Whirlpool AWM 5145/4

My problem concerns a Whirlpool AWM5145/4 front loading washing machine which is just under nine years old and has been used on average two times per week mostly on the daily wash cycle at 40 degrees C.

When switched on and the daily wash programme selected, the drain pump activates to remove any left-over water in the tub as normal. Usually at this point the main motor also operates at low speed in both directions to distribute the clothes however this does not function now.

Then the cold water valve should be activated (it is a hot/cold fill, nither operate), this does not happen and no water enters the machine.

When the pump has stopped, after approx 30 seconds, the machine justs stops. Moving the control knob on by hand, does not operate any of the machine functions, wash spin drain etc except that the control knob motor does move on through the cycle to the next position.

I have made a few electrical tests. Both water valves each show a resistance of around 3500 ohms when isolated from the controller pcb. When the valves should operate in the wash cycle there is no voltage across the terminals. They are rated at 240V. There is no sign of buzzing etc.

I have tested the continuity of the main motor and the field coils, armature windings and tacho seem to be correct. No open circuits and the tacho generates a small votage when the drum is turned by hand. (I found a circuit diagram on-line to check this). I have not checked the condition of the brushes however the machine was until recently working correctly.

I checked the water level pressure switch, it is a single level only, and the continuity checks out as per the circuit diagram when gently blowing into the tube.

The door switch and interlock appear correct, there is continuity across the switch when activated and the lock deactivates after thirty seconds or so as normal.

This leaves the main controller unit which is self-contained and has a motor activated control knob which switches the heater circuit. On the main pcb there are a three triacs, capacitors, diodes, resistors, various motor power controller circuits and three relays for the motor and on a seperate daughter board contains the microcontroller and associated circuitry. I have tested the triacs and they work correctly.
There is only a single mains pilot light and four option switches on the front panel and no obvious means to display diagnostics info.

This controller board looks brand new and shows no signs of damage or burnt-out devices. The control knob turns as before and does not feel to be damaged or loose.

It is a machine in good condition for its age, has not been hammered in regular use and I am reluctant to scrap it without a fight 🙂 It all points to the main controller board, however Whirpool require £70 for a new one which is fair but I am reluctant to buy one without knowing it is the controller that is faulty.

I welcome any ideas and suggestions…