464-date-codes.pdf (https://www.eaton.com/content/dam/eaton/products/electrical-circuit-protection/fuses/solution-center/bus-ele-faq-10464-date-codes.pdf)
Title: Re: EEVBlog 121GW Discussion thread
Post by: TheFire8472 on August 02, 2021, 05:13:01 am
Just got my meter. I plan to use it as the backup to my Fluke that I can keep at my other place. Seems great so far - well-made, durable, the measurements I made were quite precise. Great deal overall!
Title: Re: EEVBlog 121GW Discussion thread
Post by: cmumford on September 01, 2021, 09:15:07 pm
What does everybody think about unpinning the 121GW discussion threads? I love mine, but I think the topics have quieted down enough that maybe we don't need three (or even one) of them pinned anymore. Just a thought...
Title: Re: EEVBlog 121GW Discussion thread
Post by: joeqsmith on September 02, 2021, 12:06:15 am
What does everybody think about unpinning the 121GW discussion threads? I love mine, but I think the topics have quieted down enough that maybe we don't need three (or even one) of them pinned anymore. Just a thought...

I've thought that for a while as well.  I'm actually surprised that Dave didn't consider it when announcing the new Brymen meter.  Then I thought it's a Brymen and is going to work....   :-DD

The TE thread is popular enough it stays on top so it also makes little sense to me. 

Others threads also seem old and unmaintained and I wonder the same thing.  What makes them worth being sticky?  Seems like it would be reserved.   Info for beginners and rules all make sense to me.    Even a single sticky thread for each of the products Dave markets makes some sense to me, just for the advertisement.   

Not a big deal to leave it.  Dave's site anyway and I enjoy the free use of it.  So, good job Dave!
Title: Re: EEVBlog 121GW Discussion thread
Post by: tautech on September 02, 2021, 12:27:28 am
What does everybody think about unpinning the 121GW discussion threads? I love mine, but I think the topics have quieted down enough that maybe we don't need three (or even one) of them pinned anymore. Just a thought...

I've thought that for a while as well.  I'm actually surprised that Dave didn't consider it when announcing the new Brymen meter.  Then I thought it's a Brymen and is going to work....   :-DD

The TE thread is popular enough it stays on top so it also makes little sense to me. 

Others threads also seem old and unmaintained and I wonder the same thing.  What makes them worth being sticky?  Seems like it would be reserved.   Info for beginners and rules all make sense to me.    Even a single sticky thread for each of the products Dave markets makes some sense to me, just for the advertisement.   

Not a big deal to leave it.  Dave's site anyway and I enjoy the free use of it.  So, good job Dave!
Dave could easily create another board of EEVblog Products and shift all the threads there and sticky them or whatever.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Brumby on September 02, 2021, 04:07:59 am
"Could" - Yes.

"Should" - I would think not.  It's TE gear, so let's not fragment a subject unnecessarily.  Besides, it hardly impacts the use of the TE board.
Title: Re: EEVBlog 121GW Discussion thread
Post by: e0ne199 on September 03, 2021, 05:45:09 pm
What does everybody think about unpinning the 121GW discussion threads? I love mine, but I think the topics have quieted down enough that maybe we don't need three (or even one) of them pinned anymore. Just a thought...
why?
where will you get the info about new firmware if this thread is unpinned?
and who knows if suddenly Dave and the manufacturer are generous enough to share 121GW's source code, right?
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on September 06, 2021, 05:02:58 am
What does everybody think about unpinning the 121GW discussion threads? I love mine, but I think the topics have quieted down enough that maybe we don't need three (or even one) of them pinned anymore. Just a thought...

Yeah, fair enough, never thought about it.
Seemed important at the time of the Kickstarter when it was the go-to place for updated info, but now, meh, it's just another meter.
Have unstickied them.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on September 06, 2021, 05:06:44 am
What does everybody think about unpinning the 121GW discussion threads? I love mine, but I think the topics have quieted down enough that maybe we don't need three (or even one) of them pinned anymore. Just a thought...

I've thought that for a while as well.  I'm actually surprised that Dave didn't consider it when announcing the new Brymen meter.  Then I thought it's a Brymen and is going to work....   :-DD

The TE thread is popular enough it stays on top so it also makes little sense to me. 

Others threads also seem old and unmaintained and I wonder the same thing.  What makes them worth being sticky?  Seems like it would be reserved.   Info for beginners and rules all make sense to me.    Even a single sticky thread for each of the products Dave markets makes some sense to me, just for the advertisement.   

Not a big deal to leave it.  Dave's site anyway and I enjoy the free use of it.  So, good job Dave!
Dave could easily create another board of EEVblog Products and shift all the threads there and sticky them or whatever.

Well that just lit up an idea. What if there was a Specific Instruments test equipment section where each instrument of note (say several pages is the trigger) got it's own thread and they are all stickied.
It could be an easy go-to section for specific much talked about instruments?
If an ok idea I could make this a specific poll test to see what the general response is?
https://www.eevblog.com/forum/testgear/poll-specific-instruments-forum-section/ (https://www.eevblog.com/forum/testgear/poll-specific-instruments-forum-section/)
Title: Re: EEVBlog 121GW Discussion thread
Post by: tautech on September 06, 2021, 05:39:39 am
What does everybody think about unpinning the 121GW discussion threads? I love mine, but I think the topics have quieted down enough that maybe we don't need three (or even one) of them pinned anymore. Just a thought...

I've thought that for a while as well.  I'm actually surprised that Dave didn't consider it when announcing the new Brymen meter.  Then I thought it's a Brymen and is going to work....   :-DD

The TE thread is popular enough it stays on top so it also makes little sense to me. 

Others threads also seem old and unmaintained and I wonder the same thing.  What makes them worth being sticky?  Seems like it would be reserved.   Info for beginners and rules all make sense to me.    Even a single sticky thread for each of the products Dave markets makes some sense to me, just for the advertisement.   

Not a big deal to leave it.  Dave's site anyway and I enjoy the free use of it.  So, good job Dave!
Dave could easily create another board of EEVblog Products and shift all the threads there and sticky them or whatever.

Well that just lit up an idea. What if there was a Specific Instruments test equipment section where each instrument of note (say several pages is the trigger) got it's own thread and they are all stickied.
It could be an easy go-to section for specific much talked about instruments?
If an ok idea I could make this a specific poll test to see what the general response is?
Yeah well if you examine the current Products board structure there are a few options if you must move stuff around and stir up grumbles where certainly you could add a Specific Instruments board where you could also further divide it into brands.....EEVblog brand instruments too of course.

Maybe a Products> TE Brands> by Brand sub board, each with stickys of certain popular models.
Too much work ?
Title: Re: EEVBlog 121GW Discussion thread
Post by: arekm on September 12, 2021, 09:28:22 pm
I now have v2.05

Any reason it's not on https://www.eevblog.com/product/121gw/ (https://www.eevblog.com/product/121gw/) ?
Title: Re: EEVBlog 121GW Discussion thread
Post by: cmumford on September 15, 2021, 12:08:23 am
I wish that site management of eevblog.com could somehow be delegated. I'm sure that trustworthy volunteers would step up and maintain the 121GW section (I would), but I'm guessing that the site probably isn't setup for that.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on September 15, 2021, 01:24:53 am
I now have v2.05
Any reason it's not on https://www.eevblog.com/product/121gw/ (https://www.eevblog.com/product/121gw/) ?

It is now.
Title: Re: EEVBlog 121GW Discussion thread
Post by: SeoulBigChris on December 15, 2021, 10:06:36 pm
I really like my 121GW, but there is one annoying thing - using it with the bail is a bit unstable. Has anyone come up with an alternative solution, perhaps something we could 3D print? It the bail was a little bit wider, I think it would go a long way for improving the (mechanical) stability.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Kleinstein on December 15, 2021, 10:18:37 pm
A tilting bail with a handheld meter is never really stable because of the limited weight - so maybe it works with a 1960's military one that weighs in at > 2 kg. It is more like a compromise that works as long as one does not move the probes / cables. In some cases a coffey mug to put the bail part in can work for extra stability.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Muttley Snickers on December 15, 2021, 11:29:53 pm
I really like my 121GW, but there is one annoying thing - using it with the bail is a bit unstable. Has anyone come up with an alternative solution, perhaps something we could 3D print? It the bail was a little bit wider, I think it would go a long way for improving the (mechanical) stability.

Here are a couple of options in regards to an improved stand on the 121GW.   :-DMM

https://www.eevblog.com/forum/testgear/eevblog-121gw-discussion-thread/msg2455755/#msg2455755 (https://www.eevblog.com/forum/testgear/eevblog-121gw-discussion-thread/msg2455755/#msg2455755)

https://www.eevblog.com/forum/testgear/eevblog-121gw-bench-stand-(3d-printed)/msg2689518/#msg2689518 (https://www.eevblog.com/forum/testgear/eevblog-121gw-bench-stand-(3d-printed)/msg2689518/#msg2689518)
Title: Re: EEVBlog 121GW Discussion thread
Post by: beanflying on December 16, 2021, 03:26:46 am
I really like my 121GW, but there is one annoying thing - using it with the bail is a bit unstable. Has anyone come up with an alternative solution, perhaps something we could 3D print? It the bail was a little bit wider, I think it would go a long way for improving the (mechanical) stability.

Or you could always print these hanger options too in either magnetic or strap versions. On the bench the meter seems ok to me but wider is better, in the field for me at least the magnetic one works great for sticking on enclosures or equipment.

https://www.eevblog.com/forum/testgear/eevblog-121gw-discussion-thread/msg2479518/#msg2479518 (https://www.eevblog.com/forum/testgear/eevblog-121gw-discussion-thread/msg2479518/#msg2479518)

https://www.eevblog.com/forum/testgear/eevblog-121gw-discussion-thread/msg2479284/#msg2479284 (https://www.eevblog.com/forum/testgear/eevblog-121gw-discussion-thread/msg2479284/#msg2479284)
Title: Re: EEVBlog 121GW Discussion thread
Post by: SeoulBigChris on December 16, 2021, 07:48:48 am
Thanks for those links. I hadn’t thought about magnetic mount - I like that. I also really need a better 2nd meter, and put a BM786 on order today.
Title: Re: EEVBlog 121GW Discussion thread
Post by: v81 on January 27, 2022, 11:29:02 am
Terribly minor issue, and not worth a thread.
The left hand side (from rear of board) of the 400ma fuse mount is the wrong way around.
Just thought I'd mention it in case Dave wanted to shoot a note upstream.
[attach=1]

Going to have to send it back for repair... wouldn't want to void the warranty....
.... Oh.. hang on, EEVblog has no issues with competent self repair.

There was a reason I wanted this!

Great unit Dave, very happy, attention to detail is excellent.
AAs instead of 9v
Captive screws
Metal inserts
Actual HRC fuses unlike the 250v glass/air fuses in my 1000V CATIV rated UniT
 :-DMM   <-- can we get an emote with a blue housing around the multimeter?
Title: Re: EEVBlog 121GW Discussion thread
Post by: bicycleguy on January 27, 2022, 05:12:18 pm
v81,
Since this may become an issue I'll start.  SN EEVBlog 001421 is ok.

Even with its little quirks its a great meter and I'd buy again.

FYI after a few years of testing NiMH batteries I have settled on recharge at 5.0V displayed.  This has consistently provided 4-5 month intervals with more use than my wife would like to see.   (I've lately been logging my refrigerator and freezer temperatures  ^-^ )
Title: Re: EEVBlog 121GW Discussion thread
Post by: v81 on January 29, 2022, 04:56:12 am
v81,
Since this may become an issue I'll start.  SN EEVBlog 001421 is ok.

There were 2 x 121GW's in the order, have checked the second one since my last post and it's OK.
Could be just a one off.

Does this have issues using the full or at least close to the full capacity of NiMH cells?
Wonder if there would be any value in doing a 2x 14500 Lithium ion powered multimeter? Rechargeable and more voltage to play with at the same time.
Title: Re: EEVBlog 121GW Discussion thread
Post by: bicycleguy on January 29, 2022, 05:46:16 am
The issue isn't the full capacity of NiMH which only manage to get to about 5.9V with the four in series immediately after charging.  Within a few days it drops to approx 5.5 volts, then gradually drops to 5V over ~4 months of use.  The meter will continue to work properly below 5V but that isn't good for the NiMH to go much below 1.25V assuming they are all even and I remember to check them.

Earlier in this thread people talk about mods or not for Li-whatever.  They have the high side issue.  I don't think their worth the cost or hassle.
Title: Re: EEVBlog 121GW Discussion thread
Post by: v81 on January 29, 2022, 09:30:48 am
Right, i had the impression the meter might not be able to use all of the useful capacity of the NiMH.

Sounds now more of a concern for over discharge.

An alternative firmware with an alert or shutdown for 4.8v might be nice.
Title: Re: EEVBlog 121GW Discussion thread
Post by: zega on February 09, 2022, 06:08:46 pm
How about little feature for next FW update?
VCO!
Many times i was not able to look at screen but need to tune something to the maximum value without being able to look at the screen!
So to have piezo inside multimeter producing sound that would change frequency with value change (i .e. voltage goes up, frequency as tone pitch goes up)
That way you can hook up multimeter to measure certain value, and while you are away, multimeter produces tone that pitches up or down while you are adjusting something, also resetting with delta function can set "new start" or create baseline pitch that will be your baseline (440Hz? idk).
Basically Like voltage controlled oscillator (VCO)!
It would be best to tie that to fast barograph display, or what I'm trying to say, the faster the better!
What is the opinion on this one? :popcorn:
Title: Re: EEVBlog 121GW Discussion thread
Post by: e0ne199 on February 12, 2022, 06:03:47 pm
How about little feature for next FW update?
VCO!
Many times i was not able to look at screen but need to tune something to the maximum value without being able to look at the screen!
So to have piezo inside multimeter producing sound that would change frequency with value change (i .e. voltage goes up, frequency as tone pitch goes up)
That way you can hook up multimeter to measure certain value, and while you are away, multimeter produces tone that pitches up or down while you are adjusting something, also resetting with delta function can set "new start" or create baseline pitch that will be your baseline (440Hz? idk).
Basically Like voltage controlled oscillator (VCO)!
It would be best to tie that to fast barograph display, or what I'm trying to say, the faster the better!
What is the opinion on this one? :popcorn:

nah...the thing that needs real fixing here is the bug on VA mode bargraph...whenever i switch the measurement range and switch to VA mode, the bargraph scale on VA mode just won't change at all and it really annoys me whenever i use VA mode for measuring things :-//
Title: Re: EEVBlog 121GW Discussion thread
Post by: BrianG61UK on February 26, 2022, 09:46:28 pm
The issue isn't the full capacity of NiMH which only manage to get to about 5.9V with the four in series immediately after charging.  Within a few days it drops to approx 5.5 volts, then gradually drops to 5V over ~4 months of use.  The meter will continue to work properly below 5V but that isn't good for the NiMH to go much below 1.25V assuming they are all even and I remember to check them.

Earlier in this thread people talk about mods or not for Li-whatever.  They have the high side issue.  I don't think their worth the cost or hassle.

All Ni-MH I've ever seen are rated as 1.2V.
Going below 1.25V is not a problem for them.
The normal end of life is around 1 to 1.1v.
My understanding is that going lower is also not much of a problem as long as you don't let them go below zero.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Ziginox on April 19, 2022, 08:55:09 pm
Thanks, I will have a look at that video shortly.   :)

I just found this video on Youtube where someone has created a splendid addition to the tilt stand on the 121GW meter.   :-/O   

https://www.thingiverse.com/thing:3666409 (https://www.thingiverse.com/thing:3666409)        :-+

https://www.youtube.com/watch?v=vZ2xE71g_xw (https://www.youtube.com/watch?v=vZ2xE71g_xw)

Pardon if it has been answered, but does anybody know what the hole in the bail was originally designed for? I see that 121GW's cousin, the Klein MM2000, also has it. Klein's website, however, doesn't mention any accessories that fit there.

I received mine last week (here in New Potatoland, USA) from Welectron in Germany, it only took a week to get here! Loving it so far, especially the internal logging.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Ziginox on July 08, 2022, 03:20:58 pm
Ran into a small issue with my unit, or rather the bag I purchased alongside it. The stitching along the lower edge of the front came apart for no apparent reason. It seems like the fabric panel that makes up the front was cut too short, and the stitching simply pulled out of the weave. I tried emailing the store support email listed on the EEVBlog contact page a month back, but never received a reply. I purchased from Welectron, is this something I'd have to reach out to them for, instead?
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on July 09, 2022, 06:03:00 am
Ran into a small issue with my unit, or rather the bag I purchased alongside it. The stitching along the lower edge of the front came apart for no apparent reason. It seems like the fabric panel that makes up the front was cut too short, and the stitching simply pulled out of the weave. I tried emailing the store support email listed on the EEVBlog contact page a month back, but never received a reply. I purchased from Welectron, is this something I'd have to reach out to them for, instead?

Yes, you'll have to talk to Welectron. I do not sell the case, nor do I provide the meters to Welectron, they order directly from Kane Test.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Ziginox on July 09, 2022, 07:42:54 am
Yes, you'll have to talk to Welectron. I do not sell the case, nor do I provide the meters to Welectron, they order directly from Kane Test.

Much appreciated, Dave! I'll reach out to them and see what they say.
Title: Re: EEVBlog 121GW Discussion thread
Post by: unknownparticle on July 24, 2022, 05:18:48 pm
Hi all,
Regarding the firmware update procedure for the 121GW.
I have read the words in the manual but am still unsure of the exact procedure.
So, do I need an additional SD card to the one installed in the meter to load the new firmware?  What capacity SD card?  There is no mention of this in the manual.
My laptop does not have an MSD card slot, so how do I install the file on the card?

I realise these questions may induce a groan from the seasoned tech vets on here but I am just not very familiar with this stuff ???
Title: Re: EEVBlog 121GW Discussion thread
Post by: armandine2 on July 24, 2022, 06:23:18 pm

groan from the seasoned tech vets

I wonder how they look back at the skeletons in the cupboard - as still very much a beginner, I know I shudder.

Title: Re: EEVBlog 121GW Discussion thread
Post by: Ziginox on July 25, 2022, 05:15:26 am
Hi all,
Regarding the firmware update procedure for the 121GW.
I have read the words in the manual but am still unsure of the exact procedure.
So, do I need an additional SD card to the one installed in the meter to load the new firmware?  What capacity SD card?  There is no mention of this in the manual.
My laptop does not have an MSD card slot, so how do I install the file on the card?

I realise these questions may induce a groan from the seasoned tech vets on here but I am just not very familiar with this stuff ???

You can use the included microSD card. You just drop the file onto the card and name it "EEVblog.bin".  Pop the card back in the meter, push and hold the "HOLD" and "MEM" buttons while powering it on, then push the "SETUP" button. You can get the update file on the product page, if you click "Firmware" on the left side, under the picture of the meter https://www.eevblog.com/product/121gw/ (https://www.eevblog.com/product/121gw/)
As for getting the file onto the card, if your laptop has a full-size SD slot you'll just need a microSD to SD adapter. They come with just about every microSD card sold these days. If your laptop doesn't have that, you'll need a USB SD and/or microSD card reader. Just like you'd use for a camera. It shows up as a removable disk. Just drag'n'drop!
Title: Re: EEVBlog 121GW Discussion thread
Post by: Ziginox on July 25, 2022, 05:20:05 am
Yes, you'll have to talk to Welectron. I do not sell the case, nor do I provide the meters to Welectron, they order directly from Kane Test.

Much appreciated, Dave! I'll reach out to them and see what they say.

Sorry for the double post, but an update on this: Welectron issued a refund for it, hopefully I should see it hit my account soon!
Title: Re: EEVBlog 121GW Discussion thread
Post by: beanflying on July 25, 2022, 05:22:30 am
EEVblog.bin not EEVBlog.bin when you rename it.
Title: Re: EEVBlog 121GW Discussion thread
Post by: matemathieu on August 05, 2022, 01:12:30 pm
Hi,

I found it is not possible to report an issue on the store page here:
https://www.eevblog.com/product/121gw/ (https://www.eevblog.com/product/121gw/)

Hence have an issue to report.
According to the current version of the manual, the thermocouple reading cannot be calibrated.

One simple way of doing it is to use boiling/freezing water.
Capture the max temp when you put a K-type probe into your home boiler, make sure it does not touch the bottom where the heater is and you have the first point.
Water with ice would be the second one. Put water with lots of ice, wait. Make sure the probe end-tip does not touch the ice and capture the lowest value.

Is that a good idea?
Best
Title: Re: EEVBlog 121GW Discussion thread
Post by: unknownparticle on August 05, 2022, 04:42:42 pm
How long does the 121GW take to load a new update, and how do you know when it has?  Asking because I've just loaded the latest update onto a new high speed 68 gig SD card and it doesn't seem to have done anything in just under an hour!  All the display is showing is IAP in the top left and down on the main display line.
I did everything according to the manual and advice above.
Title: Re: EEVBlog 121GW Discussion thread
Post by: unknownparticle on August 05, 2022, 07:03:10 pm
Situation sorted!!
I had a think and realised the file hadn't been extracted and the renaming hadn't worked properly.  I renamed the thumbnail in the folder that I saved the new update to, but I didn't realise the file hadn't been extracted so wasn't actually renamed. Worked my way through that, dropped the SD into the meter, did the install key press thing, then I saw the download progress on the display bar graph!  Ta Da!!

If the manual had mentioned what the download progress should be indicated by, I would have known there was an issue with the file on the SD!

So, meter now updated, all good! And the boot loader seemed to tolerate my ignorance fine!
Title: Re: EEVBlog 121GW Discussion thread
Post by: ve2mrx on August 05, 2022, 09:10:49 pm
I would expect the card to require Fat or Fat32 formatting, preferably done with the SD Association SD card formatter.

If your card is too large, it won't be Fat or Fat32 and the meter won't read it.

Martin
Title: Re: EEVBlog 121GW Discussion thread
Post by: unknownparticle on August 05, 2022, 09:38:16 pm
Possibly, I actually went back to the SD card supplied with the meter, which is 8GB. Thanks.
Title: Re: EEVBlog 121GW Discussion thread
Post by: beanflying on August 06, 2022, 01:36:01 am
Hi,

I found it is not possible to report an issue on the store page here:
https://www.eevblog.com/product/121gw/ (https://www.eevblog.com/product/121gw/)

Hence have an issue to report.
According to the current version of the manual, the thermocouple reading cannot be calibrated.

One simple way of doing it is to use boiling/freezing water.
Capture the max temp when you put a K-type probe into your home boiler, make sure it does not touch the bottom where the heater is and you have the first point.
Water with ice would be the second one. Put water with lots of ice, wait. Make sure the probe end-tip does not touch the ice and capture the lowest value.

Is that a good idea?
Best

To some degree (no pun intended  ;D ) there is not a huge need to try and 'calibrate' the meter with a K type thermocouple. 'Roughly Checking the Calibration' is about all you can do with your method.

Generally accepted accuracies Type K ±2.20C or ±0.75%

While the 121GW's spec is less than that Temp °C, -200 to 1350°C, K-Type, 0.1°C (resolution), ±0.5%+3°C (stated accuracy)

So inherently because of this you can not get a reading more 'accurate' or known under the spec of the meter. The Meter if it was to be calibrated on the Temperature range would more likely be done against a calibrated source instead.
Title: Re: EEVBlog 121GW Discussion thread
Post by: matemathieu on August 11, 2022, 01:10:59 pm
To some degree (no pun intended  ;D ) there is not a huge need to try and 'calibrate' the meter with a K type thermocouple. 'Roughly Checking the Calibration' is about all you can do with your method.

Generally accepted accuracies Type K ±2.20C or ±0.75%

While the 121GW's spec is less than that Temp °C, -200 to 1350°C, K-Type, 0.1°C (resolution), ±0.5%+3°C (stated accuracy)

So inherently because of this you can not get a reading more 'accurate' or known under the spec of the meter. The Meter if it was to be calibrated on the Temperature range would more likely be done against a calibrated source instead.

It got a 100ºC error @600ºC.
Then I checked by dipping it into boiling water and it showed 107ºC.

Then I realized it was partially due to the low battery of the unit, I changed them, and it got back to something in the specs.
Title: Re: EEVBlog 121GW Discussion thread
Post by: ve2mrx on August 11, 2022, 02:36:45 pm
Remember that the temperature of the meter is part of the temperature reading, the K-type thermocouple measures temperature difference between both ends, not a temperature like a thermistor!

Calibrating the meter would only be for a specific probe. It's best to check the accuracy of the meter's internal temperature reading and calculate the offset the probe adds to it. Maybe do two points with the probe and derive an equation from the measurements and attach it to the probe. You would then correct the meter temperature and add the probe correction to it to get a final temperature... Or use a dedicated precision measurement system like a 4-lead platinum probe.

Martin
Title: Re: EEVBlog 121GW Discussion thread
Post by: JDW on February 19, 2023, 09:19:59 am
I purchased a 121GW brand new from the official store (https://www.eevblog.com/product/121gw/) in Jan. 2023, and I then downloaded the Meteor app (https://apps.apple.com/us/app/meteor-for-121gw/id1452124710) for my iPhone.  It works well enough via Bluetooth communication, but I wanted to compare with the official 121GW iOS app here (https://iphone.apkpure.com/121gw/121gw.ios). Sadly, it says Not Available regardless of whether I am signed in with my Apple ID for the USA or my other Apple ID for Japan.  Is it region locked to Australia (which would be crazy)?  Or is the official app totally dead on iOS for some reason?

The reason I even ask is because I dislike the Meteor app because it lacks a FREEZE/HOLD feature.  When logging data with the app via Bluetooth, I want to be able to tap the iPhone screen or a button in the app to freeze the waveform display so I can better examine it.  If I stop logging, the frustrating Meteor app dims out the waveform display, making it harder to see!  I wanted to download the official 121GW app to see if it works better than Meteor in that regard.  But again, I can't find the iOS official app anywhere now in 2023!
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on February 20, 2023, 09:14:24 pm
I purchased a 121GW brand new from the official store (https://www.eevblog.com/product/121gw/) in Jan. 2023, and I then downloaded the Meteor app (https://apps.apple.com/us/app/meteor-for-121gw/id1452124710) for my iPhone.  It works well enough via Bluetooth communication, but I wanted to compare with the official 121GW iOS app here (https://iphone.apkpure.com/121gw/121gw.ios). Sadly, it says Not Available regardless of whether I am signed in with my Apple ID for the USA or my other Apple ID for Japan.  Is it region locked to Australia (which would be crazy)?  Or is the official app totally dead on iOS for some reason?

The reason I even ask is because I dislike the Meteor app because it lacks a FREEZE/HOLD feature.  When logging data with the app via Bluetooth, I want to be able to tap the iPhone screen or a button in the app to freeze the waveform display so I can better examine it.  If I stop logging, the frustrating Meteor app dims out the waveform display, making it harder to see!  I wanted to download the official 121GW app to see if it works better than Meteor in that regard.  But again, I can't find the iOS official app anywhere now in 2023!

I didn't do anything with the IOS app, it hasn't changed since the original release, so AFAIK should still be available. I don't have an iPhone so I can't check.
Title: Re: EEVBlog 121GW Discussion thread
Post by: JDW on February 20, 2023, 09:30:05 pm
I purchased a 121GW brand new from the official store (https://www.eevblog.com/product/121gw/) in Jan. 2023, and I then downloaded the Meteor app (https://apps.apple.com/us/app/meteor-for-121gw/id1452124710) for my iPhone.  It works well enough via Bluetooth communication, but I wanted to compare with the official 121GW iOS app here (https://iphone.apkpure.com/121gw/121gw.ios). Sadly, it says Not Available regardless of whether I am signed in with my Apple ID for the USA or my other Apple ID for Japan.  Is it region locked to Australia (which would be crazy)?  Or is the official app totally dead on iOS for some reason?

The reason I even ask is because I dislike the Meteor app because it lacks a FREEZE/HOLD feature.  When logging data with the app via Bluetooth, I want to be able to tap the iPhone screen or a button in the app to freeze the waveform display so I can better examine it.  If I stop logging, the frustrating Meteor app dims out the waveform display, making it harder to see!  I wanted to download the official 121GW app to see if it works better than Meteor in that regard.  But again, I can't find the iOS official app anywhere now in 2023!

I didn't do anything with the IOS app, it hasn't changed since the original release, so AFAIK should still be available. I don't have an iPhone so I can't check.

Well, it's not.

I searched for the original Apple app store URL and found it on Twitter, but if you click it yourself, you will discover the app is no longer available.  Please try it yourself...

https://apps.apple.com/us/app/121gw/id1396353605 (https://apps.apple.com/us/app/121gw/id1396353605)

I'm assuming you hired someone to create that app originally, since I found a Dave Jones post on Twitter saying "I don't use anything Apple."

https://twitter.com/eevblog/status/1013951195071721472 (https://twitter.com/eevblog/status/1013951195071721472)

If so, the entity who created the app should confirm with Apple as to why the iOS version app was removed from the Apple app store, with the aim of having it reinstated.
Title: Re: EEVBlog 121GW Discussion thread
Post by: bicycleguy on February 21, 2023, 05:18:25 pm
Before you get too excited about the original app know that the 'HOLD' feature only holds the text value.  The graph continues to scroll.

I have the app on a 2015 iphone6 with ios12.  It still works as originally.

121GW does not show up in the app store because  unfortunately apple while claiming to be environmentally sensitive has determined that this phone is too old for them to allow updates to the latest ios16.  They want users to trash their perfectly fine phones and buy new ones.

Since Seppy doesn't even own an iPhone he is not a likely candidate to update the app.  It would be nice and perhaps help sales of 121GW if Seppy posted the source code on GitHub so others could update the app.  I don't understand why Dave doesn't make it so.
Title: Re: EEVBlog 121GW Discussion thread
Post by: JDW on February 21, 2023, 09:13:50 pm
Before you get too excited about the original app know that the 'HOLD' feature only holds the text value.  The graph continues to scroll.

I have the app on a 2015 iphone6 with ios12.  It still works as originally.

121GW does not show up in the app store because  unfortunately apple while claiming to be environmentally sensitive has determined that this phone is too old for them to allow updates to the latest ios16.  They want users to trash their perfectly fine phones and buy new ones.

Since Seppy doesn't even own an iPhone he is not a likely candidate to update the app.  It would be nice and perhaps help sales of 121GW if Seppy posted the source code on GitHub so others could update the app.  I don't understand why Dave doesn't make it so.

Well, I still have an iPhone 7, for what it's worth, and I cannot see the app even on that ancient phone!

Any app developer should support the iOS app store due to the sheer number of people out there who use the iPhone, but it is important to click your app links at least once a year to see if the app is still available.  Clearly, that hasn't been done here, and if any of you will kindly click the link in my previous post, you will see the app is not there.

Meteor is the only available app, and if it would allow us to FREEZE the screen to view logged waveforms so they won't scroll on by, then my biggest complaint will have been solved, and there perhaps would be no need for the official app.  So maybe a tie-up between Dave's developer of the official app (I don't think Dave wrote the app himself) and Meteor would be the best way to approach it.

It's easy for an Android user to flippantly say, "well, I don't use iOS, so I really don't care," but iOS is big worldwide, and some of us have never owned an Android phone, nor do we have plans to get one for the lone purpose of running the official app.

All said, the current status quo of the official app NOT being downloadable on the Apple iOS app store needs to change.

Thanks.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on February 21, 2023, 10:47:44 pm
Since Seppy doesn't even own an iPhone he is not a likely candidate to update the app.  It would be nice and perhaps help sales of 121GW if Seppy posted the source code on GitHub so others could update the app.  I don't understand why Dave doesn't make it so.

I thought it already was, apparently not.
The Android app has been there since day 1.
https://gitlab.com/eevblog/
I'd add it but I have no idea how to upload entire directories to gitlab  :-//
Title: Re: EEVBlog 121GW Discussion thread
Post by: Brumby on February 22, 2023, 12:43:48 am
121GW does not show up in the app store because  unfortunately apple while claiming to be environmentally sensitive has determined that this phone is too old for them to allow updates to the latest ios16.  They want users to trash their perfectly fine phones and buy new ones.

It could be even simpler than that.

I had the situation that an App could no longer work with a new release of an O/S as it used features that were discarded in favour of more up-to-date means - and this was an Andriod phone.  I can see Apple going the step further and culling any Apps that will not work on their current release - despite older phones being out there that would be capable of running the old App.

While this guides all Apple users into a consistent and current environment, it does squeeze out older - but still quite capable - equipment.


In defence of this approach, the overhead maintaining multiple O/S compatibility in an App is not insignificant - and is often impossible with new features only available with newer operating systems.
Title: Re: EEVBlog 121GW Discussion thread
Post by: JDW on February 22, 2023, 01:10:15 am
In defence of [Apple culling older apps incompatible with new iOS releases], the overhead maintaining multiple O/S compatibility in an App is not insignificant - and is often impossible with new features only available with newer operating systems.

Be that as it may, the fact remains that the smartphone APP is the killer "Logging" feature of the 121GW insofar as the app shows you a graphical waveform representation without requiring you to unscrew and open the meter to extract the SD card which in turn must be put into a computer for the purpose of seeing a TEXT-only view of logged data.  Want a visual representation of that text you extracted from the SD card?  You must make time to graph it yourself!  And after all that time-consuming work, you must put the SD card back in.  Want more data?  Wash and repeat!  Ack!  Glad the SD card is there, but man the app is so much better!

Most people who buy the 121GW, myself included, do so BECAUSE it has data logging.  If you don't need that one key feature, the BM786 (https://www.eevblog.com/product/eevblog-bm786-multimeter/) is perhaps the best pick.  And when you want data logging, you want something fast, convenient, and if possible, graphical.  The 121GW offers that by way of the smartphone app.

And so, I do hope that whatever happens now will bring us a better iOS app.  Meteor (https://apps.apple.com/us/app/meteor-for-121gw/id1452124710) isn't all that bad, but not being able to FREEZE the waveform on my iPhone's screen (without dimming) is a critically important feature that I am totally shocked and amazed that the developer of Meteor didn't consider.  It would be great if that developer could read our discussion here, as that may inspire him to improve his app, thereby making my call for the official app to be reinstated to the iOS App Store moot.

Just to let everyone know, the reason for all this discussion is because I am doing prep work for a YouTube video review of the 121GW.  It was not given to me.  I purchased it new at the end of January this year, direct from the EEVBlog store.  I had hoped to get the Fuse pack (https://www.eevblog.com/product/multimeter-fuse-pack/) too, but frustratingly, it was out of stock.  In fact, I checked just now to find it still out of stock!  Even the 121GW meter itself is often out of stock, so I snapped it up when I could.  Had I waited for the Fuse pack to get back in stock, my worry was the meter would then go out of stock.  Indeed, had I waited, I still would be waiting AND without a meter too.

By the way, selling the 121GW on Amazon (not simply on the EEVBlog store only) might be a way to give it free advertising and more exposure.  It says "Currently Unavailable (https://www.amazon.com/EEVblog-121GW-Multimeter/dp/B07W8C3T3J/)" now on Amazon, despite the fact the BM786 is available there (https://www.amazon.com/EEVblog-BM786-Multimeter/dp/B08N61LF4Z/).
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on February 22, 2023, 01:53:52 am
After spending half the day and live stream trying to do it, thesource code is now on github:
https://github.com/EEVblog/121GW-App-Apple-IOS
also gitlab:
https://gitlab.com/eevblog/eevblog-121gw-app-for-apple-ios
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on February 22, 2023, 02:57:57 am
And so, I do hope that whatever happens now will bring us a better iOS app.  Meteor (https://apps.apple.com/us/app/meteor-for-121gw/id1452124710) isn't all that bad, but not being able to FREEZE the waveform on my iPhone's screen (without dimming) is a critically important feature that I am totally shocked and amazed that the developer of Meteor didn't consider.  It would be great if that developer could read our discussion here, as that may inspire him to improve his app, thereby making my call for the official app to be reinstated to the iOS App Store moot.

I had no idea that app existed.
I haven't tried it yet, but maybe it's best if I just leave it to them (or others) to do this.
The source code for my version is out there now, so anyone is free to take it and update the app or make their own.
I still have absolutely no idea why my app vanished, or what's involved to get it back up.
Title: Re: EEVBlog 121GW Discussion thread
Post by: bicycleguy on February 22, 2023, 04:22:31 am
Thanks for the work of putting on Github.  Your effort was successful !

I was able to clone it and relatively easily get it to sort of start working on my iphone6.  Just getting it to compile and put up a window is normally half the battle.

This looks a lot more capable than the 1.7 build I have been using even though it says 1.0.5 ?

It has 17  'Deprecations',  5 from ios9 the rest from ios10 that have to be dealt with to bring it up to ios12 that I'm using.  Deprecations are functions that apple is changing or dropping that require a little work to figure out how to modify so it will run the correct new stuff.

BT comm is working but no graphing is happening.  When I get the Deprecations fixed it'll probably start working.
Title: Re: EEVBlog 121GW Discussion thread
Post by: JDW on February 22, 2023, 04:30:02 am
I just sent an email to Western Computational, developer of Meteor, informing them of this discussion thread and the fact the source is now on Github.  I also mentioned the inability to FREEZE a waveform during logging.

Hopefully the end result will be a better 121GW app.  It's not a significant change, so I don't see what it can't happen.  I simply lack the coding ability to do it.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Muttley Snickers on February 22, 2023, 05:53:31 am
(snip....)
The reason I even ask is because I dislike the Meteor app because it lacks a FREEZE/HOLD feature.  When logging data with the app via Bluetooth, I want to be able to tap the iPhone screen or a button in the app to freeze the waveform display so I can better examine it.  If I stop logging, the frustrating Meteor app dims out the waveform display, making it harder to see! 

I don't own this meter or any Apple products but wondered if as an interim measure you were able to grab a screenshot on your phone whilst logging to further assess the measured data?
Title: Re: EEVBlog 121GW Discussion thread
Post by: JDW on February 26, 2023, 09:34:46 am
I have the following 2 questions today which are NOT app-related...

(1) Why does the backlight flash on & off for a split second each and every time I switch on my 121GW?  I see no practical reason for that. It's not like you need to TEST the backlight LEDs each time the meter is switched on.  And while it comes on too briefly to have a negative impact on the alkaline batteries, the fact remains it does draw more current in that brief split second versus the backlight not flashing on/off at all.  Can it be said that is something which should be fixed in firmware?

(2) After switching the meter on, I want to know why it takes 3 seconds before I can use it.  Sure, I see it displays the firmware version for 3 seconds.  But does the meter deliberately wait 3 seconds solely for the purpose of displaying the firmware revision?  Or would the meter take that long to become usable even if the firmware version was not displayed?  The reason I ask is because if the meter could become usable faster than 3 seconds after switch-on, that would be beneficial, and perhaps the firmware version could be looked up somewhere in Setup instead of displaying every time the meter is switched on.
Title: Re: EEVBlog 121GW Discussion thread
Post by: bicycleguy on February 26, 2023, 09:14:32 pm
After spending half the day and live stream trying to do it, thesource code is now on github:
https://github.com/EEVblog/121GW-App-Apple-IOS (https://github.com/EEVblog/121GW-App-Apple-IOS)
also gitlab:
https://gitlab.com/eevblog/eevblog-121gw-app-for-apple-ios (https://gitlab.com/eevblog/eevblog-121gw-app-for-apple-ios)

Thanks again for posting these.  After spending a full day to figure out, both seem to be for the asci encoded version of the 121GW ble protocol (from 2016 b4 the kickstarter?) so won't work.  The IOS version(don't know about android) is called 'Smart Data Logger' and appears to be the long lost version mentioned here:
https://www.eevblog.com/forum/testgear/eevblog-121gw-multimeter-issues/msg2314242/#msg2314242 (https://www.eevblog.com/forum/testgear/eevblog-121gw-multimeter-issues/msg2314242/#msg2314242)

This is a screendump of 'EEVBlog Smart Data Logger', build 1.0.5 with startup screen data.
[attachimg=2]
Any thing newer?

I don't know what @JDW was talking about unless a newer version of this existed at one time.

This is a screendump of a working version of 121GW, build 1.7, loaded from app store around 2019 I have which doesn't do data logging.
[attachimg=1]

I'll probably try to merge newer parsing code from somewhere around here but a newer version would save a lot of effort.
Title: Re: EEVBlog 121GW Discussion thread
Post by: JDW on February 26, 2023, 09:43:32 pm
I don't know what @JDW was talking about unless a newer version of this existed at one time. (Attachment Link)

https://www.eevblog.com/forum/testgear/eevblog-121gw-multimeter-issues/msg2314242/#msg2314242 (https://www.eevblog.com/forum/testgear/eevblog-121gw-multimeter-issues/msg2314242/#msg2314242)

(Attachment Link)

What I was (and still am) talking about, with regards to the app, is explained clearly in my opening post on the matter here:
https://www.eevblog.com/forum/testgear/eevblog-121gw-discussion-thread/msg4711112/#msg4711112 (https://www.eevblog.com/forum/testgear/eevblog-121gw-discussion-thread/msg4711112/#msg4711112)

Since the 121GW has BlueTooth, it made sense for me, having purchased the 121GW new for the first time last month, to Google for "121GW app."  It was then I discovered information about the official app (which sadly no longer exists in the Apple iOS app store) and the Meteor app, which was not authored by Dave/EEVBlog.  Being curious about the iOS app (since I use iPhones only, not Android), I posted in this thread.

Based on that URL you provided, it seems that EEVBlog forum member @DavidWC is the author of the Meteor app.  Well, I did email Western Computational about the Github release.  No reply back or comment here though.

It would be nice if the iOS version could be made to work again.  I would like to try it out, especially since there doesn't seem to be a video out there showing its features.

If the Meteor app had a FREEZE button to stop the waveform without dimming the screen, the official app wouldn't matter so much to me.  I am merely saying that Meteor could use some work to make it better.  And I was also hoping to get the official app on my iPhone to see what features it offers.  But if the iOS app was only compatible with the 2016 edition of the 121GW and not the current version, then it would need a lot more work to get it back into the Apple App Store, I guess.

Why does any of this matter?  Because (1) the 121GW has BlueTooth for some good reason, right?  And (2) it's a bother to remove the blue bumper and unscrew the back case each and every time you want to access data logged to the SD card.  I'm very glad that SD card exists, but disassembly is required to use it.  No disassembly is required to use BlueTooth and a smartphone app, however!  Hence my posts on that topic.

By the way, if anyone has answers to the 2 questions I put forth in my previous post, which have nothing to do with the app or data logging, that would be great!
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on February 26, 2023, 10:25:03 pm
Thanks again for posting these.  After spending a full day to figure out, both seem to be for the asci encoded version of the 121GW ble protocol (from 2016 b4 the kickstarter?) so won't work.  The IOS version(don't know about android) is called 'Smart Data Logger' and appears to be the long lost version mentioned here:
https://www.eevblog.com/forum/testgear/eevblog-121gw-multimeter-issues/msg2314242/#msg2314242 (https://www.eevblog.com/forum/testgear/eevblog-121gw-multimeter-issues/msg2314242/#msg2314242)

This is a screendump of 'EEVBlog Smart Data Logger', build 1.0.5 with startup screen data.
(Attachment Link)
Any thing newer?

I don't know what @JDW was talking about unless a newer version of this existed at one time.

This is a screendump of a working version of 121GW, build 1.7, loaded from app store around 2019 I have which doesn't do data logging.
(Attachment Link)

The "Smart Data Logger" app was developed by KaneTest who make the meter. I had no input into that at all.
The "official" 121GW app was developed entirely in-house by my employee at the time David Ledger. I has not been maintained since he left. I do not have the software skills to update this myself, and at this stage I have no intention of finding someone else to update the apps.
The source code for the Android app and the iOS app and the protocol are entirely open source.

Again, I have no idea why the iOS app vanished from the store, we went through all the official red tape to get it approved and listed at the time.
Title: Re: EEVBlog 121GW Discussion thread
Post by: J-R on February 26, 2023, 11:12:35 pm
(1) Why does the backlight flash on & off for a split second each and every time I switch on my 121GW?  I see no practical reason for that. It's not like you need to TEST the backlight LEDs each time the meter is switched on.  And while it comes on too briefly to have a negative impact on the alkaline batteries, the fact remains it does draw more current in that brief split second versus the backlight not flashing on/off at all.  Can it be said that is something which should be fixed in firmware?
Actually, I had a 121GW where the backlight failed.  It was a small SMD resistor that had cracked in half on the board containing the backlight LEDs (somewhat easy fix).  So having the backlight flash is a good test and that is what made me notice it.  But this may simply be what happens when power initially flows through the board.  Either way, this is just not an issue that needs to be fixed.

Quote
(2) After switching the meter on, I want to know why it takes 3 seconds before I can use it.  Sure, I see it displays the firmware version for 3 seconds.  But does the meter deliberately wait 3 seconds solely for the purpose of displaying the firmware revision?  Or would the meter take that long to become usable even if the firmware version was not displayed?  The reason I ask is because if the meter could become usable faster than 3 seconds after switch-on, that would be beneficial, and perhaps the firmware version could be looked up somewhere in Setup instead of displaying every time the meter is switched on.
A lot of DMMs display something before they are usable, for various reasons, most likely the DMM simply needs that long to start up so might as well show something on the screen.  Given how many dozens of different firmware versions the 121GW has gone through, showing it at power on is a good place for it.
Title: Re: EEVBlog 121GW Discussion thread
Post by: J-R on February 26, 2023, 11:19:56 pm
Why does any of this matter?  Because (1) the 121GW has BlueTooth for some good reason, right?  And (2) it's a bother to remove the blue bumper and unscrew the back case each and every time you want to access data logged to the SD card.  I'm very glad that SD card exists, but disassembly is required to use it.  No disassembly is required to use BlueTooth and a smartphone app, however!  Hence my posts on that topic.

Many products have app issues over their lifetime, it is a fact of life now.  Best to just move on.  The 121GW actually has it pretty good, with the official Android and Windows app still available and working, and recently someone put together some code to data log via Linux:
https://www.eevblog.com/forum/testgear/121gw-multimeter-command-line-data-logger-for-linux/ (https://www.eevblog.com/forum/testgear/121gw-multimeter-command-line-data-logger-for-linux/)
https://github.com/chlordk/121gwcli (https://github.com/chlordk/121gwcli)
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on February 27, 2023, 12:30:21 am
Why does any of this matter?  Because (1) the 121GW has BlueTooth for some good reason, right?  And (2) it's a bother to remove the blue bumper and unscrew the back case each and every time you want to access data logged to the SD card.  I'm very glad that SD card exists, but disassembly is required to use it.  No disassembly is required to use BlueTooth and a smartphone app, however!  Hence my posts on that topic.

Many products have app issues over their lifetime, it is a fact of life now.  Best to just move on.  The 121GW actually has it pretty good, with the official Android and Windows app still available and working, and recently someone put together some code to data log via Linux:
https://www.eevblog.com/forum/testgear/121gw-multimeter-command-line-data-logger-for-linux/ (https://www.eevblog.com/forum/testgear/121gw-multimeter-command-line-data-logger-for-linux/)
There is also Sigrok support:
http://sigrok.org/wiki/EEVBlog_121GW (http://sigrok.org/wiki/EEVBlog_121GW)
https://github.com/chlordk/121gwcli (https://github.com/chlordk/121gwcli)
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on February 27, 2023, 12:31:39 am
BTW, someone just told me the iOS code I uploaded the other day is the KaneTest one instead of the official 121GW app  :palm:
I'll have to check and correct this.
Title: Re: EEVBlog 121GW Discussion thread
Post by: JDW on February 27, 2023, 01:14:16 am

Many products have app issues over their lifetime, it is a fact of life now.  Best to just move on.  The 121GW actually has it pretty good, with the official Android and Windows app still available and working...

Once upon a time, most engineering software was exclusive to Windows, and there was a lot of shaming that took place when it came to engineers who preferred Apple hardware, even to the extent that many who embraced Windows called into question the engineering credentials of those who preferred the Mac.  But in recent years Apple product adoption has increased to the level that even Microchip decided to make a MacOS version of MPLAB X.  People in the engineering world are a tiny bit friendlier to Mac users, which is a nice break from the past.  And that has been great for folks like me who are Mac and iOS users exclusively when it comes to machines I used privately at home.  Even at work, I've moved my ProMate 3 from an old WinXP machine to my iMac, since MPLAB is on MacOS now. 

So when I read something is considered "pretty good" ONLY BECAUSE it has "official Android and Windows apps", I am compelled to chuckle and whisper to myself — that doesn't help me! :-)

But like I said, the Meteor app exists for iOS, and that DOES help me; and I will continue to use it, along with the SD card for data logging.  I am merely saying that if Meteor could be improved by way of adding a FREEZE button that freezes the currently logged waveform without frustratingly dimming the screen content, that would be outstanding for iOS users like myself (and I doubt I am the only one).  And, if the release of the official iOS app's source code leads to it coming back to the App store AND offering a different set of features than Meteor, all the better!

I wish to humbly that @EEVblog for having investing the time to reply and make source code publicly available, for those (other than myself) who could possibly make productive use of it, for the good of all 121GW users.
Title: Re: EEVBlog 121GW Discussion thread
Post by: J-R on February 27, 2023, 04:33:07 am
It should be trivial to pick up a basic Android tablet or an old PC for Windows/Linux.

One reason Windows is popular is due to the backwards compatibility.  It's not perfect, but generally speaking I can run apps from even 20+ years ago by simply double-clicking on them.

Many companies like Apple, Microsoft & Google are pushing users hard towards a combined hardware & software as a service.  Apple is the worst offender here with their proprietary silicon, as you literally do not own your hardware at all and Apple controls it fully.  Windows is not far behind with secure boot and app & device driver signing enforcement.  Android has been steadily moving core functionality into closed-source code for quite some time.

So I think it's safe to say the only users who can honestly avoid shaming these days is Linux users...
Title: Re: EEVBlog 121GW Discussion thread
Post by: JDW on February 27, 2023, 04:50:17 am
It should be trivial to pick up a basic Android tablet or an old PC for Windows/Linux.
...I think it's safe to say the only users who can honestly avoid shaming these days is Linux users...

Well, I as an Apple-product user shouldn't be forced to buy a Windows PC or Android anything just to use the original app for the lone purpose of seeing if it allows me to FREEZE the current waveform being logged AND if see if it dims the display, which is really the LONE problem with Meteor on iOS at the moment.  When using Meteor, the only way to stop the waveform is to stop logging altogether, which infuriatingly dims the screen and doesn't let you get a good look at the frozen waveform.

Because you are pitching Android and Windows, and because I assume you also have a 121GW, perhaps you could give data logging a test for the purpose of telling us if the original 121GW app allows us to freeze the current waveform being logged and if it keeps the waveform in clear view.  If not, the original app is no better than Meteor, and that knowledge saves one from having to buy a Windows PC or Android device.

Thanks.
Title: Re: EEVBlog 121GW Discussion thread
Post by: J-R on February 27, 2023, 05:31:36 am
OK, sure, I can tell you that neither the Windows nor Android apps appear to allow you to "freeze" the "waveform".  Also, I don't think I would call it a waveform, just a graph/plot.  It only updates about once per second and is cumulative.  It also continues to graph even when you press Hold (the last value is used for subsequent data points).
Title: Re: EEVBlog 121GW Discussion thread
Post by: JDW on February 27, 2023, 05:55:15 am
OK, sure, I can tell you that neither the Windows nor Android apps appear to allow you to "freeze" the "waveform".  Also, I don't think I would call it a waveform, just a graph/plot.  It only updates about once per second and is cumulative.  It also continues to graph even when you press Hold (the last value is used for subsequent data points).

Useful info, thanks.

When you tell the app to stop logging, does it continue to display the logged graph/plot?  If it does keep displaying it, does the app darken the display of that graph/plot?
Title: Re: EEVBlog 121GW Discussion thread
Post by: J-R on February 27, 2023, 06:44:19 am
The graph in the app can't be stopped, you can only reset it.  Although any time the mode/selector dial is changed such that the units change, the graph is reset.
Title: Re: EEVBlog 121GW Discussion thread
Post by: JDW on February 27, 2023, 06:56:43 am
The graph in the app can't be stopped, you can only reset it.  Although any time the mode/selector dial is changed such that the units change, the graph is reset.

Thanks.

In that case, I would say Meteor is superior because it allows you to stop Logging, which stops the Plot/Graph but keeps displaying it.  The main issue I have is that Meteor stupidly darkens the screen too when you stop logging.  But perhaps the developer of Meteor can fix that.  For now, after reading your feedback on the official app, it seems Meteor has an edge over the official app.
Title: Re: EEVBlog 121GW Discussion thread
Post by: J-R on February 27, 2023, 07:34:50 am
...For now, after reading your feedback on the official app, it seems Meteor has an edge over the official app.
Certainly that makes sense, otherwise I'm not sure why they would make it!
Title: Re: EEVBlog 121GW Discussion thread
Post by: Kean on February 28, 2023, 11:04:51 am
BTW, someone just told me the iOS code I uploaded the other day is the KaneTest one instead of the official 121GW app  :palm:
I'll have to check and correct this.

I took a quick look at the GitLab hosted 121GW App source code linked earlier, and it is a Visual Studio Xamarin/UWP app with targets for Windows, Android, and iOS.

I am not sure if the iOS support in there is complete, but loading it in VS2022 gave too many errors for me to deal with right now.  Maybe someone with a bit more experience can try before I get another chance.

I use VS2022 to do some cross platform (Android & Windows) dev, but not targetting iPhone.  I do have a Mac Studio where I maintain some older Objective C iPhone apps, but I'm far from an expert.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on March 01, 2023, 11:14:00 am
BTW, someone just told me the iOS code I uploaded the other day is the KaneTest one instead of the official 121GW app  :palm:
I'll have to check and correct this.

I took a quick look at the GitLab hosted 121GW App source code linked earlier, and it is a Visual Studio Xamarin/UWP app with targets for Windows, Android, and iOS.

I am not sure if the iOS support in there is complete, but loading it in VS2022 gave too many errors for me to deal with right now.  Maybe someone with a bit more experience can try before I get another chance.

I use VS2022 to do some cross platform (Android & Windows) dev, but not targetting iPhone.  I do have a Mac Studio where I maintain some older Objective C iPhone apps, but I'm far from an expert.

Thanks Kean. So all that live show effort I did to upload what I thought the iOS version was for nothing!  :-DD
I kinda remember now that David2 did write a cross platform Android/windows/iOS version, and that's why he only uploaded the one project.
I looked at it the other week and just saw and android directory and assumed it just the android version, d'oh.
So yes, the Gitlab version is the last final official version of all three platforms uploaded by David. Maybe I need to update the readme or something.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Ro Max Well on March 05, 2023, 06:07:54 pm
Hi all,

i just had received my 121 GW Multimeter when I stumbled over the newest commit in the gitlab for the 121GW's Multiplatform App:
User Dave added to the Readme File:

Quote
This is the latest and last official EEVblog 121GW cross-platform Visual Studio Xamarin/UWP app for Android, Windows, and Apple iOS targets.

So what does that mean?  Is the 121GW phasing out? Or is it just the App development, that is discontinued? Is there any official statement?

Best regards,
Robert

P.S.: I already posted this message to another Board on the forum, but deleted it there because it seemed upon further reflection the wrong place.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on March 05, 2023, 09:12:05 pm
i just had received my 121 GW Multimeter when I stumbled over the newest commit in the gitlab for the 121GW's Multiplatform App:
User Dave added to the Readme File:

Quote
This is the latest and last official EEVblog 121GW cross-platform Visual Studio Xamarin/UWP app for Android, Windows, and Apple iOS targets.

So what does that mean?  Is the 121GW phasing out? Or is it just the App development, that is discontinued? Is there any official statement?

No, it's not being phased out. But the app has not been developed since David2 who wrote it left whenever the last commit date was. And I still have no plans to develop the app, that's why the source code is there.
I updated the readme file because it wasn't obvious this was a cross-platform source code.
Title: Re: EEVBlog 121GW Discussion thread
Post by: golftango on March 07, 2023, 09:20:10 pm
Hi all,
Regarding the firmware update procedure for the 121GW.
I have read the words in the manual but am still unsure of the exact procedure.
So, do I need an additional SD card to the one installed in the meter to load the new firmware?  What capacity SD card?  There is no mention of this in the manual.
My laptop does not have an MSD card slot, so how do I install the file on the card?

I realise these questions may induce a groan from the seasoned tech vets on here but I am just not very familiar with this stuff ???

i'm really late to this party and i wish i'd found this meter about 3-4 meters earlier! first order of business is to update the firmware and i found i had v1.22 and when i removed the sd card i found a .bin file with a date of 2018 i believe. the v2.05 file i had was named xxxx2.05.bin and the file already there was named xxxx.bin without a version number. i saved that file off just in case but i didn't rename my xxxx2.05 file and proceeded.

it all worked up to the point where i have iap- and douun on the screen, but it's frozen. i suspect i'm going to have to go back to the card and take that version number out of the file name. but there's a dire warning about aborting the procedure but i can't see how i can do anything but since it's frozen and obviously no doing any processing and maybe that's the saving grace.

>>> later note: nevermind, that was indeed the problem. this time i got a progress bar and it finished within seconds. >>>

except for the thickness, i absolutely love the size of this meter. i got two meters before this one and they are both too huge to carry without a porter or a wheelbarrow. i very nearly got a fluke 117 or an owon b41t just for the size before i came across this one accidentally.

i'm glad i opened this one up because i found a bad thing right away. the springs at the negative ends of the batteries were sticking straight up. in fact, it was quite difficult to put the batteries in so that the springs were in the proper position--they kept trying to escape elsewhere.

/guy
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on March 08, 2023, 01:57:49 am
except for the thickness, i absolutely love the size of this meter.

The original design was thinner and used AAA batteries. But for better battery life we decided on a thicker AA design.
Title: Re: EEVBlog 121GW Discussion thread
Post by: golftango on March 08, 2023, 02:27:44 am
except for the thickness, i absolutely love the size of this meter.

The original design was thinner and used AAA batteries. But for better battery life we decided on a thicker AA design.

it would be a hard decision for me if i was the designer as well. aa batteries are cheaper and more common than aaa's as well as having more capacity and that would be needed to support bluetooth, sd card r/w, and a backlight. i think you made the right decision as i'm not sure having a thinner meter would be worth giving up those advantages.

btw, the bt worked flawlessly on ios with the meteor app. i'd read there was once an ios app from you guys as well, but reading recent posts here seem to indicate it's been abandoned along with the other two platforms on the same codebase. would be great if someone would make a mac os app for it so i wouldn't have to squint at the iphone but even though many ios apps will run on the mac m1, meteor doesn't seem to be one of them.

but i do have a chromebook and an android tablet and i see there are at least two apps which support the meter, so i'll try them out for times i need a bigger display.


/guy
Title: Re: EEVBlog 121GW Discussion thread
Post by: JDW on March 08, 2023, 02:39:25 am
but i do have a chromebook and an android tablet and i see there are at least two apps which support the meter, so i'll try them out for times i need a bigger display.
Please let us know if Android or Windows apps allow you to set the Interval timing because Meteor does not.  Meteor sadly seems to lock the interval to a fixed 500ms/sample (approximate).  Bluetooth logging seems to ignore the meter's "ln" interval setting entirely.  That wouldn't be an issue if the app allows you to change the interval, but I see now way to do that in the Meteor app.  That's why I am curious if the Android or Windows apps do allow changing the interval, and if not, what their fixed interval is between samples.

For now, the only way to get the faster 200ms sampling speed is to long-press the MEM button and log to the SD card.  Would be great if it could be shorter, but I guess we need to keep our expectations in check.  Also bear in mind there is a limit of 600,000 samples total, regardless of your chosen "ln" setting Interval speed.
Title: Re: EEVBlog 121GW Discussion thread
Post by: golftango on March 08, 2023, 02:48:07 am
for now, i have no need for any logging although i will test in a couple of days after i've tested the other functions   just  in case a use case comes up. in fact, when i started meteor for the first time i was supremely annoyed that it just started logging automatically and it literally took me 20 minutes to go through every menu item and to realize that to keep it from doing that i had to set the sample size to zero. :)

but when i do install other versions i'll post back here as to your queries.

/guy
Title: Re: EEVBlog 121GW Discussion thread
Post by: JDW on March 08, 2023, 02:54:22 am
...when i started meteor for the first time i was supremely annoyed that it just started logging automatically and it literally took me 20 minutes to go through every menu item and to realize that to keep it from doing that i had to set the sample size to zero. :)

You had to see the "ln" sample size on the meter to zero (which means: 200ms/sample), as opposed to some setting in the Meteor app, correct?
Title: Re: EEVBlog 121GW Discussion thread
Post by: golftango on March 08, 2023, 02:56:43 am
i didn't set anything in the meter. the bt was literally the 2nd thing i did after updating the firmware. i'm still going through the manual and i haven't even gotten into the setup module yet. i need to do that now to get the time set--the date was ok.

just went through setup and changed a couple of things. the interval was at '0' which the manual says is 200ms/maximum. i changed this to 6 seconds for now to make calculations easier when i test it.

i connected to the meteor app and set the sample size to 100 but the app didn't seem to honor this cut off and kept counting up. when i set it back to zero it said it had logged 104 items, but by that time the counter had gone up to 170+ or so. very confusing. it was obvious the app didn't honor my 1 every 6 seconds setting, but it didn't seem to be at 200ms either. maybe 400-800ms ??? perhaps you can tell from the timestamps:

# Source: 121GW 0
# Mode: Voltage Low Z
# Start time: 03/07/2023, 21:06:44.586 CST
Timestamp, Elapsed time (s), Value, Units
21:07:37.536, 52.950, 0, V
21:07:38.048, 53.462, 0, V
21:07:39.036, 54.450, 0, V
21:07:39.547, 54.960, 0, V
21:07:40.056, 55.470, 0, V
21:07:40.535, 55.949, 0, V

/guy
Title: Re: EEVBlog 121GW Discussion thread
Post by: J-R on March 08, 2023, 08:07:31 am
Has the official ACV calibration procedure been discovered/published?  I couldn't find it.  I experimented with this and it seems the ACV calibration procedure as I understand it is not correct.  If you perform the 10% offset and full-scale calibration at a specific frequency, then the DMM is completely out of whack at other frequencies and I had to restore the previous calibration data.  Looking at the Kane555 calibration procedure, it seems possible the frequency calibration needs to be performed 3 times at various frequencies after the ACV calibration, but this is not clear, nor are the frequencies for the 121GW (the Kane 555 lists 60Hz, 10kHz and 100kHz).
Title: Re: EEVBlog 121GW Discussion thread
Post by: JDW on March 08, 2023, 10:06:29 pm
21:07:37.536, 52.950, 0, V
21:07:38.048, 53.462, 0, V
21:07:39.036, 54.450, 0, V
21:07:39.547, 54.960, 0, V
21:07:40.056, 55.470, 0, V
21:07:40.535, 55.949, 0, V

Similar timestamps as the Meteor app on my iPhone 7 generates.  I assumed the 3 digits at the far right of each time stamp to be milliseconds, so: 1000ms - 536 + 48 = 512ms, 1000ms - 48 + 36  = 988ms, and so on.  It's certainly not a stable sampling speed.  Maybe that is the only sampling speed the BlueTooth module of the 121GW can send data at?  But based on the Meteor app settings, it seems you can store up to 1 million samples.
Title: Re: EEVBlog 121GW Discussion thread
Post by: JDW on March 12, 2023, 01:22:44 pm
Just to let everyone know, the reason for all this discussion is because I am doing prep work for a YouTube video review of the 121GW.  It was not given to me.  I purchased it new at the end of January this year, direct from the EEVBlog store.

I just made my 121GW review video public here...

https://youtu.be/1iqURp-NsdM

Thanks to Dave and others who kindly offered me feedback in this forum over the last couple weeks, which helped in the video creation.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on March 13, 2023, 05:51:30 am
I just made my 121GW review video public here...
https://youtu.be/1iqURp-NsdM

Took me a minute to realise you didn't have a green screen here!
Your lighting is amazing, what are you using? Do you have a studio tour video?
Title: Re: EEVBlog 121GW Discussion thread
Post by: JDW on March 13, 2023, 06:19:24 am
I just made my 121GW review video public here...
https://youtu.be/1iqURp-NsdM

Took me a minute to realise you didn't have a green screen here!
Your lighting is amazing, what are you using? Do you have a studio tour video?

Thanks for taking a look at the video. 

Instead of a green-screen, I simply have a black felt sheet hanging on a whiteboard behind me (affixed with magnets so it won't fall down). The scenes with meters used a thinner black felt sheet placed on a table.  When editing the video, I crush the blacks to make the background go pretty much pure black.  I do it that way because I don't have a lovely scene to put behind me for my videos.  The other reason is that a pitch black background isolates me and the items shown in the video.  The viewers eyes then focus on the content rather than the background. 

No special lighting used.  Just overhead, office-length fluorescents shooting straight down on me.  I can do that because I shoot at the office after-hours.  Fluorescent tubes do produce a rather diffused light though, which is nice.

For the intro and outro sections, I often put a white felt sheet on the table before me (which isn't shown in the camera frame). The white sheet reflects and defuses the overhead lighting up and at me.  No other lights or reflectors used.

I shoot with a Panasonic GH5 in 4K HLG(Rec.2020) 10-bit, then convert to Rec.709 in post. (Not everyone has an HDR display, that's why.) Shooting in HLG offers the best dynamic range my camera offers, such that the highlights don't get blown out most of the time.

I don't use autofocus (just half-press to focus and then record a scene).  I mostly have my camera on a tripod.  I use an iPhone app to stop and start the video during the intro and outro sections.  My mic is always a wired LAV with a long cable to the camera.  Maybe not as good as wireless, but I never have audio cut out issues with the wired mic.

Any background music I use tends to be the free, no-attribution stuff YouTube gives to creators.

And that's about it.  Sounds rather simple, but editing takes hours of time, especially for a long video like this one.



Title: Re: EEVBlog 121GW Discussion thread
Post by: e0ne199 on April 11, 2023, 07:20:48 pm

Many products have app issues over their lifetime, it is a fact of life now.  Best to just move on.  The 121GW actually has it pretty good, with the official Android and Windows app still available and working...

Once upon a time, most engineering software was exclusive to Windows, and there was a lot of shaming that took place when it came to engineers who preferred Apple hardware, even to the extent that many who embraced Windows called into question the engineering credentials of those who preferred the Mac.  But in recent years Apple product adoption has increased to the level that even Microchip decided to make a MacOS version of MPLAB X.  People in the engineering world are a tiny bit friendlier to Mac users, which is a nice break from the past.  And that has been great for folks like me who are Mac and iOS users exclusively when it comes to machines I used privately at home.  Even at work, I've moved my ProMate 3 from an old WinXP machine to my iMac, since MPLAB is on MacOS now. 

So when I read something is considered "pretty good" ONLY BECAUSE it has "official Android and Windows apps", I am compelled to chuckle and whisper to myself — that doesn't help me! :-)

But like I said, the Meteor app exists for iOS, and that DOES help me; and I will continue to use it, along with the SD card for data logging.  I am merely saying that if Meteor could be improved by way of adding a FREEZE button that freezes the currently logged waveform without frustratingly dimming the screen content, that would be outstanding for iOS users like myself (and I doubt I am the only one).  And, if the release of the official iOS app's source code leads to it coming back to the App store AND offering a different set of features than Meteor, all the better!

I wish to humbly that @EEVblog for having investing the time to reply and make source code publicly available, for those (other than myself) who could possibly make productive use of it, for the good of all 121GW users.

lol in contrast to me, every single apple products are the last thing i want to touch in the world...but everyone has different preference after all  ;D
btw why don't you try using VM for iOs and smuview?? if your iOs is good then it should have no problem running windows or linux VM anyway
Title: Re: EEVBlog 121GW Discussion thread
Post by: JDW on April 11, 2023, 09:02:16 pm
lol in contrast to me, every single apple products are the last thing i want to touch in the world...but everyone has different preference after all  ;D
btw why don't you try using VM for iOs and smuview?? if your iOs is good then it should have no problem running windows or linux VM anyway
iOS running Windows...  Too funny. 
Even if that were possible, and I assure you it is not, most Apple fans tend to share your sentiment regarding Windows: "the last thing I want to touch in the world."
:-)

But the root issue is something I demonstrated in my 121GW video (https://youtu.be/1iqURp-NsdM?t=3080).  The only way to get the 200ms logging interval is to log to the 121GW's internal SD card.  Sadly, when you log over BlueTooth, for reasons I don't fully understand.  The logging interval is fixed, less consistent, and closer to once every half second to 1 second.  Sometimes you want to log consistently and quicker than that, which is why the SD card is your only option. 

If "BlueTooth logging" could be made more consistent and with the fast interval of once every 200ms like SD card logging, then that would be ideal.  That discussion seems to have nothing to do with Android or iOS, because I've not heard any of you Android users say that 121GW BlueTooth logging is a consistent interval of once every 200ms, or that the interval can be changed over BlueTooth.
Title: Re: EEVBlog 121GW Discussion thread
Post by: rthorntn on September 12, 2023, 07:13:37 am
Hi,

Apologies for the thread necro, I forgot to fix up my DMM back in the day.

I have the "repair" kit, with the round PCB shim thing and dial but I can't find any instructions on the repair, do they exist?

Also my startup screen shows "U-1.01" should I be upgrading?

Thanks,
Richard
Title: Re: EEVBlog 121GW Discussion thread
Post by: J-R on September 12, 2023, 07:58:19 am
I have two 121GW DMMs that shipped with the shim, and I removed it on both and had no issues.   I did check the spring contacts to make sure they were making a good connection with the PCB.  So my opinion is that if you're not having an issue, then don't worry about it for now.  But here is one video showing where the shim goes:

https://www.youtube.com/watch?v=u2-ot2vWLxI (https://www.youtube.com/watch?v=u2-ot2vWLxI)

The cutout portion faces the clip.  I also personally added a tiny amount of lubricant where the plastic parts rub, and also some precision lubricant to the contacts.  There is debate about this, but I think it's far easier to clean up some old lube than try to fix a worn component.

I do think you want to be on the latest firmware.  Maybe just double-check to make sure you can go directly to the latest release.  I don't recall off-hand.
Title: Re: EEVBlog 121GW Discussion thread
Post by: ploxiln on October 15, 2023, 07:14:59 am
Google Play won't let me install the official 121GW app on my android phone ... I think because it's pretty new and I'm on the latest android version (13), and they have a scheme to try to force apps to target later "api level" if they want to submit updates, or want to support the latest Android, in order to get newer security/permissions rules rolled out over time ...

Anyway, I was able to find the APK on some mirror sites, a little bit sketchy, but I cross-checked a few to try to ensure I got the authentic thing:

bytes: 20624429
sha256: e9ecb6c86b1012b6829c813e0c6fb6929526d85218b50f3a3d2ac832ab32e1d5

I side-loaded it (possible on almost all android phones) and it worked just fine.

It would be nice to get an official download link on the product page for the APK, and for the "modern windows" app if that's even possible ... realistically I understand Dave is just not a software guy, but has provided the full source for these apps to enable others. So will I be the one who steps up to at least provide recent builds, to appease the fast decay of modern app platforms? hah I dunno ... I've never worked with these particular technologies (server/infra seems a lot more stable :P) but that's a lame excuse ...
Title: Re: EEVBlog 121GW Discussion thread
Post by: J-R on October 15, 2023, 11:21:07 am
The official app is linked from the 121GW store page: https://gitlab.com/eevblog/app-121gw
However, neither it nor the one currently on the Play store will work with Android 14.
I think most folks are using the Meteor app these days, which does work with Android 14, although I didn't fully test all the features.
The best solution in my opinion is to get an old phone and dedicate it for this specific purpose.  If you don't have one, check eBay, family members, friends.  Get a phone that is supported by LineageOS: https://wiki.lineageos.org/devices/
Title: Re: EEVBlog 121GW Discussion thread
Post by: ploxiln on October 16, 2023, 06:52:12 am
Ah, I see the built android apk was recently-ish added to the gitlab repo, I didn't spot it there before - I was looking for "releases". It is a bit bigger than the copy I found on the mirror sites - maybe it's a debug build, or google re-compresses it? I'll have to extract and compare them ...

Google Play also says Meteor 121gw is not compatible with my phone, either - I guess I should mention it's a Sony Xperia 5 IV. Maybe it's a weird bluetooth version thing? I suspect it would work fine if side-loaded, like the original 121gw app does.
Title: Re: EEVBlog 121GW Discussion thread
Post by: J-R on October 22, 2023, 03:16:24 am
Did a couple posts get deleted?

Anyway, the app available for download on GitLab doesn't work, I've tried a few versions of android and the screen is just mostly blank after connecting.

So the app store app and Meteor app are the way to go for now.
Title: Re: EEVBlog 121GW Discussion thread
Post by: tszaboo on November 09, 2023, 01:50:06 pm
Just got a 121GW at work. It's a cool little meter, I think it's full of nice have features, still haven't tried all the options.
One thing that I would like to submit as an error report:

When measuring power, negative current values and positive voltage results positive mVA (watt). So you get positive results when measuring on a battery if it's charging or discharging. I haven't verified this myself, just reported by my colleague.
Title: Re: EEVBlog 121GW Discussion thread
Post by: JDW on December 13, 2023, 04:33:50 am
Dave,

I was contacted by a viewer of my 121GW review video who says he cannot order the meter from your product page (https://www.eevblog.com/product/121gw/).  I just checked.  Pretty crazy.  Says 2 in stock, but when you try to add to your Cart you can't.  Why?  Because it then says this:

Quote
You cannot add "121GW Multimeter" to the cart because the product is out of stock.

Yet another problem you need to fix is the blue info bar at the bottom which says this...

Quote
Some EEVblog store products are also available from Simon's Electronics in the UK, Welectron in Germany, and Amazon in the US and Australia.

"Amazon in the US" is not accurate.  I just checked.  Says UNAVAILABLE.
Title: Re: EEVBlog 121GW Discussion thread
Post by: GraXXoR on December 13, 2023, 03:26:41 pm
Hi. I am the person who intended to purchase 121GW accessing your store from Japan After watching a thoroughly comprehensive review by fellow Japan resident youTuber, JDW.

Unfortunately, While I was able to add the device to my cart and check in to PayPal to make the payment, when I confirm my address it says shipping to that address is not available.

Yet the confirm payment button is still clickable Despite the product supposedly being on shippable.

Not sure what the problem is. It’s the address that is already registered with PayPal so I know that it’s correct because it’s auto entered into the fields.

Hope this problem can be resolved so that I can get my 121GW ASAP.

Regards.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Veteran68 on December 13, 2023, 04:12:30 pm
Didn't Dave or someone mention recently that the 121GW was discontinued or soon to be?

That may explain the availability issues and lack of Amazon presence while the BM786 and BM235 are still available. Dave needs to update his site, if so. Then again he still advertises the uCurrent Gold too, even though he hasn't made/sold them in years now it seems.

Also interesting to note he's also selling the UT61E (but not the much improved E+) model. Did I just overlook that before? I didn't realize he resold Uni-T meters.
Title: Re: EEVBlog 121GW Discussion thread
Post by: JDW on December 13, 2023, 09:49:55 pm
Didn't Dave or someone mention recently that the 121GW was discontinued or soon to be?

Curious you seem to be asking that question to either myself or GraXXoR, when it's rather clear that neither one of us are aware of any mention of product discontinuation.  You didn't even link to any post citing discontinuation.  And as you said, the website has not been updated, still showing inventory, which makes no sense if a product has been discontinued.

Dave?
Title: Re: EEVBlog 121GW Discussion thread
Post by: thm_w on December 13, 2023, 11:27:49 pm
Dave,

I was contacted by a viewer of my 121GW review video who says he cannot order the meter from your product page (https://www.eevblog.com/product/121gw/).  I just checked.  Pretty crazy.  Says 2 in stock, but when you try to add to your Cart you can't.  Why?  Because it then says this:

He was having issues with store and shipping prices, I don't know if its fully moved over to shopify or not. But can try ordering from here if you want to take the risk, OR wait for him to respond: https://eevblog.store/products/121gw-multimeter?variant=45270685581620 (https://eevblog.store/products/121gw-multimeter?variant=45270685581620) (thread here: https://www.eevblog.com/forum/chat/ot-shopify-kinda-sucks/msg5020315/#msg5020315 (https://www.eevblog.com/forum/chat/ot-shopify-kinda-sucks/msg5020315/#msg5020315))

If the stock was accurate (2 or 0) then you may have to wait until the meter is in stock again, so could be some months.

Quote
Quote
Some EEVblog store products are also available from Simon's Electronics in the UK, Welectron in Germany, and Amazon in the US and Australia.

"Amazon in the US" is not accurate.  I just checked.  Says UNAVAILABLE.

Just means out of stock, may or may not be restocked, depending on if dave decides to sell through amazon or find a US reshipper.
Title: Re: EEVBlog 121GW Discussion thread
Post by: J-R on December 13, 2023, 11:43:07 pm
I have not heard anything about the 121GW being discontinued, and they are still selling out regularly.  But of course it is possible.

If you want one right now, Welectron has 9 in stock: https://www.welectron.com/EEVBlog-121GW-Data-Logging-Multimeter-with-Bluetooth (https://www.welectron.com/EEVBlog-121GW-Data-Logging-Multimeter-with-Bluetooth)

Is the UT61E listing maybe just be his way of doing an affiliate/click-through?  Seems like it will be drop shipped direct from China rather than through Dave in Australia.
Title: Re: EEVBlog 121GW Discussion thread
Post by: JDW on December 13, 2023, 11:50:22 pm
If you want one right now, Welectron has 9 in stock: https://www.welectron.com/EEVBlog-121GW-Data-Logging-Multimeter-with-Bluetooth (https://www.welectron.com/EEVBlog-121GW-Data-Logging-Multimeter-with-Bluetooth)

I myself already have one. I am simply commenting here to help out someone who wants one for a reasonable price. And the best pricing seems to be available from Dave’s website. That €250 price is extremely expensive because it seems to include the VAT that only applies to Europe. So if someone wants to buy it outside Europe, it doesn’t make sense at that price.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on December 13, 2023, 11:57:12 pm
Hi. I am the person who intended to purchase 121GW accessing your store from Japan After watching a thoroughly comprehensive review by fellow Japan resident youTuber, JDW.

Sorry about the problems, I've actually moved to a new store website, so try that.
https://eevblog.store/products/121gw-multimeter
It now has an exta cheaper shipping option with Sendle, in addition to DHL express.
The link on my website menu has changed to reflect that, but the old Woocommerce product pages and order system are still there and searchable by goolgle.
So I'm currently getting about 50/50 order split from the old and new website.
Had too many issues with Woocommerce, one of which is a buggy stock system, so I switched to shoppify and used the new domain name.
Will eventually shut down the old product pages so they are purged from Google search.

I do still have some stock left, and have ordered some more stock due late Jan. But Kane have advised that they are basically using up their remaining stock of parts, and I get the vibe that once that's done they might not want to make it any more.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on December 14, 2023, 12:01:13 am
Is the UT61E listing maybe just be his way of doing an affiliate/click-through?  Seems like it will be drop shipped direct from China rather than through Dave in Australia.

Correct. Shopify has a plugin that allows affiliate link integration via Aliexpress, and that product was just a test to see how it works. Ultimately I'd like to get around to adding a bunch of useful product suggestions there.
Title: Re: EEVBlog 121GW Discussion thread
Post by: Veteran68 on December 14, 2023, 01:01:39 am
Didn't Dave or someone mention recently that the 121GW was discontinued or soon to be?

Curious you seem to be asking that question to either myself or GraXXoR, when it's rather clear that neither one of us are aware of any mention of product discontinuation.  You didn't even link to any post citing discontinuation.  And as you said, the website has not been updated, still showing inventory, which makes no sense if a product has been discontinued.

It wasn't directed at anyone in particular. It was just me rhetorically commenting that I *thought* I'd heard something about availability being in question. I didn't link anything because I wasn't even sure I'd heard that, just that I seemed to recall it. Obviously if I were sure and had a link, I wouldn't have expressed it as a question.

Many store listings, including Dave's, often keep products that are permanently or at least indefinitely out of stock. That's not unusual, whether it makes sense or not. If something never comes into stock, then one can argue it's discontinued (if they're the manufacturer, anyway). Again, uCurrent Gold is a good example. It's been OOS for years and Dave has suggested he may not make/sell any more.

I do still have some stock left, and have ordered some more stock due late Jan. But Kane have advised that they are basically using up their remaining stock of parts, and I get the vibe that once that's done they might not want to make it any more.

This is probably what I'd heard/read somewhere and was remembering.
Title: Re: EEVBlog 121GW Discussion thread
Post by: JDW on December 14, 2023, 01:06:19 am
Sorry about the problems, I've actually moved to a new store website, so try that.
https://eevblog.store/products/121gw-multimeter

I am updating the purchase links in the text description under my 121GW Review video now, Dave.  But even though I see the FUSE PACK on your new shop site, it has been out of stock for at least a year and as long as I can remember.  And news about availability?

https://eevblog.store/products/multimeter-fuse-pack

Same issue with the Soft Case for 121GW too:

https://eevblog.store/products/bm235-121gw-case

Thanks.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on December 14, 2023, 01:11:42 am
I am updating the purchase links in the text description under my 121GW Review video now, Dave.  But even though I see the FUSE PACK on your new shop site, it has been out of stock for at least a year and as long as I can remember.  And news about availability?

https://eevblog.store/products/multimeter-fuse-pack

Same issue with the Soft Case for 121GW too:

https://eevblog.store/products/bm235-121gw-case

Cases are at the local port, so will have them next week.
Fuses I need to order again, no ETA on that.
Title: Re: EEVBlog 121GW Discussion thread
Post by: J-R on December 14, 2023, 06:05:34 am
Welectron has the including/excluding VAT pricing clearly listed.  So 121GW + Brymen silicon test leads (the default if you simply add it to your cart) is $239.74USD delivered to USA via DHL Express Worldwide (less than a week).

121GW from Dave direct is $223.68USD delivered to USA via Sendle International (Estimated delivery Tuesday, Jan 2–Monday, Jan 29) or DHL Expresss Zone 4 for a couple dollars more (sssent by sssnake? no ETA listed).

So pricing is not too drastically different.  It also fluctuates with the exchange rates, which you can gamble with if you like.  I personally like Welectron because I can add fuses, test leads, carrying cases, etc. to my order and save on shipping.
Title: Re: EEVBlog 121GW Discussion thread
Post by: GraXXoR on December 16, 2023, 03:58:05 pm
Hi there there seems to be some confusion about what issue I’m having here.

The thing is I go through the entire shopping process added to my cart, it does actually seem to be in stock…. And once I’ve added it to my cart I go to the PayPal checkout and then I enter my business address or use the one register with my PayPal (home address) and then it says that it cannot be shipped to my country.

However there is still a pay button underneath it which seems a bit odd considering it can’t be shipped and I don’t want to press it.

I have attached the error message which I am receiving.

My address is central Tokyo.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on December 16, 2023, 10:50:58 pm
Hi there there seems to be some confusion about what issue I’m having here.

The thing is I go through the entire shopping process added to my cart, it does actually seem to be in stock…. And once I’ve added it to my cart I go to the PayPal checkout and then I enter my business address or use the one register with my PayPal (home address) and then it says that it cannot be shipped to my country.

However there is still a pay button underneath it which seems a bit odd considering it can’t be shipped and I don’t want to press it.

I have attached the error message which I am receiving.

My address is central Tokyo.

Email me your address.
Title: Re: EEVBlog 121GW Discussion thread
Post by: GraXXoR on December 17, 2023, 05:59:49 pm
Message sent. Let me know if the system is having a problem handling my address...
Tho I suspect I'm not far from JDW who successfully received one.
If it doesn't work, I'll order one with a set of brymen probes from that German site.

Seriously, thanks a for the rapid feedback.... Shows the calibre of the man when he can handle individual posts so quickly on an enterprise as big as EEVBLOG.

Cheers,
  Grx
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on December 18, 2023, 04:03:28 am
Message sent. Let me know if the system is having a problem handling my address...

Sorry, Japan wasn't set correctly in Shopify. Should work now.
Title: Re: EEVBlog 121GW Discussion thread
Post by: GraXXoR on December 18, 2023, 01:54:53 pm
damn. the price went up O_O
It was $204 now I have to pay in yen (29,000) not dollars and when paypal converts that back into dollars it's $214... and I'll likely have to pay 10% local tax on that bringing it to ¥31,900.

I can currently get the Sanwa PC7000 locally with a 3 year guarantee for ¥24,800 (~ $180) including tax and postage, so I will have a bit more of a think on it. ¥26,000 ($190) with gold plated test leads.

... thanks for fixing it in any case. I might pick something up from you if the Yen recovers a bit against the dollar. My limit for a tester is 30,000 and this just unfortunately tipped over to the other side.
Title: Re: EEVBlog 121GW Discussion thread
Post by: thm_w on December 19, 2023, 01:18:26 am
Don't let paypal do the conversion, 29,000 JPY is $203.56 USD at current exchange rates.
You'll almost certainly have to pay local tax and likely DHL brokerage fee on top of that yes (guessing $10-15 USD but I can't find any references for your country).

Sanway PC7000 is probably a fine meter, but does not datalog, do power measurement, low burden, etc. So not quite the same feature class. But yes due to low yen its going to make more sense to purchase locally.
Title: Re: EEVBlog 121GW Discussion thread
Post by: HKJ on December 19, 2023, 11:52:08 am
Don't let paypal do the conversion, 29,000 JPY is $203.56 USD at current exchange rates.
You'll almost certainly have to pay local tax and likely DHL brokerage fee on top of that yes (guessing $10-15 USD but I can't find any references for your country).

Sanway PC7000 is probably a fine meter, but does not datalog, do power measurement, low burden, etc. So not quite the same feature class. But yes due to low yen its going to make more sense to purchase locally.

The PC7000 is basically the same as Brymen BM867 including computer connection.
Title: Re: EEVBlog 121GW Discussion thread
Post by: GraXXoR on December 19, 2023, 09:10:31 pm

No. It’s not PayPal doing the conversion. It’s Shopify. They are charging ¥29,000. PayPal have a decent rate right now ¥134 per dollar. This is slightly better than the current ¥140 per dollar standard.
When you use PayPal’s considerate rate of exchange then based on Shopify’s Price, Reverse calculated to usd you get $214
.
Title: Re: EEVBlog 121GW Discussion thread
Post by: thm_w on December 19, 2023, 11:59:58 pm
The PC7000 is basically the same as Brymen BM867 including computer connection.

Yeah, that is not local datalogging, to be more specific. eg Fluke 289.

No. It’s not PayPal doing the conversion. It’s Shopify. They are charging ¥29,000. PayPal have a decent rate right now ¥134 per dollar. This is slightly better than the current ¥140 per dollar standard.

You are missing the point. "It was $204 now I have to pay in yen (29,000)". These were the same numbers given yesterdays exchange rate, that is how his store works, you can check the numbers today and they will also work out.

Quote
When you use PayPal’s considerate rate of exchange then based on Shopify’s Price, Reverse calculated to usd you get $214.

Which is higher than current exchange because its not generous! Paypal are charging you a fee on top of the exchange rate (~4.5%), they will ALWAYS do that. So will most credit cards and banks. Being in Japan, people would expect you to have JPY in the bank not USD...

https://www.xe.com/currencyconverter/convert/?Amount=1&From=USD&To=JPY (https://www.xe.com/currencyconverter/convert/?Amount=1&From=USD&To=JPY)
Title: Re: EEVBlog 121GW Discussion thread
Post by: J-R on December 20, 2023, 09:11:06 am
Same story with me, here in the US I've purchased internationally a few times using PayPal and they do "overcharge" a bit for any currency conversions.  So I use one of my credit cards that specifically does not charge for that which means PayPal bills the credit card in that foreign currency directly.
Title: Re: EEVBlog 121GW Discussion thread
Post by: GraXXoR on December 20, 2023, 04:52:27 pm
Am I misunderstanding? I believe the shop has determined the Yen price of the product... 29,000 Yen is far too neat and tidy to be a dynamic translation of $204.

Whenever I use Paypal to convert cash, the price ends up something random looking, like ¥28,459... 
29,000 is clearly a set price in YEN.

which translates to 142 Yen per $...

Title: Re: EEVBlog 121GW Discussion thread
Post by: thm_w on December 20, 2023, 10:38:01 pm
Am I misunderstanding? I believe the shop has determined the Yen price of the product... 29,000 Yen is far too neat and tidy to be a dynamic translation of $204.

Go to the store again today as I suggested above, you'll see the price has changed to the current days exchange rate, rounded to 100 JPY.
No one is going in and manually setting a price in a hundred different currencies.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on December 20, 2023, 10:49:58 pm
Go to the store again today as I suggested above, you'll see the price has changed to the current days exchange rate, rounded to 100 JPY.
No one is going in and manually setting a price in a hundred different currencies.

Correct. All my store prices are set in AUD for a stupid reason to do with Shopify (I'd prefer USD, as I buy all my stock in USD), and any other displayed currency is Shopify doing the conversion automatically. I have no idea where it gets the conversion data from.

Use the coupon code orderofmagnitude for 10% off.
Title: Re: EEVBlog 121GW Discussion thread
Post by: GraXXoR on December 21, 2023, 05:43:59 pm
Correct. All my store prices are set in AUD for a stupid reason to do with Shopify (I'd prefer USD, as I buy all my stock in USD), and any other displayed currency is Shopify doing the conversion automatically. I have no idea where it gets the conversion data from.

Use the coupon code orderofmagnitude for 10% off.
Yes, that is what I suspected. Shopify is converting to Yen when I could be purchasing it in Dollars since I have funds in both currencies.


But on another note....

Good grief!!!


I think me and this 121GW are destined to be unhappy together.

I just came here feeling chuffed that the exchange rate got better and the $214 has dropped back to about $205 and that puts it 200 yen below the purchase threshold. of 30,000 + tax.

And then now I see that there is a 10% discount on offer that I wasn't made aware of until after I put my order in!!!

My paypal order went through and it was immediately processed... not even a pending on order being accepted by the seller so I'm unable to rescind it within 10 minutes of making it.

Is there a way to apply the code to my order?
Any help much appreciated.

Cheers.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on December 24, 2023, 09:40:34 am
Is there a way to apply the code to my order?
Any help much appreciated.

No, but I just refunded 10% manually.
Title: Re: EEVBlog 121GW Discussion thread
Post by: GraXXoR on December 24, 2023, 02:13:44 pm
Just want to say it once again; your response to individual requests in a forum of this size is outstanding. And not only that but during the Christmas holidays to boot!

Thank you so much for the post hoc discount. It’s very much appreciated and unexpected little Christmas bonus!
I look forward to putting the 121 through it paces in the new year!

Apologies if I came off as acerbic in my previous post…
Best regards and have a Merry Christmas if you’re celebrating tomorrow!

Grx.
Title: Re: EEVBlog 121GW Discussion thread - Tips repair
Post by: Dr. Frank on January 21, 2024, 10:36:05 am
I bought the 121GW on Kickstarter in 2018.
It came with that nice pouch, and those great test tips from B.T.C.
One of the useful feature of this combo is, that it is possible to make quite stable mΩ measurements in its 50 Ohm range.

After 6 years of intense use, the red tip now showed unreliable Ohm measurements, as the shorted tips are reading unstable ~100..1000 mΩ, instead of < 100mΩ, as before.
This prevented a quick analysis of the power supply fault of my FLUKE 5442A calibrator, see here:

https://www.eevblog.com/forum/metrology/lowest-drift-lowest-noise-voltage-reference/msg5258283/#msg5258283 (https://www.eevblog.com/forum/metrology/lowest-drift-lowest-noise-voltage-reference/msg5258283/#msg5258283)

I already wanted to discard the tips, but had a closer look, as the tip needle could somehow be rotated inside the rubber grips.
To my big joy, the grips can be pulled downwards, if you carefully grab the tips with a pliers at the thread.

(https://www.eevblog.com/forum/testgear/eevblog-121gw-discussion-thread/?action=dlattach;attach=1987309;image)

The tip needles were tightly clamped to some cable clips, and the cable's wire, maybe silver plated copper, is clamped at the other side.
Latter seemed to be the problem, that due to oxidation this connection made bad contact.

(https://www.eevblog.com/forum/testgear/eevblog-121gw-discussion-thread/?action=dlattach;attach=1987297;image)

So I used a 20W soldering iron with a bigger tip, and soldered the end of the wire to the clip.

(https://www.eevblog.com/forum/testgear/eevblog-121gw-discussion-thread/?action=dlattach;attach=1987303;image)

Afterwards, the test tips are again showing stable 100mΩ when shorted.

Great quality, and I just love such repairable test tips. Very rare!

Frank
Title: Re: EEVBlog 121GW Discussion thread - Tips repair
Post by: EEVblog on January 21, 2024, 10:58:17 am
I already wanted to discard the tips, but had a closer look, as the tip needle could somehow be rotated inside the rubber grips.
To my big joy, the grips can be pulled downwards, if you carefully grab the tips with a pliers at the thread.

I've never tried that!
Title: Re: EEVBlog 121GW Discussion thread
Post by: AVGresponding on January 21, 2024, 11:05:10 am
This also raises the question, are new tips available from Brymen? I have two sets of those leads, one is perfect (I owned that from new...) but the other is heavily scarred (came with an abused bench meter I bought) and could use fresh tips.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on January 21, 2024, 11:44:50 am
This also raises the question, are new tips available from Brymen? I have two sets of those leads, one is perfect (I owned that from new...) but the other is heavily scarred (came with an abused bench meter I bought) and could use fresh tips.

Not that I know of.
Title: Re: EEVBlog 121GW Discussion thread
Post by: J-R on January 21, 2024, 12:07:51 pm
Only 10.90 € for a complete new set:
https://www.welectron.com/Brymen-BL21S2-T4SC-Silicone-Test-Leads (https://www.welectron.com/Brymen-BL21S2-T4SC-Silicone-Test-Leads)
Title: Re: EEVBlog 121GW Discussion thread
Post by: Martin72 on January 21, 2024, 01:23:06 pm
However, they can still work on the translation of their homepage:
Quote
Silicone Test Leads with vergoldeten Testspitzen und aufschraubbaren Bananensteckern, 1000V CAT IV, 10A

 ;)
Title: Re: EEVBlog 121GW Discussion thread
Post by: J-R on January 21, 2024, 01:53:12 pm
If you can't read German, you could buy them from Dave:
https://eevblog.store/products/brymen-bl21s2-t4sc-gold-plated-silicone-test-probes (https://eevblog.store/products/brymen-bl21s2-t4sc-gold-plated-silicone-test-probes)

Or 99centHobbies on eBay:
https://www.ebay.com/itm/171162377470 (https://www.ebay.com/itm/171162377470)

Of course kidding about the German part...
Title: Re: EEVBlog 121GW Discussion thread
Post by: TrickyT on January 27, 2024, 12:10:48 am
My function switch has become flaky and I need to know if the shim and replacement knob are still available and, if so, where do I get them. I was part of the original Kickstarter project and my meter was one from the 2nd production batch. (I received it in August 2018, s/n 1418) I didn't pursue obtaining the shim and knob when the switch problem first starting appearing because my meter was working fine and I figured that the thickness tolerance on my PC board must have been such that my meter was not one of those affected. But things have gradually gotten worse to the point where now the meter only powers up if I mess with the function switch a bunch of times. Maybe the springs in switch contacts have lost some oomph or something else has worn. Anyway it would be great to source the updated knob and shim now and any help from this forum would be appreciated.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on January 29, 2024, 12:30:38 am
My function switch has become flaky and I need to know if the shim and replacement knob are still available and, if so, where do I get them. I was part of the original Kickstarter project and my meter was one from the 2nd production batch. (I received it in August 2018, s/n 1418) I didn't pursue obtaining the shim and knob when the switch problem first starting appearing because my meter was working fine and I figured that the thickness tolerance on my PC board must have been such that my meter was not one of those affected. But things have gradually gotten worse to the point where now the meter only powers up if I mess with the function switch a bunch of times. Maybe the springs in switch contacts have lost some oomph or something else has worn. Anyway it would be great to source the updated knob and shim now and any help from this forum would be appreciated.

I've got a few left, email me your postal address.
Title: Re: EEVBlog 121GW Discussion thread
Post by: EEVblog on January 29, 2024, 12:32:35 am
If you can't read German, you could buy them from Dave:
https://eevblog.store/products/brymen-bl21s2-t4sc-gold-plated-silicone-test-probes (https://eevblog.store/products/brymen-bl21s2-t4sc-gold-plated-silicone-test-probes)

I also sell them on Amazon:
https://www.amazon.com/EEVblog-Brymen-BL21S2-T4SC-Plated-Silicone/dp/B0CQH1CXR6/ref=sr_1_1 (https://www.amazon.com/EEVblog-Brymen-BL21S2-T4SC-Plated-Silicone/dp/B0CQH1CXR6/ref=sr_1_1)
Title: Re: EEVBlog 121GW Discussion thread
Post by: TrickyT on January 29, 2024, 11:53:28 pm
My function switch has become flaky and I need to know if the shim and replacement knob are still available and, if so, where do I get them. I was part of the original Kickstarter project and my meter was one from the 2nd production batch. (I received it in August 2018, s/n 1418) I didn't pursue obtaining the shim and knob when the switch problem first starting appearing because my meter was working fine and I figured that the thickness tolerance on my PC board must have been such that my meter was not one of those affected. But things have gradually gotten worse to the point where now the meter only powers up if I mess with the function switch a bunch of times. Maybe the springs in switch contacts have lost some oomph or something else has worn. Anyway it would be great to source the updated knob and shim now and any help from this forum would be appreciated.

I've got a few left, email me your postal address.

Done.  And thanks!
Title: Re: EEVBlog 121GW Discussion thread
Post by: AVGresponding on January 30, 2024, 06:36:30 am
Only 10.90 € for a complete new set:
https://www.welectron.com/Brymen-BL21S2-T4SC-Silicone-Test-Leads (https://www.welectron.com/Brymen-BL21S2-T4SC-Silicone-Test-Leads)

Yes, but I'm cheap!
Title: Re: EEVBlog 121GW Discussion thread
Post by: PhilipG on February 02, 2024, 09:16:13 am
I'm new here, but I have a 121GW with firmware 2.05.  Can anyone tell me how to turn the beeper off when making low resistance measurements?
Title: Re: EEVBlog 121GW Discussion thread
Post by: BILLPOD on February 02, 2024, 02:22:39 pm
Page 61 of the manual:
Last Revised: 1 March 2020 121GW User Manual

BUZZER ON/OFF
If you wish to disable/enable the buzzer to perform the following steps:
1. Navigate to the b-OFF or b-ON menu item using the SETUP button.
2. Press and hold SETUP, until display flashes.
3. Press UP/DOWN to toggle between “b-OFF” and “b-ON”.
4. To save the setting press and hold SETUP, until display no longer
flashes. :popcorn:
Title: Re: EEVBlog 121GW Discussion thread
Post by: J-R on February 03, 2024, 02:52:12 am
I'm new here, but I have a 121GW with firmware 2.05.  Can anyone tell me how to turn the beeper off when making low resistance measurements?
The 121GW doesn't beep during low resistance measurements unless you have the continuity mode selected.  "b-OFF" and "b-ON" do not apply to continuity mode.

So it sounds like you need to switch from continuity mode to resistance mode.