Hello! I have a 1980 Stern Galaxy which I've been working on on and off for a while. Only problem I have left I think is occasionally during play when something big happens (like someone hits the special) the game sometime resets back to the power on test, or otherwise seems to freeze up. The rectifier board has been replaced by me, and I've added X-Pin displays so the game can now display scores in the millions, and the original means for saving high scores has been upgraded, but other than that I think it's pretty much stock.

Where should I start? Should I "re-cap the power supply", as that seems to be a popular step on these machines? Haven't looked closely but on this machine other than the rectifier and the transformer I don't know of other parts to improve (i.e. don't know that there are capacitors or Zener diodes for me to work on, only the big transformer). Is there basic troubleshooting to try and determine if the problem can be narrowed down to the power supply, vs something on the backboard?

Thanks much for any assistance!

Great thank you and much appreciated. The caps don’t look great on the solenoid board, I’m going to go ahead and just replace the board. Any way to get a sense that it’s probably a solenoid board problem vs a MPU board problem?

No thanks on the regulator capacitor kit; I received and installed a new regulator board. Problem appears to be solved, thanks for everyone's help!