The start capacitor on a washing machine motor gets the motor up to speed quickly before transferring power to the run capacitor. When the start capacitor fails, the temptation is to replace the motor because it will hum, but it won't turn. Before considering the costly decision of replacing a motor, test the start capacitor to see if that's the problem.
- Skill level:
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Things you need
- Needle nosed pliers with insulated handles
- Insulated jumper wire with alligator clip on each end
- Flat bladed screwdriver with an insulated handle
Unplug the washing machine and remove the rear panel to access the motor. Remove the metal cover from the start capacitor. It is the larger of the two capacitors on the motor.
Draw a diagram of how the motor wires connect to the capacitor terminals and disconnect the wires from the terminals with insulated needle nose pliers.
Discharge the run capacitor by attaching one alligator clip of the jumper wire to the metal shaft of the screwdriver and the other alligator clip to the housing of the capacitor. Touch the blade of the screwdriver to one set of terminals and the shaft of the screwdriver to the other set of terminals to short out the capacitor. This will bleed the charge from the capacitor and make it safe to handle without the danger of a shock.
Set the multi-meter to the OHM scale and touch the two lead points together. Move the adjusting wheel until the needle is at "zero." The needle should point straight up in the center of the dial.
Touch the capacitor terminals with the leads, red lead on left and black lead on right. The needle should move away from "zero" and point slightly toward the right side, then go back to "zero." Reverse leads and the needle should move away from "zero" even further and then go back to "zero."
Replace the start capacitor if the needle doesn't move. It means the capacitor is bad. If the test shows the capacitor is good, look for another problem.
Tips and warnings
- Don't touch the terminals with your bare hands because the start capacitor has a stored charge which can deliver a severe shock, even when the machine is unplugged.