Quoted from Hazoff:For the first time today while playing the flippers all stopped working and I noticed the red light for over voltage triggered on the Alltek MPU board, I checked the fuses and fiddled a little with the connectors and it worked fine again but now sometimes upon even turning on the game the red light comes on, I think all this might be in the Solenoid driver board and as I was not the one who installed the MPU and after reading the instructions maybe the previous owner by not checking for proper voltage before installing the MPU board has damaged something. God damn
Start at the rectifier board in the bottom. Check those test points. The solenoid board then regulates some of the rectifier board voltages. If you had a cheap scope you could measure the ripple on the 5V. You could also use the AC setting on your volt meter to see if that large cap is doing its job, its been replace at some point. The high voltage one looks original.
