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(Topic ID: 267795)

Stern Galaxy Game Resetting Occasionally During Play


By fxvielander

7 months ago



Topic Stats

  • 6 posts
  • 4 Pinsiders participating
  • Latest reply 6 months ago by fxvielander
  • No one calls this topic a favorite

You

Linked Games

  • Galaxy Stern Electronics, 1980
#1 7 months ago

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 The rectifier board has been replaced by me, and I've added X-Pin displays so the game can now display scores in the millions, and the original means for saving high scores has been upgraded, but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!

#2 7 months ago
Quoted from fxvielander:

Where should I start? Should I "re-cap the power supply", as that seems to be a popular step on these machines?

Yes, recap the solenoid driver board. Repin connectors J3 on the solenoid driver board and J4 on the MPU, replace header pins also.

If it continues after that you may have a faulty 5V regulator or a problem in the switch matrix causing it to falsely slam tilt.

#3 6 months ago

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?

#4 6 months ago
Quoted from fxvielander:

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?

This sort of problem is usually due to the 5v & 12v supply to the MPU being crappy. As you've already replaced the rectifier board, the next step is the part of the power-supply located on the SDB. It is almost always the large electrolytic capacitor, but sometimes can be the voltage regulator (transistor). It can also be the connectors, the power-on reset circuit on the MPU, or even the sockets for RAM/ROM on the MPU.

#5 6 months ago

I also have a galaxy and ordered a bunch of kits from Big Daddy Enterprises, I somehow got a 2nd bally/stern solenoid driver board regulator capacitor kit.

1 ea. 15,000uF, 25 Volt Electrolytic Capacitor (Radial Snap-in)
1 ea. 150uF, 400 Volt Electrolytic Capacitor (Axial)
4 ea. Nylon zip strips

If you were interested in doing some rebuilding of boards I'd sell that cheap and ship.

#6 6 months ago

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!

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