Polysix Repair Help- Nothing but Clicking with Decay set at 1-5 on dial

Hey guys, hoping there is someone on here with experience in Polysix repair. I’ve tried a few other places with no luck.

I’ve been restoring a Polysix, and now that battery and other issues are out of the way, I’m moving on to the fun stuff like tuning adjustment and throwing in the ModyPoly. One thing that has become an obvious problem right out the gate is Decay set to anything under 5 on the dial. Its made sound design impossible with short decay times.

All I get is almost inaudible clicking at 1, to pitter-patter clicking at 4. By 5 it acts as if I would expect a Decay knob to act. This happens no matter what I set the other parameters to. The only comparison I can use as a control is the plugin, and it seems my decay knob is 2-3 steps behind the plugin’s decay all around the dial.

What I’ve checked so far-

  • I am getting -5 to +5 volts at the CN05 pin 7 connector when turning the decay knob. Also, at the decay pot itself, I’m getting 0-10k when checking the output.

  • I’ve checked the Service Manual and I’m getting the correct voltage just about everywhere else I’ve checked, minus one spot-

    • When following the manual for adjusting attack time, CN05-12 is not giving me +0.9V no matter how I adjust the attack VR. 0.001V mostly. Waiting to test with oscilloscope before I call this a problem. Listing in case it’s helpful to the overall issue.

One confusing thing about the service manual is that is states the procedure for checking the decay time, but offers no way to adjust. I have a new oscilloscope on the way, so I can follow the service manual’s steps for checking attack time, but it doesn’t give a point of reference for the decay. Is there an overall envelope adjustment? I know VR12 is a time adjustment per unit, but would that even have any effect on decay?

I could post a video if that helps. My ears aren’t sensitive enough to tell if attack/release is also off on the shorter times, but like the decay knob, anything over 5 seems to be working just fine. Maybe they all are off 2-3 steps. but without a new O-scope I can’t tell. Or, this could all be normal, and I just look stupid… but I doubt it is.

Edit- I made a video highlighting the problem in case it helps- https://youtu.be/Y6NDUvvrP7A