[jmfp702]

On a older technics tuner for house components when you adjust the volume and it crackles they say it is a "dirty switch" is there any way to fix this problem without having to track down parts for this ancient tuner?

[KISS]

Clean the control with contact cleaner. You can buy contact cleaner and lubercant at a hardware store and probably Radio Shack.

Then spray with WD-40.

You'll have to locate the opening to spray into. Some controls are sealed.

[DanielF]

A volume control (in older equipment) is not a switch; it's a variable resistor - it's technical name is a 'potentiometer', or 'pot' for short. Two things can cause them to become crackly ('noisy'): (1) dirt or contamination on the resistive element, or (b) DC current passing through the resistive element, usually as a result of the electrolytic capacitor that feeds it becoming 'leaky'. In ancient equipment, they are equally likely causes. (1) is relatively easy to fix, (2) is harder, so let's try the cure for (1) first. I disagree slightly with KISS's recommendations, though...

Firstly, we need to know whether your volume control is rotary or a slider. If rotary, you'll probably need to remove the equipment cover to get sufficient access to the pot to squirt some cleaner in (do all the following work with the equipment unplugged from the mains power). The body of the rotary pot will have (at least) three terminals ('lugs') sticking out one side, and there's usually a gap in the body where those lugs come out, where you can spray the cleaner in. After squirting in the cleaner, rotate the volume control back and forth from one end to the other, several times. Leave it for 15 minutes or more for the cleaner to evaporate, then switch the equipment on again and see if it's better.

If it's a slider control, you can just fit the thin tube (supplied with the cleaner spray can) to its nozzle, and poke that tube through the slot above the slider knob, and spray there. Again, you should then slide the control up and down (to its limits) several times and let the cleaner dry before re-testing.

Where I disagree with KISS is in the choice of cleaner. I would not recommend WD-40. This is a moisture-repelling cleaner/lubricant intended for 'non-sensitive' electrical applications, like car distributors. The kerosine-like lubricant can attack some electronic construction materials. Though you could use a contact cleaner with lubricant if it is targeted at sensitive electronic equipment, I also prefer not to use these on pots due to the lubricant film remaining on the resistor element indefinitely, and collecting dust and muck so that the 'dirty pot' problem simply returns later. I prefer the non-lubricating contact cleaners ('CO' is a common type in Australia), which you can identify by the label on the spray-can saying "Leaves no residue".

Just my 2-cent's worth!

If that doesn't fix the noise problem, then you probably have a leaky capacitor feeding the pot, and that will require some electronic expertise to identify the specific capacitor and replace it, best done by a technician if you don't have these skills. If you get someone to do this, ask them to use a 'solid tantalum' capacitor for the replacement, as this type doesn't 'go leaky' (should last forever).

Daniel

[Stratmando]

I like Channel Master, on can, it says, "Safe on Plastics" and "Leaves no Residue.
If Front allows, turn receiver with the controls facing up, remove knob spray along shaft, then turn back and forth several times.
Worse case you could remove Power, Cover, and spray the control directly.
Kiss, thanks for the TV Fool link. Take Care