I've got a system 80 version 1 converted to version 2 with the GPE U2/U3 module loaded with a combined file of U2 and U3 starting at address 0x2000 on a 27c512 eprom. The game eprom at Prom 1 is a 2716 loaded with Mars God of War.
The board passes the Quickscan80.
When the board is placed in a MGOW it boots OK without the driver board attached. With the driver board attached, the board will not boot. Without the driver board attached but all other connectors attached, the MPU boots and the game will coin-up and will start a game showing ball one in the credit display.
Attach the driver board and the MPU will not boot.
This game is fully working with another MPU so the machine and driver board can be ruled out as possible sources of trouble.
The voltage is 5.04 VDC at the MPU capacitor by the power connector with the driver board attached.
All ground mods are in place. New cap in the bottom.
What do you think is broken?