Bally Star Trek repairs, part 1

I got a Bally Star Trek back in November 2014. I knew the computer would be corroded, so I pulled it and removed the battery. I didn’t leave myself enough lead and I don’t think I’ll ever get both terminals out. There are quite a few missing traces and damage. I hurt my hands trying to get the damage out.

I picked up another board from a sale on RGP, also from a Star Trek, that is a better candidate. It only had a little corrosion, but it doesn’t boot.

As a stopgap I picked up an Alltek CPU. I want a -35 CPU for some reason, so I’ll probably still fix the clean one when I have a chance to get some help.

When checking out the head, I found my driver board (one of the nice Stern ones with really elaborate silkscreening) was missing two transistors. I replaced them. While I had the board out, I removed the filter caps for the high voltage and the +5V. The +5V cap was bulging—so its days were numbered anyway, as if being 34 years old wasn’t enough reason to replace it.

Power cord was missing ground prong and was a little damaged, so I replaced it.

My lack of skill at drilling out the lock left lots of metal shavings in the game, and since the lock is over the rectifier/transformer assembly, I pulled it and vacuumed out the head.

The sound board was removed to make it easier to get the transformer out, so I re-capped it. I re-installed it and the game had a loud hum tied to the number of lights on. I removed the sound board a second time, and discovered about a third of the header pins had obvious cracked solder joints. I resoldered them and plugged the board in and it worked great. Then I screwed it down and the hum was back. I’m guessing I have a floating ground somewhere. Given the obvious age of the header pins, that is not surprising.

I was missing a full row and a full column of switches, including the outhole and the saucer. (When I bought the game, the seller told me that it didn’t work. He didn’t know about any of the other problems.) I re-pinned the connector to the MPU and I have most of the switches. I suspect cleaning will make the rest work.

So, it plays. Just not well.

After I wrote this, the draft sat around for years. So did the game. That’s the problem with old games: they are great for storage. Around 2017 I borrowed the SDU board. It sat outside the cabinet for three years until I got around to re-installing it.

In 2020 at the beginning of the pandemic, I got an offer for the game as-is. Since I had too many projects, I sold it, and a CPR playfield. And I finally have some space for the Eight Ball Deluxe project.

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