I was playing my Williams IJ tonight, and I noticed the upper GI lights went out while playing. I shot up the right ramp, and the lights went back on. A minute later I hit the drop targets and the lights went back out, and didn't come back on.

Looking at the manual, the upper lights are all connected with the white brown wire. I checked this fuse in the back box, it looked good but I replaced it anyways, and the lights are still out.

There are about ten lights on this circuit. The three under the diverters below the NDY light up extremely dimly, and the rest are out completely. When I touch the white brown wires underneath the playfield, they feel very hot to the touch. I checked but didn't find any obvious loose wires, and I tried to reseat what i thought would be the appropriate connectors.

I'm not very experienced with this, but I'm desperate to learn. I'd greatly appreciate any advice/suggestions. Thanks for your time, any insights, and patience!

_{Post edited by ab3 : Problem solved}

Thanks,

I looked at J121 on the power driver board, but no sign of crispiness. Any other thoughts?

Don't know if it's important, but all of the lights on this circuit are LEDs. Anything unique about LEDs that might have caused this?

The LEDs were put in about a week ago, and no problems noticed until today. I tried reseating all of the connectors underneath. What I can't understand is why are the three lights under NDY diverters lit very dimly (clearly they're getting some power), and why does the white brown wire underneath feel so warm. Thanks again for any other ideas to try.

Edit: I had to reseat and move the wires around in the LEDs in the pop bumper several times until they would light, but they have be working fine for a week since.

_{Post edited by ab3 : Maybe related}

I can remove all of the bulbs in the circuit relatively easily from under the playfield, except for the pop bumpers from above. Do you recommend I remove all of them? Thanks.

Solved-

I decided to start taking the plastics off so I could access the upper playfield GI from above. It turns out the raise jackpot when flashing plastic had managed to push the wires from the left ramp opto slightly out of position (making contact with something it shouldn't). When I readjusted them, all the upper GI lights came back on!

I'd be happy to be educated by anyone here as to why the left ramp opto wires could cause the upper GI lights to go out. Thanks for everyone's help and time.

The opto wires were not cut into (this was the part of the opto on the right side of the left ramp by the way). The exposed part of the lead going to one side of the opto was long enough, such that it managed to touch one small solder point beneath it that it shouldn't have been touching.

I'd be grateful if you were able to tell me how this shorted the upper GI, thanks.