I'm seeking help in identifying this potentiometer in order to find a suitable replacement and/or to understand its pinout. It is a thumbwheel volume control from a circa 2005 external computer speakers control. unknown audio thumbwheel potentiometer The measure top of frame is in millimeters. The upper tabs were soldered, but I'm pretty sure they were only for mechanical support against the PCB.

The thumbwheel diameter is ~20mm, the manufacturer mark seems to be Delta, and through the oval window is the designation "C103." Difficult to see in the lighting, but it's C103.

I would take ohm readings between the pins, but this is the part that failed, so I do not trust any readings I get. I have looked on Digikey and of course I see many potentiometers, but most with three contacts and some with six -- but I cannot find one with five contacts. Can someone suggest what might be a suitable replacement for this, or what exactly this is so that I can find a datasheet that explains the pinout?

EDIT: Questions in comments addressed:

  1. This is not an on-off switch. The unit is switched on and off using a toggle pushbutton located elsewhere on the PCB. That switch works properly.

  2. I do not think this is an encoder; the thumbwheel rotates through about 300°, not quite a full revolution. When it worked properly, volume increased steadily from one extreme of rotation, from silent to full volume. There were no audible "steps." It failed slowly. At first, there was a loud popping and static when adjusting volume. Then fewer settings would work. Then no adjustment was possible and only a particular setting worked. Finally, I was moving stuff around on the desk and it moved again, and I was unable to ever find the "working spot" again.

I'd love to fix this because I really like the sound from this old external speaker -- the bass/subwoofer is particularly good for its size and price.

  • \$\begingroup\$ Are you sure it's a potentiometer and not an optical encoder? Those are often 5 pins and the company "Delta" makes them, although I don't readily see this form factor. An encoder won't show a variable resistance between pins but rather abrupt connect/disconnect events as the dial is turned. What's the failure mode of the part? \$\endgroup\$
    – td127
    Feb 22, 2022 at 1:34
  • \$\begingroup\$ look carefuly inside the oval window ... you can see the purpose of each pin ... the component probably contains an on/off switch \$\endgroup\$
    – jsotola
    Feb 22, 2022 at 2:16
  • \$\begingroup\$ Did you try a contact cleaner such as DeoxIT, it may just be oxidized / dirty contacts on the pot tracks. \$\endgroup\$ Feb 22, 2022 at 22:06
  • \$\begingroup\$ @ColinKenworthy Too late for that... hard to see from this photo, but I had to clip the part loose to see the identifying information shown. But a good suggestion, had I not had to destroy the part to get it off and identify it. \$\endgroup\$
    – TomServo
    Feb 23, 2022 at 3:06

3 Answers 3


Digikey has this part, which looks similar:

enter image description here

Do the sizes and pin locations match?

enter image description hereenter image description here

103 is almost certainly a 10k pot. You can try checking the rough resistance values, or if you can crack off the knob, you can likely infer the topology from the resistive layer geometry. enter image description here

If this isn't an exact match, hopefully it provides a starting point for further search, and an idea what the five pins might be doing on a pot.

  • \$\begingroup\$ Although the part you referred to it out of stock and obsolete, the diagrams are most helpful and deserving of the accepted answer, thanks! Now I have options. \$\endgroup\$
    – TomServo
    Feb 22, 2022 at 13:02

It's a dual 10K, common-ground potentiometer also known as

'103 Gear Potentiometer'.

enter image description here


The magic words to search for are: volume wheel duplex potentiometer

You may find one like this, which is discontinued: Artou 14*2mm Double Gear Tuning Potentiometer C103 10K 5Pin Dial Potentiometer found on AliExpress.


Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.