So here's one for the "pulled what's left of my hair out" file. Recently fixed up this Elvis machine and after putting it on location at The Arcade in Wichita a few weeks back, it immediately began blowing the fuse for the lower right flipper. Found the control transistor shorted. Every time I thought I had it fixed, it did it again. Replaced the transistor, the fuse, and the flipper began working again...for about 3 flips and the control transistor shorted again. Replaced it once more. Inspected all the wiring and the cabinet flipper switch. Found the spark gap transistor had a broken leg on the switch for the lower flipper. Figured that was the issue but was still somewhat skeptical. Re-soldered the capacitor on the switch leg and everything seemed good. Played a couple games and on the third game...the control transistor shorted again. Sigh.

So to rule out something with the driver board causing the issue, I threw in a Rottendog. That solved the issue (or so I thought - keep reading), so I attributed it to being something on the driver board that was bad and taking out the control transistor. After installing the Rottendog, something new began happening. The transistor was no longer shorting, but both the right upper and lower flippers were intermittent and would randomly lose power. When the flippers died, I could reach into the cabinet and apply more pressure to the cabinet switch contacts and the flippers worked again as long as I applied pressure from the inside. However if I held the button, both flippers would causally just die. So I figured the switch was bad. Replaced it. Nope. Same issue.

I decided to take another look and just watch things with the playfield lifted. In this state, I found the issue. The lower flipper fuse was actively 'sparking' when being activated. It looked like the fuse was loose in the holder and sparking due to a bad connection. Closer inspection showed there was a stray piece of return spring that was in fact touching the hot side of the fuse wires when the flipper was flipped. It was coming into direct contact with the solder joint on the fuse holder. This was putting the circuit into protection mode with the replacement driver board, which is why the flippers were dying instead of shorting the transistor, but the original board did not have the protection circuit, so the transistor was shorting. NEVER seen this exact issue before. Replaced the spring and it's working perfectly now.

So keep this in your back pocket in case you ever run into something similar.

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