Dual Gang Center Tapped Potentiometer

[stenzer]

Hi,

I'm repairing a Toshiba RT-SF1, where I have to replace the volume potentiometer. It is a 7 terminal dual gang linear 50kOhm potentiometer (50KBx2 from Alps). Both resistors have a fixed center tap (e.g. R_71 = 25k constant). Unfortunately it seems such potentiometers aren't available anywhere. Can anyone tell me where I can get this type of potentiometer?

BR

 

[BradtheRad]

Electrical contact cleaner works on some potentiometers but not all.
Even so that model looks so small and near-impossible to take apart and reassemble.
Its entire design looks so unusual it's not likely to find a replacement.

Consider putting in photosensors (cadmium sulfide type) which are covered and uncovered by the linear actuator. Illuminate the sensors with a single led. Adjust for matching response.

If a DC volt level were present you might instead consider some kind of dual transistor (fet, mosfet) volume control.

I can't figure the 7 pin arrangement. How many and which ones are ground. Signal In, signal out?

 

[stenzer]

Hi,

thank you for your input. Indeed, the pin-out is quite uniqe, I haven't seen this configuration before. I couldn't find thr service manual of the RT-SF1, so I checked a similar model, the RT-SF5. Here a snipped of the power ampliefer section, taken from page 12 (figure 21) can be seen.

Here also some clarification of the wiring of the potentiometer, it seems even the reference designators match between the models.

BR

 

[aliarifat794]

You can search here: https://tech.alpsalpine.com/e/products/category/potentiometers/

 

[stenzer]

You can search here: https://tech.alpsalpine.com/e/products/category/potentiometers/

I already did and I couldn't find a suitable replacement. The radio is from the 80s .