PGM motherboard, no screen, no sound

Not much else to say. Cab is turning on as if nothing is plugged into the harness. I haven't used the mobo in a while. If the battery is dead, does that prevent the mobo from booting?

I don't spot any broken traces or damaged components on the board.

From memory it should be fine without a battery, just won't save scores and book keeping info obviously.

Check for battery acid leak, might have eaten traces.