Hello All - I picked up a DE Star Trek recently, and I've been working on it for a few days. I've already fixed several issues, including a dead column in the switch matrix (turns out to be a bad 2N3904 transistor). Removed the batteries as they were ancient and going bad. No NVRAM yet (on its way in the mail). Minor signs of corrosion, which I neutralized and cleaned up. Since getting those issues fixed, the game seemed to be playable, so I have been running some games, testing all the scoring, etc. All seemed well for a handful of games.

Now, however, the problem is that the game will radomly freeze up in terms of Scoring/DMD. The music keeps on playing, the flippers and lights still work, etc.

Originally, I noticed that during gameplay the DMD display would randomly "reboot" showing the "version x.xx" on the screen, go blank briefly, then continue doing its job in most cases. I thought this odd, and did some of the suggestions I found (reseat connectors, etc.) Then today, I noticed that during gameplay the game will simply stop scoring, registering switches, and the DMD will freeze (without being able to score I'm not 100% sure it's frozen I guess).

Edit - I forgot to mention, when I leave it sitting in attract mode, it doesn't freeze, or have any issues. It just does normal attract mode stuff.

Turning the game on and off resets it and it plays again, until the next lockup. So far, I have not been able to tie it to anything in particular. I have tried starting a game and just letting it sit, sometimes hitting a single switch now and then so it doesn't keep looking for a ball. That didn't tell me much, as the game didn't freeze. I've tried just hitting lots of random targets, covering everything, hoping to find that one triggered the issues, but nothing has become evident so far.

Thoughts?

Thanks in advance for the assistance