After years of service, my DP832 gave up a ghost. The processor board won't boot any more. I checked the voltages and tried to isolate the problem with no success. There's not much else I can check or replace on that board so I think I'll just let this one go.
Although... the two analog boards seem to be fine. A quick look around revealed communication is done using isolated UART at 115200 with another 2 isolated signals (output enable maybe?). I haven't done any more of RE in hopes that someone else can't keep their logic analyzer to themselves.
So! Has anyone reverse engineered the protocol used to control those boards? Or at least captured some packets.
Have you tried to reinstall the firmware? How did your unit die, at turn-on or while using? Do you see anything appearing on the display when you turn the power on? With some more description of the issue it might be solvable after all...
It just failed to start one day. It did have the well known overheating problem even with improved heat sink. It was so rare though that I didn't bother to fix it.
I didn't try to re-flash it. Rigol wants SN and current version when requesting firmware update. I guess they'll make exception but it's still a PITA.
I suspect the logic board failure is a bit more involved because I couldn't see any FLASH IO activity on the scope.