Now that I have got the DECstation 5000/240 working again it is time to move on to the TURBOchannel Extender that came with it. This is in a terrible state, with lots of corrosion all over the place. The worst of it though is the H7826 power supply. A lot of the heat sinks have corroded, leaving metallic flakes all over the board, presumably capable of creating shorts.
In some areas there seems to be some traces of a liquid which seems to be holding a lot of dirt and some of the flakes that have come off the heat sinks. I suspect this could be leaked electrolyte from some of the capacitors. However, none have obviously leaked, although they are mostly in contact with the surface of the board, so they could have leaked from underneath.
I will have to source some new heat sinks and find a way to clean the board thoroughly, and probably replace all the electrolytic capacitors. Only then will I dare to try to power it on. In its current state it is just too risky.
I don’t think the pictures below really do the problem justice, but hopefully they give a flavour of what state it is in.