Who the heck makes these? They're junk!
The original pot is a two-terminal jobbie in the cathode ckt, unlike the three-terminal voltage divider style used in many radios. If you hook up the the wiper and the counter-clockwise terminal, the control works backwards from the conventional direction - i.e., CCW for higher volume. So, you have to use the other terminal, plus the wiper terminal. But, then, an audio tapered pot is tapered in the wrong direction, causing the volume control to be extremely touchy.
I used a 100-K linear taper pot, and it worked better, but still somewhat touchy.
I disassembled the original Centralab pot - it was more-or-less an audio taper, but tapered in a different direction.
The original pot was 75K, I think. You might get a better control range with a 25-K or 50-K pot and adding a series fixed resistor if necessary. I haven't tried that though.
Doug
:So I used one of those Radio Shack alpha pots in my Majestic. I didn't really know at the time that alpha stands for the audio curve type pot. When I turn up the volume in my Majestic, for a very small part of the rotation, nothing happens. Then the audio jumps up once, and then again. Then, for the rest of the rotation, the increase is smooth. Not knowing what I know now, I bought an audio taper pot from Radio Daze. Turns out that they sell the same thing Radio Shack sells. I took readings with my meter, and the pot stays at 0 for about 10 degrees. Then it jumps up to about 350 ohms. Then it jumps up to like 10,000 ohms in several very rapid jumps (like maybe 20 degrees of rotation total).
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:Who the heck makes these? They're junk!
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marv
:Thomas, I had a similar problem after replacing the volume control on my Majestic 90-B: http://www.nostalgiaair.org/PagesByModel/018/M0040018.pdf (I intitially used an Alpha 100-K audio taper which I bought from RadioDaze.)
:
:The original pot is a two-terminal jobbie in the cathode ckt, unlike the three-terminal voltage divider style used in many radios. If you hook up the the wiper and the counter-clockwise terminal, the control works backwards from the conventional direction - i.e., CCW for higher volume. So, you have to use the other terminal, plus the wiper terminal. But, then, an audio tapered pot is tapered in the wrong direction, causing the volume control to be extremely touchy.
:
:I used a 100-K linear taper pot, and it worked better, but still somewhat touchy.
:
:I disassembled the original Centralab pot - it was more-or-less an audio taper, but tapered in a different direction.
:
:The original pot was 75K, I think. You might get a better control range with a 25-K or 50-K pot and adding a series fixed resistor if necessary. I haven't tried that though.
:Doug
:
:
::So I used one of those Radio Shack alpha pots in my Majestic. I didn't really know at the time that alpha stands for the audio curve type pot. When I turn up the volume in my Majestic, for a very small part of the rotation, nothing happens. Then the audio jumps up once, and then again. Then, for the rest of the rotation, the increase is smooth. Not knowing what I know now, I bought an audio taper pot from Radio Daze. Turns out that they sell the same thing Radio Shack sells. I took readings with my meter, and the pot stays at 0 for about 10 degrees. Then it jumps up to about 350 ohms. Then it jumps up to like 10,000 ohms in several very rapid jumps (like maybe 20 degrees of rotation total).
::
::Who the heck makes these? They're junk!
::
T.