[Amps] Stuck setscrews

[Victor Rosenthal 4X6GP]

I have an older Palstar AT-Auto tuner. It uses stepper motors to turn a 
rotary inductor and a capacitor. It works very well in my station (or it 
did).

The motors are connected to the coil and capacitor with semi-flexible 
insulated couplings that are made out of some kind of plastic strip. The 
plastic on the one for the capacitor has disintegrated. I have a good 
quality metal and ceramic coupling to replace it with, but I can't budge 
the setscrews holding the old one. Allen wrenches twist to no effect.

The screws are held with some kind of glop. I don't think it is Loctite 
but I don't know for sure. I put some penetrating oil on them and am 
waiting to see if that works.

I suppose I could drill them out if needed, but that is a last resort 
because I am afraid of damaging the motor or the capacitor. Any suggestions?

-- 
73,
Victor, 4X6GP
Rehovot, Israel
Formerly K2VCO
http://www.qsl.net/k2vco/