Miele W5872 111 power/control pcb issue…

[AllanGreen]

Hi Everyone,

I last wrote to this forum about 3 years ago with respect to the same washing machine which is (or rather was) still soldiering on at about 10 years old! And it was thanks to the help I got here that I managed to fix it last time. But as you’ll have guessed I have a new problem with it.

The symptoms were pretty clear; immediately on switch on the display glowed faintly, brightened, then went back to black. No text, just a feint background glow which lasted perhaps 3 seconds.

I guessed at a PSU fault, and on inspecting the power/control board discovered that something of a minor explosion had wiped out 5 of the 6 GB10NC60HD IGFETs. Probably the sixth failed too but at least it is still in one piece 🙂

It turns out that these are readily available (10 for about £16!) and I’m used to soldering surface mount, but before I take the job on does anyone know whether this failure could occur spontaneously, or is it likely to have been a consequence of something else? How scared should I be? Ought I to order a new pcb before wasting time on an attempted repair?

At the very least, is there anything I should check before powering up again after replacing the semiconductors? The drum is free, so I’m reasonably confident that the motor bearings haven’t siezed up but beyond that I’m well out of my depth 🙂

Best wishes, (and thanks for any thoughts you might have!)

AllanTheBrummie
PS my gf says “Hi”… see my last thread!

[electrofix]

have seen the failure but never went to thr trouble of soldering new components

only problem i can see is the drivers that activate the IGFET’s. if they have been damaged during the failure then it either wont work or go bang again

Dave

[AllanGreen]

Thanks Dave, its great to find that you are still on this forum! And the fix you suggested all those years ago was spot on. 🙂

Anyway, first I should apologise for posting to a general forum. I should of course have used the Washing Machines forum. Is there any way to move it to its rightful place?

Back to the PCB… I pulled out the PCB and with the benefit of better light and access I could see that about a dozen driver transistors had exploded too. I wish I could have seen it happen. It was starting to look like there might be something Very Wrong with this board. I tried to get hold of a service manual (or even just a circuit diagram) but have not been able to locate one with all the power of the Internet at my disposal. The best that the friendly lady at Miele UK could offer was a parts list with a diagram identifying the PCB. (As a PCB…) So much for the “Right to Repair” legislation. If there are any Miele service engineers in this group it would be great if one of them could post a part number for the manual! Even anonymously! Once upon a time I used to work in medical electronics and every single product I ever worked on had a service manual…happy days 🙂

Anyway, at risk of running out of clean clothes (combined with terrible drying weather), I decided to take the coward’s way out and ordered a new board from Miele. Which to their credit arrived on the promised day, (today). I now have to keep my fingers crossed that there isn’t something outside the board that caused the failure… or otherwise I am about to blow the best part of 200 quid finding out the hard way!

I’ll try to fit it tomorrow, and let you all know what happened next!

Goodnight,

AllanTheBrummie.

[electrofix]

best of luck

moved the post

Dave

[Author]

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