Corvette (1994), booted after years in storage.
After a good inspection it booted up fine.
After minutes leaving it in attract mode, the DMD started losing the picture. Came back up after reset.
I checked cables but eventually ended up with the situation where the system didn boot up.
With batteries inserted, there is no picture on the DMD. With batteries not inserted, the message "FACTORY RESET ..." is barely visible and unusually flashing on the DMD.
Game cannot be started. GI is is ON. No sound.

I replaced the WPC-S CPU board with a different one and it works. So the problem must be on the CPU board.
There is no sign of any battery leakage. Resistors were all measure and are fine.

The only thing is that the U23 was replaced with a one in bigger casing. Afaik, this chip is responsible for switches.. And the game was working before I got this boot issue.

I uploaded a video where you can see how this thing looks.

Bump

I've been pressing some chips in but will try again with more focus on that.

Diagnostics buttons or any other button don't work on this failed boot.

SOLVED!

It was the big ASIC chip!
Pressing the ASIC made it work.
We cleaned the connectors, put it back in and it boots now.
Thanks!