Hi Andrew,

Couple of things to check. Would look at the switches under the mini PF and check switch is now bent or shorted. Sound like you don't have 12v running to the playfield (optos, motors ,etc). You have ruled out most of the boards. Could possibly be the connector pins to the driver board. Would try measuring 12v at TP3 and at TP1 on the driver board for starters. Could also be a wire under the playfield for the 12v has come off.

regards Derek