I thought I would mention to all this tip that may help some of you......we had alot of trouble with a Gottlieb STARGATE pinball machine in a fancy house with a separate game room. They had the one pinball and 4 video games.....they complained the pinball shut off sometimes and flippers were weak. (Video games were all fine) Our service guy could find nothing wrong...went back several times with boards, bottom transformer...and no change...we would leave and it was fine and next day customer screaming.
Curt went back out a 4th time and then it DID IT WHILE HE WAS THERE! He took a voltage reading of outlet...and it was 100 volts....then in 10 minutes back up to 115 volts. Turned out a huge sump pump was on same circuit. Couldn't hear it, but it managed to screw up that pinball. Oddly, the video games worked fine the whole time...so that's why we never suspected the voltage. So now, we read line voltage as part of our service call. We also ask people if they recently bought new appliances, like a small refrigerator. Hope this helps some folks out! Todd