Here's the sequence of operation on your machine
Add a credit or hit the start button on the coin door will get the S relay up. It is self holding so if you manual latch it the relay should hold. This should also get the GI lighting turned, spin the score motor, and reset the scores to zero.
The SB relay should pick which in turn will pick Z. The game should be ready to play.
I have one of these machines but it's been a long time since I have had any problems. I hope what little I can contribute helps.