Several radios have scratchy volume controls and I know a little bit about what causes this, but it can be annoying when trying to set a radio for just the right volume level.
When rotated a typical volume control, or "pot", which stands for potentiometer (I think the "potentio" part of the word is an abbreviation for "potential"), drags a "wiper" or "slider" over a resistor/resistive surface, thus varying the impedance and so the volume level. It's when the slider makes imperfect contact with the surface the audio can momentarilly drop out or jump to a high level that offends the ears.
Dirt and grime can build up inside pots, or a cheap part might have imperfect contact. Better pots are sealed and cannot be opened.
At least one radio I have has a cheaper "linear" pot as compared with the better "audio taper" pot, and is almost impossible to set for a low level.
Pots can be disassembeled and cleaned, but it's been years since I knew what chemicals are best, and other chemicals might be harmful.
Another cause of noisy controls might be capacitors that build a charge which discharges across the wiper as it's rotated, resulting in pops and static.
What experience have you had?
I've used something called DeOxit (there appear to be several manufacturers using the same name) with good results.
A shot of this into the offending component generally cleans it out, lubricates it and eliminates problems.
Sounds right...
I've got some DeOxit, use it to clean off plugs and contacts. Alright, I'll try it on the scratchy pots.
Neil Radio8Z has spoken highly of DeOxit.
It's not the same as the stuff used to hide the oil spill in the Gulf.
The only chemical which I have used which produced lasting results was carbontetrachloride but this is no longer available because our leaders have decided we might hurt ourselves with it.
Products with lubrication will work for a while but the lubrication will attract and hold dust and dirt recreating the problem.
The problem with scratchy pots can be caused by dirt but it is more likely that they are just worn out.
It is worth a try however.
Neil
We use this at work but be careful. It'll destroy certain plastics but is usually safe on most pots. Check the MSDS.. 😉
I have a product called NU-TROL control cleaner with lube in it....works good, made by MG chemicals.
Plain 99% alcohol from any drug store will work fine too.
Alcohol (isopropyl and ethanol) is not a good choice for cleaning electronic equipment since it reacts with solder and other metals leaving a white residue.
1,1,1 trichloroethylene is a good choice for flux cleaning but it also has been removed from retail shelves.
Fluorocarbon based compounds are available but they do not seem to be very effective.
Potentiometer noise can result from wear on the resistance material and wear on the moving slider contact as well as from accumulated dirt. Removing the dirt will help but this will not repair the wear and the life of the pot is only extended a bit by cleaning.
Neil