I'm resurrecting this thread. I am helping a friend with an Old Chicago that he just acquired. The issue sounds similar: no playfield feature lamps are working. All GI (backbox and playfield) and the "feature" lamps in the backbox work (ball and player number, etc). On the playfield, we can get the Extra Ball lamp to light when an extra ball is earned. No other insert/feature lamps show anything on the playfield. Scoring, bonus, etc all seem to work correctly.
I replaced the fuse holders in the front of the machine (3 of them). The plug by the fuse holders had one pin that was discolored and I direct wired/soldered that to bypass the plug. I have reset the various plugs going to the playfield from the cabinet. As noted in Mr Bally's note - I checked the Game Over relay and tilt relay and it looks like the open/closed is correct (I will need to double check that, but I didn't notice any switches that remained open or closed when the solenoid was engaged.
One thing I noticed was on the score motor in the cabinet - see the picture. It looks like a couple switch stacks are blanks (no wires attached). Then, there are a number of wires that aren't attached to anything. The switch stacks look clean (not hacked - if somebody removed the wires, they did a nice, clean job of desoldering). Anybody with an Old Chicago - can you check your score motor switches and wires to see if it looks like the one in the picture?
He has the schematics - I am not very familiar with EMs. Any further suggestions/ideas? Thank you - Conrad
Update: feature lights are working now - the Game Over Relay contacts needed to be cleaned.
Old C score motor (resized).jpgOld C game over (resized).JPG