Vintage Synth Repair

I recently scored a non-working DX21 on the cheap, and it will not power up. No lights, response, or life whatsoever is in this machine. I don't even hear the audible "click" when I turn the machine on. I tested the power cord, the switch, the fuse, and replaced most of the capacitors on the main PSU board, and it still is doing the same thing.

What worries me is that a previous owner replaced the big black cap in C5 with a 100uf 50V capacitor, and I know that it is MUCH too low of a voltage to be there. I'm not even sure if the capacitor is even the right value... I'm used to seeing things like 2200uf and such in power supplies like this one. If anyone could point me to the proper replacement, that would be great.

Anyway, before I start to go nuts tearing this thing apart, I was wondering if anyone here could possibly help me out, I had great success bringing a dead TX81Z back to life thanks to the collective minds on this group. Where should I start? Many thanks!