Rigol DP832 - Channel 1 Analog Board - wanted

[pedro48]

I'm one  many folks that has managed to fry the Channel 1 analogue board of my venerable Rigol DP832. Replacing the usual dead components   F3, R52, Q5, Q15 has at least got most of the analogue board back working but  has failed to resolve a couple of issues. Thanks to TurboTom and others for the notes, I now have a bit of an  understanding on the functions on the board, and have documented about 60% of the schematic.

There are two faults remaining, they may be linked, that being there is 33.1V at the output at idle without enabling the CH1 ON switch, also that voltage setting works on the digital board, but not the analogue. The waveform out of the MCU looks about right. The lower half of the waveform at U6 ( CC Set) operates correctly in small increments 0-3.1A. As does the upper half the waveform (CV set) between SET voltages  12.0 -30v. voltages set 0v-11.7v are highly erratic, and the charge pump reflects the MCU signal leaving pin 11

I'm looking to see if anyone has a spare DP832 CH1 Analog board you'd be prepared to Sell or Gift - Working or Not. I have already managed to have a couple of 'accidents' with the board live on the bench on extension cables. And circuit tracing is necessarily incomplete as many traces disappear under components and some paths  are positively diabolical (E.g U3 below). With a spare board, tracing the PCB under chips become viable.

I realise this is a long-shot, appreciate any help

cheers Peter