Gibson G10 hum

[Axtman]

I recently got in a small solid-state Gibson G10 amplifier that hummed really badly.

I replaced all the electrolytic caps, removed the death cap and installed a 3 prong cord. The main filter cap was dead. The amp still hums, but not as loud.

Here is the weird part. If I lift the ground on the power cord, the humming reduces in volume. You would think it would be the other way.

So I am stumped on this amp.

Gibson G10 schematic: gibson_g10_amplifier_schematic.pdf

Gibson G10 parts list:

[galaxiex]

Is this a small combo amp?

If so....

Does this amp have a pot mounted in the chassis,
somewhere near the power supply with the pot shaft sticking down below the chassis into the speaker area?
IOW..... NOT a front panel control.

If so, remove/unfasten the pot from the chassis and move it away from the power supply.

See if the hum reduces.

Pics would be helpful.....