I’m looking for a part ID / source for this potentiometer with built in push-pull switch (3 clear pictures attached). It has markings that say “/ LM3089” and “R137482” stamped into the metal case of the potentiometer, and “K UND. LAB. INC. LIST 3A. 125V. A.C.” molded into the back of the housing of the built-in switch. It is the stock master volume knob and channel 1 / channel 2 switch on an old guitar amplifier. Struck out with the usual searches, thanks a million for any help!
Hello mccormick.mark,
Welcome to the DigiKey TechForum.
I’m not sure what potentiometer that is. I found some that have the Push-Pull type switch within them with either DPDT or SPDT that are push-pull or push-push type as in the link below.
Rotary Potentiometers, Rheostats | Potentiometers, Variable Resistors | DigiKey
Do you have any specs on the potentiometer? Like the resistance, wattage, type of taper?
Regards,
Hey Irfan thanks a million for the help! This is a push-pull switch, looks to be spst, and the pot is used as a volume knob so I’m betting it’s an audio taper. If I can’t figure it out from the markings in the next day or two I’ll unsolder it and measure the taper and resistance on the pot and I’lll reply again in case you know of an equivalent all-in-one spst push-pull pot with a matching resistance and taper. If I absolutely have to I can just add a 3a 125V AC rated spst toggle and a regular pot at that point, but I’m hoping to avoid new holes in this control panel. Thanks again very much.
UND. LAB. INC. is an old way of saying “Underwriter’s Laboratory”, and the LIST points toward this being an IRC brand potentiometer. While I’ve found several listings on eBay that are similar to yours, I have not been able to find an exact match.
Maybe this info will be helpful to you in finding a replacement pot/switch. We definitely don’t like drilling holes in our amps!
Good luck!
EDIT: Just out of curiosity, what is the make and model of your amp?
Thanks a million!
Hi slycer2002, mccormick.mark,
I believe it’s correct about the “UND. LAB. INC.” meaning "Underwriter’s Laboratory”. However, the “LIST” almost certainly means “Listed”, meaning it’s an Underwriters Lab Listed part. That’s basically just a blessing given by UL to the switch as to meeting its standards.
I’m pretty certain it’s a CTS brand part, as indicated by the circled portion of the back of the switch:
Unfortunately, I think CTS usually lists the resistance value on the rear of the potentiometer portion of the body, which is obscured by the black switch body behind the potentiometer in this case. If it is non-functional, then perhaps the part could be dissected (separate the switch section from the potentiometer section) to see if it is indeed printed on the back of the potentiometer body.
Regardless, though I can’t say with any certainty at all in this case, I believe that a fairly large percentage of such parts used in audio applications will be 10k log-taper parts.
I will say that I found a few very similar looking parts on Google by searching the following string:
“cts audio potentiometer with switch”
If you don’t have any luck finding the original part or an identical alternative, then hopefully you could find something among the parts that @Irfan_Koric linked above.