Author Topic: EEVblog 121GW Multimeter Issues  (Read 445584 times)

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Offline J-R

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Re: EEVblog 121GW Multimeter Issues
« Reply #1300 on: January 13, 2021, 10:51:41 pm »
Calibration is great on the 121GW because you can back it up to a file on the microSD card and restore it if you make a mistake.  Or copy it to your computer for safekeeping.  You can calibrate each function and range individually.
 

Offline curiousmuch

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Re: EEVblog 121GW Multimeter Issues
« Reply #1301 on: January 14, 2021, 12:09:49 am »
That's sick. Awesome thanks so much. I'll review it now. Thanks so much y'all.
 

Offline drvtech

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Re: EEVblog 121GW Multimeter Issues
« Reply #1302 on: January 18, 2021, 08:45:19 pm »
dcac and J-R, thanks for the tips. The company I bought it from are on the case. The leads were the UEI type so really should have been ok. We'll see...
 

Offline EEVblog

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Re: EEVblog 121GW Multimeter Issues
« Reply #1303 on: January 25, 2021, 01:54:24 am »
NOTE: I moved the battery mod discussion to it's own thread:
https://www.eevblog.com/forum/testgear/121gw-multimeter-battery-mod/
 
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Offline nemail2

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Re: EEVblog 121GW Multimeter Issues
« Reply #1304 on: February 04, 2021, 07:54:30 pm »
UPDATE:
The issue with the cracked input jacks is as several suspected, a molding issue.

Quote
input jacks which were injected from the uncompletely-cleared mould probably resulting in for ABS mixed with any foreign materials so the injected jacks could be more easily broken.

Units potentially affected are with serial numbers S/N 18087001 to 181008000
The sockets for these were manually inspected for this issue but it seems that some slipped passed the inspection and have resulted in cracking.

They also mention the Brymen leads are not ideal:
Quote
2. Our input jacks were designed to be ideally matched with our test lead probe with 4.2 - 4.3 phi.  However, Brymen's probe has 4.5 - 5.0 phi, which can give more mechanical stresses to our input jacks.

"Phi" means diameter of the banana plug.
I'm not sure about their measurements because I measured the Brymen at 4.3mm or a smidge over. The UEi ones are spot on 4mm and not the lantern type ones the Brymen use.
They aren't saying don't use the Brymen leads, just that could be a contributing factor in this case. Welectron have been supplying Brymen leads.
My new stock of meters will all come with UEi leads.

They will be sending me a bunch of replacement jacks so I can send to people who want that option.
If you have been affected by this and prefer to replace it yourself, please email me your address so I can send you one. Use the email Title "121GW Connector"
Alternatively you send your meter back to UEi at this address. I'm not sure if they will rework or replace the meter or board.

Attn: (Mr.) Heegoo Kang
Tel: 82-32-837-5777
309, A-dong, Smart Valley,
Songdomirae-ro 30, Yeonsu-gu, Incheon,
21990, Korea

Hi Dave,

my 121GW seems to be affected as well, however my serial number is 190505920... Do you still have input jacks and would you be willing to send them to Austria? If shipping is more expensive and you don't want to pay for it, I'd do that, if it is not ridiculously expensive. I'd say I'd pay up to about EUR 100,- (LOL) because i don't see another option of repairing this ~EUR 300,- DMM...
Please let me know, I'll then drop you an email with the "121GW Connector" subject...

btw I was using the 121GW with the Probemaster 8043SK kit. https://probemaster.com/8000-series-test-lead-master-kits/

Thanks!
Boron rhymes with moron
 

Offline crispus

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Re: EEVblog 121GW Multimeter Issues
« Reply #1305 on: February 08, 2021, 12:25:13 pm »
Hi guys,

I must confess I didn't read all the pages in this thread, but I have this issue with my 121GW (001802) multimeter:


I changed the batteries, I updated to the last fw version, the fuses are ok (the leads are fine).
« Last Edit: February 08, 2021, 12:29:46 pm by crispus »
I know I'm numskull, but I look around me and I feel better.
 

Offline nemail2

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Re: EEVblog 121GW Multimeter Issues
« Reply #1306 on: February 08, 2021, 01:33:12 pm »
could it be the mode select knob contacts?
Boron rhymes with moron
 

Offline crispus

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Re: EEVblog 121GW Multimeter Issues
« Reply #1307 on: February 08, 2021, 08:45:58 pm »
could it be the mode select knob contacts?
Altough it cannot be seen in the video (I changed the exposure to -2 otherwise Rigol multimeter couldn't be read), by default the 121GW starts in DC auto. It doesn't matter if I change the range manually, or I change the mode (same in AC, LowZ)...
I know I'm numskull, but I look around me and I feel better.
 

Offline EEVblog

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Re: EEVblog 121GW Multimeter Issues
« Reply #1308 on: February 08, 2021, 11:00:11 pm »
Hi guys,

I must confess I didn't read all the pages in this thread, but I have this issue with my 121GW (001802) multimeter:


Is that reading hundreds of volts? Very hard to see detail.
Is it just the voltage range? Does ohms work ok?
How old is the meter?
 

Offline crispus

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Re: EEVblog 121GW Multimeter Issues
« Reply #1309 on: February 09, 2021, 01:28:08 am »
Hi Dave,

Yes, it was starting at 4-500V and decreasing. The funny thing is that after a power cycle the value could change, like a disconnect between the MCU and the divider (or whatever is in front of it).

On the ohm range is more close to the real values (for a 5.6k it shows 5.07 and slowly increases like a cap is charging). L.E: 10 minutes later is reading 5.228

The meter is from the kickstarter days (serial number 180701206 / EEVblog 001802 ), it was shipped in July 2018. It was used pretty rarely.
I know I'm numskull, but I look around me and I feel better.
 

Offline EEVblog

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Re: EEVblog 121GW Multimeter Issues
« Reply #1310 on: February 09, 2021, 03:28:02 am »
The meter is from the kickstarter days (serial number 180701206 / EEVblog 001802 ), it was shipped in July 2018. It was used pretty rarely.

Does the switch have the shim fitted under it?
Sounds like a switch issue.
 

Offline crispus

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Re: EEVblog 121GW Multimeter Issues
« Reply #1311 on: February 09, 2021, 09:36:13 am »
It never occurred to me to open it up. I don't recall any mishap with it, but here it is (did I move the switch while connected to the mains?) :
[attach=2]
[attach=3]
It seems that the cover plastic melted as well:
[attach=4]
« Last Edit: February 09, 2021, 09:39:12 am by crispus »
I know I'm numskull, but I look around me and I feel better.
 

Offline Brumby

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Re: EEVblog 121GW Multimeter Issues
« Reply #1312 on: February 09, 2021, 09:46:27 am »
Ouch.  That could easily cause problems.
 

Offline crispus

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Re: EEVblog 121GW Multimeter Issues
« Reply #1313 on: February 09, 2021, 10:22:13 am »
I cleaned it, still doesn't work but the shim is not the issue as one could see the above pictures  ;D but that lead me to the issue.

At close inspection it doesn't seem that any other component misses the magic smoke, but hey, after an event like that anything could go wrong:
[attach=1]
I know I'm numskull, but I look around me and I feel better.
 

Offline nemail2

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Re: EEVblog 121GW Multimeter Issues
« Reply #1314 on: February 09, 2021, 11:13:03 am »
could it be the mode select knob contacts?

that's what I meant/what I was saying...

@Dave: have you seen my post/e-mail about the cracked input jack? are you still shipping replacement jacks? I'd even buy one if I had a source. Please, help! Thanks!
Boron rhymes with moron
 

Offline joeqsmith

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Re: EEVblog 121GW Multimeter Issues
« Reply #1315 on: February 09, 2021, 01:26:39 pm »
I cleaned it, still doesn't work but the shim is not the issue as one could see the above pictures  ;D but that lead me to the issue.

At close inspection it doesn't seem that any other component misses the magic smoke, but hey, after an event like that anything could go wrong:

Nice pictures.  Always good to see cheap meters damaged in action.  The melted area along the side of the case is a nice touch.   This was another member's meter which was damaged from a HV source. 



Shouldn't be too difficult to track down if you plan to attempt repairs. 
How electrically robust is your meter?? https://www.youtube.com/channel/UCsK99WXk9VhcghnAauTBsbg
 

Offline nemail2

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Re: EEVblog 121GW Multimeter Issues
« Reply #1316 on: February 09, 2021, 06:36:13 pm »
UPDATE:
The issue with the cracked input jacks is as several suspected, a molding issue.

Quote
input jacks which were injected from the uncompletely-cleared mould probably resulting in for ABS mixed with any foreign materials so the injected jacks could be more easily broken.

Units potentially affected are with serial numbers S/N 18087001 to 181008000
The sockets for these were manually inspected for this issue but it seems that some slipped passed the inspection and have resulted in cracking.

They also mention the Brymen leads are not ideal:
Quote
2. Our input jacks were designed to be ideally matched with our test lead probe with 4.2 - 4.3 phi.  However, Brymen's probe has 4.5 - 5.0 phi, which can give more mechanical stresses to our input jacks.

"Phi" means diameter of the banana plug.
I'm not sure about their measurements because I measured the Brymen at 4.3mm or a smidge over. The UEi ones are spot on 4mm and not the lantern type ones the Brymen use.
They aren't saying don't use the Brymen leads, just that could be a contributing factor in this case. Welectron have been supplying Brymen leads.
My new stock of meters will all come with UEi leads.

They will be sending me a bunch of replacement jacks so I can send to people who want that option.
If you have been affected by this and prefer to replace it yourself, please email me your address so I can send you one. Use the email Title "121GW Connector"
Alternatively you send your meter back to UEi at this address. I'm not sure if they will rework or replace the meter or board.

Attn: (Mr.) Heegoo Kang
Tel: 82-32-837-5777
309, A-dong, Smart Valley,
Songdomirae-ro 30, Yeonsu-gu, Incheon,
21990, Korea

Hi Dave,

my 121GW seems to be affected as well, however my serial number is 190505920... Do you still have input jacks and would you be willing to send them to Austria? If shipping is more expensive and you don't want to pay for it, I'd do that, if it is not ridiculously expensive. I'd say I'd pay up to about EUR 100,- (LOL) because i don't see another option of repairing this ~EUR 300,- DMM...
Please let me know, I'll then drop you an email with the "121GW Connector" subject...

btw I was using the 121GW with the Probemaster 8043SK kit. https://probemaster.com/8000-series-test-lead-master-kits/

Thanks!

hmm dave, did you miss my request? short ack that you'll look into it would suffice... wrote you a mail as well (did so a few months ago as well)...
Boron rhymes with moron
 

Offline EEVblog

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Re: EEVblog 121GW Multimeter Issues
« Reply #1317 on: February 10, 2021, 01:27:38 am »
could it be the mode select knob contacts?
that's what I meant/what I was saying...
@Dave: have you seen my post/e-mail about the cracked input jack? are you still shipping replacement jacks? I'd even buy one if I had a source. Please, help! Thanks!

That's a a concern if it's outside the affected range.
Email sent.
 
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Offline Robosity

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Re: EEVblog 121GW Multimeter Issues
« Reply #1318 on: February 19, 2021, 08:51:28 pm »
I have a 121gw (s/n 180807803) with the dreaded 'disintegrating socket' problem.  Surprised it took this long to fail as I use this gem nearly every day on the bench and bought it new from this site.


How do I get replacement parts for this unit?  I'm happy to pay for the replacements plus shipping.  I just need to know where to get them.  From you? From a distributor?

FWIW, all four socket plastic 'tubes' have disintegrated, some entirely.  I am using 'shrouded' probe plugs so I don't think it's completely unsafe yet, but it's getting there :-)

Also, I think I'm completely capable of replacing the parts - proper soldering / desoldering workbench here.

Thanks,
Gary
 

Offline nemail2

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Re: EEVblog 121GW Multimeter Issues
« Reply #1319 on: February 19, 2021, 11:05:33 pm »
I have a 121gw (s/n 180807803) with the dreaded 'disintegrating socket' problem.  Surprised it took this long to fail as I use this gem nearly every day on the bench and bought it new from this site.


How do I get replacement parts for this unit?  I'm happy to pay for the replacements plus shipping.  I just need to know where to get them.  From you? From a distributor?

FWIW, all four socket plastic 'tubes' have disintegrated, some entirely.  I am using 'shrouded' probe plugs so I don't think it's completely unsafe yet, but it's getting there :-)

Also, I think I'm completely capable of replacing the parts - proper soldering / desoldering workbench here.

Thanks,
Gary

Dave has just sent me a new input jack assembly and I have replaced them today. Took me about 30 minutes.
Thanks Dave, for sending me the replacement part!
Boron rhymes with moron
 

Offline drvtech

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Re: EEVblog 121GW Multimeter Issues
« Reply #1320 on: February 25, 2021, 11:09:55 am »
Received replacement jacks a few days ago. Also got good service from Simon's Electronics so my 121GW is now up and running again.
 

Offline J-R

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Re: EEVblog 121GW Multimeter Issues
« Reply #1321 on: February 25, 2021, 05:37:17 pm »
It seems a recent production of the jacks have the metal portion slightly smaller than previous versions.  Can anyone comment on their experience with that?
 


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