Is your question that your power supply works as normal, but are there modifications to it you can make that would improve the sound quality from the mixer? What channel count do you have on the mixer? Are you also asking about modifications or component replacements to the channel strips on the mixer itself?

There's a GS thread on PSU upgrades for this mixer series, but I guess you have already seen that.

Thanks a lot Boswell and no I haven't seen the Gs thread.

my channel count is 24 inputs 16 tape returns and 8 busses. I am basically asking for modifications on the power supply.
I own this console for 3 years and the last owner had done all the maintenance on the channel strips and the master.
Since one month I am getting noise on my master output both the"remix master" and the master output. The direct outs are clean though.
I troubleshooted almost everything I could and after cleaning the power supply with a blower I realised that most of the noise , if not all of it was gone. the console sounded clean for some hours and
then it started making noise again. I would really be interested in spending some money ,hopefully not much, in changing parts on the power supply.
Thanks

My guess is that the air jet made a small mechanical change that temporarily affected a component or a joint.

Does your tech have an oscilloscope? It would be worth looking at the +/-18v rails a.c. coupled on a 100mV/div range to check for instability. It's possible that the electrolytics in the power supply need replacing.

Did you get it sorted out?