EEVblog 121GW Multimeter Issues

[GeoffreyF]

You are looking for a pipe dream.  Actually complies with spec is very precise.   It actually does comply with the spec.   There have been improvements made and a quite a few more than most vendors make.   Let's live in the real world.  If you want to start a company that makes electronic instruments in a totally transparent, yet completely reliable way then do it.  I think you will learn a lot right before you end up broke.

Nobody is going to do what you "think" they should. Please do not be tedious. This is a thread about issues - you have raised no issues at all!  Issues are not "novel ideas" they are specific things which show lack of compliance to the spec or common beliefs of what a DVM should be.  If the tedious "What if" or "what about" posts never happened in this thread it would be more useful and not as tedious.

[Alex Rodriguez]

So sad that Mr. Jones does not care replying to messages regarding his multimeter's issues, the 121GW.  The 121GW bluetooth is not working with the iPhone. I have the iPhone XS MAX, I cannot make  121GW bluetooth to work on this phone. I read the manual, I followed the outlined steps, no luck. I sent two messages to Mr. Jones, he cares less replying.   I did not buy this meter from Amazon, otherwise, I would have sent it back long ago.
Somehow I still like the little thing, so sad that there is zero support from Mr. Jones.   

[IanB]

So sad that Mr. Jones does not care replying to messages regarding his multimeter's issues, the 121GW.  The 121GW bluetooth is not working with the iPhone. I have the iPhone XS MAX, I cannot make  121GW bluetooth to work on this phone. I read the manual, I followed the outlined steps, no luck. I sent two messages to Mr. Jones, he cares less replying.   I did not buy this meter from Amazon, otherwise, I would have sent it back long ago.
Somehow I still like the little thing, so sad that there is zero support from Mr. Jones.

Which application have you installed on the iPhone?

I don't recall any other reports of the Bluetooth interface not working with iPhones, so it is impossible to say what might be the problem in your case.

Yes, I turned bluetooth  ON, I followed page 53 instructions. I pressed the "1ms PEAK," and I see the "BT" on the screen, but the iPhone does not see the meter at all.  So the application is blank.

Just for clarity, are you looking for the meter on the iPhone, or inside the app? The iPhone does not need to connect to the meter, only the app does.

[tautech]

So sad that Mr. Jones does not care replying to messages regarding his multimeter's issues, the 121GW.  The 121GW bluetooth is not working with the iPhone. I have the iPhone XS MAX, I cannot make  121GW bluetooth to work on this phone. I read the manual, I followed the outlined steps, no luck. I sent two messages to Mr. Jones, he cares less replying.   I did not buy this meter from Amazon, otherwise, I would have sent it back long ago.
Somehow I still like the little thing, so sad that there is zero support from Mr. Jones.

Direct any messages to Seppy (David #2) as IIRC he wrote the app.

[GeoffreyF]

So sad that Mr. Jones does not care replying to messages regarding his multimeter's issues, the 121GW.  The 121GW bluetooth is not working with the iPhone. I have the iPhone XS MAX, I cannot make  121GW bluetooth to work on this phone. I read the manual, I followed the outlined steps, no luck. I sent two messages to Mr. Jones, he cares less replying.   I did not buy this meter from Amazon, otherwise, I would have sent it back long ago.
Somehow I still like the little thing, so sad that there is zero support from Mr. Jones.

What is really sad is that you feel people should respond to "Issues" which you define and are not actually issues.  No? OK tell us another DVM provider that meets your standards for response and "issues" that go beyond what you paid for!

[Alex Rodriguez]

Which application have you installed on the iPhone?

I installed the 121GW iOS. I think that's the only application available for this meter, am I right?

Just for clarity, are you looking for the meter on the iPhone, or inside the app? The iPhone does not need to connect to the meter, only the app does.

Well I tried both  ways. I looked for the meter on the iPhone in  Settings, Bluetooth.  The iphone does not find the meter. Then I tried just the application,  it never finds the iPhone as well. I delete the app, and reinstalled it, no help.

[DavidWC]

I installed the 121GW iOS. I think that's the only application available for this meter, am I right?

Actually, I just published a third-party app ("Meteor for 121GW") for the 121GW on the App Store.  I think there also used to be another third-party (manufacturer?) app called "EEVBlog Smart Data Logger", but I don't see that one on the Store anymore.

You're welcome to try my app (it's free), but honestly if you can't connect with the 121GW app then you're unlikely to succeed with mine.  All BLE iOS apps use the same system library to detect nearby devices and connect to them when requested, so there's really nothing any third-party app can do to find a meter that doesn't show up in the main app.

Well I tried both  ways. I looked for the meter on the iPhone in  Settings, Bluetooth.  The iphone does not find the meter. Then I tried just the application,  it never finds the iPhone as well. I delete the app, and reinstalled it, no help.

A BLE device like the 121GW meter doesn't require (or support) Bluetooth pairing, so there's no need to go to the iOS Settings page to connect to it.  Instead, you need to go through the (BLE) scan-list page that comes up in the 121GW app when you first start it up.  (This page has the title "Select the 121GW to connect to:").  This page will list any nearby meter that's currently "advertising" its presence over BLE.

If your meter is turned on and you don't see any meters listed on that page in the app, then make sure that you've pressed the "1ms PEAK" button for long enough for the "BT" symbol to appear on the meter's LCD.  Once you see the BT symbol on the meter LCD, try the Refresh button in the app to see if anything shows up in the list.  If that doesn't work, try turning the meter off and back on, and then repeat the 1ms-long-press / BT-symbol / app-refresh cycle once again to see if that helps.

If none of that works, then you should verify that your phone's Bluetooth is actually turned on, and not disabled by something like Airplane Mode.  If Bluetooth is on, then you should try turning it off for a few seconds and then back on again, and then repeat the process above.  (Turning Bluetooth off and back on fixes a _lot_ of problems on Android, but I've also seen it fix temporary problems on iPhones.)

If the app still can't see your meter, then the remaining explanations are pretty rare.  One is that another device (iPhone, iPad, Android phone) nearby is connecting to your 121GW before your iPhone gets a chance to see it.  (Any connection will turn off the meter's advertising, making it invisible to the 121GW app). Or, you could be operating in a _really_ noisy radio environment, and your phone is having trouble getting a clean signal.  Or, finally, the Bluetooth radio in your meter could be broken - to check this, there are several apps available on the App Store that will let you detect all nearby devices and will at least tell you if your meter is actually advertising.

[afedorov]

By the way I found a different serious bug regarding logging, where all measurements become corrupted/incorrect, will try to replicate it now... Will post it later if can figure out when and why it happens.

I also encounter incorrect logging values (VA mode, with fw v1.53, v1.58beta), thou the display values are OK at the same time. On earlier fw versions (1.2-ish) same type of logging was OK.
Logging values are somewhat stuck at some point, but least significant digits are changing.

Done some tests on various fw versions, down to v1.22, and that works fine, anything above produces log with incorrect values, like one in attachment.
Values become incorrect after random number of samples captured. Around one to three hours of logging at 1s interval.

[EEVblog]

So sad that Mr. Jones does not care replying to messages regarding his multimeter's issues, the 121GW.  The 121GW bluetooth is not working with the iPhone. I have the iPhone XS MAX, I cannot make  121GW bluetooth to work on this phone. I read the manual, I followed the outlined steps, no luck. I sent two messages to Mr. Jones, he cares less replying.   I did not buy this meter from Amazon, otherwise, I would have sent it back long ago.
Somehow I still like the little thing, so sad that there is zero support from Mr. Jones.

Contact Seppy (David Ledger) eev.davidledger@gmail.com he wrote the app.
But please not that we do not have an iPhone XS MAX, nor do either of us use iPhone or any other apple hardware so we are not across any inctricacies of quirks of the iPhone and Apple stuff.

[tautech]

But please note that we do not have an iPhone XS MAX, nor do either of us use iPhone or any other apple hardware so we are not across any inctricacies of quirks of the iPhone and Apple stuff.

Really, well then plead for some member to send in their old iPhone and/or iPad so you can better support some of the most popular HW on the planet.

[Brumby]

I would not expect Dave or David to be across all platforms with a high degree of expertise in them all.

What I might expect is a 121GW owner who does have such expertise in iOS and could write an App for the Apple ecosystem.

[DavidWC]

I would not expect Dave or David to be across all platforms with a high degree of expertise in them all.

What I might expect is a 121GW owner who does have such expertise in iOS and could write an App for the Apple ecosystem.

As I mentioned earlier in this thread, I am a 121GW owner and a software developer who's working on an indie iOS app for the 121GW.  If the meter is popular enough, I expect that there will be other apps besides mine, especially ones tailored for industry-specific uses such as HVAC, etc.

But in my opinion the first-party app is a reasonably-good iOS app, better than a lot of other multimeter or electronics apps that I've tried.  And again, there's not much that another iOS programmer can do to solve the original poster's problems connecting with, or even seeing, his meter from the app.  If the meter doesn't show up as an advertising BLE device in the meter-scan list, then something else is going on other than how the app was programmed.

I didn't start writing my own app for the 121GW because the first-party app didn't work for me or succeed in its main function, which is to display measurements at a distance on my iPhone.  Perhaps I've missed them, but I haven't seen a lot of other complaints on this board about the app itself, so I'd say David Ledger did a pretty good job of writing an iOS app for an Android-only guy.

The reason I started my own app is that there are certain features I'd like for my own work with the meter: I wanted spoken (voice-synthesized) measurements and a dark-mode display, and I'd like to add cloud-data support and the ability to connect to other meters and sensors.

I didn't know (before this thread) that Dave & David are not iOS (or Apple) users, so yes there are probably things that the first-party app will not get around to supporting - that's where the aftermarket developers like myself will have to step up.  I happen to like Apple stuff and an iPhone is my main device, so I will eventually add things like a Watch client and Siri shortcuts to my app, and even a Mac version if Apple's "Marzipan" (cross-development) program is officially announced this summer as expected.  I wouldn't expect these kind of esoteric, Apple-specific features to be supported by the first-party app, given Dave&David's limited development resources.
   

[EEVblog]

I would not expect Dave or David to be across all platforms with a high degree of expertise in them all.
What I might expect is a 121GW owner who does have such expertise in iOS and could write an App for the Apple ecosystem.

That's why all the source code is open source. No need to write your own, take our code and modify/improve it.

[MichaelW]

Hello everyone.

I bought my 121GW during the kickstarter (SN 1501) and while it is a very nice meter, I didn't have a lot of time to spend playing around with it and just mostly defaulted to my trusty old Brymen BM257. So recently, while working on a project, I wanted to give my 121GW a good go, and noticed some problems. One example is while probing around on a board with a 5v supply, it was reading 10v for some reason. I switched to the Brymen and it read correctly. Back to the 121GW and it read 5v at first then switched back to 10v. I was also noticing that the value was changing slowly, as if it was a discharging capacitor, while the Brymen didn't exhibit this issue.

Anyway, there were a couple of other weird issues so since I never updated the firmware (as it was just sitting there all this time looking pretty), and it was running v1.22, I decided to download the latest (non-beta) version and update it. I downloaded v1.57, put it on the SD card, (file size is ~135k) and put the SD card back in the meter. I pressed HOLD+MEM, turn it on (to the first place, lo-z) and on the IAP screen, press SETUP and it goes to the Douun screen and there it sits. Does nothing more. It has been sitting on that screen now for about half an hour.

Anyone have any suggestions? Since it is such an old firmware version, do I need to install an "intermediate" version first or something? I've seen such things before.  Thanks for any help.

[Brumby]

Was the FW file named correctly?  (Refer to the manual)

[MichaelW]

Yea, the name was correct in the zip file.  I figured it out about an hour later.  I'm embarrassed to say, it was low batteries. There was an icon on the screen that in retrospect was telling me the problem, I just didn't realize it. haha. Since it was used in total about 10 minutes since I got it, I never thought the batteries could be low. After replacing them, I was able to flash it no problem, and the other issues are gone. /facepalm.

[kelemvor]

Hello,

I posted a seperate thread and was advised to post here instead.  Forgive me if I misunderstood, I don't usually post in extremely long threads on a forum.


I'm kind of a noob so I'm sure I'm just doing something stupid here.  I keep getting vac readings on my 1.21gw when there shouldn't be anything.  They tend to drop off over time.  I was just playing with the meter connected to my crappy 30v bench power supply (pevono ps305H).  I'm pretty sure it's the meter that has the problem because I do the same test with my no-name meter and get 0vac also with my fluke 117 I get 0vac.  I don't think it's within the range of my crappy meter, but it should be in range for the fluke.  I don't have a scope to connect to the ps. I did add two 1000μF filter caps to the power supply when I got it.

I've included a screenshot from the 121gw app that shows the reading over time.

http://www.kellyphotos.org/ForumPics/eevblog/121gv%20ac%20voltage.jpg

Seems odd to me.  Am I making some noob mistake?

I get similar behavior from it if the probes aren't connected at all.

Firmware: 1.57

I just got the meter today.

[tautech]

Seems odd to me.  Am I making some noob mistake?

I get similar behavior from it if the probes aren't connected at all.

Quite normal behavior for any high input impedance meter and nuthing to get worried about.
Sanity check; where is the decimal point ? 2mV is nothing but environmental EMI.

[kelemvor]

Seems odd to me.  Am I making some noob mistake?

I get similar behavior from it if the probes aren't connected at all.

Quite normal behavior for any high input impedance meter and nuthing to get worried about.
Sanity check; where is the decimal point ? 2mV is nothing but environmental EMI.

Thanks, I appreciate the feedback.  I thought that might be the case, as the room I'm in has lots of active electronics. The difference in results from the fluke kind of surprised me though.

[1anX]

Forum members are reporting that firmware V1.61 is shipping with new meters.
I have checked Dave's website and the EEVBlog Github but cannot find this version available for download.
The latest available on Dave's website is V1.58 beta!

Can anyone please post a link to firmware V1.61?

[e0ne199]

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?

[Dorz]

Hi guys,

I have recently bought this multimeter to do some data logging work, and have come across the issue where at some point through the recording it stops reading new data and starts repeating the last 60 entries in the CSV over and over again.

This was on the firmware version it shipped with (U-1.57), 1 second polling interval over a period of about 19 hours, it started occurring after about the 5 hour mark.
I have verified it is exactly the 60 lines repeating by referencing the last 60 cells and checking for differences through the cells preceding it until the trend changes.

See attached image, i can attach the spreadsheet or send it if anyone wants to review the raw data?

[afedorov]

fw after v1.22 all have this bug (I checked all). v1.22 seems to work properly in this regard. The meter seems to tolerate a fw rollback.
I didn't spot the pattern, and you absolutely right, all my corrupted logs have the same repetition pattern. First repetition is 120 rows and following are 60 rows of repeated data.

[jtu]

Hi,

I did not find exact reference in documentation, but a reply here suggests, that AV mode is limited to ranges less V and A/mA. Is it so?

My test case was VA for tube power supply: 280V with 100k load, meaning 2.8mA and should be ~0.8VA, but nada. OFL, to be more precise. 12.3V with 50ohm load measures allright ~3VA.

Veiksmi,
Jānis

[hyvamiesh]

Has anyone else had the beeper fail on them intermittently? Was measuring continuity a month ago and noticed the meter to be all quiet, but last week i turned on the meter and was surprised to hear it beep when turning on. This joy lasted only a few minutes, after it went silent again..

I don't currently have access to a oscilloscope, but i have a cheap USB logic analyzer i could use to probe the meters circuit-board. Anyone have suggestions where to concentrate my search for a bad solder-joint?