So I already put a post on here about this F-14, which was insisting the 6116 memory (u25) was bad. I changed the output chip below the processor and it went back to working fine. Today, it has decided that once every dozen boots or so, it has a u10 error. This doesn't stop the game, which then boots and goes on working. But it's not right, and someone would like to buy this machine. There's clearly something pooping on the data or address line, and doing it very rarely. How does one determine what chip is at fault?

I read on pinwiki that sometimes having an old socket on your PROM or processor will make this happen. So I replaced the socket on U27. So far so good, but I'm not calling it okay until at least Tuesday.

So the game ran fine for 3 days. Then yesterday, when I powered it on, it just hung. Nothing on the display. Turning it off and on again fixed it, but I need to fix the problem. Anyone have any ideas at all?

Hmm. Must admit I haven't touched the power supply. Worth a shot. Did you use a particular rebuild kit, or just replace all the caps?