Found: 38-690 Volume Control - Printable Version

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+--- Thread: Found: 38-690 Volume Control (/showthread.php?tid=20769)

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Found: 38-690 Volume Control - tbone - 12-27-2019

When received, my 38-690 had a replacement dual pot volume control. The issue I have is that the volume cranks up loud really fast with the control just cracked. I suspect the pot was replaced with a linear taper instead of audio taper.

Can you confirm how sensitive the volume control should be when starting from all the way down?
If what I suspect is really the case, I’ll look for a replacement through an add or Mark Opatt.

Thank you.

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RE: 38-690 Volume Control - Radioroslyn - 12-27-2019

What you can do is set the control @ the center of it's rotation and measure the resistance from the wiper to each end. If it's about the same it's a linear taper.

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RE: 38-690 Volume Control - tbone - 12-27-2019

I measured both pots and they are roughly equal to wiper on each side when centered. I guess that answered my question. Before I start looking for one, would both pots be audio taper? My gut says yes.

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RE: 38-690 Volume Control - Nathan Slingerland - 12-27-2019

According to the service info the original part is 33-5240.

There's a previous discussion of that part here:
https://philcoradio.com/phorum/showthread.php?tid=13625

Quote:Part #75 is 500K and part #76 is 100K, for the dual pot.

No mention of the taper type but I'd bet on audio taper too (it is a volume control after all).

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RE: 38-690 Volume Control - tbone - 12-27-2019

Thank you guys for your help. I’ll start searching. The radio works, just has a volume control that’s too sensitive.

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RE: Found: 38-690 Volume Control - tbone - 12-28-2019

Mark Oppat is making one up for me.

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