[jan-jaap]

I also have some photos of the carnage of the filter capacitors from the output modules which were beyond disgusting.

Rifa! The magic smoke has escaped! (SCNR, 07:00)

I was more talking about the electrolytic capacitors... the thing is, I never expected it to be this bad. After all, the power supply worked. The functional problem was with the aux bias supply on the mainboard, not with the output modules.

But then I removed the capacitors from the -5/-12/+12V module and found this:





The PCB looked like this (C12 site has been cleaned already). Fortunately it cleaned up fine and in the end the PCB wasn't damaged (yet?). I thought of dumping the whole PCB in pure alcohol in the ultrasonic cleaner, but not all components like ultrasonic cleaning so I just cleaned it by hand with lots of alcohol.





This is what the little PCB on the bus bars of the 5V module looked like, before and after cleaning. Minor damage to the silkscreen, but copper layer and PCB intact. This is what came out of the 5V module:



These capacitors were completely shot. Still, the PCB cleaned up nicely. It has to be 100% clean, or new solder won't flow properly:



To the left you can spot four mosfets on individual heat sinks. They likely form a H-bridge inverter circuit. The hole is where the transformer goes. Below you can see what it looks like, with it's four diodes making the rectifier.



Transformer and diodes are a pretty compact unit, if you know that 170A can flow through it.

Right now, the Crimson's PSU is probably fine again (I ran it for a couple of hours with a 40A load and it didn't blow up). But the internals of the PSUs of my 4D/380VGX rack and my 4D/440 are likely a similar toxic waste pile so I don't dare running those anymore until I've rebuilt the PSUs. I will also have to check up on the 4D series circuit boards, see if anything is leaking there...

NB: I used mostly Panasonic FR series capacitors for the rebuild. These are long life 105c capacitors with very low ESR and able to handle high ripple currents. Ideal for SMPS applications.