I have a RCA 9X561. It has a 2 meg volume control with a center tap. 400K on one side and 1.6M of the other side. Is there anyway to replace this with an ordinary 2M audio taper control?

Steve, this is a 4-terminal pot. The center tap has a R-C in series attached to it. This provides some tone compensation.

I would substitute a 3-terminal, 2-Meg, audio-taper pot and forget the center tap and R-C. This isn't exactly a high-fidelity set anyway. If you wind up not liking the tone at all, check back and somebody here can suggest a permanent cap installation that might help.

What's wrong with the original pot? Can you bring it back to life with a squirt of WD-40?

Doug, thanks for the reply. I cleaned the pot with Radio Shack contact cleaner. I guess I'll take the pot apart and see if I can bend the wiper. If I can't fix it I will replace it with a 2Meg pot. I would like to know if there is a better fix. Thanks again.
Steve

You might try fishing around on PTOP to see what you come up with: http://www.oldradioparts.com/ The problem is, even if you find a suitable pot, Gary has a relatively high minimum order.

Another possiblity is Mouser. There the problem is that they have everything organized by the manufacturer's name, so you can't just browse through "pots."

Digi-Key is, I think, less likely to have something like this, but you can try. They are easier to shop.

There are people who say they can successfully disassemble pots and fix them. They are better men than I, Gunga Din.

Thanks Doug. I printed in info. I don't post very often but I read the post everyday! I have learned from other post and print out stuff I might need later. Thanks again.
Steve

Steve, if all else fails you can take a 2Meg pot and open it up, rotate wiper to the ohms you need (care should be taken that you measure from the correct end of pot to the spot). Using the conductive paint for circuit boards bring out a lead from the carbon path and put a small brass nail through the phenol and the condutive paint out of the path of the wiper. You have to notch the tin body of the pot over the area where you made you attachment before you reassemble. You now have a pot with a tap at your desired ohmage. This is condensed, you have to solder a lead to the nail before you assemble as the heating may break contact with the paint, if that happens repaint only around the head of the nail to make the contact. If you have one of those small printed circuit board grommet tools you can attach a small terminal lug to the phenol instead of the nail. Those grommets are small enough that they won't interfer with the wiper. I used rear window defogger repair paint but it is thick and I ended up with a small "hiccup" as the wiper passes the tap. Pat

With a thin piece of plastic and some super glue, you could bridge a piece of circuit board to the side of the new control. Take a small strip of thin brass and super glue it to the extension after soldering a wire to the brass. Then paint the defogger paint out to the brass from the volume control resistor.

With the original control, try not to use WD-40. It may make matters worse, especially with a high impedance pot like that one. Bits of carbon eventually migrate through the WD-40, and form a leak path to the pot. housing, which will cause hum and tone problems. Instead, clean the control well with soap and water (control opened). Then wipe a thin film of dielectric grease onto the resistor. This can be found at an automotive store. If the control has a bad wear pattern, bend the wipers over to a fresh area. Make sure that they do not hit anything, and make sure that there are no sharp edges on the wipers that might damage the resistance material. If this doesn't solve your problem, try modifying a new control as per above.

Thomas

planigan, Thanks for the info. Sounds like a good idea. Volume control pots are cheep enough I will see if I can pull it off.

Thomas, I always use contact cleaner. Some in our club use WD-40. I don't trust it. Thanks for the tip on using dielectric grease.

Steve

I would suggest some copper tape used to repair pc boards, (has conductive glue), and conductive epoxy for a permanent repair. Notch the metal case as required, attach the tape to the edge of the resistive element away from the path of the wiper, and use the epoxy to make it permanent. Leave the tape rather long and slide insulation over it. Soldering heat may destroy the epoxy bond, so use a small heat sink just beyond the solder joint when connecting to circuit components.

marv

: Steve, if all else fails you can take a 2Meg pot and open it up, rotate wiper to the ohms you need (care should be taken that you measure from the correct end of pot to the spot). Using the conductive paint for circuit boards bring out a lead from the carbon path and put a small brass nail through the phenol and the condutive paint out of the path of the wiper. You have to notch the tin body of the pot over the area where you made you attachment before you reassemble. You now have a pot with a tap at your desired ohmage. This is condensed, you have to solder a lead to the nail before you assemble as the heating may break contact with the paint, if that happens repaint only around the head of the nail to make the contact. If you have one of those small printed circuit board grommet tools you can attach a small terminal lug to the phenol instead of the nail. Those grommets are small enough that they won't interfer with the wiper. I used rear window defogger repair paint but it is thick and I ended up with a small "hiccup" as the wiper passes the tap. Pat

Marv: Thanks for the reply. I have several options to try now. If I can pull one off I'll take the info to our club meeting.

Steve

Try to repair the original first, though. It may be salvagable.