I disconnected the wiper from the wiring on a Philco Mod 80 and hooked up my ohm meter to the antanna wire (input) and the wiper arm post.

When fully counterclockwise, I read 18K (schematic calls for a 20k, so this looks good). As I start to turn clockwise, I go to 1.7M at about 1/8 turn and thereafter an open until fully clockwise, there I get about 6 ohms. Is this a bad control? I took it apart and cleaned it up. There was a lot of carbon that wiped off when I did that. Maybe it was all that was left of the original surface. I havent seen one of these before so I dont know.

It looks to me that the control is inoperative? The radio plays when at full clockwise position, but only one channel and no others.

In this type circuit, would the volume control cause this?

Thanks for the help.

:I disconnected the wiper from the wiring on a Philco Mod 80 and hooked up my ohm meter to the antanna wire (input) and the wiper arm post.
:
:When fully counterclockwise, I read 18K (schematic calls for a 20k, so this looks good). As I start to turn clockwise, I go to 1.7M at about 1/8 turn and thereafter an open until fully clockwise, there I get about 6 ohms. Is this a bad control? I took it apart and cleaned it up. There was a lot of carbon that wiped off when I did that. Maybe it was all that was left of the original surface. I havent seen one of these before so I dont know.
:
:It looks to me that the control is inoperative? The radio plays when at full clockwise position, but only one channel and no others.
:
:In this type circuit, would the volume control cause this?
:
:Thanks for the help.
:

In your radio, this potentiometer is used in the antenna circuit to couple the signal from your antenna into the front end of the receiver.

This could be at least part of the problem with your set.

If the pot reads around 20K from each end, it could the the center lug connections to the wiper arm. Sometimes it's the rivet that's not making a good connection.

I did jump the antenna to the wiper arm and I still only get one channel. I do think this pot is bad, so I will probably change it out. In the meantime I have to figure out why I cannot get any other stations. I have a lot of strong channels in my area, so I am not sure why I can only get one.

The oscillator connections are all ok. But the trimmers have no effect.

:If the pot reads around 20K from each end, it could the the center lug connections to the wiper arm. Sometimes it's the rivet that's not making a good connection.
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