Have a Crate VXF5112 with a loud 60Hz hum, that suddenly started, and is unaffected by inputs or gain/volume controls. I don't see (scope) a filtering problem in the power sections. I'd like to isolate amp sections, but it would help the have a schematic, specific to this amp. I can't find it with any Google searches. There are other Crate schematics, but they are too different.
Ken
Ken