Chesterfield, MO
J120/121 are interchangeable and electrically identical. They were made that way so that the PF and head harnesses could be manufactured separately and then rough together at the board at final assembly.
You will need to find the shorted wire or socket. Close visual inspection is the first step. If you’ve used LEDs, they can short internally and cause this. After that, it’s a matter of removing lamp sockets from the circuit until you find the offender. I use a “binary search” technique for this.
A 5A circuit breaker with a blown fuse soldered across it will save you fuses.
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Chris Hibler - CARGPB #31
Http://chrishiblerpinball.com/contact
http://www.PinWiki.com/ - The new place for pinball repair info
