Other than swapping the pot with another one that you know is good, the only easy way to detect bad spots reliably is only if there is an actual dead spot in the control. You could try to applying a fixed tone audio source across it, and a scope on the tap, and see what the waveform looks like.
:I'm working on a 1941 Emerson radio that seems to have a bad volume control, though I'm not positive it's the problem. As you tap the potentiometer, the clarity of sound pops in and out. As you turn it, there is a scratchy noise. There is negative voltage on both sides. Does anyone know if a way to test it without replacing it?
:Hi,
:Try some tuner cleaner, or LPS 1 and see if that will remedy the situation- Many times that is all that is needed.
:
:Other than swapping the pot with another one that you know is good, the only easy way to detect bad spots reliably is only if there is an actual dead spot in the control. You could try to applying a fixed tone audio source across it, and a scope on the tap, and see what the waveform looks like.
:
:
::I'm working on a 1941 Emerson radio that seems to have a bad volume control, though I'm not positive it's the problem. As you tap the potentiometer, the clarity of sound pops in and out. As you turn it, there is a scratchy noise. There is negative voltage on both sides. Does anyone know if a way to test it without replacing it?
:I gave it a shot of WD40, and it cleaned up almost instantly! The old radio is working great. Thanks for the advice.
If you do not use it regularly, or have another lubricant/solvent mixing with it over time, WD40 over time will turn into a hard brown crust.
Which is why I switched to LPS 1.
::I've been in TV/Radio repair since 1969 and found over the years that WD40 is by far the best tuner/control cleaner.
:
::I gave it a shot of WD40, and it cleaned up almost instantly! The old radio is working great. Thanks for the advice.
:Hi,
:I got away from using WD40 a long while ago when I heard why Convair- Who held the original patents stopped using it altogether.
:
:If you do not use it regularly, or have another lubricant/solvent mixing with it over time, WD40 over time will turn into a hard brown crust.
:
:Which is why I switched to LPS 1.
:
:
:
:::I've been in TV/Radio repair since 1969 and found over the years that WD40 is by far the best tuner/control cleaner.
::
:::I gave it a shot of WD40, and it cleaned up almost instantly! The old radio is working great. Thanks for the advice.
The same company that produces 3 in 1 oil.
Actually, WD-40 is not intended as a penetrating oil, although it is used that way many times. It is not really good as a long term lubricant, nor intended for that purpose either, as the lightweight aromatics are about as volatile as kerosene and evaporate almost as fast. It does evolve from oil to tar- but the rate of transition does vary due to the environment. I have used WD-40 on many things with no problem, but I had used it as the vehicle for polishing the rust off of a saw table, it was the only liquid used, I had mixed it with a little bit of furniture grade pumice, then wiped everything clean, and sprayed the surface clean, and left a thin layer- I had set a flat metal plate on that saw table- Two weeks later that metal plate was firmly glued to the saw table with dark brown tar of WD40 residue.
It is that kind of inconsistency that can turn on you at inoportune times. LPS 1 has it's own drawbacks, but not with the potential problems that WD-40 can cause.
If you have not had a problem up to now, that is great, but there is always that chance you may have a problem tomorrow with it.
:I've never had any problems with it. I used it on my 1973 Sherwood stereo over 10 years ago and the switches and controls are like new. I've also never had any problems with anything else I've used it on, and I've been using it for about 15 years. Most of the other cleaners I've used lasted only 2-3 years tops. But it's crap for hinges, etc.... You make it sound more like 3 in 1 oil (first it's oil, then it turns to grease, then it turns to glue).
:
::Hi,
::I got away from using WD40 a long while ago when I heard why Convair- Who held the original patents stopped using it altogether.
::
::If you do not use it regularly, or have another lubricant/solvent mixing with it over time, WD40 over time will turn into a hard brown crust.
::
::Which is why I switched to LPS 1.
::
::
::
::::I've been in TV/Radio repair since 1969 and found over the years that WD40 is by far the best tuner/control cleaner.
:::
::::I gave it a shot of WD40, and it cleaned up almost instantly! The old radio is working great. Thanks for the advice.