(Topic ID: 255760)

High voltage fuse blows on boot up

By bobnatlanta

4 months ago

Topic Stats

  • 5 posts
  • 3 Pinsiders participating
  • Latest reply 4 months ago by bobnatlanta
  • No one calls this topic a favorite


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#1 4 months ago

All new boards except for lamp driver. This is an ultimate SDB. Test voltages from the power supply are all in spec. The 1/4 amp FB high voltage fuse blows as soon as I turn on the power switch. For the moment, pinwiki is no help, as I get a message saying I’m the 5 billionth something and please click for prize when I try to open the Bally/Stern section.

Any thoughts appreciated!!

#2 4 months ago

Sorry that the Wiki is down right now...Casey is working on that.
But, even better, you have one of the authors helping now.

Disconnect all displays.
Replace the fuse.
Power on.

If the fuse blows, the issue is on the PDB. If not, then one (or more) of your displays is shorted. At this point, it's trial and error. Connect the least likely suspect display based on simple visual assessment and power on. Repeat until you find the shorted display.
Chris Hibler - CARGPB #31
http://www.PinWiki.com - The Place to go for Pinball Repair Info

#3 4 months ago

I think F2 should be 3/4 amp slow blow.

Disconnect J3 on the rectifier board - does the fuse blow? If yes - check the diodes.

If no - disconnect pin 8 on the J3 connector on the driver board. If the fuse blows you have a problem in the high voltage section.

If no - you have a short in one of the displays.

#4 4 months ago

Thanks guys - Chris, you’ve confirmed what I suspected. All the displays look pretty suspect... And Bob, this is a replacement SDB, so 1/4 amp is the correct fuse.

Now I just gotta find a pile of 1/4 amp fuses. Only had two in my stash...

#5 4 months ago

Moot point. Further examination of the displays shows 4 of 5 are outgassed. I’m replacing with pinitech LEDs, so the high voltage circuit isn’t going to be used.


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