37-630T Volume Control - Printable Version

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+--- Thread: 37-630T Volume Control (/showthread.php?tid=17698)

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37-630T Volume Control - Tucker - 12-25-2017

The schematic shows this radio using a 2 megohm volume control with a 1 meg center tap. I measure the resistance between the two outer lugs and I see 3 megohms on my meter. When I measure between the center and an outer lug I see 1.5 megohms and it goees down to .7 meg with the control all the way clockwise (full volume) position.
is this poteniometer ok ?  While cleaning the track I noticed one spot that appears rough while the remainder is smooth.

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RE: 37-630T Volume Control - Radioroslyn - 12-25-2017

With the shaft facing towards you and the 3 closest terminals pointing downward. Connect your ohm meter to the two terminals to the left. With the shaft turned all the way ccw you should read pretty close to 0 ohms (shorted). This is typically were most of the wear happens and is the failing point. Turn the shaft cw so it is in the half way position and you should read about 10% of the total resistance in your case 300K. With the shaft turned full cw should read the full resistance of 3M. Best to use an analog meter as worn spots with cause the needle to jump around.

GL

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RE: 37-630T Volume Control - Tucker - 12-26-2017

With the shaft all the way ccw I don't get zero ohms, I'm reading 99 ohms. All the way cw I get 3.1M. On the analog meter the needle moves smoothly. Should I replace this control ?

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RE: 37-630T Volume Control - morzh - 12-26-2017

You almost never get 0 ohm. 99 ohm is very good.

As for 3M i/o 2M, I'd test it befor getting it condemned: it is likely to work.

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