First thing to do, would be check all fuses and fuse holders. Bally fuse holders are often bad. It's best to just replace them. If they're not a problem now, sooner or later, they will be.

Then I would clean all the jones plugs with a small wire brush or fine sandpaper.

Once you eliminate these potential problem areas, you can start looking at switches and relays.

The playfield lights run off of a different path than the backbox lights. See schematic. Red path is for back box (and front door), blue path is for playfield. It uses a different fuse/fuse block and it runs through a different jones plug #20.

gi1 (resized).jpg

Yes, what Ken said, with special attention give to junction 20, that I mentioned previously. Here is where it's at. It will have a heavier gauge wire than the others. When in doubt jumper it.

jonesc (resized).jpg

Are you sure you checked continuity THROUGH the fuse holder to the white/green wire when you tested it without fuses?

Remove the fuse. Put one probe of the meter on the fuse holder solder tab with the white/green wire and the other probe on the opposite solder tab with the blue wire. With the fuse removed, it is an open circuit. It should read infinite ohms. If you have continuity, something is definitely wrong.

Somethings fishy. If you are showing no resistance through an open fuse block, then there would be no point to a fuse. When the fuse blows (or is removed) it opens the circuit.

What type of meter or tester are you using?

Try checking to see if you have voltage on both sides of the fuse.

Check that one again (Blue side) with the fuse IN. You should get the same 7v reading you got when you used the Green/White wire.

The only thing I saw on the schematic in line between the transformer and the GI Playfield lighting was the fuse and the jones plug. Since it started working after messing with the fuse. It was most likely the fuse or holder. Strange, since you replaced the holder but hey... It's working!

Sounds like your step up units aren't fully resetting. Probably need to clean your coin and player up unit, but really you should just clean all the step up units until they advance and reset easily when manually activated with your finger.