Parasound HCA 806 with some bad channels

My Parasound HCA806 has at least 3 bad channels. The symptom is a heavily distorted sound.

I have done quite a lot of basic electronics repair over the years so I'd like to try my hand at fixing it. I have a few questions:

1) It seems like the capacitors are the common problem in old solid state amps. Should I just go ahead and replace them in one of the bad channels as a first step? What model of capacitor should I buy?

2) I couldn't find schematics for this one, but I have them for the 800 and 855. Is anyone here familiar enough with Parasound to know if these will be helpful (or even better, does anyone here have the 806 service manual or schematics)?

3) Should I let the amp sit for awhile before opening it up? I have read that if you're not careful, amplifiers can discharge quite a lot of electrons even when they are unplugged.


Thanks!
Mark