My Heavy Metal Meltdown backbox light won't turn on, regardless of the bulb used. What is interesting is that when I put a CFL in, the bulb does flicker briefly but then goes out. The bulb in the topper strobes on and off constantly, which is also incorrect behavior (I believe).

Going back to the transformer output, I found that it is producing ~135VAC, which is well above the 120VAC expected. My hypothesis is that the winding powering this particular voltage output is somehow faulty. Perhaps because a bulb that was rated much higher than spec (which is 34W, according to the Operator's Manual) was used in one of the fixtures and caused damage? Regardless, I have a plan to mitigate that I wanted to post up here and see if there were any strong objections to.

I'm going to:
- Clip and tie off the existing "120VAC" output leads from the transformer
- Use tap splices to tap into the line voltage (the blue and gray wires on the left side of the plug below)
- Connect the old connector I cut from the transformer into the tap splices
- Verify the wiring from the other side of the connector I moved is correct per the schematics (going through the Dual Solid State Relay board and light fixtures)
- Power on the game without the 9-pin connector below and my newly mounted connector connected, verifying line voltage output is good everywhere (~125VAC, matching my wall socket)
- Plug the connectors in
- Put some standard E26 base LED bulbs into each of the fixtures
- Power on and enjoy the working lights

My only concern is that the fixtures are now going to be drawing amperage ahead of the transformer, rather than downstream of it. I don't think this is an issue, but I did want to flag it here just in case I'm misunderstanding the electrical principles at play here.

Thoughts? Concerns?

IMG_20201116_110739 (resized).jpg

After a bit of troubleshooting, I believe I have this sorted.

The splicing into power ahead of the transformer sadly did nothing. While it brought the voltage down to spec at ~122VAC (which is what I get on the wall outlet feeding it), it didn't solve the issue. Plus, I realized that the top light wasn't supposed to behave as it was. So at this point, I began to believe it was a logic, and not a voltage, issue.

To test this, I jumpered around the Dual SS board (from J1 to J2 and J1 to J3) and, to my delight - both of the lights fired up always on! So now I knew that there was either a there or perhaps further back.

Looking over the schematics, I found that the Dual Solid State Relay board has two AC transistors (Q1/Q2) that feed logic to both the topper and the backbox lights. The latter should be always on (or perhaps flicker during some game modes, TBD), while the former was supposed to be dynamic and highlight certain game modes, it seemed.
Bally 6803 Dual Solid State Relay Board

But these two AC transistors were just inheriting logic coming from the MPU at J9-9 and J6-7 (special thanks ChrisHibler for pointing this out to me).
AC-controlling transistors on Heavy Metal Meltdown
The next logical step then, was to see if the transistors on the MPU (Q9 and Q10), were to blame. So I grounded the tabs on both of them with banana clips and VOILA - the lights came on solid!

At this point, I knew that at least the transistors on the MPU were bad, plus perhaps the two on the Dual SS board as well. While I'm comfortable doing minor repairs, I figured I'd give Chris the business on this one (I love this game too much to muck it up!).

Once I have the boards back from Chris, I'll post up here with the final results.