Help with Light Matrix issue (Williams System 7)

Looking for some advice on a Light Matrix I am having on my Firepower II

There have been a number of problems with the wiring that we have been sorting out, but this is the last one and it has been harder to figure out.

I have four lights in the same row that are staying on during play. They will turn off during attract, but now always in time with how they should.

I attached the light matrix with the lights that are stuck on circled.

In the process of sorting out the wiring problems I have fixed an issue where column 4 and column 5 wires were connected together on the "W", "E", "R" bank, fixed a backward diode on #26, and fixed a broken diode on #51 (which meant that socket now worked, but also added #49 to the lights staying on during play list). I have also replaced the Driver and MPU board with new ones from PinballPCB to fix other issues.

Looking at the wiring and testing the diodes with the multi-meter row doesn't seem to show any obvious issues. Any suggestions on next steps?
FP2 Light Matrix (resized).png

Post last edited 3 years ago: “Maek grammars gooder ”

#2 3 years ago

???

Spybryon

Pinside member

OP
Quoted from bwill:
Any suggestions on next steps?

Run an all lamps test and describe what each one of those lamps do?

Run a single lamp test (if Sys 7 supports that, forget if it does or not) for each of the malfunctioning lamps and describe what happens for each one of those?

#3 3 years ago

BJW

bwill

Pinside member

Quoted from Spybryon:
Run an all lamps test and describe what each one of those lamps do?
Run a single lamp test (if Sys 7 supports that, forget if it does or not) for each of the malfunctioning lamps and describe what happens for each one of those?

The all lamps test lights them up, no problem. I’m pretty sure the single lamp test isn’t supported by system 7, at least how to do it is not in my manual.

#4 3 years ago

???

Spybryon

Pinside member

OP
Quoted from bwill:
The all lamps test lights them up, no problem.

So they stay lit all the time in all lamp test, and do not flash like the rest of the lamps?

#5 3 years ago

BJW

bwill

Pinside member

Quoted from Spybryon:
So they stay lit all the time in all lamp test, and do not flash like the rest of the lamps?

They flash like the other lights.

#6 3 years ago

???

Spybryon

Pinside member

Think that there might be a short between some wires running to those malfunctioning lamps. Want to try to isolate the problem a bit more.

Try removing all the bulbs from the sockets of the malfunctioning lamps.

Using a voltmeter set to diode test - the setting where it beeps for continuity, measure between each "ground" wire to the malfunctioning sockets.
So, measure between YEL-RED and YEL-BLK, YEL-RED and YEL-GRN, YEL-RED and YEL-VIO
Next, measure between YEL-BLK and YEL-GRN, YEL-BLK and YEL-VIO, YEL-GRN and YEL-VIO
Any shorts found?

Now, repeat the same tests again, but with the red and black probes swapped.

Then install 1 bulb in one of the malfunctioning sockets (turn off power to game whenever installing bulbs). Start a game and see what they do. Stuck on? If not stuck on and that lamp is off, turn it on by setting off the correct switch in the playfield. For example to get the "2x" lamp lit you might have to complete the top lanes (or something similar). Once all 4 malfunctioning sockets have been tested this way report back what they are doing.

Next, move on to installing 2 or more of the bulbs to try to narrow the problem and identify any shorted wiring issues.

Post last edited 3 years ago: “mention swapping red and black probes and turning off power”

#7 3 years ago

???

Spybryon

Pinside member

Also, double check for burned out bulbs in the following locations: Game over, 9,000 bonus, Lower left jet bumper, release target 100k. Are all of those lamps lighting up at only the correct times?

#8 3 years ago

BJW

bwill

Pinside member