Working on a Gottlieb Goldwings. Have it booting reliably and playing just fine. I have two remaining problems of which no controlled lamps is a puzzle. I found no 6VDC at the bridge rectifier, and a small AC voltage going in. The fuse was hot but not blown. I don't know what the fuse value is but someone has replaced it recently with an unreadable value -- new fuse, likely from China. There is negligible voltage on the bridge outputs.

I pulled the fuse and measured the transformer outputs for the controlled lamp circuit and found a respectable 9VAC at the transformer lugs.

I test the bridge rectifier and it tests OK. I have seen this before with a bad bridge, so I replaced it thinking I have solved this problem.

But no, the problem remains. There must a short somewhere with the controlled lamps. I don't have a manual for this machine and until the manual arrives I would likely to isolate the problem somehow. With the fuse in place the AC measured at both the fuse and bridge terminals is
less than two.

What is the next step?

This machine doesn't have any controlled lamps in the head, so obviously the problem is with the playfield. As the controlled lamps are powered with a non-insulated round braid wire I thought that there was a short somewhere. I couldn't find any place where there was a short. So using a binary search, I cut the braid and found the same results. So I cut the braid where there where only 6 controlled lamps at the top of the playfield, near where the power comes in, but there was still a large voltage drop and the fuse still getting warm. I removed the wire where the power enters the playfield, powered up, and no voltage drop.

As the fuse looked unusual and I couldn't read the value, I replaced it with a 7A slow blow, as I believe that other system 80's used an 8A slow blow with backglass controlled lamps. Well it turns out, the weird fuse was the problem. It must have been a China resister fuse as with a 7A slow blow the voltage didn't drop and all is well. Case closed. I'll keep the 7A in until the manual arrives.