Magnavox console radio/phono assistance

[cabinover]

Hi guys,
I've been watching all the hubbub about tubes so I found a couple of pieces to learn about and enjoy. If this is the wrong forum and should be in Tube Audio, just let me know please. I have a Magnavox console model 1ST268 that is in great shape, plays (although after warming up volume goes hi&lo). The amp has numbers 406426 ink stamped, and 636750 8 stamped into the chassis. It uses a 6EU7, 2 6BQ5's, and a 6CA4. Where can I find service manuals or schematics to help me figure out just how this works?
The other piece I have is a Motorola phono model number SK14M. I'd give a tube rundown but the back is still on it. Thanks a million folks, now if I can only understand why these electrons go here, I'll consider myself a genius Bob