What are you lifting to cause the symptoms you described to go away? It seems something may be shorting to the board. Make sure the paper under the pots doesn’t have any holes in it from the leads poking through. Make sure none of the pot backs are touching anything they shouldn’t be touching.
Make sure chassis is grounded to the board (use a continuity test).
Also use a continuity test to see if the tap switch wires are connected…they shouldn’t be unless the switch is pressed down.
Let me know what you find.
-Brach