is it possible to take the cover off of the volume control and clean it up on the philco 70 there is a cap on the back and i am not shure if there are parts that will fall out of place
benny

It should be fine to do that, no loose parts, unless it's broken... Also, make sure you replace it in the same orientation as before.

I am thinking that on mine, being an early non AVC model, that it consists of two wirewound pots. Not carbon. Mine has an issue that it must have a bad wire bond at one end as if you turn it all the way to the stop at min, sometimes it will intermittently open up one end of one of the pots and cause excessive gain and distortion. But wiggling the wiper brings it back to life at the bond or whatever. Since the power switch is seperate, I just do not turn the control to full min. anymore, as that is well below where the output fades out. You could probably clean it with isopropyl alcohol. That is how I cleaned up some dirty wirewound rheostats in the past. Either disassemble and wipe the wire edges with Q tips and alcohol, or at least get it inside the rheostat wet with alcohol and work the wiper back and forth a bunch. Then let it dry out. The wiper may be (may) something like phosphor bronze and might oxidise besides crud buildup on the resistance wire wrap.

WD-40

WD 40 in a wirewound rheostat? Explain.

WD 40 in a wirewound rheostat? Explain.

Ok ..... take the back off the control . Pick up a can of wd-40 and point the red extension hose into the control and give it a real small short blast of wd-40 , work the control around a few times and wipe up any wd-40 that may have run out to keep things tidy . Replace the back of the control and enjoy the nice working control .

Does your radio have a DUAL pot for the volume control, or a single pot? As has been mentioned, the dual pot is used in the EARLY non-AVC version of the radio. The single pot is used in the later version. The disassembly and cleaning/repair processes are different for each one. My restoration log for a EARLY Philco 70 goes through the disassembly and repair of a DUAL wire-wound control in detail (the rear section was open). http://mcclellans.com/Philco70BRestoration.htm. This does NOT apply to the later version.

-1 on WD40

Properties of WD 40:

FunctionThe long-term active ingredient is a non-volatile, viscous oil which remains on the surface, providing lubrication and protection from moisture. This is diluted with a volatile hydrocarbon to give a low viscosity fluid which can be sprayed and thus penetrate crevices. The volatile hydrocarbon then evaporates, leaving the oil behind. A propellant (originally a low-molecular weight hydrocarbon, now carbon dioxide) provides gas pressure in the can to force the liquid through the spray nozzle, then itself diffuses away.

These properties make the product useful in both home and commercial fields; lubricating and loosening joints and hinges, removing dirt and residue, and extricating stuck screws and bolts are common usages. The product also may be useful in displacing moisture, as this is its original purpose and design intent.

Probably not the best for electrical contacts.
David.

I have used deOxit and WD-40 for years. Used to clean the encoders on CNC machines with Freon and then shoot them with WD-40 (recommended for contacts in electronic sensors and limit switches by Boston Digital Corp).