This time around, I am working on one of my own pinball machines. This machine had a couple of problems. The first one was the flipper would get stuck in the upright position and wouldn’t release. Once the first problem was fixed, then the game wouldn’t boot or would reset during game play.

Flipper Problem

I had this problem before and is pretty well documented at Pinside. The left flipper would flip once and would stay engaged in the upright position. I have a Rottendog board in Terminator 2 and what happens is the optocoupler and the associated resistor burns up and both go bad. I had to sort this problem out years ago and actually socketed the optocoupler and resistor when I was troubleshooting it. The problem (again) was the flipper diode had become loose. I checked to make sure it was good (and it was) then I resoldered the diode back to the flipper coil. I also switched out the optocoupler and resistor and the flipper and lane change were both working. I played a couple of game and then another problem developed. The game wouldn’t boot or would reset.

schematic of U7 and R210
My problem was with U7 and R210. Both would go bad due to a loose diode on the flipper.

Reset Problem

Pinwiki has a great walkthrough with WPC reset problems. I have a Rottendog board, so a lot of the write-up didn’t help with my problem. I checked the +5 volts on the driver board, and it was 4.98 volts, which is good. The Rottendog boards have a nice convenient test points on the board. I then measured the +5 volts on the CPU board, and it was quite a bit lower. I didn’t get a picture of it, but was around 4.6 volts. I wiggled the power connection on the CPU board and the +5 volts went up some. I decided at this time to just replace both power connectors on the driver and CPU boards.

I also noticed that the GI plug by the transformer was pretty toasted. I went ahead and replaced the plug and connector since I already had the tools and parts out.


I ended up resoldering one diode and replaced 3 connectors. Pretty easy and cheap fix to get this game up and running. It always amazes me how one loose diode or a bad connector can render a machine useless. I’ll be shooting for Super Jackpot soon on this game. It’s one of my favorites in my collection.

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