[Phlogiston]

Use the Deoxit for plastic (green) the gold stuff can clean the conductive coating right off.

DeoxIT D5S-6 spray - seems to be the "red stuff"; there is also "Gold" (G5) and F5 - "Green stuff".

So, which one? Green?

Actually, only Gold and Red have the word "contact" in their names.

I think "F5" (green) is the one, as it is for "Conductive Plastics".

Yes, that is the safest one to use, especially on old Philcos. If you are SURE that it is a wire wound you can use the gold #5.

[morzh]

Wire-wound is easily told from graphite. It is, well, wire-wound.

Yesterday I bought the D5S-6 DeoxIT and opened up my volume control.
As I don't have any Varsol, I used some undiluted isopropyl alcohol to clean the surface. The Q-tip came out fairly black each time (alcohol does not dissolve graphite or the substrate), so at some point I stopped, and re-measured the resistance of the scale, and it did not change; so I applied DeoxIT, one short small blast, worked it with moving the regulator back and forth, waited, applied a second blast, waited few minutes for it to dry a bit (it won't dry all the way, no matter how long you wait).

Then, as I was told by Codefox, I mixed some WD40 and Lithium, and with a toothpick applied a little and worked it moving the wiper.

Then I re-assembled the potmeter.

Result: for the most part the scratch (it was not egregious in the first place) has disappeared.
However when cleaning, I noticed that the part at the one end of the scale (minimum volume) is fairly worn down, showing discolored large spot, where the graphite is almost absent; this part still produces scratch, and no amount of DeoxIt, I think, will be able to remove this.

That's fine with me.

[Phlogiston]

Wire-wound is easily told from graphite. It is, well, wire-wound.

Yes, but some people spray first and look later.

[Pepperoni]

I've been following this post because of the Philco 90 I'm almost done with. My volume control has stamped right on the back "DO NOT OPEN". Of course they were possibly being cautious but I don't even see a way to get it open unless by prying around the edges. Mine will be ready for power today or tomorrow so I don't even know if I have a volume control problem. But what is Philco trying to warn me about with the words "DO NOT OPEN"?

Pepper

[morzh]

Well....none of these potmeters were supposed to be ever opened. It is formally not consider "repairable" part; it is a resistor and it is replaced when going bad.
Some of them had some ways of being cleaned, some did not, but other than spraying "blue shower" in a hole that was it.

But people with some dexterity, of course, can open them up and fix them, if at all possible.

I would say, first, when ready, power it up and see if it works at all. A volume control is not something that is going to kill anything.
Then you will see if you have problems with volume adjusting.

For instance, my potmeter in my 80 Jr. is beyond repair - there is a bald spot, right where the minimum volume should be. No amount of Deoxit will fix that.

[Chuck Schwark]

Well....none of these potmeters were supposed to be ever opened. It is formally not consider "repairable" part; it is a resistor and it is replaced when going bad.
Some of them had some ways of being cleaned, some did not, but other than spraying "blue shower" in a hole that was it.

But people with some dexterity, of course, can open them up and fix them, if at all possible.

I would say, first, when ready, power it up and see if it works at all. A volume control is not something that is going to kill anything.
Then you will see if you have problems with volume adjusting.

For instance, my potmeter in my 80 Jr. is beyond repair - there is a bald spot, right where the minimum volume should be. No amount of Deoxit will fix that.

I've never heard "potmeter" used as a slang or contraction for "potentiometer" before. Is it regional? Just curious...

Chuck

[morzh]

Well....none of these potmeters were supposed to be ever opened. It is formally not consider "repairable" part; it is a resistor and it is replaced when going bad.
Some of them had some ways of being cleaned, some did not, but other than spraying "blue shower" in a hole that was it.

But people with some dexterity, of course, can open them up and fix them, if at all possible.

I would say, first, when ready, power it up and see if it works at all. A volume control is not something that is going to kill anything.
Then you will see if you have problems with volume adjusting.

For instance, my potmeter in my 80 Jr. is beyond repair - there is a bald spot, right where the minimum volume should be. No amount of Deoxit will fix that.

I've never heard "potmeter" used as a slang or contraction for "potentiometer" before. Is it regional? Just curious...

Chuck

I have no idea, Chuck. I picked it up while working here in the US and acquiring the local terminology (did not know it before - in my language it is a "poh-ten-tsi-oh-meh-tr", potentsiometr, if you transliterate) from speaking to sales folks or some engineers I worked with. Wouldn't remember where and when - but I've heard it more than once since, along with "pot". When I use it, it never creates any misunderstanding, so I assumed it is known well enough. "Potentiometer" for me is a bit of a tongue-breaker, and "pot"...suggests something different than a variable resistor

[Chuck Schwark]

Well....none of these potmeters were supposed to be ever opened. It is formally not consider "repairable" part; it is a resistor and it is replaced when going bad.
Some of them had some ways of being cleaned, some did not, but other than spraying "blue shower" in a hole that was it.

But people with some dexterity, of course, can open them up and fix them, if at all possible.

I would say, first, when ready, power it up and see if it works at all. A volume control is not something that is going to kill anything.
Then you will see if you have problems with volume adjusting.

For instance, my potmeter in my 80 Jr. is beyond repair - there is a bald spot, right where the minimum volume should be. No amount of Deoxit will fix that.

I've never heard "potmeter" used as a slang or contraction for "potentiometer" before. Is it regional? Just curious...

Chuck

I have no idea, Chuck. I picked it up while working here in the US and acquiring the local terminology (did not know it before - in my language it is a "poh-ten-tsi-oh-meh-tr", potentsiometr, if you transliterate) from speaking to sales folks or some engineers I worked with. Wouldn't remember where and when - but I've heard it more than once since, along with "pot". When I use it, it never creates any misunderstanding, so I assumed it is known well enough. "Potentiometer" for me is a bit of a tongue-breaker, and "pot"...suggests something different than a variable resistor

I, too, usually just use "pot" to describe a panel mount variable resistor.

Chuck

[LASJayhawk]

I pretty much use ACF50 on everything. Pots, tuners, stuck hardware, squeaky garage doors, hood hinges on the car, and yes aircraft.
Good stuff, pretty much the 8th wonder of the world.

http://www.aircraftspruce.com/catalog/cspages/acf50.php