The weak magnetic clutch problem on your CL ETC is solved. After removing the amp to get a better look at things, the first thing I noticed was some cold solder joints on some of the clutch delay circuitry. Solder joints did not turn out to be the problem, but while fixing them I checked all the components in the delay circuit, removing the switching transistor TR2 and electrolytic capacitor C136, the 220uf timing capacitor for testing out-of-circuit. Everything seemed good to go, but I replaced the capacitor anyway for good measure. After reinstalling the amp the same problem existed.

Taking some measurements, I found that the 35 volt supply (39 volts in this case) dropped to about 29 volts only when in rewind. I also measured an AC component of about 8 volts only while in rewind. Checking the schematic, the 35 volt supply is filtered by two 1000uf, 50VDC electrolytics. The first one, C131, is always across the 35 volt supply, and the second one, C128, is across the power input to the audio amp. When the machine is switched into rewind, it switches the 35 volt supply from the amplifier to the mag clutch delay circuit. This leaves only C131 as filtering for the supply during rewind. At this point C131 was suspected as it appeared C128 was doing its job and filtering the DC well for the amplifier...no noticeable hum or buzz. The amplifier will normally see both of these capacitors across its supply for a total of 2000uf of capacitance when not in rewind.

I removed the amp again and removed C131. I found leakage under it and one of the leads pulled out while desoldering. I cleaned the circuit board of the leakage as best I could as that stuff can be corrosive and electrically conductive. The nearest cap I had for replacement was 1000uf at 80 VDC, which I installed. It's a bit taller than the original cap but does not interfere with the flywheel.

The replacement of C131 remedied the voltage droop during rewind and the delay circuit gives full voltage to the mag clutch for full torque after about 3 seconds. I suspect C131 was presenting no capacitance but it's impossible to test it now since one of the leads pulled out.

well done paul , had very similer problems with one of my bell and howell 16mm 1568 projectors, always
a process of elemination

Maybe something the cl owners didn't know, the GS 1200 leatherette cover fits this machine perfectly, not sure if there was a cover specifically made for it by Elmo, but this is a great fit .......