Recently, Caveman will be in middle of game, then all of a sudden the displays go blank and the speaker emits a drone sound until I turn off the game.
Wait 10 seconds, then once I turn it back on, it can play fine. It has been doing this for 6-8 months now but lately it's been happening almost every time I play it.
It has original SYSTEM 80A boards and I did the ground wire mod shown on Todd Tuckey's SYSTEM 80A Ground wire video (allows ground to both side of the connector of CPU board to driver board.

Thanks for any tips.

Game starts and plays fine after I turn it back on.
Only happens once in a while causing me to power down then back up if I want to start a new game and hope for the best.

Tried to play tonight. Turned on the game and let it sit in attract mode. About 3 minutes later, displays all blank out, game reboots itself.
Then it it reset itself again in 2 minutes and restarts. This time the speakers were hissing. So I started a game like this. It played thru two balls (3 minutes) with no resets and no sound. When I entered the maze, no sound either. Just hissing.

Turn off pin, turn on pin. Now playable again with sound but for how long....

Any clues on SYSTEM80A issues like this?

No, but I will if it's a good shot at fixing the issue. Is that your gut feeling on this reset issue?
Would it be easier to just replace the power supply board?
Or is there a repair kit available?