There seems to be a dead spot about midway between "low" and "high" in the volume control of a Philco 70 that I am repairing. Does anyone know what would cause this and whether the control can be opened up and cleaned or repaired? Thanks

:There seems to be a dead spot about midway between "low" and "high" in the volume control of a Philco 70 that I am repairing. Does anyone know what would cause this and whether the control can be opened up and cleaned or repaired? Thanks
:
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Could be just dirt, or the pot track could be damaged at that point. These controls are not really repairable if a shot of pot cleaner spray doesn't help. Fortunately, similar replacement pots are available.

You may be able to take the pot apart and reposition the wiper arm to avoid the "dead spot". Not all pot types are amenable to this, but it might be worth a shot.

::There seems to be a dead spot about midway between "low" and "high" in the volume control of a Philco 70 that I am repairing. Does anyone know what would cause this and whether the control can be opened up and cleaned or repaired? Thanks
::
:= = = = = =
:
:Could be just dirt, or the pot track could be damaged at that point. These controls are not really repairable if a shot of pot cleaner spray doesn't help. Fortunately, similar replacement pots are available.
:
:You may be able to take the pot apart and reposition the wiper arm to avoid the "dead spot". Not all pot types are amenable to this, but it might be worth a shot.
:
The fact that it is a dead spot, rather than suddenly going from zero to full volume is good news, that means that the carbon does not have a crack in it. If the pot is not easily taken apart, a small hole drilled in it may allow you to scoot some contact cleaner into it and fix the dead spot. A dab of epoxy, solder or super glue will seal the hole, and it may not give trouble for years. Then, again it might. You are working in an area where there ain't no rules.
lewis

:::There seems to be a dead spot about midway between "low" and "high" in the volume control of a Philco 70 that I am repairing. Does anyone know what would cause this and whether the control can be opened up and cleaned or repaired? Thanks
:::
::= = = = = =
::
::Could be just dirt, or the pot track could be damaged at that point. These controls are not really repairable if a shot of pot cleaner spray doesn't help. Fortunately, similar replacement pots are available.
::
::You may be able to take the pot apart and reposition the wiper arm to avoid the "dead spot". Not all pot types are amenable to this, but it might be worth a shot.
::
:The fact that it is a dead spot, rather than suddenly going from zero to full volume is good news, that means that the carbon does not have a crack in it. If the pot is not easily taken apart, a small hole drilled in it may allow you to scoot some contact cleaner into it and fix the dead spot. A dab of epoxy, solder or super glue will seal the hole, and it may not give trouble for years. Then, again it might. You are working in an area where there ain't no rules.
:lewis
:
OK. I'll give it a shot of cleaner and see what happens. By the way, the schematic for the 70 doesn't seem to give a value for the volume control. If I need to replace it, what am I looking for? Thanks

:OK. I'll give it a shot of cleaner and see what happens. By the way, the schematic for the 70 doesn't seem to give a value for the volume control. If I need to replace it, what am I looking for? Thanks
:
= = = = =

Is this an "early" or "late" model 70? The early sets had tandem-linked pots, one in the antenna circuit and one in the tube-bias circuit. This was superseded by a single pot in the input to the first audio.

::OK. I'll give it a shot of cleaner and see what happens. By the way, the schematic for the 70 doesn't seem to give a value for the volume control. If I need to replace it, what am I looking for? Thanks
::
:= = = = =
:
:Is this an "early" or "late" model 70? The early sets had tandem-linked pots, one in the antenna circuit and one in the tube-bias circuit. This was superseded by a single pot in the input to the first audio.

It's a single pot. The good news is that I was able to shoot some cleaner into it, and that resolved the problem. I'd still like to make a note of its value. Thanks
:

I assume you know this but.....Disconnect the wiring to the pot and measure ohms across terminals.

:It's a single pot. The good news is that I was able to shoot some cleaner into it, and that resolved the problem. I'd still like to make a note of its value. Thanks

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250K-500K audio taper should work fine. Exact resistance value is not critical for audio-stage pots.

:
: :It's a single pot. The good news is that I was able to shoot some cleaner into it, and that resolved the problem. I'd still like to make a note of its value. Thanks
:
:= = = = = = = =
:
:250K-500K audio taper should work fine. Exact resistance value is not critical for audio-stage pots.
:

::
:: :It's a single pot. The good news is that I was able to shoot some cleaner into it, and that resolved the problem. I'd still like to make a note of its value. Thanks
::
::= = = = = = = =
::
::250K-500K audio taper should work fine. Exact resistance value is not critical for audio-stage pots.

Thanks for the info.
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