[Texasrocker]

Hello Harv. If the set has been previously "hacked", perhaps there is a missing bypass cap previously removed and not replaced? You mentioned the schemat doesnt match. Ive had luck in the past locating orig missing caps by taking a .05/600v , clip a wire with alligator clips to ground one end of the cap to chassis. Then by probing around with the other end of the capacitor lead-wire "point to point" on different connections one at a time can find missing bypass locations and rid hum. Just remember to discharge the cap "probing lead" back to chassis before touching it to all your different test points one test at a time!