I have a STTNG that died the other night. The initial symptom was D20 wouldn't flash. I played around with the connectors and discovered that if I disconnected J601 from the display board, then D20 would flash. So I ordered a Rottendog replacement display board. But when I installed it, the symptom was the same. And when I disconnected J601, I discovered that the D20 flashes (and the game starts), but it eventually stops flashing, usually within a minute after powering on.

Any ideas what might be going on or where to look? I assume it must be a CPU board issue. Just for fun I tried a Kahr board to make sure I had a clean 5V & it didn't change the symptoms at all.

I wish it were the ribbon cable, but even when all the connectors except the power connector are disconnected from the CPU, the LED blinks for a while and then goes dead. I'm just hoping that the answer isn't "your ASIC is bad."

The problem stays the same. If the ribbon cable is connected from the CPU board to J601 on the display board, the game is completely dead and won't boot. If it's not connected to J601, then it will boot (cannons homing, lights turning on, etc.) but dies after about a minute. Disconnecting the other boards doesn't change this unfortunately.

Just to follow up on this, I got the CPU board out of the game on a bench supply & still saw the board die around a minute after power-up. So before going down the path of getting out my soldering iron, I tried replacing the socketed chips using ones from another game. First swapping the WPC ASIC was no help, but lo and behold, replacing the 6809 seemed to work without the board dying. Now I just have to wait for a new one to get here & then I'll try to verify that it works in the game.

Thanks for all the troubleshooting help!