Randell amp

Are you able to point to a schematic? I am thinking hum-loop, dirty controls or a leaking bypass cap. As to the two electrolytics you did replace, make sure that you followed the schematic exactly. In some cases these caps are part of a voltage-doubler circuit, so (at least) one will be above ground on both ends. Similarly for an LC circuit.

Peter Wieck Wyncote, PA

Peter...thanks for your answer....I got this unit to repair and whoever ...... replaced the 2 large caps in the pwr supply... but they had them reversed....and it kept kicking the breaker out...I rewired them and it don't kick the breaker now but the hum is there..I checked the caps with an ESR meter and they look ok...but I wonder if wiring them backwards ruined the caps....what other test can I do on them.....thanks

It is quite likely that the caps are ruined. In any case, I would not trust them given the (relatively) low cost of replacements. Additional tests that I perform even on new caps right out of the box/bag is a full-voltage test on a cap checker, as well as a simple confirmation of basic capacitance.

Good luck with it.

Peter Wieck Wyncote, PA