AVR 300 Powers up, 8 seconds, powers off

My AVR 300 is 4 years old and has developed a problem.

It will power up and begin it's self check, then shuts off.

I opened it up, and there is a large capacitor (3300Uf) on
what looks like the Digital Analog board (the big board that
lays flat along the bottom of the chassis under the add-on
cards, which is bulging. It also has a darkening of the
board under that capacitor like it has been heating and cooling there.

I can't see any other caps that are bulging, including the
4400uf.
The diodes around that cap are larger than the others on
that board.

Someone mentioned that they had a PDF file for this model, which was a schematic?

It was expressly for finding the problem diodes. But Id
be curious if anyone has any thoughts on this