I'm working on a friends Meteor that is having a strange issue that I can't figure out. In switch test, it's showing that switch 8 (slam/vibration tilt) is active. I've checked all 3 of the slam/vibration tilt switches (coin door, inside left cabinet and underside of playfield next to the left flipper mech). The diodes, switches and wiring on all three are good. I've even unsoldered the wiring at the switch for those 3 switches but it still shows switch 8 active. It's not the MPU board as I tested it in my Meteor and it works fine. All the MPU connectors have been repinned as well.

I've went thru and checked the diodes including all the switches up from switch 8 and they are good. All the switches under switch 8 register in switch test but nothing over 8 will register. That is normal behavior for a switch # above the switch that is active to not register in switch test as my Meteor does this as well.

One odd thing is that when I manually close the slam tilt switch by the left flipper mech, a few of the insert lamps flicker while it's closed. The other two slam tilt switches do not do this.

This one has got me stumped. Any ideas?

Thanks for pointing me in the right direction!

I isolated the issue to the orange wire which was common to switches 8 (slam tilt switch), 16, 24, 32 and 40. If I unplugged that MPU wire at J2 pin 15 the problem went away and all the other switches worked. Using my meter I had continuity between the orange wire and the common bare wire for the lamps that were flickering when I closed the slam tilt switch that used the orange wire. Finally found that the orange wire was rubbing against this bare wire for the lamps. I never would have found it with my eyes. I had my meter connected to the orange wire and the bare lamp wire. After I pulled a bundle of wires that were tight against the bare lamp wire the meter went open. Taped it up and now all the switches are working properly.

Someone had also did a number on the wiring going to the coin switches, such as soldering the wires to the wrong leads, adding wires that went to nothing, etc. I cleaned all that up and all three coin switches are working as they should.

Now it just needs a good cleaning and some new rubbers. Thanks again!