Game had been working. Now it coins up and responds correctly to the first press of the credit button by putting up player 1. Additional presses will not get player 2 into the game. When the ball is launched and rolls over the ball in play lane switch, the Game rely clicks and the credits are reduced by one. No scoring works as the ball moves out onto the playfield, although the pop bumpers do work.
Also, the backbox controlled lamps have not worked since I got the game. My bet is that is a bad common ground, but I bring it up here in case it is important to the diagnoses.