Author Topic: EEVblog 121GW Multimeter Issues  (Read 90122 times)

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Offline lowimpedance

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Re: EEVblog 121GW Multimeter Issues
« Reply #175 on: March 08, 2018, 01:25:48 pm »
Minor manual correction, the 500mA text on the front cover picture is still missing next to the A text over the current input jack.
The odd multimeter or 2 or 3 or 4...or........can't remember !.
 

Offline lowimpedance

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Re: EEVblog 121GW Multimeter Issues
« Reply #176 on: March 14, 2018, 11:39:37 am »
 When in Ohms (auto range) mode and shorting the probes the display will show some random numbers for a short time before ranging down to display the value of the shorted probes.
So 95 % of the time the random numbers come up instead of blanking the display while changing ranges. It only occurs on the top M Ohm range and will blank as soon as the auto ranging starts.
Do others see this effect on theirs with firmware version 1.07. ?.
Not a major issue, but hopefully will be corrected at some point.
The odd multimeter or 2 or 3 or 4...or........can't remember !.
 

Offline morrone

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Re: EEVblog 121GW Multimeter Issues
« Reply #177 on: March 17, 2018, 04:09:42 am »
So 95 % of the time the random numbers come up instead of blanking the display while changing ranges. It only occurs on the top M Ohm range and will blank as soon as the auto ranging starts.
Do others see this effect on theirs with firmware version 1.07. ?.

Yes, I see the same thing with 1.07.  When the probes are applied to a resistor the screen blanks for a moment, then shows a random bad value and pauses for a second or two with no sign that it is still working to find the correct value, then it blanks again briefly before showing the correct value with relatively rapid updates to the lest significant digits.
 

Offline bicycleguy

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Re: EEVblog 121GW Multimeter Issues
« Reply #178 on: March 30, 2018, 03:41:51 am »
minor Manual, 07 March 2018,

Page  kind  description
7  spelling 'VERION'
29 grammar (twice), 'for the is jack'
59 grammar, 'and is can be'

Starting to look pretty good !
 

Offline Candid

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Re: EEVblog 121GW Multimeter Issues
« Reply #179 on: April 07, 2018, 09:33:02 pm »
I already posted in the discussion thread about a problem I have with Vac readings. Now I will switch to the correct place for this.

In 5Vac mode I get wrong readings.

Today I checked the ZERO OFFSET CALIBRATION and had to find out, that only in 5Vac range mode with shorted inputs I get a reading of 0,499xVac. With open input I get nearly the same value of about 0,5Vac.

In all other Vac (and Vdc) ranges I get 0,0xxV. So I tried to calibrate only the zero offset in Vac 5V range mode. During the count down it displays the 0,499xV and after the calibration I still have this offset with shorted inputs on the 5Vac range. At the end of the calibration countdown I see "OFF-E" for about half a second what is not mentioned in the manual.

I have two references from voltagestandard.com. The 121GW is spot on for all voltage measurements I can do (Vdc 0,350V up to 10.000V and Vac 5V).

So there must be something wrong with the 5Vac range mode of my 121GW.

Another thing happened today while testing for the first time. When I switched from left side off to V mode the meter did not turn on. I taped on the mode switch still in this mode and it turned on. So there must be another problem with my 121GW.

You can read my postings and realted answers if you want to get the complete story:
http://www.eevblog.com/forum/testgear/eevblog-121gw-discussion-thread/msg1446232/#msg1446232
http://www.eevblog.com/forum/testgear/eevblog-121gw-discussion-thread/msg1447697/#msg1447697
http://www.eevblog.com/forum/testgear/eevblog-121gw-discussion-thread/msg1447957/#msg1447957
http://www.eevblog.com/forum/testgear/eevblog-121gw-discussion-thread/msg1465469/#msg1465469
http://www.eevblog.com/forum/testgear/eevblog-121gw-discussion-thread/msg1469130/#msg1469130
http://www.eevblog.com/forum/testgear/eevblog-121gw-discussion-thread/msg1469890/#msg1469890
« Last Edit: April 08, 2018, 09:23:25 pm by Candid »
 

Offline Seppy

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Re: EEVblog 121GW Multimeter Issues
« Reply #180 on: April 09, 2018, 10:53:54 am »
I already posted in the discussion thread about a problem I have with Vac readings. Now I will switch to the correct place for this.

In 5Vac mode I get wrong readings.

Today I checked the ZERO OFFSET CALIBRATION and had to find out, that only in 5Vac range mode with shorted inputs I get a reading of 0,499xVac. With open input I get nearly the same value of about 0,5Vac.

In all other Vac (and Vdc) ranges I get 0,0xxV. So I tried to calibrate only the zero offset in Vac 5V range mode. During the count down it displays the 0,499xV and after the calibration I still have this offset with shorted inputs on the 5Vac range. At the end of the calibration countdown I see "OFF-E" for about half a second what is not mentioned in the manual.

I have two references from voltagestandard.com. The 121GW is spot on for all voltage measurements I can do (Vdc 0,350V up to 10.000V and Vac 5V).

So there must be something wrong with the 5Vac range mode of my 121GW.

Another thing happened today while testing for the first time. When I switched from left side off to V mode the meter did not turn on. I taped on the mode switch still in this mode and it turned on. So there must be another problem with my 121GW.

You can read my postings and realted answers if you want to get the complete story:
http://www.eevblog.com/forum/testgear/eevblog-121gw-discussion-thread/msg1446232/#msg1446232
http://www.eevblog.com/forum/testgear/eevblog-121gw-discussion-thread/msg1447697/#msg1447697
http://www.eevblog.com/forum/testgear/eevblog-121gw-discussion-thread/msg1447957/#msg1447957
http://www.eevblog.com/forum/testgear/eevblog-121gw-discussion-thread/msg1465469/#msg1465469
http://www.eevblog.com/forum/testgear/eevblog-121gw-discussion-thread/msg1469130/#msg1469130
http://www.eevblog.com/forum/testgear/eevblog-121gw-discussion-thread/msg1469890/#msg1469890

Thankyou for your message we are aware of your issue, the issue with the on-off is almost certainly due to the shim fix (this will be shipped to you at some point soon, it will resolve the issue if that is an issue). It does sound like your 5V AC range has an issue, there is a new firmware update coming out. It might improve the situation for you and if you did want to recalibrate it would be better to do it after the next update.
« Last Edit: April 09, 2018, 10:55:50 am by Seppy »
 

Offline Candid

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Re: EEVblog 121GW Multimeter Issues
« Reply #181 on: April 09, 2018, 03:47:06 pm »
Thank you for the response. I will try to calibrate with the next firmware update. I really wonder what the problem is. In all other ac/dc ranges the zero offset is ok so it hopefully is something that can be fixed with a firmware update.
 

Offline Doctorandus_P

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Re: EEVblog 121GW Multimeter Issues
« Reply #182 on: April 15, 2018, 07:22:06 am »
Source code not available.
To me this was the biggest bug of them all and enough reason to not buy this meter.
I really would have liked to be able to add some customized measurements, without too much effort, but having to rewrite all firmware from scratch would cost me far too much time.

Maybe I'll revise my opinion when a "community" alternative version of the software for this meter becomes available.
 

Offline morrone

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Re: EEVblog 121GW Multimeter Issues
« Reply #183 on: April 26, 2018, 01:03:58 pm »
Bug in firmware 1.10:  If you try to start logging to the SD card while there is no SD card in the slot, the meter locks up.  Granted, user error, but it would be nice if the meter displayed an error rather than locking up.
 

Online EEVblog

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Re: EEVblog 121GW Multimeter Issues
« Reply #184 on: April 26, 2018, 04:17:24 pm »
Source code not available.
To me this was the biggest bug of them all and enough reason to not buy this meter.

Name another commercial meter on the market that has open source firmware?

Quote
Maybe I'll revise my opinion when a "community" alternative version of the software for this meter becomes available.

We encourage that.
 
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Offline Candid

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Re: EEVblog 121GW Multimeter Issues
« Reply #185 on: April 28, 2018, 09:47:32 am »
I already posted in the discussion thread about a problem I have with Vac readings. Now I will switch to the correct place for this.

In 5Vac mode I get wrong readings.

Today I checked the ZERO OFFSET CALIBRATION and had to find out, that only in 5Vac range mode with shorted inputs I get a reading of 0,499xVac. With open input I get nearly the same value of about 0,5Vac.

In all other Vac (and Vdc) ranges I get 0,0xxV[...]

Thankyou for your message we are aware of your issue, the issue with the on-off is almost certainly due to the shim fix (this will be shipped to you at some point soon, it will resolve the issue if that is an issue). It does sound like your 5V AC range has an issue, there is a new firmware update coming out. It might improve the situation for you and if you did want to recalibrate it would be better to do it after the next update.
Ok the new firmware is out. I flashed v1.15 and tried again. But it is still the same. In 5Vac range I have an offset of about 0,5V (shorted or opened port is nearly the same). I tried to calibrate the zero offset for the 5Vac range but it did not help. So there must be a problem with the 5Vac range of my 121GW.

What can I do? The shim fix did not arrive up to now bot I don't think it will help with this.
 

Offline Iagash

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Re: EEVblog 121GW Multimeter Issues
« Reply #186 on: May 03, 2018, 06:17:59 am »
Firmware 1.15 has a regression vs. 1.10.

When connecting via bluetooth and disconnecting again by closing the app (or the bluetooth connection) no connection is possible until bluetooth is switched on and off on the meter.
 

Offline Seppy

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Re: EEVblog 121GW Multimeter Issues
« Reply #187 on: May 03, 2018, 11:13:30 am »
Firmware 1.15 has a regression vs. 1.10.

When connecting via bluetooth and disconnecting again by closing the app (or the bluetooth connection) no connection is possible until bluetooth is switched on and off on the meter.

That is unlikely as the Bluetooth is basically a UART-BLE bridge module and it hasn't been updated. It is more likely an update to windows or android that caused the issue, otherwise i'm not really sure how this could have happened.

One important thing to know is that if you simply minimize the app it is still using the bluetooth device until it is properly closed this means if you opened another instance it will not connect as the bluetooth device is already in use.
 

Offline Scottjd

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Re: EEVblog 121GW Multimeter Issues
« Reply #188 on: May 03, 2018, 11:31:41 am »
Firmware 1.15 has a regression vs. 1.10.

When connecting via bluetooth and disconnecting again by closing the app (or the bluetooth connection) no connection is possible until bluetooth is switched on and off on the meter.

That is unlikely as the Bluetooth is basically a UART-BLE bridge module and it hasn't been updated. It is more likely an update to windows or android that caused the issue, otherwise i'm not really sure how this could have happened.

One important thing to know is that if you simply minimize the app it is still using the bluetooth device until it is properly closed this means if you opened another instance it will not connect as the bluetooth device is already in use.

Sounds  logical. As and admin do you have the power to modify the fist post in this thread?
I was thinking somehow of informing people when reporting issues to include as much details as posable. As with most trouble shooting issues or working on replicating the same issue the more details the better.
Like the OS or remote device being used to connect to the meter via Bluetooth. What app was used, and what version of the app used? And so on?
It’s usualy a time saver and others besides admins and EEVBlog employees can try to replicate the same issue and help confirm if it’s an issue that affects all or just one persons systems from an bad registered driver or older app version.
Just a thought?
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Offline Iagash

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Re: EEVblog 121GW Multimeter Issues
« Reply #189 on: May 03, 2018, 08:12:10 pm »
Firmware 1.15 has a regression vs. 1.10.

When connecting via bluetooth and disconnecting again by closing the app (or the bluetooth connection) no connection is possible until bluetooth is switched on and off on the meter.

That is unlikely as the Bluetooth is basically a UART-BLE bridge module and it hasn't been updated. It is more likely an update to windows or android that caused the issue, otherwise i'm not really sure how this could have happened.

I did some more tests and I guess it's the decreased data rate, that seems to cause a longer time to be able to reconnect. It just needs a lot longer until a reconnect is possible. I guess the BLE module resets the connection, when some buffer overflows when it couldn't send the data for some time making a new connection possible.
 

Offline Candid

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Re: EEVblog 121GW Multimeter Issues
« Reply #190 on: May 06, 2018, 09:26:11 am »
Didn't I already read about this? I am not sure so I post it here in the issues thread.

When I turn off the beeper and afterwards go to diode test I get a nonstop beep with firmware 1.15.

PS: On 19th april I got a message telling me that the repair parts for the 121GW have been sent to me. They still not arrived ;-(
 

Offline Seppy

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Re: EEVblog 121GW Multimeter Issues
« Reply #191 on: May 07, 2018, 11:19:39 am »
Didn't I already read about this? I am not sure so I post it here in the issues thread.

When I turn off the beeper and afterwards go to diode test I get a nonstop beep with firmware 1.15.

PS: On 19th april I got a message telling me that the repair parts for the 121GW have been sent to me. They still not arrived ;-(

That is another strange issue your meter has, do you have steps to reproduce? I've tried a few things and couldn't get it to hold on beep.
 

Offline knapik

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Re: EEVblog 121GW Multimeter Issues
« Reply #192 on: May 07, 2018, 11:30:10 am »
I believe that I used to have the same issue, and it was due to the wobbly knob not making correct contact with the pads.
 

Offline Candid

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Re: EEVblog 121GW Multimeter Issues
« Reply #193 on: May 07, 2018, 05:15:23 pm »
Ok so I will go on waiting for the replacement parts and hopefully they will solve bot problems I have. I think I can remember that I already read about someone having this issue too here but could not find the post.
 

Offline Seppy

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Re: EEVblog 121GW Multimeter Issues
« Reply #194 on: May 16, 2018, 05:40:25 pm »
@ Candid

Did you receive your shims and whatnot, any update with the issue you were having?
 

Offline Candid

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Re: EEVblog 121GW Multimeter Issues
« Reply #195 on: May 16, 2018, 11:23:18 pm »
@ Candid

Did you receive your shims and whatnot, any update with the issue you were having?
No, I did not receive anything up to now. And no update to the issue except that it is getting worser. Very often from off to any position the meter stays off or resets/starts from time to time and still having the +0,5V with shorted leads on ac 5V-range.

I got the mail about the delivery on 19th May but without any tracking Url. Maybe you can track something but not me:
Your order is on its way!

We are pleased to confirm that your order has now been shipped.

    Our Reference: 11633

    Your Reference:

    Carrier: Plain Labels
    (Australia Post for within Australia)

    Carrier's Reference:

    Tracking Url:
 

Offline Candid

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Re: EEVblog 121GW Multimeter Issues
« Reply #196 on: May 17, 2018, 09:24:03 pm »
Today I got the switch and shim and installed them. So now the known issue seemes to be fixed.

But the fault concerning my 0,5Vac offset with shorted input in the 5Vac range still exists. So there must be something else with my meter.
I have firmware 1.15 installed and I just tried ZERO offset calibration of the 5Vac mode and it is still at about 0,5Vac with shorted input. When I open the input it is slightly higher (about 0,499xV against 0,515xV). The other Vac ranges are ok this only applies to the 5Vac range.
« Last Edit: May 17, 2018, 09:40:40 pm by Candid »
 

Offline Scottjd

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Re: EEVblog 121GW Multimeter Issues
« Reply #197 on: May 19, 2018, 08:30:46 pm »
Has anyone reported or noticed when you zero out the meter on voltage or resistance (I think all settings) and use the auto hold at the same time, the auto hold results ignore the zero out value when it displays the auto hold results.

Then if you turn off the Auto hold the relative triangle symbol is still displayed on the meter, but it’s not the truly zeroed out value being displayed. It’s the normal value ignoring the relative value it should be doing math with like you didn’t zero it at all. But the triangle is still displayed on the LCD. So I pushed the relative button again, instead of the triangle turning off it blinks on and off real fast and sets a new zero value.

Or, once you get the Auto hold reading without the relative value calculated into the Auto hold reading displayed, then turn off the relative set value by pressing the button again the triangle on the LCD does turn off and the Auto Hold is still displayed on the LCD. But it’s not doing any auto holding despite the LCD showing Auto hold being displayed, the meter will display the live readings with no holding at all or beep indicating it’s captured a hold.

Seems these two functions just don’t know how to work together or play nice with each other.

The other thing I noticed with Auto hold is it seems to have difficulties capturing changes in values when the meter is set in a manual range instead of auto ranging. I set the meter to a manual range, and probe the DUT like voltage from my power supply or voltage reference so I know it’s a steady contact source. No beep, not auto hold after maybe 5 to 8 seconds. So I remove the probes and try again, sometimes it will work the second time, sometimes it won’t. Then I try again if it doesn’t work and eventually it will beep and display the hold value captured. This issue seems intermittent. I tried it also changing the voltage when it didn’t work and still had the same intermittent issue, and I’m not talking about small changes in the value. I tested this with 2.5VDC differences or 5VDC differences in the voltage.

And then also Auto hold might capture a value and beep, but if you don’t immediately remove the probe from the point being measured really fast it will display a lower value as you disconnect the probes from the source.
Example, let’s say I’m measuring a 5V source. When it does a hold and then beeps, if I hesitate and wait a second before I remove the probe it will change from 5V to a lower value like 3.856V as I remove one of the probes. So I have to take a reading again and wait for the beep, and remove the probe from the points I’m messing really fast for it to keep and hold the 5V measurement on the display. The voltage source doesn’t change and stays powered on the whole time.

And it doesn’t detect small changes like mV or uV changes even when it’s set to the highest resolution using auto range or selecting a manual range. I think it’s looking for pre-set amount of change in the value it’s measuring before it will display a new hold value. I’m not sure how much difference it needs to see before it captures and display the new hold value? I think it’s between 35mV and 40mV?
I found myself reversing the probes between each reading before taking probing the next reading. This way I forced it to the negative value before taking the next reading so it would capture even the smallest change in the next reading in case the next reading didn’t have a big enough change in value that would result in dillaying the same reading as before. No new beep if the value change isn’t big enough, or you start to think it’s just not working on the next reading you take.

And I know this is common with some meter, so maybe I shouldn’t mention this next one. But like some other cheap meters the reading are more accurate if you don’t use auto hold compared to the auto hold results. This might be from the meter displaying the results to fast before the measument settles all the way or not taking a few samples before display the hold number?

As I type this I’m starting to realize the auto hold might be the main issue from the fist thing I wrote about using auto hold with a zero set relative value first. I think Auto hold needs a little code tuning in the firmware.

Latest firmware 1.15, just recveied it today.
Scott
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Offline BiOzZ

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Re: EEVblog 121GW Multimeter Issues
« Reply #198 on: May 23, 2018, 07:45:06 am »
(i moved this here from the general discussion, was not aware this was a thread)
Got my multimeter today and it arrived with problems, the ohm mode is reading a constant 0 ohm, diode mode reads 1 volt, high Z mode gives an over range, wont read AC volts, 15v diode mode reads overload
anyone else having these same problems? any fix?
My one regret in life is learning to speak English on the internet ...
 

Offline BiOzZ

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Re: EEVblog 121GW Multimeter Issues
« Reply #199 on: May 23, 2018, 08:40:18 am »
Video of the issue is still being processed but the link is down below

my serial number is #420 (heh)

EDIT: i should add that AC and DC volt reading in the standard (non-lowZ) mode read fine (not sure about accuracy but it looks good enough compared to my UT61E)
« Last Edit: May 23, 2018, 08:42:23 am by BiOzZ »
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