How to repair the noise of carbon film potentiometer

Due to frequent use of potentiometers in household appliances (for example, the volume potentiometers in radio cassette recorders are often repeatedly turned), they are prone to malfunction after a period of use. The malfunction of the potentiometer is easier to show on the whole machine. For example, when the potentiometer is turned, the noise is very loud, the sound is loud and sometimes small, the power switch fails, etc. At this time, the potentiometer needs to be repaired.

The most prone fault of carbon film and synthetic carbon film potentiometers after a period of application is high noise (especially non-sealed potentiometers with switches), mainly due to oil stains or resistive film between the contact reed and the lead-out terminal reed Being worn makes the contact resistance unstable. At this time, repair can be carried out according to the following steps:

1. Use a screwdriver to pry open the metal shell of the potentiometer and remove the metal shielding shell;

2. Use tweezers to clamp a cotton ball dipped in anhydrous alcohol (or high-grade gasoline), gently wipe the resistor chip to remove the carbon powder and dirt generated by friction, and then use a small cotton ball to remove the contact reed and the lead reed Oil stains at the joints. The bakelite holders of some potentiometers that contact the reeds can be removed from the rotating shaft soil, so that it is easier to remove the oil and carbon powder on the reeds and resistors;

3. After cleaning, install it according to the original steps, and the repair work will be completed.

The above repairs are not always effective, and the potentiometers that are severely worn need to be replaced with new ones. It is best to use the potentiometer of the original model and the original resistance value when replacing, and pay attention to the length of the potentiometer shaft and its cross-sectional shape, and it should be able to match the original knob. When the original model and the original resistance potentiometer are not found, the appropriate model can be used instead.