Hi,

I did a bad bid on Ebay. I bought a Stark 9-66 in bad shape. Clean outside but a bit rusty inside. I know this tester will work with a lot of time spend on it.

But for now I have 2 ceased pots. The one for shorts and the one for bias. I tried electronic cleaner and lubricant. Usually it works, but not today. I can't turn any of these pots. And I do not want to break them by applying too much force.

What can I do?

Thank you.

I would start with penetrating oil on the shaft where it enters the threaded bushing, and give it a few days to work. If that doesn't free the shaft, you can remove the C-ring in front, and push the shaft out of the bushing. Clean it, lubricate and reassemble.

Ok, I will try. Thanks

I bought a Kodascope Model L about 5 years ago in practically mint condition (without case). However, all of the shafts were seized. The projector uses this innovative oiling system where you oil a trough and tubes (about 13 of them) carry oil to all of the bearings. Well, either this didn't work or someone forgot to oil it, because nothing would move. After trying all other methods, I finally resolved to using a torch on the bushings that wouldn't free up. Worked well. Once apart, I cleaned and oiled them, and the projector has been working well ever since (had to do some other work, too, like clean the commutator, replace belts, and replace the cork drive wheel--this I made myself from layers of cork contact-cemented together).

Anyway, if you can remove the potentiometer and soak with P-B Blaster, and if this doesn't free up the control, try heating the bushing with narrow torch flame or the barrel of a soldering iron strapped to it. Heat quickly, and try to avoid burning the phenolic or the resistance material inside. Heat the bushing until it smokes, and this will surely drive penetrating oil through it and break loose any solids.

T.

I used DeoxIT D5 on these pots and they are turning very well now.

Thanks DeoxIT! :)

:I used DeoxIT D5 on these pots and they are turning very well now.
:
:Thanks DeoxIT! :)
:The best penetrating oil I have found is Kroil made by Kano Laboratories. They make a line of products that work really well. Check their web site.
Martin