I have had the same problem with mine (a 1989 model).
In my case it appeared to be due to rain having splashed on the front of the machine (blown in through an open door).
I removed the top cover and allowed the machine to dry out for two days, then it worked fine again.
However if that is not the case, a good starting point is to ascertain whether the unit trips as soon as you switch it on, whatever the program position, or whether it does not in some positions.
If it trips all the time then it may be a problem with the program selection switch or the motor starter capacitor.
The starter capacitor is a 50mm dia metal cylinder under top cover with two pairs of spade terminals on it. Capacitors have a finite life. If you follow the mains connections in from the rear of the machine you will find that the live and neutral connect to this. Disconnect the other two wires and see if your RCD still trips. If it does then this is the trouble so replace it. If it does not then this device is OK and the problem is probably with your selector switch assembly.
If the fault does not occur in all program positions then you can try to identify the faulty item by disconnecting components, assuming that you are a competent person capable of working safely with mains voltages AND that the mains supply powering your machine is fitted with an RCD protection device (otherwise you may die and I wouldn't want that on my consience). Also remember when disconnecting stuff ALWAYS record how it is connected BEFORE disconnecting it. Taking photos on your phone may help...
Some possible culprits to try would be:
1. The main drive motor. The brushes in these wear and they can suffer winding insulation failure. This is accessible from under the machine. Disconnect the main multiway connector and see if the RCD still trips. If it doesn't then this is the most likely failed component.
2. Next try the motor controller. These also have a finite life. From the rear of the machine the motor controller is located under the drum on the LHS. Disconnecting the two spade connects from the top and multiway board edge connector from the bottom will isolate the controller.
Try powering up with this disconnected. If it no longer trips then this is probably the fault area.
4. Try similar experiments with all the other power components associated with washing (the drain pump located under the drum, the water inlet solenoids, at the top left of the rear and the drum heater element).
5. If the fault only occurs when the drier program is operating then it is worth checking the fan and heater elements of this also.
When you think you have found the fault repeat the test: does it still trip when connected and not when disconnected?
If you don't do this you will be caught out by the intermittent fault gremlins who will laugh their socks off when you splash out good money on replacements that don't cure the problem...
Having found the fault you can then contact a service agent to discover that it would be nearly as cheap to buy a replacement machine on ebay as to buy the part you need. Do not be deterred. Visit the local recycling centre or used machine seller or even find a dumped machine at the roadside for yourself. Get the parts you need. Re-assemble the machine. Smile with satisfaction that it works.
Then storm off in disgust when a brand new machine, your partner ordered because they had no faith in your mending abilities, appears in your house and your old faithfull gets consigned to the rear of the garage.
But remember, your old machine will have its day again (assuming you manage to keep it out of the elements). All too soon the new machine will fail (because the life count down timer the manufacturer embedded in its microprocessor will have signalled that it has been powered longer than for the warranty period or has completed more wash cycles than the manufacturere considers reasonable for the warranty period, and the machine will have therefore decided to stop working. And being a computerized machine, you wont be able to fix it!
Me? Cinical?
Torquil, October 2008
