Quoted from arolden:
Thanks. Looks like it requires more modification than I thought.
All I want to do is test that the MPU boots properly. Without the changes made to the MPU100, would it still boot in the Paragon? At least then I would be able to narrow the issue down to the MPU board.
The MPU-100 (with its original ROMs) will boot fine in Paragon. All it needs to boot is the voltages coming in J4. You could fully hook it in too for more testing, but it might not interface with the sound board correctly, and the solenoids it fires won't make sense. If you unplug the sound board and remove the solenoid fuse on the playfield you should be fine for testing. Lamps will look a bit weird since the patterns won't line up, but that's fine