1978 Bally Star Trek Repair

Star Trek came back for a few repairs over the weekend. I worked on this game four years ago and made a little post about it back then. It had a problems that developed recently. Such as the top saucer was stuck and the game wouldn’t boot up completely. I found a fuse blown for the solenoid bus that also affects the MPU booting. Once that was replaced, the top saucer was still intermittent and a the pop bumper switch was activating one of the sling shots.

Every switch has a capacitor that can cause issues over time. The best fix is to just cut them off and erratic problems are fixed. The top saucer repair was more in-depth. I replaced it’s controlling TIP102 transistor since it tested out of specifications. I replaced a connector and header pin (actually all of them for good measure) on the driver board, plus the solenoid’s diode. It all appeared fixed after testing it 100 times.

I rechecked the game after a few hours and the problem was back. I traced it back to the controlling¬†IC that was causing erratic behavior. The solenoid wasn’t always getting the signal to activate. Once the IC was replaced, the problem was fixed.

After that, I replaced all the burned out bulbs and the game was ready for play. And, ready for pick up.

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