(Topic ID: 356469)

Gottlieb System 80B Auxiliary Light Board - dim lights, need help

By TheGreyhoundWA

12 days ago



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#1 12 days ago

Gottlieb Monte Carlo

Chasing Aux lights all work, correct speed, but all very dim. Topper lights AND the 10M shot lights. All same dimness, but all work and chase.

Tested with known good/bright LEDs, no change.

Pins 2 to 4 at the aux boards connector reads 5.1V so I believe the board is getting good power.

Stumped from there.

Has anyone had this issue or similar on any 80B games? Advice on what to check next? I have basic electrical skills, but please explain like to an apprentice. Thanks!

1 week later
#2 4 days ago

Bump (sorry!)

PXL_20240504_044029099.NIGHT (resized).jpgPXL_20240504_044029099.NIGHT (resized).jpg
#3 3 days ago

I had this same issue on Black Hole. One of the bridge rectifiers was bad.

#4 3 days ago

If it's the same as Black Hole, the bulbs are powered from 6 vdc, not the 5 vdc supplied to the aux lamp driver board.
On BH it's pin 1 on connector A10 from the lightbox.

#5 3 days ago

Pull out your Monte Carlo manual:

Page 41 shows the auxiliary lamp board's connections to the lamps. The lamps get their power from the '666' wire.
You can traced that back to A12P1 connector pin 4.

Page 45 shows the A12J1 connector. Pin 4 goes to the bridge rectifier 8vac in, 6vdc out.

Set your multi-meter to DC volts and put the red lead on the bridge rectifier lug with the '255' wire (red-green-green) and the
black lead on the ground lug (opposite lug). You should see 6vdc.

#6 4 hours ago
Quoted from TheSpeeder:

Pull out your Monte Carlo manual:
Page 41 shows the auxiliary lamp board's connections to the lamps. The lamps get their power from the '666' wire.
You can traced that back to A12P1 connector pin 4.
Page 45 shows the A12J1 connector. Pin 4 goes to the bridge rectifier 8vac in, 6vdc out.
Set your multi-meter to DC volts and put the red lead on the bridge rectifier lug with the '255' wire (red-green-green) and the
black lead on the ground lug (opposite lug). You should see 6vdc.

First. Thank you kindly for that detailed and easy to follow instructions. This helps me learn the hobby better!! (New to owning older games)

Second. I do measure 6.7V from 255 to the opposing lug. So I believe that rectifier to be good.

I reckon I will then need to chase the wire toward the relay to see where it's losing voltage?

Testing at the socket wasn't very useful as it flashes too quickly to get a believable voltage on my meter.

Thanks again for helping me learn. What would the next points of test be? 677 into the relay, and a ground?

#7 3 hours ago
Quoted from TheSpeeder:

Pull out your Monte Carlo manual:
Page 41 shows the auxiliary lamp board's connections to the lamps. The lamps get their power from the '666' wire.
You can traced that back to A12P1 connector pin 4.
Page 45 shows the A12J1 connector. Pin 4 goes to the bridge rectifier 8vac in, 6vdc out.
Set your multi-meter to DC volts and put the red lead on the bridge rectifier lug with the '255' wire (red-green-green) and the
black lead on the ground lug (opposite lug). You should see 6vdc.

So at the a12j1/a12p1 both sides read the same 6.7v

However once I get to the a9p8,a9j8 I only read 3.6v, that's also what it reads at the relay.

Attempting to read the schematic on page 41, I believe there is a .33ohm resistor somewhere in that path. Not seeing one visually.

Or does that indicate the expected resistance between the two terminations of the wire/plugs?

So, somewhere between the rectifier and the relay I am losing 3v. Which would explain why the lights are dim...

Thank you SO much for the assistance... Just gotta find why it's losing 3v between those points on the wire...

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