I have a JITB that I am trying to get going. Starts up and resets fine and kicks ball out on first player ball one as it should. No playfield lights (once in a while they will come on for just a few seconds, slight flickering, then go off). I have checked, cleaned, tested fuses, fuse holders, jones plugs, and such. I have 6 volts at fuse, transformer (supply and return), light socket, and return wire under playfield, switch on hold relay, and at jones plug connections (white/black and black/white wires. Am I missing something? It also goes beyond ball 3/5 without going to game over. The drop targets do not score bonus after each ball either. I have cleaned/lubed rivets, and adjusted so rivets make proper contact with shoes on bonus unit. Switches on targets seem ok. Thanks in advance for any help, Ed.

Thanks Curriedog for quick response. I have checked that switch on Hold relay and I will check switches on QB. This is same machine I posted a few weeks back about score motor turning too fast. It was a 50hz motor in score motor (pin was in Germany and shipped back to the states recently). I found a used 60hz motor and made the swap. That part works great now and I am finding these other issues. Thanks again, Ed.

@ Curriedog
After checking switches on QB I found a blob of solder and I see where someone before me had been messing with this pin. The switch involved with my problem seems closed as it should be and tested continuity. But as you can see in the photo, I wonder if this is causing more problems? Any thoughts, and I will remove the blob.

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Ok, got solder off switch stack, no help. Decided to replace fuse holder. That fixed the playfield light issue for about 15 seconds. The pin now starts a game (all lights on, then as I knocked down a couple drop targets (lights for targets lit up) then fuse blew for playfield lights. I put another fuse in and hurriedly started a game, knocked down a few targets, then activated out hole switch to see if bonus would count (it did). Then before it would go to ball two, light fuse blew again. Not sure what is causing fuse failure, but did notice the playfield lights actually brighten when pin is scoring points (like when I would knock down drop targets). I have seen lights dim when something else is firing such as flipper/pop bumper coils and such but not brighten....? Any ideas? Thanks again, Ed.

Ok, I just received circuit breakers in 10, 15, and 25 amp ranges so will try the tips you all suggested this weekend and keep posted. Thanks again for all the help. Greatly appreciated, Ed.

First thing, circuit breaker works great. I soldered a popped fuse to it and works like a charm. Now here's what we have so far. First, removed all bulbs, then start a game. Pin resets as it should, then after about 20 seconds, pops breaker. Added bulbs, still pops. While doing this I noticed the A (alternating) relay was humming a little bit. The wrapper is toasted and relay was pretty warm. I thought maybe it was becoming a dead short so I unsoldered one wire to it to see what would happen. Breaker did not pop. But....I manually activated the relay switches and held them for the 20 seconds or so and breaker popped. I have attempted to trace where the wires go and looking at schematic, they are pop bumper lights and a few rollover switches and feature lights. I have not found anything wrong with these yet but need to give my nearly 60 year old eyes a break...LOL. Am I on the right track ? Thanks again, Ed.

OK, found playfield light issue. It was in the alternating relay circuit. The red hole light tab where power feeds (orange-green) to bulb was barely touching its mounting bracket. Was hard to see because it is right behind drop target assembly. Now on to not going to game over issue. Bonus now scores since playfield light circuit works. Thanks again for everyone's help, Ed.