Whirlpool W120 Motor Test

This thread was marked as solved. Here's a summary of the problem and the fix, generated from the discussion below.

Whirlpool W120 motor continuity checks suggest motor not obviously open-circuit; engineer diagnosed timer fault

The problem

Whirlpool W120 washing machine was being checked for a suspected motor fault on a CESET MCA52/64 - 148 IRN1 motor with a 7-pin connector. The owner wanted to know whether the motor could be tested with an analogue multimeter without an insulation tester.

Likely cause

Based on the accepted reply, the continuity readings suggested the motor windings, brushes/armature and tacho coil were not obviously open-circuit, so the motor should at least try to run. A subsequently called engineer advised that the fault was the timer. The exact failed timer component was not documented.

What fixed it

No motor repair was confirmed. The accepted advice was that a standard multimeter can only give limited continuity checks and cannot confirm insulation safety; if brushes were not burnt or charred and continuity was present, the fault likely lay elsewhere. The owner then reported that an engineer diagnosed the timer and said it was not worth repairing, so replacement of the washing machine was chosen.

Checks to try

• Pins 1, 2 and 3 showed continuity to each other
• Pins 4 and 5 showed continuity to each other
• Disconnecting one carbon brush removed continuity between pins 4 and 5
• Pins 6 and 7 showed continuity of 4 ohms
• Visual brush condition mentioned: check whether brushes are burned or charred

Parts or tools mentioned

• Analogue multimeter
• Insulation tester (megger)
• Timer
• Carbon brushes