[audin]

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:

[Image: http://farm3.staticflickr.com/2220/23672...99fe_z.jpg]
Crazy Philco volume control by Audin, on Flickr

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

[Alan Douglas]

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.

[exray]

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

[audin]

Thank you!

Any idea what the resistance strip is made of?

[Alan Douglas]

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