Zanussi FJS1597W wiring damage from short

[davearn]

Hi,

We have a Zanussi FJS1597W which suddenly made an ‘electrical blowing up noise’ on being switched on. The on light continues to light up but nothing else happens. I have removed and inspected the timer/controller. The timer/controller motor runs OK. However there is some damage to the circuit board visible.

I am looking to find out what component may have failed (shorted) and so caused the damage.

Looking at the circuit board from the spindle end, towards the motor end, on the right hand side, the second edge contact strip from the back (between the labels ‘N2’ and ‘1’) ends the track that leads to point labelled ’16’. This track has been blown off and at point 16 the soldered joint appears to have been re/over heated.

The contact connects to a black wire that runs down to a plastic duct that leads to/passes the door switch.

The solder joint at 10 o’clock from point ’16’ which connects to the track running to the next contact (away form the motor end) marked ‘6’ (connector has mauve wires), also looks to have overheated, but in this case the remains intact.

Can anyone tell from this me what component(s) may have failed?

Thanks,
David

[Seamy]

Re: Zanussi FJS1597W wiring damage from short

Just looked at circuit diagram, no num’ 16 on, edge connectors should have numbers like J1 to J6 etc.
You would need to use a multimeter to test it, & other components to check which is at fault.
Sometimes even if a door interlock blows for instance it can take out p.c.b, similarly pump, motor & heater short circuits will damage p.c.b.

[davearn]

Re: Zanussi FJS1597W wiring damage from short

Many thanks for responding Seamy.

The p.c.b. (which in this case just consists of tracks, wire links and edge connector strips) is not marked with J1 etc.

I would use a multimeter to do checks but without a circuit diagram it is almost impossible without taking out/accessing all the components, so I am hoping someone will be able to identify which components are connected to those specific p.c.b. connections.

I will attempt to test the door catch switch tomorrow.

I will also take a picture of the p.c.b. and post that tomorrow.

[davearn]

Re: Zanussi FJS1597W wiring damage from short

I have now taken some pictures of the controller and circuit board:

controller: http://newberry-it-ltd.co.uk/publicdocs/controller_indentifier.jpg

blown track: http://newberry-it-ltd.co.uk/publicdocs/blown_track.jpg

full circuit board: http://newberry-it-ltd.co.uk/publicdocs/full_circuit_board.jpg

I have looked at the door switch but cannot see anything visually wrong.

[davearn]

Re: Zanussi FJS1597W wiring damage from short – SOLVED

I have now tested the door switch and found that none of the three contacts are made when it is operated. To confirm this and to find out which contacts are meant to be made and when, I carefully cut off one side of the switch to reveal the inner workings. Three wires connect to the switch: two pink and one black.

It appears that the two pink wire contacts are made to allow the washing machine to operate. Power to the outer pink connection first flows through a heating block inside the switch to the black connection. When the heat inside the switch is high enough the internal mechanism ‘buckles’ to make the other contact (between the pink wire connections) to be made and at the same time the interlock for the door is engaged.

When the washing cycle stops I believe the heating block is disconnected (externally in the timer?) and the switch starts to cool. It takes a short while for the cooling to be sufficient for the mechanical ‘buckle’ to return to the original position, disconnecting the power and undoing the interlock so that the door can be opened. This temperature dependent mechanism may also prevent the door opening while the machine is full of very hot water (whether the power is on or off) – can anyone confirm this?

There fine cooling slots in the switch body – in my case these were partially blocked with dust/fluff etc. Maybe that caused the switch to overheat and fail?

Having established the proper working of the switch I temporarily linked the two pink wires together and the machine worked! Now waiting for a spare door switch to do a proper repair.

Here is a picture of the inside of the opened up switch:

http://newberry-it-ltd.co.uk/publicdocs/switch.jpg

Hope this is of use to others.

[Seamy]

Re: Zanussi FJS1597W wiring damage from short

You will need to repair the blown tracks on the timer P.C.B for it to work correctly when the new interlock is fitted.

:lesson: It should be stated that its not recommended to bypass the door interlock switch on any appliance as its a safety device.

Track Burnt Component affected
N2-1 to 16b Door lock

[davearn]

Re: Zanussi FJS1597W wiring damage from short

I had already repaired the track, of course, (how else would I have run a test).

A new switch has now been installed.

I agree basically with the safety statement – I should have made it clear I took great care and only ran a minimal test with an empty machine and just trying briefly a couple of actions eg fill, empty, spin.

In no way would I encourage anyone to run the machine for normal use with the door interlock switch disabled.

[Author]

Posts