The input section has severe AC hum when recording via the Microphone & direct line but playback through the output & headphone jacks is fine. If anybody is familiar with working on these any help with listing the usual high failure suspects & what parts should be upgraded would be greatly appreciated. I just moved & misplaced my ESR tester so I'll definitely need to find it to test all the old caps in this one some of which obviously need to be replaced. I tried printing out the schematic off the net but for some reason my computer (Powerbook G4) wouldn't print it. I repaired TVs/VCRs/stereos for 35 years but not many vintage tube audio units.
Thanks, Mark