The PHILCO Phorum

So my 112 has a type of volume control I have never seen before. Sort of a spring-loaded brass wheel running around inside a resistive metal band. I'm guessing that after 77 years it could do with a cleaning (though i have not heard audio through it yet...so maybe it is fine? it appears scratchy when i monitor its resistance with my multimeter).

So is there a good way to clean these? Should I just leave it alone?

Here is a picture of the workings:


Crazy Philco volume control by Audin, on Flickr

http://www.flickr.com/photos/audin/2367257525/

These were expensive but they avoided a rubbing contact to the resistance element.

I would unhook the spring, then back off the hex-head screw and remove the roller assembly. Then clean its outer surface with DeOxit or Bill Turner's substitute (chemically the same). Wipe any contamination off the resistance strip, and reassemble.

Uh-oh...I hear Caig's lawyer's cellfones ringing already.

Thank you!

Any idea what the resistance strip is made of?

I haven't taken one apart in years, but I expect graphite-coated paper.