I found that if I clean the volume control and it’s still intermittent, it helps if I connect a resistor from the center pin of the volume control to the ‘cold’ or common or ground end. The resistance was about 10 percent of the value of the pot. Say it’s a 5k pot, the resistor might be 560 ohms or less.
There are two kinds of malfunctions of volume control potentiometers. Both are caused by excessive wear on the resistive element. One malfunction is where the worn spot is causing the resistance from the center wiper pin to the cold or ground end to go higher when intermittent. This sounds like the audio is going from normal to louder. This is where using the resistor from center pin to cold end does the most good.
I connect a resistor from the center pin of the volume control to the ‘cold’ or common or ground end. The resistance was about 10 percent of the value of the pot. Say it’s a 5k pot, the resistor might be 560 ohms or less.
The other malfunction is where the resistance from the center pin to the pin on the hot end of the pot goes from normal to higher when intermittent. This sounds like the audio is going from normal to silent. This is where using a resistor from the center pin to the hot end of the pot does the most good.
I connect a resistor from the center pin of the volume control to the ‘hot’ or maximum volume end. The resistance was about 10 times of the value of the pot. Say it’s a 5k pot, the resistor might be 47k ohms or so.
The values of the resistors can be adjusted to cause the normal volume point on the pot to move to a new, unused good spot. This can reduce or stop the intermittence.
These changes take only a few minutes to do. It’s easy to do, and undo if needed. And it can save a lot of hassles of obtaining a replacement pot and replacing the original intermittent pot.
But probably the best thing about this is it can rescue a bad pot and avoids having to cannibalize some other radio to get a working pot, because it is often impossible to obtain an exact new replacement pot.
