Fixing a washing machine - the mechanical controller unit

[Lieutenant Scott]

I have a 13 year old Bosch WFB 2005 washing machine.

When I switched it on the other day, set to a normal wash cycle, it started to fill with water, then 20 seconds later there was a small bang and a flash, and a small amount of smoke from the top front right of the machine (where the program dial is). The smoke was about the same amount as you get from blowing out a candle. It smelt a bit but not much, rather ozone-ish.

I switched the machine off immediately after the bang, then when I turned it on again later, it made the same bang. After rotating the program dial to spin, I switched it on again, and got a sizzling noise.

I then turned the drum by hand a little (thinking the motor may be jamming), and the machine started working.

I tried again on wash cycle with the lid off the machine, and got the bang again, and the smoke clearly came from the program selector.

The main motor's brushes and commutator are in perfect condition. I can see nothing burnt on any of the little circuit boards.

The program selector has been removed and is pictured here:

idea how to take this apart? The little motor looks fine, and if that was the problem, I can't see it being able to make a bang three times, I suspect something arcing inside the switchgear, but I can't get in to see what's going on in there. It appears to be clamped together by 4 copper tubes, splayed out at the ends, too small to squash with a pair of pliers.

[ss]

Looks like it would need to be drilled out and the if repairable a similar diameter tube and use a ball pein hammer to `rivet` it.

[Lieutenant Scott]

I shall take it round to a friend with a load of these sort of things in his garage....

[Andrew Gabriel]

fill with water, then 20 seconds later there was a small bang and a flash, and a small amount of smoke from the top front right of the machine (where the program dial is). The smoke was about the same amount as you get from blowing out a candle. It smelt a bit but not much, rather ozone-ish.

on again later, it made the same bang. After rotating the program dial to spin, I switched it on again, and got a sizzling noise.

and the machine started working.

again, and the smoke clearly came from the program selector.

nothing burnt on any of the little circuit boards.

the problem, I can't see it being able to make a bang three times, I suspect something arcing inside the switchgear, but I can't get in to see what's going on in there. It appears to be clamped together by 4 copper tubes, splayed out at the ends, too small to squash with a pair of pliers.

Fault might not be anything to do with the programmer. It might be trying to switch on something else which is shorted out. Since moving the motor might have had some effect, you might have a shorted commutator contact, or something like that.

I rather suspect that if you take the programmer apart, the chances of it ever working again are not high, which would be particularly sad if there wasn't anything wrong with it in the first place.

[Fredxx]

I would have thought any direct short would have taken out the fuse and/or the MCB.

The only things that draw substantial current on a washing machine are the heater and motor.

LOL That is my experience as well. Rather than trying to replace the riveted copper tubes, I'd be tempted to replace then with an appropriate diameter of studding and a nut at either end.

[Andrew Gabriel]

Yes, so a short in the commutator will generate a higher than locked-rotor current, but probably not high enough to blow the fuse.

Assuming you recovered all the pingfuckits, worked out where they came from, and how to get them back in the right place again ;-)

[Tim+]

That programmer looks like it's full of "pingfuckits" so I'd agree with Andrew.

As an aid to diagnosis, how about disconnecting the motor power supply and setting it running? Obviously it won't wash but it might indicate whether the problem is in the motor or not (which seems likely).

Tim

[DerbyBorn]

I wonder if they have pingfuckits when they are assembling them at the factory? /I suppose they have jigs that hold things in the right place.

[Fredxx]

I would have expected that burnt motor smell rather than hearing a "bang" from the controller.

A short between a segment wouldn't have caused a significant increase in motor current over its starting current.

[Lieutenant Scott]

It does it on coldwash too. And the motor doesn't look damaged, and it didn't blow the plug fuse. Mind you I don't have circuit breakers - 13A plugfuse is the most sensitive thing in the circuit. Would that go before I got a flash and smoke from the programmer?

I will have a look inside it tomorrow.

[Fredxx]

Although a good idea, without any knowledge of the machine, it could be that the motor is driven from a PCB and not entirely obvious which signals from the controller need to be live for the motor to spin.

If the OP is lucky he can obtain a wiring diagram, if exceptionally lucky one is glued to the inside of the lid!!

[Brian Gaff]

Yes, well I had a Service do this and to be honest if you do take one apart the chances of getting back together are rather remote. Lots of little plastic and metal bits. I wish I knew how they made them!

In the end I junked the machine as it was uneconomic to find a new controller. Brian

[Mike Tomlinson]

En el artículo , Andrew Gabriel escribió:

+1. It's far more likely to be the mains interference suppressor. They vary in size and shape but usually look something like this:

[Lieutenant Scott]

I have found (well a friend found, the one I turned up was =A34000!) one= for =A350. But I can buy a 2 year old 2nd hand machine for that.

What I can't believe is in 2013 they are still making new washing machin= es with mechanical controllers. I thought we invented electronics in th= e last century.

Here's the 4 grand one if you want a laugh. What the hell are this comp= any thinking?

[per.karlander.pk]

Hi there. It seems like the fuse to my washingmachine bosch wfb 4000 is broken. I want to know where it is located.. Can I change it myself? Best per karlander Stockholm.

[Tim+]

Firstly, here in the UK machine fuses are in the plug. I suspect that in Sweden you're reliant on a fuse in the fuse box. So, if the socket works, it's not the fuse.

Why do you think it's the fuse? Plenty of other reasons for a washing machine to stop working.

Tim

[Thomas Prufer]

To find out anything about the machine, you need the "E-Number", and the "FD-Number". The first codes the model, the second the manufacturing date.

With these, you will find diagrams and exploded views online at .

Thomas Prufer

[Brian Gaff]

Besides, a fuse is only an indication that a fault exists, not usually the fault. Most modern gear seems to have also, a wired in fuse in the power supply, and if that is blown, depending on how the unit is designed, can mean that the switch mode device has died and then you are into, why did it die? 1. try to get a service manual for the model 2, look for what does work. Do lights appear or mechanical noises happen when its on If its completely dead, then one needs to start to trace the mains and see if its getting to the machine and then it starts to get harder. Personally, if I got to this point and all was well and a fuse inside had gone, I'd get the man in. Brian

[DerbyBorn]

"Brian Gaff" wrote in news:nc36d1$msb$ [e-mail]:

And think about the logic of the machine - nothing will work until it knows th edoor has closed - is that okay? Next the water valve needs to allow the maching to fill - is that working?