Just finished a Domino and sometime when the roto unit activates there is a loud buzzing when the plunger is pulled in. Seems to be mostly when the ball exits the playfield and very rarely when the ball activates the roto in the kick outholes. I install a new coil sleeve and the plungers look brand to be in brand new condition? Any thoughts??

Thanks, that was my next venture

Yea, I know another person and he said his Domino buzzes occasionally when the roto spins. I've restored many games with roto units and have never run into this problem. Ive changed the plunger, coil stop, coil sleeve to no avail. In fact other plungers buzzed even more. Gonna run continuity and voltage drop test on the circuits. Maybe the coil is not getting enough juice, although the roto spins super fast!

thanks