Author Topic: EEVblog 121GW Multimeter Issues  (Read 88580 times)

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Offline ChunkyPastaSauce

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Re: EEVblog 121GW Multimeter Issues
« Reply #225 on: May 26, 2018, 05:23:32 am »
Did you check these on 1.15 or 1.17 for the things you want to me check?
I checked on both 1.15 and 1.17

In Amp if you measure current, hold the reading and pull the probes out the reading stays displayed.
In the mA/uA jack if you do the same thing when you pull the probe out, the screen goes blank. And if you had it set to a manual range it changes over to Auto range when you pull the probe with the reading on hold.
Same behavior on mine on 1.17

Mine has a weird viewing angle also, straight on is dim compared to looking up at it. But looking at a down angle it get worse, almost unreadable.
The view angle bias seems ok on mine - viewable flat on a table or looking straight on at meter (contrast does fade a little bit straight on but it's not bad). The default contrast setting on mine (4) was way too low though, I have mine set at max (7) and do wish it would go a little higher.

Noticing input jack warning doesn't function if both plugs are in the current jacks (one in A, other in uA). If in mV AC, and set 1ms peak, then input jack warning is not displayed. Similarly if one sets hold, then jack warning not displayed.   1.17
 

Offline BiOzZ

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Re: EEVblog 121GW Multimeter Issues
« Reply #226 on: May 26, 2018, 10:43:37 am »
A little update on my meter, the problem looks to be at least partly software as i cannot update the firmware, i checked out the mcu and there was some gunk over some pins as seen in attached but this appears not to be the issue, i cleaned it up and hit it with the rework station and the problem persists

when i attempt to update the firmware it looks like the micro locks up (with both 1.15 and 1.17 firmware) as some segments stay on and appear to build up and loose charge as it sits, i let it sit for an hour to no avail

at this point i have basically given up trying to repair it and hope for a replacement, i sent my details off to Seppy (i think i have, its not appearing in my sent messages)
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Offline ChunkyPastaSauce

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Re: EEVblog 121GW Multimeter Issues
« Reply #227 on: May 26, 2018, 11:35:17 am »
Bummer, but you tried

For sent messages to appear in outbox, you have to make sure "Save a copy in my outbox" is checked before sending. If you go to preferences there's a "Save a copy of each personal message in my sent items by default" option too.
 

Offline BiOzZ

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Re: EEVblog 121GW Multimeter Issues
« Reply #228 on: May 26, 2018, 11:49:33 am »
Bummer, but you tried

For sent messages to appear in outbox, you have to make sure "Save a copy in my outbox" is checked before sending. If you go to preferences there's a "Save a copy of each personal message in my sent items by default" option too.
Oh okay, thanks for the heads up ill keep that in mind
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Offline nidlaX

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Re: EEVblog 121GW Multimeter Issues
« Reply #229 on: May 26, 2018, 12:06:25 pm »
I noticed a potential quality issue with the rubber boot. On the right side, the lip is a bit deformed and doesn't adhere to the contour of the meter. Based on videos I've seen of the production meter, my problem doesn't seem to be a one-off (didn't notice it with Joe's pre-production meter though).

Any thoughts?


« Last Edit: May 26, 2018, 12:08:45 pm by nidlaX »
 

Offline BiOzZ

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Re: EEVblog 121GW Multimeter Issues
« Reply #230 on: May 26, 2018, 12:08:51 pm »
I noticed a potential quality issue with the rubber boot. On the right side, the lip is a bit deformed and doesn't adhere to the contour of the meter. Based on videos I've seen of the production meter, my problem doesn't seem to be a one-off (didn't notice it with Joe's pre-production meter though).

Any thoughts?

mine does the same thing, but does slowly pull it self back together after an hour after pulling it out of its sheath
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Offline ChunkyPastaSauce

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Re: EEVblog 121GW Multimeter Issues
« Reply #231 on: May 26, 2018, 12:35:28 pm »
Pulled away a bit as well on same side, but higher up near LCD/buttons; out of box. Not as bad as yours though, but enough to notice immediately when holding first time.
 

Offline nidlaX

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Re: EEVblog 121GW Multimeter Issues
« Reply #232 on: May 26, 2018, 01:31:07 pm »
I noticed a potential quality issue with the rubber boot. On the right side, the lip is a bit deformed and doesn't adhere to the contour of the meter. Based on videos I've seen of the production meter, my problem doesn't seem to be a one-off (didn't notice it with Joe's pre-production meter though).

Any thoughts?

mine does the same thing, but does slowly pull it self back together after an hour after pulling it out of its sheath
Mine is probably permanent, it was like this out of the box. I'm guessing it's either an issue with the way they're pulled out of the mold or with how the meters were handled when they were opened up to install the shim.

Not sure if this is worth a warranty inquiry though. Maybe if many other customers have the same problem.
 

Offline ChunkyPastaSauce

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Re: EEVblog 121GW Multimeter Issues
« Reply #233 on: May 26, 2018, 04:30:00 pm »
Burden voltage function doesn't seem to work? Set current range, then change bd.off->bd.on - doesn't seem do anything (unless not understanding something?) v1.17
 

Offline Mickatroid

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Re: EEVblog 121GW Multimeter Issues
« Reply #234 on: May 27, 2018, 09:12:34 am »
Mine has a weird viewing angle also, straight on is dim compared to looking up at it. But looking at a down angle it get worse, almost unreadable.

As I said in my original post a bump on the bench appeared to fix mine properly. Whether the problem will come back I cannot say. Our symptoms were about the same. You will see Dave thinks it could be the zebra strip.

Edit: thanks mod :) sorry about the quote pebcak
« Last Edit: May 27, 2018, 07:44:41 pm by Mickatroid »
 

Offline Scottjd

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Re: EEVblog 121GW Multimeter Issues
« Reply #235 on: May 27, 2018, 09:39:26 am »
I noticed a potential quality issue with the rubber boot. On the right side, the lip is a bit deformed and doesn't adhere to the contour of the meter. Based on videos I've seen of the production meter, my problem doesn't seem to be a one-off (didn't notice it with Joe's pre-production meter though).

Any thoughts?

mine does the same thing, but does slowly pull it self back together after an hour after pulling it out of its sheath
Mine is probably permanent, it was like this out of the box. I'm guessing it's either an issue with the way they're pulled out of the mold or with how the meters were handled when they were opened up to install the shim.

Not sure if this is worth a warranty inquiry though. Maybe if many other customers have the same problem.
Does anyone know the material that the outside boot is made of? Ifs it TPU, or some combined mix of stuff?
Sometimes depending on the material a little heat like a blow dryer on low can help re-shape it back to normal.
Do it use high heat like a 1,000 watt har dryer on high, or a hot air soldering station. This could melt or burn it. But that’s why the type of material is important to know the limits for temperature durring it’s original molding.
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Offline bitwelder

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Re: EEVblog 121GW Multimeter Issues
« Reply #236 on: May 27, 2018, 05:21:40 pm »
Does anyone know the material that the outside boot is made of? Ifs it TPU, or some combined mix of stuff?
That's a piece of information that if it's not already in the manual, I think it should be added there, also for ecological disposal purposes.
 

Offline Scottjd

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Re: EEVblog 121GW Multimeter Issues
« Reply #237 on: May 27, 2018, 08:35:31 pm »
Does anyone know the material that the outside boot is made of? Ifs it TPU, or some combined mix of stuff?
That's a piece of information that if it's not already in the manual, I think it should be added there, also for ecological disposal purposes.
Nope, it’s not in the manual. Unless I missed it both times I gone over the manual.
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Offline IanB

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Re: EEVblog 121GW Multimeter Issues
« Reply #238 on: May 28, 2018, 07:57:55 am »
I noticed a potential quality issue with the rubber boot. On the right side, the lip is a bit deformed and doesn't adhere to the contour of the meter. Based on videos I've seen of the production meter, my problem doesn't seem to be a one-off (didn't notice it with Joe's pre-production meter though).

Any thoughts?

I might suggest to immerse the boot in hot water and see if it "relaxes" back to the correct shape? Proceed carefully though in case anything bad happens like shrinking or greater deformation.
I'm not an EE--what am I doing here?
 

Offline drtaylor

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Re: EEVblog 121GW Multimeter Issues
« Reply #239 on: May 28, 2018, 08:11:09 am »
Regarding the material the boot is made from:

Those kinds of boots are almost always made of "Elastomeric Rubber" which actually is a form of Silicone. Same stuff that insulates very flexible test leads. Available in many viscosities.
 

Offline Seppy

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Re: EEVblog 121GW Multimeter Issues
« Reply #240 on: May 28, 2018, 02:11:55 pm »
Hi Dave, you did this video a while back with voltage. I’ve been :palm: trying to figure this out, and I think I finally figured out why my resistance testing is gettting such large differences in readings.

I haven’t had time to check the voltage and temperature change but it also didn’t jump out at me during basic testing so I’m assuming it’s probably ok.
What I have noticed is the resistor mensrment range being severely affected by the internal meter temperature. I’m going off what the internal temperature is showing on the meter.

Can you run this again in the resistance mode? Specifically the 50M resistance mode maybe with a 10M resistors? Although I’ve noticed the temperature affecting all resistance modes, the 50M ohm range seems to be the worse and most sensitive. The ambient temperature in the lab did not change more then 1C but the internal temp on the meter with backlight on went from 21.1C to 26.1C.

My Caddock 10M resistor at 0.1% tolerance is a 15ppm temp coefficient but as I mentioned the lab room temperature hardly changed at all. At internal meter reading temp it showed 10.005. By the time the meter internal temp reached 26.1C the resistor was reading 10.158. And the day my air con was off the lab was at 24.4C and the internal temp on the meter reached 28.9C and the reading was much higher at 10.356.

Despite the 10M resistor being 15ppm I also testing with Vishay that are 2ppm at 0.025% tolerances and those are affected also with all ranges I own 1, 10, 1K, 10k, 100k ohm resistors.
I will also note the 50M range seems to be the most sensitive jumping around a lot just going to push a button on the meter or waiving your hand around it.
I just want to know if this is mine only, or if you can repeate the test with the resistance mode and see if this is a common thing? And maybe the sensitivity can be adjusted in the firmware, it reminds me of your 2016 mV range video showing it being so sensitive that I believe was corrected with firmware or maybe a hardware change? If it not just mine maybe theirs a specific component this resistance mode uses that can be changed to something that has better temperature coefficiency?

The sweet spot for internal meter internal temperature seemed to be about 21.1C for all ranges.



Hello scott!

Just did some long term logging of 10MR. Don't see the same error you discuss, is there any specific things I missed with my tests?


Test 1: Simply connected 10M resistor to the multimeter and logged for an hour.
Test 2: Placed multimeter in a thermal chamber starting at 26.6 degrees and raised it to 35.6. The 121GW measured a 10M resistor that was outside the thermal chamber (so it was unaffected by rising temperature or humidity), logging for an hour.

NOTE: There are some glitches in my logging, thats just when I bumped the leads with my computer mouse, try not to move wires when measuring such high impedances.

The next test starts at 26.6 and raises to 35.6. These were logged using the windows app over bluetooth. At about 2000 I left the room for lunch and the erroneous readings stopped entirely, again high impedance readings are very sensitive.

Are you able to show something similar? I recommend using the Windows App for this is as it will make saving and posting the data a little easier.

 




 
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Offline dcac

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Re: EEVblog 121GW Multimeter Issues
« Reply #241 on: May 28, 2018, 10:42:52 pm »
did this thread get unpinned by accident? - it no longer appear at the top of the thread list.
 

Offline EEVblog

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Re: EEVblog 121GW Multimeter Issues
« Reply #242 on: May 28, 2018, 11:01:20 pm »
did this thread get unpinned by accident? - it no longer appear at the top of the thread list.

Yeah, no idea how it got unpinned, fixed.
 

Offline Scottjd

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Re: EEVblog 121GW Multimeter Issues
« Reply #243 on: May 29, 2018, 07:36:12 am »
Hello scott!

Just did some long term logging of 10MR. Don't see the same error you discuss, is there any specific things I missed with my tests?


Test 1: Simply connected 10M resistor to the multimeter and logged for an hour.
Test 2: Placed multimeter in a thermal chamber starting at 26.6 degrees and raised it to 35.6. The 121GW measured a 10M resistor that was outside the thermal chamber (so it was unaffected by rising temperature or humidity), logging for an hour.

NOTE: There are some glitches in my logging, thats just when I bumped the leads with my computer mouse, try not to move wires when measuring such high impedances.

The next test starts at 26.6 and raises to 35.6. These were logged using the windows app over bluetooth. At about 2000 I left the room for lunch and the erroneous readings stopped entirely, again high impedance readings are very sensitive.

Are you able to show something similar? I recommend using the Windows App for this is as it will make saving and posting the data a little easier.
Nope, no difference. I didn’t log the results, I just watched it change.
I’ll have to find my wondws laptop and install the software.

Speaking of apps, do you know what happened to the iOS app for Apple devices? I had it downloaded and it controls thing like ranges, hold, but doesn’t display any numbers. Then I realized it was removed from the iOS App Store, do you know when we can expect this to be returned?

I also took into the consideration based off Dave’s video showing a grounded ESD mat affecting mV readings and moved it to another room that is latterly empty. Still the same results.
I’ll try to log it if I find the computer, It might just be my meter?

Thanks for checking and running the tests,
Scott
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Offline Seppy

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Re: EEVblog 121GW Multimeter Issues
« Reply #244 on: June 01, 2018, 11:18:07 am »
Hello scott!

Just did some long term logging of 10MR. Don't see the same error you discuss, is there any specific things I missed with my tests?


Test 1: Simply connected 10M resistor to the multimeter and logged for an hour.
Test 2: Placed multimeter in a thermal chamber starting at 26.6 degrees and raised it to 35.6. The 121GW measured a 10M resistor that was outside the thermal chamber (so it was unaffected by rising temperature or humidity), logging for an hour.

NOTE: There are some glitches in my logging, thats just when I bumped the leads with my computer mouse, try not to move wires when measuring such high impedances.

The next test starts at 26.6 and raises to 35.6. These were logged using the windows app over bluetooth. At about 2000 I left the room for lunch and the erroneous readings stopped entirely, again high impedance readings are very sensitive.

Are you able to show something similar? I recommend using the Windows App for this is as it will make saving and posting the data a little easier.
Nope, no difference. I didn’t log the results, I just watched it change.
I’ll have to find my wondws laptop and install the software.

Speaking of apps, do you know what happened to the iOS app for Apple devices? I had it downloaded and it controls thing like ranges, hold, but doesn’t display any numbers. Then I realized it was removed from the iOS App Store, do you know when we can expect this to be returned?

I also took into the consideration based off Dave’s video showing a grounded ESD mat affecting mV readings and moved it to another room that is latterly empty. Still the same results.
I’ll try to log it if I find the computer, It might just be my meter?

Thanks for checking and running the tests,
Scott

Due to the Packet change of the 121GW the iOS app stopped working. We are porting our app to the iPhone now, it won't be available immediately as I need to do a whole song and dance to get Apple to approve Apps, not a show stopper just a slow process.
 

Offline iainwhite

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Re: EEVblog 121GW Multimeter Issues
« Reply #245 on: June 06, 2018, 11:33:37 am »
Still waiting for my missing 121Gw yellow shim that I was promised twice in the last 3 weeks.
 

Offline ChrisG

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Re: EEVblog 121GW Multimeter Issues
« Reply #246 on: June 06, 2018, 07:26:49 pm »
Hi all, Dave, Seppy, I've received my shim and selector switch and installed it. The internal selector with the wipes is still causing abrasion to the PCB by the looks of it. Initially the selector knob could not be operated with one hand and I had to fix the 121GW with my left-hand. I've loosened the internal 2 screws and this helps (a bit). What remains now is that when the selector is in the ohms range and I wiggle or pull the V+/Ohm cable the 121GW goes into black/reset mode. I loved the 121GW from the on-start due to the crowd funding, the discussions, the feature set and specifications. But I need to come to the conclusion that this is not workable for me and need to revert back to my trusted BM869s. I can inspect the socket on the PCB but suspect it's the wipes and internal selector which causing the issue since it only happens when in the Ohms range. A genuine pitty it is.
 

Offline Seppy

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Re: EEVblog 121GW Multimeter Issues
« Reply #247 on: June 07, 2018, 12:47:50 pm »
Hi all, Dave, Seppy, I've received my shim and selector switch and installed it. The internal selector with the wipes is still causing abrasion to the PCB by the looks of it. Initially the selector knob could not be operated with one hand and I had to fix the 121GW with my left-hand. I've loosened the internal 2 screws and this helps (a bit). What remains now is that when the selector is in the ohms range and I wiggle or pull the V+/Ohm cable the 121GW goes into black/reset mode. I loved the 121GW from the on-start due to the crowd funding, the discussions, the feature set and specifications. But I need to come to the conclusion that this is not workable for me and need to revert back to my trusted BM869s. I can inspect the socket on the PCB but suspect it's the wipes and internal selector which causing the issue since it only happens when in the Ohms range. A genuine pitty it is.

Please ensure that shim's routed cutout faces downwards into the plastic rotary selector assembly. The cutout is NOT for the circlip, a lot of people have had that issue with upside down shims.
There is also chance that some burs on the plastic are causing the shim to raise up too far, you might want to remove the injection molding burs if possible. It is a shame that the shim was needed.
It might also be worth opening up the device and removing the selector switch, carefully (this can be pretty tricky), making sure the PCB underneath it is fine.

It could be that the brushes aren't perfectly housed, or that one of the brushes has two spring contacts stacked on-top of each other (happened once in pre-production, but thought this was sorted out).
 

Offline bicycleguy

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Re: EEVblog 121GW Multimeter Issues
« Reply #248 on: June 07, 2018, 04:22:26 pm »
..
Please ensure that shim's routed cutout faces downwards into the plastic rotary selector assembly. The cutout is NOT for the circlip, a lot of people have had that issue with upside down shims.
...
Up, down, into selector assembly?  A picture of the proper installation by the seller would be worth 1000 posts. 
 

Offline 1anX

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Re: EEVblog 121GW Multimeter Issues
« Reply #249 on: June 07, 2018, 04:43:14 pm »
..
Please ensure that shim's routed cutout faces downwards into the plastic rotary selector assembly. The cutout is NOT for the circlip, a lot of people have had that issue with upside down shims.
...
Up, down, into selector assembly?  A picture of the proper installation by the seller would be worth 1000 posts.

Its already been done, available as a pdf and on youtube!
https://www.eevblog.com/files/How%20to%20Replace%20121GW%20Rotary%20Switch-180411.pdf

« Last Edit: June 07, 2018, 07:32:32 pm by 1anX »
 
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