I’ve got a lamp row in my game (BoP) that seem to have a short or something weird going on, although I don’t get any error messages in the machine tests.

I’ve read many posts and websites but I’m not understanding the process to find what I assume is a short. I’ve visually inspected every lamp on this row and I can’t see anything obvious.

I have a DMM but I’m not sure what setting to use or what to look for.

The light row is connected to a brand new Rottendog board that has been tested and confirmed to work correctly.

I’ve tried replacing the bulbs on the lights that appear always lit or flash when they’re not supposed to.

If anyone can explain the troubleshooting process to me like I’m 5, I would greatly appreciate it.

Thanks!

Ok. I said explain it like I am five - if I knew what I was doing, I probably would be able to explain the problem better

Row 1, Column 1 (left outlane light) flashes all the time in game, even when it’s not supposed to.
Row 1, Column 2 (circle, light jackpot) - same sort of behavior, although not flashing all the time - only when other lights in the row do
Row 1, Column 4 (50k skill shot) - same sort of behavior - only when other lights in the row do

Those lights (and every other light in the game) test fine using the machine light tests, as I mentioned above. They light up as they are supposed to. In fact, every single light and switch in the game tests perfectly when I run diagnostics.

There might be other problems with that row but I haven’t noticed them.

All of the problem lights light up correctly and brightly when they’re supposed to in game.

I have checked that the diodes are facing the right way on the lights
I have looked for obvious bare wires, touching wires, etc
I have tried replacing bulbs
Some of the lights on this row are on individual circuit boards, others are in sockets

As I said, the board is new and was tested by a professional recently and confirmed to be working. The molex to the board looks fine - no obvious damage, nothing is loose.

I've read the pinwiki and reviewed the lamp matrix and I'm still baffled. Here is the result of 10 single lamp tests. I found some consistency in tests 1-8 (although I'm not sure how to narrow that down to a single problem).

Test 1(a) and Tests 9 and 10 also make this even more confusing.

1. If I do a single lamp test for Left Outlane (1,1 in the matrix above), Circle Light Jackpot (1,2) flashes dimly in time with Left Outlane.
1(a) If I remove the Circle Light Jackpot lightbulb, Circle 250k (1,3) flashes dimly in time with Left Outlane.

2. If I do a single lamp test for Left Return Lane (2,1), Left Outlane (1,2) and Skill Shot 75k (2,4) flash brightly in time with Left Return Lane.

3. If I do a single lamp test for Right Return Lane (3,1), Left Outlane (1,2) and Skill Shot 100k (3,4) flash brightly in time with Right Return Lane.

4. If I do a single lamp test for Right Outlane (4,1), Left Outlane (1,2) and Skill Shot 200k (4,4) flash brightly in time with Left Outlane.

5. If I do a single lamp test for Left Standup (5,1), Left Outlane (1,2) and Skill Shot 25k (5,4) flash brightly in time with Left Standup.

6. If I do a single lamp test for Right Top Standup (6,1), Left Outlane (1,2) and Head Left Eye (6,4) flash brightly in time with Right Top Standup.

7. If I do a single lamp test for Right Bottom Standup (7,1), Left Outlane (1,2) and Head Right Eye (7,4) flash brightly in time with Right Bottom Standup.

8. If I do a single lamp test for Shoot Again (8,1), it didn't light up this morning (although I'm pretty sure it works fine in game), but Left Outlane (1,2) and Head Mouth (8,4) flash

9. If I do a single lamp test for Circle Light 1 Billion (2,2), Skill Shot 75k (2,4) flashes in time

10. If I do a single lamp test for Circle Extra Ball (3,2), Circle 1 Million (6,3) and Skill Shot 100k flash (3,4) in time

Since Left Outlane seems to light up throughout my Column 1 tests, I tried replacing that bulb and desoldering - no change. Pics attached are the Left Outlane board, as well as the circle lights board (see test 1a). Both look fine to my untrained eye.

IMG_8106 (resized).jpeg

IMG_8107 (resized).jpg

I have all brand new non-ghosting LED’s installed from Comet, but I’ll try testing with all incandescents. I have tested the diodes on all of the lights but wasn’t sure what I was supposed to be seeing on the meter. I will try again.

Is it strange that the problem seems to be across multiple rows and columns?

I tested most of the diodes and got correct readings (didn’t test anything that wasn’t very accessible).

I replaced a few LED’s with Incandescents and many of the problems went away. All of the LED’s in this game are brand new, non-ghosting Comet LED’s. I have no understanding of why they would cause the weird light problems I’m seeing.

Another problem that I had previously has returned - when the pinballs enter the Bride’s head on the 2nd stage (both eyes full) the game essentially stops. Music stops, balls are locked and only eject when the machine goes into its lost ball routine and starts firing all of the solenoids. At that point, the game doesn’t know what state it’s in and gets out of sync.

I have a feeling all of these problems are related, but I don’t understand what to look for to troubleshoot.

Could a cabinet ground braid issue cause these problems? I notice that random light up when they’re not supposed to if I raise the playfield (i.e. I’m testing one lamp, and it works fine in test, but if I raise the playfield during the test, another bulb will also light up). Wondering if the ground braid is not done correctly, or if the braid is touching something it shouldn’t, etc.