(Topic ID: 275562)

Williams Doozie - Intermittent Backbox Lighting

By essmeier

3 years ago


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Topic Stats

  • 12 posts
  • 6 Pinsiders participating
  • Latest reply 3 years ago by essmeier
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#1 3 years ago

For a while now, I've had issues with the backbox lights on my Williams Doozie, though this problem (and the solution, once I find one) could apply to any EM game.

Sometimes the lights are on; sometimes not. They'll come and go during the course of a game.

Note: This is strictly an issue with backbox lighting; playfield lights are OK.

A couple of years ago, I replaced the fuse block, thinking that might have been the problem, and it worked for a while and then the problem returned.

Obviously, I have a flaky connection somewhere. It does not seem to have anything to do with the Jones plug that provides 6 volt power and common to the backbox. If the lights are on, I can't turn them off by pulling, tugging, or wiggling anything on that Jones plug. Connections there seem good and the pins and sockets are clean.

My question is this: Is there a relatively simple way to troubleshoot this problem?

I'm just not sure how to approach it.

#2 3 years ago

Intermittent problems are hard because we're never sure if we fixed them. On the upside, they usually get better or worse over time.

Use Alligator clip jumper wires to temporarily bridge across various combinations of potential trouble spots to eliminate some areas as the problem, and narrow down on other areas.

http://www.planetimming.com/Pinball/troubleshooting/EM%20Troubleshooting.pdf
http://www.pinrepair.com/em/index3.htm#features

#3 3 years ago

We're talking on GI lighting right? And it's all the lights?

Jumper from any working GI playfield light to the first lamp in the string of GI and see what happens. My guess is you have a bad solder either on the power side or the ground side. Another possibility is a broken wire somewhere in the circuit.

Are you sure the fuse itself isn't flaky? It can happen.

Intermittent problems suck as Howard said.

#4 3 years ago

(ignore bad advise about fuse)

#5 3 years ago
Quoted from dr_nybble:

It shouldn't be the fuse as the schematic shows that most of the lights including the playfield lights are downstream from the fuse. I agree with emsinkc, when the lights are not working is the time to wiggle the sockets or employ the jumper.

My thinking was sometimes the fuse filament isn't blown but making intermittent contact on one end. Not likely but an easy check.

#6 3 years ago

The doozie schematic is wired like most Williams games of that era. The backbox lights have their own fuse and are gated by a large contact on the lock relay. That’s the first thing I would clean, adjust, and jumper around (since you’ve already triple checked the Jones plugs).

I mean jumper around the lock relay contacts, never the fuse.

Dave

#7 3 years ago

Dang you’re exactly right I misread the schematic. If ALL the backbox lights are out then the lock relay would be the first place to clean and gap.

#8 3 years ago

I missed that too. That's what happens when you don't look at the schematic.

#9 3 years ago

Sorry for not responding sooner; I've had a few crises to deal with the past couple of days.

Not the fuse; I've replaced the fuse multiple times, replaced the fuse block, and I've even jumpered around the fuse completely.

It's not just the general illumination lighting; it's all of the lighting in the backbox. I completed a game the other day and everything was on - GI, match, and "Game Over."

Two minutes later, while I was nowhere near the machine, all of the lights mentioned above just suddenly turned off. Then I started a new game and they all came back on. That's not reproducible; that was just a random occurrence. Starting another game with the lights off might not cause them to come back on.

Wherever the problem lies, it's something that's common to all light circuits in the backbox.

I'll have a look at the lock relay (in between crises.)

More later; thanks for the tips.

#10 3 years ago
Quoted from essmeier:

Two minutes later, while I was nowhere near the machine, all of the lights mentioned above just suddenly turned off. Then I started a new game and they all came back on. That's not reproducible; that was just a random occurrence. Starting another game with the lights off might not cause them to come back on.

A short somewhere. Poke and prod.

#11 3 years ago

"A short somewhere. Poke and prod. "

I'm pretty sure that a short won't cause a circuit to lose continuity. I've been looking for an open.

I adjusted and cleaned the switches on the lock relay, and that may have fixed the problem. I've only played 3-4 games, but so far, the lighting is holding up. I'll need to spend some time with it to see if it holds.

I'll post back when I have an idea as to whether this has fixed the problem.

#12 3 years ago

After a bit more testing, I think the Lock Relay was the likely culprit. I completely missed that switch when I was looking at the schematic.

After cleaning and adjusting that switch yesterday, I played about a dozen games without incident, and then put the machine back in its place, put the glass back on, locked it up, and played a game.

...and the lights went out at the end of the fifth ball. They came on again immediately when I started a new game. That's the only time it acted up, so it's doing it a lot less now.

I still think it's the switch on the Lock Relay. I cleaned and adjusted it again and I'll keep an eye on it. If it acts up again, I'll jumper around it and see if that offers something definitive in the way of an answer.

I've occasionally encountered flaky switch blades that, for whatever reason, offer intermittent continuity even when they appear OK. They test fine with a meter, work intermittently while in use, and then everything's OK once you replace it. Had that problem a while back with a bell on a Bally slot machine. The switch appeared OK, but sometimes the bell rang and sometimes it didn't, and cleaning and adjusting the switch didn't make a difference. But when I replaced the switch the bell worked perfectly.

Perhaps that's the case here. Time will tell.

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