Had a weird failure in my Multi-Williams over the weekend. I'd had a BitKit2 in the second slot of the JAMMA switcher that usually alternates between a JROK and a Moon Patrol stack (with a JAMMA adapter). Decided I wanted Moon Patrol back, so I pulled the BitKit and plugged the stack back in. The game started up with no issues, but didn't have sound. After I checked the connections and powered back up, I got some smoke and a burning smell, so I immediately killed power.
Check of the power outputs from the PSU (Happ 200W Power Pro, new one) were all nominal. When I looked at the main JAMMA connector, Pin 4 was burnt at the harness connection to the switcher, and the finger on the switcher was fried:

The two wire inserts there are for +12v (Moon Patrol audio amp) and sync. They've both been in for a couple of years with no issues.
Really have no idea what exactly happened here. Something got bumped and made a short would be my best (and probably incorrect) guess. Have not tried to test either game board yet, but at least there's no visible damage.
Any thoughts/suggestions? I'm inclined to move the +5v wire on the harness (custom job for this build) over to Pin 3 and start testing carefully from there... I have a crap 60-in-1 board that can be a guinea pig. I've cleaned all the fingers on the switcher since this picture was taken, but nothing further.
Check of the power outputs from the PSU (Happ 200W Power Pro, new one) were all nominal. When I looked at the main JAMMA connector, Pin 4 was burnt at the harness connection to the switcher, and the finger on the switcher was fried:

The two wire inserts there are for +12v (Moon Patrol audio amp) and sync. They've both been in for a couple of years with no issues.
Really have no idea what exactly happened here. Something got bumped and made a short would be my best (and probably incorrect) guess. Have not tried to test either game board yet, but at least there's no visible damage.
Any thoughts/suggestions? I'm inclined to move the +5v wire on the harness (custom job for this build) over to Pin 3 and start testing carefully from there... I have a crap 60-in-1 board that can be a guinea pig. I've cleaned all the fingers on the switcher since this picture was taken, but nothing further.
Last edited:

