This is on Old Chicago Bally 1975.

The GI dims when you press a flipper button, including the Backglass GI.

Is this normal? What should I check?

Thanks. I think most of the lamps are 47s. I'll check.

The left flipper EOS switch was not opening. Now I'm having trouble getting it adjusted to where it won't machine gun. Maybe that's why someone had it adjusted incorrectly. The coil bracket is a little bit loose. Maybe that's the trouble.

The left flipper has a cut diode. An EM shouldn't need a diode, right?

Yup. It was a replacement coil . Can’t read the label until I remove it . Light blue wrapper.

I’ll order the correct coil.

Thank you, but I’m confused. Why would the Jones plugs be the issue?

New coil.

Buzzes loudly, but all screws are tight. Perhaps need a new coil stop?

Still dims the GI. But, only on this flipper. The other flipper doesn't (and didn't before).

The jones plugs with the thick yellow wire and thick yellow gray wire look ok to visual inspection.

Turned Out the coil was mis-wired and I duplicated the mistake installing the new coil. Got u wired correctly & put in a new coil stop. All is good.

Lesson learned- It never occurred to me someone would have wired a coil wrong. Go figure.

With the help of some great pinsiders!