(Topic ID: 53679)

System 6 - Coil Voltage Too High - Bridge Rectifier?

By dtown

6 years ago

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  • 8 posts
  • 5 Pinsiders participating
  • Latest reply 6 years ago by dtown
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#1 6 years ago

I performed the fused bridge mod on my Firepower and I keep blowing the 4 amp fuse for BR2, the coil fuse. I can play for about a minute and then the coils go dead after the fuse blows. The 2.5 on the P/S board is fine. I measure 40 volts DC coming from BR2 which is way higher than the 28 that it should be. Is the bridge shot? Is this causing the fuse to blow?

I also measure 17 volts and 18 volts at the two AC lugs going into the bridge. Schematics say it should be 25.5 AC. Problem with the transformer? I doubt it but just putting it out there.

#2 6 years ago

Voltage going out not under load tends to be higher.

Don't know how you are measuring AC, hot to common ?

But voltage in is usually closer to voltage out.

LTG : )

#3 6 years ago

check the end of stroke switches on the flippers and make sure they open up. Make sure all grounds,specifically between head and cabinet are connected and solid.

#4 6 years ago

Not really too out of whack for a system 6, mine is in the mid 30v range I believe, not sure if a 4A is enough for that circuit to be honest, IIRC I'm running 8A


#5 6 years ago

I got 40 volts at the coil lugs. It's actually 41-42 at BR2. I bypassed the mod and its not blowing the 2.5 amp fuse on the P/S. The mod called for 4 amp slow blows. Maybe it's not enough. This was a dead game so all switches and coils were checked and cleand prior to powering on.

#6 6 years ago

I found two different repair sites which describe the mod. One says to use 4 amp slow blows and the other says 8 amp. Which is it? I'm guessing 8.

One is Mark's Pinball Page - 4 amp
The other is easypinballpro - 8 amp

Easypinballpro mentions that Mark helped write the site so I'm at a loss.

#7 6 years ago

Below is part of a write up that I used the first few times I added the fuses to the rectifers. It says 8 amp.


#8 6 years ago

Thanks. I wish I had read the right one the first time. Out two fuses for misprinted instructions.

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