I have a Sample (or early production EarthShaker) that I have restored with a new playfield cabinet decals etc... I was working great until the sinking building started having issues. It sometimes would not move or would move but with significant motor noise. It would always fully drop or fully exstend when it did work. I first changed the 3906 transitors did not fix it. Then I changed the motor that seemed to correct the problem however now I'm getting a switch error for opto2 which is the height switch and the building only raises half way. I changed the opto did not help. In testing the optos they only register in the switch test upon exit of the blocking portion of the opto interuptor. in other words when the interuptor first block the opto beam nothing when the interuptor exits the opto it the registers which causes the motor to stop and the building is only half way. This exists in both optos.

Any ideas?

Don

Thanks for taking a look at this. I think the issue maybe the motor. I replaced the motor due to it getting older and not working. I noticed that if th motor turns clockwise the building functions properly if reversed it does not as the interrupters are passing the optics at a differepoint. In bench testing bothe the old and new motor I noticed that it would randomly change directions when starting up at tdifferent times. I installed back in the game and it exhibits the same behavior. It’s a 24v ac motor and in reading to change direction of an ac motor the polarity must be switched. So I’m not sure how Williams is maintaining the polarity?