Old Potentiometer Replacement Part


I’m a DIY Modular synth maker and have recently bought an old oscilloscope to measure audio waveforms with.

Problem is, the On/Off Potentiometer broke as soon as I brought it home and I’m having trouble finding the right replacement.

As you can see in the photos, the Oscilloscope is powered on via this potentiometer, which also controls phase amount.

Any advice on what piece to buy would be great as it’s involving mains power.



Hi Jack
I started to reply before but the post was deleted by author, now back again so here goes.

Pots with power switches seem to be pretty scarce these days. They were mostly used for volume control an would have been log curve (curve A). Yours appears to be linear (curve B). I think your best bet might be Element 14 but be prepared for a search as they stock a LOT of pots. The filters are good so you can usually narrow the search quite a bit.

If it is only the switch broken and the pot is OK an alternative would be drill a hole and mount a toggle switch to switch power on/off. Another method would be join the wires and switch at the power point.

Make sure it is only power being switched. Sometimes this could be a 2 pole switch and a “Spot killer” connection is switched also. This prevents a burn on the centre of the CRT when switching off.
Cheers Bob


Hi Jack,

Another thing to note about this project. I would steer well clear of any components that might have a high voltage across them, it might even be worth bringing it to a local repair shop to see if they tips.

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