Author Topic: DP832 channel 1 UR  (Read 349 times)

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Offline RustyCaliper

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DP832 channel 1 UR
« on: February 05, 2018, 06:37:05 am »
Hi Forum,

I have an issue with my Rigol DP832. Something seems wrong with the current sensing on channel 1. It displays the mode as UR (unregulated) and shows an actual current of 0 A. Apparently it's a mechanical issue becuase the issue disappeared when I disassembled the unit, but unfortunately reappeared when I reassembled it. Knocking on the top board seemed to "fix" it. So likely bad connector/broken soldering joint.

However, I'm unable to locate the issue and I do not have any docs. I've done my RTFMing: http://www.eevblog.com/forum/testgear/dp832a-problem-ch1/msg424491/ and http://www.eevblog.com/forum/beginners/nonsense-behaviour-of-rigol-dp832/msg575509/ and http://www.eevblog.com/forum/testgear/another-issue-with-the-rigol-dp832-power-supply-sense-wires-carrying-3-amps!/ and http://www.eevblog.com/forum/testgear/what-is-actually-fixed-in-rigol-dp832(a)-rev3/ -- however no real leads.

My top board HW rev is DP832A V2.10 2013-03-26. Any help greatly appreciated.

Thanks, Rusty
 

Offline _Wim_

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Re: DP832 channel 1 UR
« Reply #1 on: February 05, 2018, 08:14:10 am »
Does the output itself work correctly? Does the voltage measurement still work? If yes, I would expect it would be quite easy to follow the signal from the shunt resistors back to the ADC/Processor (not to many components in between I guess).

 I would also expect channel 1 and channel 2 to be fairly identical, so it should be possible to do a side by side comparison between the two when tracing back the signals.
 

Offline Pinkus

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Re: DP832 channel 1 UR
« Reply #2 on: February 05, 2018, 08:36:20 am »
I would open the cover and use a non conductive (e.g. plastic) stick to press on different PCB areas / components to narrow down the area. If it is a cold joint is is usually easy then to find the problem.
However if it is a broken trace with a micro crack on an inner layer it will become more difficult.
 

Offline RustyCaliper

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Re: DP832 channel 1 UR
« Reply #3 on: February 06, 2018, 04:22:29 am »
Hey there, thanks for your suggestions. I believe the culprit in my case was J15, a two pin header that seems to feed the current sense resistor. It was optically *completely* inconspicuous, but since I've replaced it, it hasn't shown the error since. The contacts and everything looked completely pristine. Interesting...

All the best, Rusty
 

Offline _Wim_

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Re: DP832 channel 1 UR
« Reply #4 on: February 06, 2018, 04:01:17 pm »
Hey there, thanks for your suggestions. I believe the culprit in my case was J15, a two pin header that seems to feed the current sense resistor. It was optically *completely* inconspicuous, but since I've replaced it, it hasn't shown the error since. The contacts and everything looked completely pristine. Interesting...

All the best, Rusty

Glad to hear you could fix it, and thanks for reporting back what caused it.
 


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