(Topic ID: 297582)

Tech: Bally 2518-54 power module blows 20A

By Mudflaps

2 years ago



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  • 10 posts
  • 4 Pinsiders participating
  • Latest reply 2 years ago by Mudflaps
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#1 2 years ago

I completed a playfield swap on Medusa a few weeks back. All was working, no issues.

I recently removed/adjusted the zipper flippers, added some Mylar and re-installed. After a few games, the F1 20A fuse blew on the 2518-54 power module board. I checked to make sure I didn’t accidentally short something during the flipper fix.

I swapped the fuse and played about 20 normal games when the fuse blew again. I don’t have the schematics, unfortunately. The F1 fuse is for switch illumination (all inserts went dark after it blew). Yet the first time it blew, the zipper flipper coil wouldn’t engage. Weird.

Anyway, it seems I shorted or snagged something while the playfield was up. Can someone with a schematic or better understanding help me trace the issue?

Picture attached. The J5 connector is hacked, but I have replacement connectors and a new board on the way. I plan to overhaul when I re-stencil the cabinet in the next few weeks. Thanks!

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#2 2 years ago

I’m going to guess the braid is touching something it shouldn’t, but just barely. Schematics are on ipdb.

#3 2 years ago

Yep check your supply wire feed along the edges of the playfield, specifically where the playfield meets the cabinet, by metal hinges, etc. Also anywhere it gets close to a mech or a piece of metal on the bottom of the playfield.

#4 2 years ago

F1 is switched illumination. Check that bus braid for contact to a metal surface. Since you were fiddling with the zipper flippers thats where I would start looking.

Don't forget the backbox. The ground braid coming up from the cabinet, if it's too long might be shorting against the insert braid when you shake the game.

#5 2 years ago

Thanks everyone. I checked for about 20 minutes, made some adjustments underneath the playfield, swapped the fuse and powered on.

Inserts worked for about 5 seconds, then the 20A blew again.

Quoted from BigAl56:

F1 is switched illumination. Check that bus braid for contact to a metal surface. Since you were fiddling with the zipper flippers thats where I would start looking.
Don't forget the backbox. The ground braid coming up from the cabinet, if it's too long might be shorting against the insert braid when you shake the game.

I’ll check the backbox and ground braid next.

Edit:
I may have found the culprit. The ground braid from the cabinet to the backbox had about an extra 12”. If the extra slack touched one of the controlled lamp bus wires on the backbox, would that cause the short?

I clipped the extra ground braid just in case.

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#6 2 years ago

Yes that for sure will do it.

#7 2 years ago
Quoted from Xenon75:

Yes that for sure will do it.

Yeah, I think it’s either the ground braid or something else I haven’t seen. I cleaned up the backbox ground braid to be sure.

The inserts will illuminate intermittently. Everything is normal after a power cycle, then a few minutes later the inserts will go out. The fuse, though, does not blow.

#8 2 years ago

Try different playfield positions, playfield up on the prop rod, up against the backbox, fully down, etc. I had a short where the playfield met the support brackets because it was missing one of the hard rubber nibs.

#9 2 years ago
Quoted from Xenon75:

Try different playfield positions, playfield up on the prop rod, up against the backbox, fully down, etc. I had a short where the playfield met the support brackets because it was missing one of the hard rubber nibs.

Thanks, and I think you're right. It's likely some crazy small thingy somewhere that I brushed my elbow against and now it's causing havoc. I even added electrician's tape around the brackets to be sure.

The game works, though intermittently the inserts will go dark until I start a game. Rather than beat my head against the wall, I'll restore the cabinet and try to bulletproof the boards, ground braid and connections. I'm sure more gremlins will pop up when I'm finished, so I'm sure to reach out again.

Thanks everyone for chiming in!

4 months later
#10 2 years ago

To close the loop, cabinet restore is finished. I replaced pretty much everything (boards, ground braid, etc) and the game works flawlessly.

The lesson is that if you have any issue, do a total restore and you should be okay.

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