How to repair the repeater's volume regulator

The volume regulator is an adjustable resistor.

(1) There are three possibilities if there is a clicking sound when rotating;

1, wet or dusty inside. Turn the knob back and forth hundreds of times, and the noise will gradually disappear. You can also open it carefully (some need to unscrew the screw in the center of the knob, some need to tilt it at four fixed angles) and wipe the black carbon rail with a cotton swab.

2. The internal copper brush (in contact with the carbon rail) has poor contact with the carbon rail. Open it carefully, and increase the inclination angle of the copper brush to make it fully contact.

3. Wear of black carbon rail (it can be seen that the carbon rail has obvious strip wear scratches when disassembled). If it can't be replaced, disassemble a battery, find out the carbon rod inside, scrape off a large amount of carbon powder with a blade (outdoor, wear a mask and gloves to prevent contact with mercury), mix a small amount of glue into sticky colloidal carbon, dip some with a cotton swab, apply it to the worn part of the carbon rail, and apply it several times after drying.

(2) Silence, four possibilities;

1.2. Same as (1) 2.3, (heavier)

3. If the pin is damaged, solder it again with a soldering iron.

4. The carbon rail is broken and replaced with a new one.