I have a Super Spin that I'm reviving, and I'm having a tough time getting the roto target assy to work properly. I have had it completely disassembled, cleaned, lubricated, and reassembled with new spring kit from PBR. All the parts appear to be in good shape. The pawl stops are adjusted to the Gottlieb instructions. When I actuate the drive lever by hand and hold it the "energized" position, it spins freely. When the solenoid actuates it during game play, it might move one target location but usually not at all, because it basically jams. I think it jams because it is just getting a short duration pulse from a score motor switch - not long enough to allow the gears to spin freely before the stop pawl (and drive pawl) are snapped back to engage the gear teeth by the return springs. If I momentarily depress the the drive lever by hand and let it go, I can basically replicate the jamming issue I'm having during game play.

In looking at youtube videos of Roto Units, they spin in smooth manner (pretty much like when I manually hold the drive lever down on this one). This is my first experience with a Roto Unit. The operating principle looks easy enough, but it has me baffled! Anyone have any ideas what I might be overlooking?

boilerman - your diagnosis was absolutely dead on. The motor 3E NC switch was making weak contact. Cleaned & adjusted it and the roto unit spins like a top now. Thank you for helping me out on this!

MarkG - thanks for your reply as well. The Roto Unit circuit on this machine is switched on by "P" or "D" relays, and those relays are held on by motor 2B, which, as you surmised, opens at the very end of the motor run (see motor seq attached). What's interesting with this machine is that motor switch 3E never opens on 2 out of the 3 score motor cycles. This is because there is only one long actuating post that will trigger it - the other two posts are too short to reach the "E" level (see attached pic). I guess this was designed to shorten the "on time" a little bit during that particular revolution, thereby injecting a little "randomness" into the spin. Motor_Sequence_Chart_(resized).pngScore_Motor_3E_(resized).jpg

Boatcat - There is only one motor 3E switch on this machine. It is a B-type (NC) switch and it is only wired to the roto unit coil. It does not tie into anything else on the machine. The feature is a random "spin time" generator - EM style.