General question for a newbie

[hokiehog]

I just got my first pinball and of course something is wrong.  It's a 1985 Williams Space Shuttle.  I played about 10 games with it and then it had a a ball get stuck under one of the plastics.  I turned off the game and removed the ball, but it will not eject balls or anything.  All lamps are working fine.  The game goes into gameover mode, but it will not accept a new game or anything...

Any ideas?

The MPU board shows a 0 which i understand is good

Help me and please dont laugh if it's obvious