Set the multimeter to resistance (Ω) mode and measure between the two outer pins; the reading should be close to the potentiometer’s rated value (such as 10 kΩ or 100 kΩ). If the value is open (infinite) or significantly different from the rating, the potentiometer is likely faulty.

Next, check the smooth operation of the wiper by measuring between the middle pin and one outer pin while slowly rotating the knob; the resistance should change smoothly without sudden jumps or drops.

Repeat the test with the middle pin and the other outer pin. Signs of a worn-out potentiometer include erratic resistance jumps, dead spots where no change occurs when turning, noisy readings, or an open circuit at certain positions. For more accurate results, avoid touching the metal probe tips with your fingers during measurement to prevent interference from body resistance.