Contrary to Mars478 post, Larry Pina's Mac Classic Repair and upgrade secrets, readily and affordably found around the internet, is an extremely useful quide. In particular, one passage caught my attention about no power. He recommends checking resistance across RP2 surgistor from the solder side. It should read 12 ohms. If 0, then desolder, reshape the leads and resolder.
Also if you do want schematics, Bowmarc has a set of reasonably priced Classic reverse engineered schematics (click computer, then search for "classic").