RIGOL you defeat me ..!! .... DP832 has found a new home ! - Page 1
Forum section: electronics / repair

author: pedro48
author_rank: Contributor
timestamp: January 10, 2022, 12:56:46 am
content: Hi all,I have a Rigol DP832 programmable power supply, that has died, spent the past few months on the bench, and nowneeds afound a new home.THE SITUATIONThe DP832 suffered a dead short to the output terminals of Channel 1, taking out the usual suspects (The MOSFET, fuse and R52), all tested dead and now replaced. There is also at least one other fault. That is ~30v appear on the output with no voltage set and or the output enabled or disabled. This appears to be the Charge Pump being driven high at all times, and hence forcing the Triacs to enable. This may not be the only issue.The digital board appears to be working, I can update the firmware and set voltages. From what I can tell the analog board appears to be the issue. I can see the 7060 microprocessor on the analog board signalling to the digital board. Earlier today I posted my reverse engineered schematic of Channel 1, so that might assist any would be repairer.The DP832 has had only light work, though it has lived in hostile environment very close to the beach. It was 100% working immediately prior to the 'Accident'The machine is intact, I have replaced one flat flex with a longer one, and bodged a ribbon cable extension, so I could work on it on the bench. I could not source a longer ribbon cable, or connectors despite buying numerous that looked closeTHE OFFERI'm offering to donate the DP832 ( Serial No DP8C153401504) free of charge to somebody on this forum. My preference is that it would be repaired, but once donated you are free to do what ever you like with it. The DP832 is currently in regional Victoria (AUS), and I'm happy to deliver it in Metro Melbourne free of charge, and possibly regional Vic, depending on time and distance. I have no ability to ship it, it is heavy and would be expensive to ship, not working, shipping hardly seems viable.I no longer have the DP832, Muttley Snickers was the successful bidder, here's hoping a fresh set of eyes can see what I missed. In the meantime thanks to M K, TurboTom, Giosif et al for the help along the waycheers ...

author: Muttley Snickers
author_rank: Unknown
timestamp: January 10, 2022, 03:15:18 am
content: I'm interested and have been considering updating some of my gear including a better power supply.PM Sent.

author: Daixiwen
author_rank: Frequent Contributor
timestamp: January 11, 2022, 08:13:27 am
content: It would be interesting to know if you manage to fix it

author: Muttley Snickers
author_rank: Unknown
timestamp: January 11, 2022, 11:31:02 am
content: Quote from: Daixiwen on January 11, 2022, 08:13:27 amFirst and foremost, I would like to sincerely thankpedro48(Peter) for his generosity, not only for the power supply itself but also the work, effort and research he has put into the unit in trying to ascertain how it failed in the first place.I spent a couple of hours this afternoon on the power supply just getting familiar with it and recording some initial measurements and will no doubt need some assistance and guidance with the repair so will likely create a new thread at some point.Initial findings are as follows:Channel 1 is buggered and displays 37.218V at 3.677A with no output and an annoying screen message "CH1 overvoltage protection, disable the output of CH1".Channel 2 works perfectly across all ranges and settings.Channel 3 also works perfectly but dies if the current limit is set below 280mA regardless of OVP or OCP status.

author: m3vuv
author_rank: Super Contributor
timestamp: January 11, 2022, 04:12:59 pm
content: is this a linear psu or switcher?

author: alm
author_rank: Super Contributor
timestamp: January 12, 2022, 10:30:25 am
content: The DP832 is a linear power supply, see thisteardown. As many bench supplies it uses transformer tap switching to limit dissipation in the pass transistors.