I'm not really making progress on the GI short yet. (ie, I haven't found it) But I had to replace a couple coils, and this is where it got beyond me.

It appears that a past owner did a sort of hack job with repairs. There's a Williams coil in one place, and another is a Gottlieb coil, but the wrong one for that particular spot. There's a broken lamp socket that's been "repaired" by soldering it back together. Not sure why, I think that amount of solder would cost more than a new socket. The wires to the transformers weren't soldered on at all, just sort of looped through the lugs. One of the fuses is direct soldered to the wire on one end.

Anyway, that's all things to address later. (well, I did solder the transformer wires, that kind of scared me.) I had a bad bumper coil and the replacement came today. But the diode on the new coil is reversed from the diode on the old one. I know that sometimes they can come that way, but it's just as possible the old diode and coil blew because that diode was on backwards. How do I know which way it goes? I measured voltage on both wires going to the old coil lugs (I haven't swapped the wires over yet) thinking that one would be high and that would be my high voltage and go to the banded side of the new coil. But one side is not high. They are the same. I measured the voltage on some other random coils and they are ALL the same on both sides.

Am I doing it wrong? One lead of the DMM on the side rail, one on the wire at the coil; game turned on, in game mode (also tested in coil test) and tested while the switch was being activated by the spoon closing it and when it was not. There was a jump when the switch closed, but it was the same jump on both sides of the coil lugs. I'm stumped.

While I'm asking...how do you tell which lamps are on the GI string? Is it just everything connected to the ground braid? What about the upper and lower playfields? I've read that the bumper lamps are part of the GI too. I can't find a map of the GI string anywhere.

Thanks,
Sharon

Partially solved.

The problem? More hack job repair.

The diode on the old coil was reversed. But only because the copper leads off the coil had been crossed and tied to the opposite lugs.

A wire from the large capacitor under the basement pf to the basement upkicker is going to the wrong side of the coil.

Pop bumper fixed. I think the basement VUK is also fixed, but. I need to replace the K coil. When I got it off, I could see extra bits of winding ends poking out. It was working in a way though - it pulled in and closed the switch when it should have, but it didn't send the signal to the VUK.

I replaced the VUK coil too, and powered it on and the fuses didn't blow! Then I saw the coil still wasn't firing, so I started looking at why. Hopefully, this is it.

I'll say. Sometimes, the colored wires aren't even the color they are supposed to be! At least it's interesting! Thanks Chris. The biggest hurdle was discovering how G. labels their wire colors.

PVC! That's special However, I can sort of see some reasoning process to that one, if the op wasn't able to get a replacement. And a 30 year old battery! That's kind of neat. They sure don't make them like that anymore! It must have been kept in a very dry environment to not get any corrosion from the outside either. This was my first Gottlieb. I'm not impressed with the manual so far, or the need to do everything slightly "original" though I suppose a lot of that was because of patent issues. Good luck with your restore! Oh, and a word of warning, make sure the playfield is secure (tie/bungie cord it in place or something) if you are working on it; mine fell suddenly (random gravity well in my house, I think) and I sprained my wrist trying to catch it and couldn't even PLAY pinball for a month!