I have a Gottlieb Spiderman System 80 pinball. I need advice. I just recently passed it down to my son which called for a moving of the unit. The trip from my house to my sons was about 5 uneventful miles. It was working fine the last time I powered it up. Unfortunately, I did not power it up and test it just before I moved it. I had previously shipped it 1000 mile across the country with no problem.

When we got it set up, we powered it up and the lite box came on with the tilt light and the other lights. There were no lights on the play field and there was no 5 second reset. We checked and verified the following:

The wall outlet for power and ground
The power LEDs lights on
Good ground for the two Slam switches
No Score lights
No Match light
5.05 VDC @ the Control Board
4.93 VDC @ the Driver Board
5.07 VDC @ the Sound Board

The play field will come on if we manually move the Tilt relay. We physically inspected each board and sprayed electrical contact cleaner on the pins. We visually inspected the three coin switches. We moved and wiggled wires in the harness in many areas

We went back and performed the ground modifications for all the boards. We also removed cleaned and reset all the pins for the connector between the MPU and the Driver boards. We adjusted the 5 volts on the MPU to 5.03 volts. The symptoms did not change. We can get the playfield lit and the flippers working by manually disengaging the Tilt relay. On power up the door switches resistance fluctuates related to frame ground using a multimeter on ohms. We would expect this reading to be infinite. We have the jumper installed on the MPU to override the Slam switches. We took the two connectors off the MPU to eliminate the front door. We have a Orange cap replacement on order. We want to know what else we should check before considering replacing the MPU boars itself.