Variable capacitor detection

1. Gently rotate the shaft by hand, it should feel very smooth, and should not feel sometimes loose or even stuck. When the axial direction of the load is pushed forward, backward, up, down, left, right, etc., the shaft should not be loose.

2. Rotate the shaft with one hand and gently touch the outer edge of the group with the other hand. There should be no looseness. The variable capacitor with poor contact between the rotating shaft and the moving piece can no longer be used.

3. Place the multimeter in R×10k block, one hand connects the two test leads to the movable piece of the variable capacitor and the lead end of the fixed piece, and the other hand will slowly rotate the rotating shaft several times back and forth, the multimeter pointers are Should not move at infinity. In the process of rotating the shaft, if the pointer sometimes points to zero, it means there is a short circuit between the moving piece and the fixed piece; if it touches an angle, the multimeter reading is not infinite but a certain resistance value appears, indicating that the variable capacitor is moving. There is leakage between the film and the stator.