Especially the power supply.
If you smoke, this is what you do to your lungs. Reconsider

Lots of scrubbing and cleaning later, especially of my bathtub.

The IIsi wasn't as dirty, but leaking SMD capacitors started to do their evil thing.

First a general recap of all electrolytic capacitors was on order for both of them, and while I was at it, I also replaced the tantalums.

I also replaced a couple affected resistors and transistors.

The power supplies had a couple obviously bad capacitors. I didn't bother shotgun replacing them. The owner wanted to outright replace the PSUs with modern ones.