(Topic ID: 256555)

Symptoms of a Damaged High Voltage Power Supply

By dearliza98

2 years ago

Topic Stats

  • 8 posts
  • 7 Pinsiders participating
  • Latest reply 2 years ago by KenLayton
  • Topic is favorited by 1 Pinsider


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#1 2 years ago

Hey all. I’m pretty sure I understand that the high voltage section on the PS is what powers the displays. Does it affect anything else?

I have a Police Force and I checked the +100/-100 on the PS and it reads properly. However, the game has to “warm up” before the displays will come on. I thought they were shot and then I left the game on for a few hours and came back to see that the displays seem totally fine.

#2 2 years ago
Quoted from dearliza98:

I’m pretty sure I understand that the high voltage section on the PS is what powers the displays. Does it affect anything else?

Correct. Nothing else is affected.

Sounds like the display is outgassed a bit. Replacing all the capacitors on the power supply may help it come up a little quicker.

Here is a list of the capacitors to be changed. These do fail over time anyway.


#3 2 years ago

Is the machine in a warm room or in a garage where the temperature is to cold or cool?

#4 2 years ago

You should probably just let me come and get it

#5 2 years ago

woody76 haha you know me... I may give up before it’s done.

PinballManiac40 thanks for the tips. I’m gonna rebuild that section either way. When the displays finally do come on, they are bright and vibrant. I don’t see any missing sections. It’s taking at least an hour for them to come to life as it is.

pinmike I have it in my garage but it stays around 60 in there. None of my other machines have this issue.

#6 2 years ago

When you have the power supply out for recapping, look at the back of the board for cracked header pins. Also make sure the 3 fuse holders and fuses for the high voltage are clean and shiny and have good tension on the fuse.

#7 2 years ago

Don't have a ton of experience with this problem, but I find when something needs to warm up to start working, caps are often the culprit.

#8 2 years ago

I've seen this problem before. It was resistors R1 and R4 on the power supply board. They had increased value. They each should be 39k. You have to unsolder one lead to test them. If tested "in circuit" you'll get false readings and think they're good.

Originally Williams used a one watt rating on these two resistors. They found these resistors after a while were under rated and increased the wattage rating to two watts. So I suggest if one or both are bad, replace them with 39 k @ 2 watts resistors.

I have found in my experience over the years, if you find only one of those resistors bad to replace BOTH of them. If you don't, a week later the other one (the one you didn't replace) will crap out.

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