Need some help finding a replacement potentiometer for an older piece of equipment
Sep 26, 2010 at 3:27 PM Thread Starter Post #1 of 7

HiGHFLYiN9

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So I picked up a cute antique radio and was pleasantly surprised to find that it still works fairly well. Unfortunately, the potentiometer has seen better days, and is incredibly scratchy during normal operation. It's a mono pot that also powers up the radio on when initially turned. Rating is 100K, 3A @ 125V, 1A @ 250V. CTS made it, but it doesn't look like they offer the same item any longer. 
 
This is inscribed on the pot: VRS-100K-70S   137.6932
 
Below are photos, any suggestions for a decent replacement? Thanks in advance.
 

 
 

 
 
 

 
Sep 26, 2010 at 4:08 PM Post #2 of 7
Before you replace the pot, give it a shot of ProGold or a similar lubricant.  You'll find it at Radio Shack, electronic hobbyist stores and it can be ordered online.  It will lubricate and protect the pot - you'd be surprised at how seemingly bad pots come right back to life.
 
Sep 26, 2010 at 8:37 PM Post #4 of 7
Nice find! That may be what the doctor ordered.
 
I'm considering, for the sake of using better quality parts, relegating the switch function to the back of the unit with a SPST toggle and use a standard slotted $6 Alps up front. A couple of the capacitors are looking like they've seen better days, so I figure I'll swap them out of there while I'm working on it. If I feel like wasting another $50, I may put a nice 5" full range driver in there and make the unit really worth listening to. 
 
Sep 26, 2010 at 8:44 PM Post #5 of 7
I like the second bet to use a separate switch...
I found LOTS of switched 100Kohm pots at mouser, but the switches were only rated for 12-24v
frown.gif
 
 
Keeping the AC mains away from the pot cant hurt hum either
smily_headphones1.gif

 
Oct 2, 2010 at 7:54 AM Post #6 of 7
Soild state or tube based "cute antique radio"?
 
Quote:
I like the second bet to use a separate switch...
I found LOTS of switched 100Kohm pots at mouser, but the switches were only rated for 12-24v
frown.gif

 
Keeping the AC mains away from the pot cant hurt hum either
smily_headphones1.gif

 
 
I also agree with the separate pot and power switch.  Easier to find new pots and more quality options.  I've seen older pots with wattage ratings as well (with and without power switches); make sure it is of the same wattage or higher if labled.  I think it matters more for tube radios.
 
That's to say it's in great condition, and parts are updated.  My tube radio is in such a state that it's imposible to hear hum.  ;P

Thanks OP you've reminded me I need to place my crappy pot on my tube radio.
 
Oct 2, 2010 at 2:31 PM Post #7 of 7
It's solid state, but I really liked the looks of it, so I was able to overlook such a glaring fault
wink.gif
I decided to go with the separate throw switch and a pair of mono alps, one for the volume and one for the tone control.
 

 
 
I snagged one of these to replace the crusty old speaker:
 

 

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