Author Topic: EEVblog 121GW Multimeter Issues  (Read 88672 times)

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Offline fanOfeeDIY

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Re: EEVblog 121GW Multimeter Issues
« Reply #100 on: January 15, 2018, 02:07:35 pm »
The data is corrupted as bellow in the middle of the data.
59625,DCV,049.997,V,,,,,,,,
59626,DCV,049.997,V,,,,,,,,
59627,DCV,049.996,V,,,,,,,,
59628,DCV,049.997,V,,,,,,,,
59629,DCV,                                                                                                                                                                                        59641,DCV,050.001,V,,,,,,,,
59642,DCV,049.996,V,,,,,,,,
59643,DCV,049.996,V,,,,,,,,
59644,DCV,049.998,V,,,,,,,,
59645,DCV,049.996,V,,,,,,,,

The garbled line only happened in one line out of four files of data logging.

It looks to me as if samples 59629 through 59640 are missing from the file? So it's not just a garbled line, it's some dropped data.

Good comment, I should have attached the raw data of the log file from the beginning why I thought it was a garbled line.

I just opened the file with binary editor.
Attached is the screen shot when opening the log file with binary editor.
0x00 is not in ASCII code.

This is my pure guess based on my software engineering experience. The firmware is trying to write the data to SD card however it could be it has memory writing over flow, memory leak or improper locking between other threads.

« Last Edit: January 15, 2018, 02:10:22 pm by fanOfeeDIY »
 
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Offline iainwhite

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Re: EEVblog 121GW Multimeter Issues
« Reply #101 on: January 16, 2018, 03:07:31 am »
My issues:

1. The manual is not very clear on the type of Setup button press that is needed e.g. long press to save a value after editing it.
2. The constant beeping is driving me mad. Please can we have an option to turn off the beeper.

I realize that both these issues have already been reported.
 

Offline EEVblog

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Re: EEVblog 121GW Multimeter Issues
« Reply #102 on: January 16, 2018, 05:03:06 pm »
Seems like YOU are the one polluting it.  Have anything technical to add?

I'll be very clear again.
This thread is for REPORTS of bugs and issues and CONFIRMATIONS of those bugs and issues.
DO NOT discuss them here, PLEASE!
 

Offline amspire

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Re: EEVblog 121GW Multimeter Issues
« Reply #103 on: January 16, 2018, 05:36:11 pm »
Addition to Dec 11th Manual:

Firmware Version 1.01 has an extra setup field "00000" not mentioned in the manual. It is between the hour-minute setting and logging interval setting.

I gather it is a programmable Serial number or ID number used in Bluetooth communication to identify a meter.
 
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Offline joeqsmith

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Re: EEVblog 121GW Multimeter Issues
« Reply #104 on: January 16, 2018, 08:11:46 pm »
Seems like YOU are the one polluting it.  Have anything technical to add?

I'll be very clear again.
This thread is for REPORTS of bugs and issues and CONFIRMATIONS of those bugs and issues.
DO NOT discuss them here, PLEASE!


I did not realize you were censoring posts in this area.   I resubmitted the post you removed twice because I literally thought I had forgotten to press the send key, not because I was trying to be a dick about it.     
How electrically robust is your meter?? https://www.youtube.com/channel/UCsK99WXk9VhcghnAauTBsbg
 

Offline lewis

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Re: EEVblog 121GW Multimeter Issues
« Reply #105 on: January 17, 2018, 12:24:12 am »
...CONFIRMATIONS of those bugs and issues.

I can confirm the meter beeps and beeps and beeps and beeps and beeps and beeps and BEEEEEEEPPPPS which makes it basically unusable, because I BEEP, I mean keep, wanting to throw it at great BEEP, I mean speed, across the workBEEP, I mean workshop. I've taken back off and covered the sounder in many layers of tape but it's still annoying as hell.

I can also confirm It also takes about 9 seconds to measure a low resistance. The fuse rating printed on the back label does not match the fuse inside (440mA 1kV vs 400mA 600V). Update rate on the bluetooth app is abysmal, and the connection keeps dropping out. I don't know if the measurement displayed on the smartphone is what the meter is actually measuring, or if the connection has died.

If I remember correctly, there is also a large-ish offset under an open-probe condition on AC and DC voltage ranges (will edit this post later when I have the meter in my hand to confirm). Nope! mV range was showing on display, but selector switch was set to V! Had a -0.5mV DC offset, thought it was -0.5V. I think I had a dicky selector switch, very difficult to reproduce now the switch has had some (ab)use.

Dave, I can't see how you would have approved the prototype and thought it acceptable.

Beep <shudder>
« Last Edit: January 17, 2018, 02:27:15 am by lewis »
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Online exe

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Re: EEVblog 121GW Multimeter Issues
« Reply #106 on: January 17, 2018, 03:10:27 am »
Firmware Version 1.01 has an extra setup field "00000" not mentioned in the manual. It is between the hour-minute setting and logging interval setting.

I thought it's a logging interval or screen refresh interval in ms... Or a sample number... Uhm...
 

Offline MatthewEveritt

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Re: EEVblog 121GW Multimeter Issues
« Reply #107 on: January 17, 2018, 03:59:15 am »
It's apparently a sort of 'serial number' that gets added to the bluetooth data to help distinguish multiple meters [source].
 

Offline Iagash

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Re: EEVblog 121GW Multimeter Issues
« Reply #108 on: January 18, 2018, 03:14:05 am »
While I consider the autoranging speed not particularly good, it is at least correct and works.

The fails in the adnvanced functions, that distinguish this meter from the rest of the market are much more annoying. They are not just "slow", they are plain unreliable and broken.

After fanOfeeDIY showed the broken logfile I decided to do a test to the maximum extend the meter logs.

I don't get why there is a limitation on 600k lines, but well, maybe Dave will explain some day or it's extended.
The 600k lines don't even last 48h.
I know I could reduce the log interval, but why?

I got the corrupt logfile in my first try.

The data is corrupted as bellow in the middle of the data.
59625,DCV,049.997,V,,,,,,,,
59626,DCV,049.997,V,,,,,,,,
59627,DCV,049.996,V,,,,,,,,
59628,DCV,049.997,V,,,,,,,,
59629,DCV,                                                                                                                                                                                        59641,DCV,050.001,V,,,,,,,,
59642,DCV,049.996,V,,,,,,,,
59643,DCV,049.996,V,,,,,,,,
59644,DCV,049.998,V,,,,,,,,
59645,DCV,049.996,V,,,,,,,,

The garbled line only happened in one line out of four files of data logging.

It looks to me as if samples 59629 through 59640 are missing from the file? So it's not just a garbled line, it's some dropped data.

Good comment, I should have attached the raw data of the log file from the beginning why I thought it was a garbled line.

I just opened the file with binary editor.

I can confirm the file corruption. I let the meter log for almost 2 days in VA mode and have several corrupted lines in the log.

I ran a small awk script on the file to find lines where the line counter didn't match the actual line number of the log lines.

Code: [Select]
awk -F, '/^[0-9]+,/{if ( c != $1 ) { printf("%6d %6d %s\n", l, c, $0); c = $1 } c++; l++; }BEGIN{l=1;c=1}' < 18011500.CSV
It prints the real line number, the line number it expected and the line from the logfile. The result is this:
Code: [Select]
61501  61501 61502,DCVA,01959.5,mVA,DCV,04.4482,V,DCA,0440.52,mA,,
139554 139555 139562,DCVA,01959.5,mVA,DCV,04.4482,V,DCA,0440.52,mA,,
243949 243957 243962,DCVA,01959.5,mVA,DCV,04.4482,V,DCA,0440.52,mA,,
267167 267180 267182,DCVA,01959.5,mVA,DCV,04.4482,V,DCA,0440.52,mA,,
344797 344812 344822,DCVA,01959.5,mVA,DCV,04.4482,V,DCA,0440.52,mA,,
356188 356213 356222,DCVA,01959.5,mVA,DCV,04.4482,V,DCA,0440.52,mA,,
412106 412140 412142,DCVA,01959.5,mVA,DCV,04.4482,V,DCA,0440.52,mA,,
431304 431340 431342,DCVA,01959.5,mVA,DCV,04.4482,V,DCA,0440.52,mA,,
478699 478737 478742,DCVA,01959.5,mVA,DCV,04.4482,V,DCA,0440.52,mA,,
523695 523738 523742,DCVA,01959.5,mVA,DCV,04.4482,V,DCA,0440.52,mA,,

So there are 10 errors in just one logfile.

Here are the errors:
Code: [Select]
61499,DCVA,01959.5,mVA,DCV,04.4482,V,DCA,0440.53,mA,,
61500,DCVA,01959.5,mVA,DC^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@61501,DCVA,01959.5,mVA,DCV,04.4482,V,DCA,0440.52,mA,,
61502,DCVA,01959.5,mVA,DCV,04.4482,V,DCA,0440.52,mA,,
Code: [Select]
139553,DCVA,01959.5,mVA,DCV,04.4482,V,DCA,0440.53,mA,,
139554,DCVA,01959.5,mVA,DCV,04.4482,V,DCA,044^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@139561,DCVA,01959.5,mVA,DCV,04.4482,V,DCA,0440.52,mA,,
139562,DCVA,01959.5,mVA,DCV,04.4482,V,DCA,0440.52,mA,,
Code: [Select]
243956,DCVA,01959.5,mVA,DCV,04.4482,V,DCA,0440.53,mA,,
24395^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@243961,DCVA,01959.5,mVA,DCV,04.4482,V,DCA,0440.52,mA,,
243962,DCVA,01959.5,mVA,DCV,04.4482,V,DCA,0440.52,mA,,
Code: [Select]
267178,DCVA,01959.5,mVA,DCV,04.4482,V,DCA,0440.53,mA,,
267179,DCVA,01959.5,mVA,DCV,04.4482,V,DCA,0440.53,mA,^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@267181,DCVA,01959.5,mVA,DCV,04.4482,V,DCA,0440.52,mA,,
267182,DCVA,01959.5,mVA,DCV,04.4482,V,DCA,0440.52,mA,,
Code: [Select]
344810,DCVA,01959.5,mVA,DCV,04.4482,V,DCA,0440.53,mA,,
344811,DCVA,01959.5,mVA,DCV,04.4482,V,DCA,0440.53,mA,^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@344821,DCVA,01959.5,mVA,DCV,04.4482,V,DCA,0440.52,mA,,
344822,DCVA,01959.5,mVA,DCV,04.4482,V,DCA,0440.52,mA,,
Code: [Select]
356212,DCVA,01959.5,mVA,DCV,04.4482,V,DCA,0440.53,mA,,
35621^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@356221,DCVA,01959.5,mVA,DCV,04.4482,V,DCA,0440.52,mA,,
356222,DCVA,01959.5,mVA,DCV,04.4482,V,DCA,0440.52,mA,,
Code: [Select]
412138,DCVA,01959.5,mVA,DCV,04.4482,V,DCA,0440.53,mA,,
412139,DCVA,01959.5,mVA,DCV,04.4482,V,DCA,0440.53,mA,^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@412141,DCVA,01959.5,mVA,DCV,04.4482,V,DCA,0440.52,mA,,
412142,DCVA,01959.5,mVA,DCV,04.4482,V,DCA,0440.52,mA,,
Code: [Select]
431338,DCVA,01959.5,mVA,DCV,04.4482,V,DCA,0440.53,mA,,
431339,DCVA,01959.5,mVA,DCV,04.4482,V,DCA,0440.53,mA,^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@431341,DCVA,01959.5,mVA,DCV,04.4482,V,DCA,0440.52,mA,,
431342,DCVA,01959.5,mVA,DCV,04.4482,V,DCA,0440.52,mA,,
Code: [Select]
478735,DCVA,01959.5,mVA,DCV,04.4482,V,DCA,0440.53,mA,,
478736,DCVA,01959.5,mVA,DCV,0^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@478741,DCVA,01959.5,mVA,DCV,04.4482,V,DCA,0440.52,mA,,
478742,DCVA,01959.5,mVA,DCV,04.4482,V,DCA,0440.52,mA,,
Code: [Select]
523736,DCVA,01959.5,mVA,DCV,04.4482,V,DCA,0440.53,mA,,
523737,DCVA,01959.5,mVA,DCV,04.4482,V^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@523741,DCVA,01959.5,mVA,DCV,04.4482,V,DCA,0440.52,mA,,
523742,DCVA,01959.5,mVA,DCV,04.4482,V,DCA,0440.52,mA,,

The last logline in the file is:
Code: [Select]
600000,DCVA,01959.5,mVA,DCV,04.4482,V,DCA,0440.53,mA,,

So logging stops after the meter thinks it logged 600k lines, but in reality it logged only 599956 lines.

Interestingly the display counted to more than 600.00k lines. The highest value I saw on the display was 602.xxk lines (I don't remeber the xx).

So on the display it either kept counting after it stopped logging or didn't number and write all lines it actually thought it logged.

In the end there was "SDend" displayed and the "MEM" LCD-segment was not active anymore.

I can't attach the logfile since the forum says it's too big (even zipped it is 1.7MB). But I can send it to anybody who is interested.
 

Offline lowimpedance

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Re: EEVblog 121GW Multimeter Issues
« Reply #109 on: January 18, 2018, 02:14:37 pm »
Bug/mechanical issue in the Diode test mode. When selected if you jiggle the plugs at the meter you get the short double beep and sometimes a continuous beep which requires further lead or switch jiggles to stop. So the switch seems to be very sensitive mechanically to trigger the continuous beep. Also via some PCB flexing (i guess), due to the test lead plugs will also trigger the beep.

Others can test to confirm.
As Dr diesel noted the temperature display is on until the range button is pressed for either 3 or 15v test.

Also to note that continuity function sometimes does not work either(similar switch issue?).
Ohms appears unaffected by any mechanical jiggling.

firmware 1.01
The odd multimeter or 2 or 3 or 4...or........can't remember !.
 

Offline amspire

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Re: EEVblog 121GW Multimeter Issues
« Reply #110 on: January 18, 2018, 03:22:00 pm »
Bug/mechanical issue in the Diode test mode. When selected if you jiggle the plugs at the meter you get the short double beep and sometimes a continuous beep which requires further lead or switch jiggles to stop. So the switch seems to be very sensitive mechanically to trigger the continuous beep. Also via some PCB flexing (i guess), due to the test lead plugs will also trigger the beep.

firmware 1.01
I do not get the jiggling issue, but for some reason, when the diode mode senses any change (like a 10K resistor or anything else), it double beeps and then a second later double beeps again. Not sure why that is wanted. If the probes are shorted, it beeps continuously just like the continuity test mode.

Also in diode mode, the bar graph seems to be not normalised for the measurement. In the default 3V diode mode, the bar graph is at 60% on open circuit. For the 15V mode, it is at 33% on open circuit. These correspond to the positions the bar graphs would be in the 5V and 50V DC ranges respectively. A minor issue, but it probably should be tidied up.

Edit: Looking closely at the bar graph and it goes from 0 to 5. So it is on 3 for the 3V range and 1.6V (16V) on the 15V diode range. I guess that makes sense.

firmware 1.01 Diode Mode
« Last Edit: January 18, 2018, 03:35:49 pm by amspire »
 

Offline lowimpedance

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Re: EEVblog 121GW Multimeter Issues
« Reply #111 on: January 18, 2018, 03:43:12 pm »
By jiggling I mean moving the lead plugs intentionally forward and back "a bit" in their sockets causes the continuous beep to engage with out shorting the probes together. And further to this once the continuous beep has started I can remove the probes from the meter and it carries on beeping until I "wiggle" the selector switch a little bit then it will stop followed with the 2 short beeps.
Unfortunately I cannot do a video which would make it very clear whats going on.
The odd multimeter or 2 or 3 or 4...or........can't remember !.
 

Offline Kean

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Re: EEVblog 121GW Multimeter Issues
« Reply #112 on: January 18, 2018, 03:47:30 pm »
I tried to reproduce this "wiggling" problem in diode mode, but I can't.  Sounds like you have an intermittent internal short.  Strange if you cannot also reproduce in continuity mode.
edit: FW 1.01
 

Offline amspire

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Re: EEVblog 121GW Multimeter Issues
« Reply #113 on: January 18, 2018, 03:59:12 pm »
By jiggling I mean moving the lead plugs intentionally forward and back "a bit" in their sockets causes the continuous beep to engage with out shorting the probes together. And further to this once the continuous beep has started I can remove the probes from the meter and it carries on beeping until I "wiggle" the selector switch a little bit then it will stop followed with the 2 short beeps.
Unfortunately I cannot do a video which would make it very clear whats going on.
Sounds like you have an intermittent supply of 3V and 15V to the sockets. Could be a poor contact on the switch or a broken trace on the board. Can you connect a voltmeter to the probes and see if the voltage drops when you wiggle?
 

Offline lowimpedance

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Re: EEVblog 121GW Multimeter Issues
« Reply #114 on: January 18, 2018, 04:54:57 pm »
Okay checking the output with a voltmeter still gives 3 or 15V when continuous beep is going, also when this condition has started the display also goes to all '0' from OFL so no short at the input terminals it would seem.

Just tried a short drop of a few inches height to my desk (no probes) and that can also trigger the continuous beep. This is with no holster BTW.

When the Diode function is not doing the odd behaviour it does measure a diode correctly.

edit: The drop test is not as repeatable as the movement of the probes in the input jacks. I still get the feeling its related to the switch. 
 I will crack it open and take a look tomorrow  to see what movement on the PCB can be induced from the probe jacks.
« Last Edit: January 18, 2018, 05:03:28 pm by lowimpedance »
The odd multimeter or 2 or 3 or 4...or........can't remember !.
 

Offline amspire

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Re: EEVblog 121GW Multimeter Issues
« Reply #115 on: January 18, 2018, 05:12:48 pm »
Okay checking the output with a voltmeter still gives 3 or 15V when continuous beep is going, also when this condition has started the display also goes to all '0' from OFL so no short at the input terminals it would seem.
So it looks like the intermittent connection is somewhere between the measurement IC and the point at which the 3/15v is connected. I still think a switch connection is the most likely cause. You probably should contact Dave directly, unless you want to just Take-It-Apart yourself and have a look.
 

Offline maukka

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Re: EEVblog 121GW Multimeter Issues
« Reply #116 on: January 18, 2018, 06:32:48 pm »
This was already reported by mattselectronics in the other thread, but the VA mode reports voltage wrong. On 5V range it is too high, on 50V range is much better but a bit too low. Gets worse with higher voltages. Tested with a resistor and a Rigol DP811A with remote sense active. No problems when only measuring voltage, only max 1 digit off. Current is spot on.







EDIT: Did the same test with a Mooshimeter which also has VA (and real power) measurement and it is even more off

Actual measured with a 34401A from DMM terminals: 1.0008V
112GW 1.0133V
Mooshimeter 1.02022V

The Mooshimeter shows 2.0% more than it should, but it is consistent regardless of voltage while on the 112GW error gets larger with increasing voltage.


« Last Edit: January 18, 2018, 09:29:30 pm by maukka »
 
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Offline maukka

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Re: EEVblog 121GW Multimeter Issues
« Reply #117 on: January 19, 2018, 12:51:46 am »
How much burden voltage do you guys have on the 10A range? Mine is 0.035V/A measured externally while the manual says 0.02V/A. The 112GW itself reports 28.7mV/A.

« Last Edit: January 19, 2018, 01:00:23 am by maukka »
 

Offline EEVblog

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Re: EEVblog 121GW Multimeter Issues
« Reply #118 on: January 19, 2018, 10:08:15 am »
How much burden voltage do you guys have on the 10A range? Mine is 0.035V/A measured externally while the manual says 0.02V/A. The 112GW itself reports 28.7mV/A.

Latest edition of the manual has this revised to 0.03V/A, will upload this when I get back tomorrow.
The previous one didn't include the fuse resistance.
 
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Offline cpposteve

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Re: EEVblog 121GW Multimeter Issues
« Reply #119 on: January 19, 2018, 10:25:18 am »
Hello mr Jones..!!
Just curious as to when people will get their answers to these on going faults? I’m in the second batch of meters not yet shipped and wondering if all these faults will or most likely be able to be fixed in software?
Hope you had a great holiday.

Steve
 

Offline lowimpedance

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Re: EEVblog 121GW Multimeter Issues
« Reply #120 on: January 19, 2018, 12:58:51 pm »
 I created a Youtube acc. and uploaded a very short video clip of the Diode test mode continuous beep after giving the probe plugs a wiggle in the meter sockets.
I then removed the probes from the meter to show no external short circuits being the cause and then how a light press on the range switch will stop the tone.



I hope this clarifies my earlier posts.

(I will open the meter to investigate this after a weeks holiday)
The odd multimeter or 2 or 3 or 4...or........can't remember !.
 
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Offline Iagash

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Re: EEVblog 121GW Multimeter Issues
« Reply #121 on: January 19, 2018, 01:33:54 pm »
I created a Youtube acc. and uploaded a very short video clip of the Diode test mode continuous beep after giving the probe plugs a wiggle in the meter sockets.
I then removed the probes from the meter to show no external short circuits being the cause and then how a light press on the range switch will stop the tone.
(I will open the meter to investigate this after a weeks holiday)

I can confirm this. I also experienced the switch to be unreliable some times.

I fixed it by mounting two small sheets of 0.25mm telson below the snap ring of the switch.

I'll attach a photo.
 
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Online 1anX

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Re: EEVblog 121GW Multimeter Issues
« Reply #122 on: January 19, 2018, 03:24:07 pm »
I created a Youtube acc. and uploaded a very short video clip of the Diode test mode continuous beep after giving the probe plugs a wiggle in the meter sockets.
I then removed the probes from the meter to show no external short circuits being the cause and then how a light press on the range switch will stop the tone.
(I will open the meter to investigate this after a weeks holiday)

I can confirm this. I also experienced the switch to be unreliable some times.

I fixed it by mounting two small sheets of 0.25mm telson below the snap ring of the switch.

I'll attach a photo.

Hmmm, looks like it requires some form of spring/wave washer type tension device included. Case may not be rigid enough to provide consistent tension for the contacts without a simple spring tension device being fitted!

Wave washer info here http://www.globalspec.com/learnmore/mechanical_components/springs/wave_washers

That's not a good indicator for the construction robustness of the meter and hopefully a simple mechanical fix will be found. Well documented and fixed Iagash, we all benefit from your faulty switch investigation.
« Last Edit: January 19, 2018, 07:39:53 pm by 1anX »
 

Offline EEVblog

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Re: EEVblog 121GW Multimeter Issues
« Reply #123 on: January 19, 2018, 07:53:46 pm »
I can confirm this. I also experienced the switch to be unreliable some times.
I fixed it by mounting two small sheets of 0.25mm telson below the snap ring of the switch.
I'll attach a photo.

I do not understand this.
That fix is on the case of the meter, not on the carrier that holds the switch contacts which is a different assembly mounted and clipped to the PCB that has it's own tension with the plastic insert clip.
 

Offline EEVblog

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Re: EEVblog 121GW Multimeter Issues
« Reply #124 on: January 19, 2018, 07:54:23 pm »
Hello mr Jones..!!
Just curious as to when people will get their answers to these on going faults?

When I know, you'll know.
 
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