Seeburg 100-78D

I have an unusual problem that just cropped up with a 100-78D. It has a PPCC-1 code A (maybe a 56-1 stamped in ink, but it's hard to tell for sure) control center. It had been working ok, but now the count down solenoid has a small voltage (maybe 5-6 volts) that at times will not let the count down solenoid release so it can count down. If I manually pull down the solenoid you can hear it chattering. I thought it was residual magnetism, but after cleaning and checking it I found that not to be the case.
I then cleaned the service switches to no avail. The odd thing is you can manually pull in the countdown solenoid and it will stay energized. It seems to leak enough voltage to keep solenoid pulled in (5-6 volts as best I can tell).
It will select normally, but solenoid has enough voltage leaking thru to not let it release and count down. So after last selection is played it keeps scanning. I tried a good solenoid and no change. I then replaced the capacitors and some diodes on the circuit board in CC. I didn't think that would help, but they were the originals so figured it wouldn't help. The voltages on the test points on edge of CC check ok so I don't think any zener diodes are bad.
I was looking at a reprinted manual (AMR) for the CC, but the copying is so poor you can't tell any values etc. and no voltage readings for the circuit board.
I'm missing something I know, but I need some minds better than mine to help me out.

Hi Robert,
My mind is shot--What is a "count down solenoid"? Are you speaking of the "scan control add or subtract coils"?
I can not re-call exactly what Seeburg did on the D models, for scan control--is it the same as in the 160 models--two coil/plunger assemblies ? If so, which coil is hanging up--the add, or subtract ? Ron Rich

yes, it's the scan control. They just used one coil. When selection is made it energizes the coil and then instead of having a coil to subtract, it does it mechanically.
I initially thought it was a problem with either crud in coil or residual magnetism. I cleaned coil and checked plunger to see that it was all right. It is an electrical problem because even when the coil is at relaxed position it still has a slight hum from the coil. Very small, but enough to hold the plunger up into the coil if I manually push plunger in.

I don't have the schematic handy--and have never had a problem ( other then broken "rubber bands") with one, but if there is leakage, you will need to determine what controls that coil and go from there-- My path would be to begin by un-plugging the "red box"--if no leakage now, I would assume it is BDT driven, and the BDT is bad. If there is still leakage, perhaps the WI relay, or "service switch" ?? Ron Rich

Finally got back to checking this out. After unplugging the red box, the scan control released normally. I assume the problem is in the red box, but I am not familiar with them. I have had quite a time finding diagrams. The amr reprinted manuals don't have any schematics. Found the most info in Anthony miller's book on red boxes. I need someone that can test the red box or buy another one or tell me what to test next.

Since Tony designed the "Red-box", I would think his book should do it-- Find the BDT (triac) that fires the add coil, and change it--I would guess it's the same, or similar to, the circuit used in all the DCC's ? Ron Rich