Hey Dan,
Good to see you back again! The Coin-in jam along with Meter's disconnected error messages indicate that that there is a problem with the SENET bus. It can be a I/O card issue like Cowboygames said, or a problem with the MPU board. Try reseating/swapping the I/O cards, and if that doesn't work check out U74 on the MPU board. It's near the sound card connector, and sometimes shows signs of physical damage if bad. If you have another MPU board change it out. One of those three will most likely solve the problem.