Replacement MPU shows two solid red LEDs after setup: DIP switches set upside down
A new replacement MPU passed its bench test with only power connected, but locked up with two solid red LEDs once the game connectors were plugged in and the DIP switches set for the game. The switches had been read upside down: on this board the setting called 1 is the down position. Setting them the right way for the game fixed it. If a board still locks up, reconnect the plugs one at a time to find the one that causes it.
Systems
Games
Related tips
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Source: Pinball Repair help group!! (Facebook group)