What’s this component on Miele W504 board?

[leavemetogetonwithit]

Got a rinses flashing but motor perfectly OK job on here. Took along my kit of relay and fuse as for earlier models but turned out Miele have changed the board design 👿 .
Have gone through it with a coarse-toothed comb but everything checks out more or less. What I take to be the motor triac reacts differently from usual to my test lamp but may be it’s not a triac. Have ordered a new one just in case.
But I’m a bit puzzled by the red plastic-encased thing seen here:

I think it has four legs. Anybody out there know what it is and/or what it does? It was hiding under the heatsink.
And what a pain these boards are to unplug and extract. Just as bad as a Lux, maybe worse. Is there a special tool for getting tight rast plugs out that are stuck inaccessibly in holes surrounded by plastic?
Mike.

[leavemetogetonwithit]

Re: What’s this component on Miele W504 board?

Well, I’ve burnt some more midnight oil on this board and the only thing I can find is a trace of possible smoke – could be something, could be nothing, generally spread over the board but may have emanated from the general area of the “triac”(actually an “insulated gate bi-polar transistor” 😕 ). Also there is a 33 milli-ohm 2W smd resistor in series with the “triac” between its emitter and the -ve of the bridge rectifier. This resistor is very slightly humped as though it might have got a tiny bit hot although it measures up more or less OK. (Not sure my meter is sufficiently accurate at that level.) Anyone know what its purpose is? Can’t find one of exact same value at RS.
Shall return to job today as it’s only a couple of streets away and look for loom damage (prompted by reading the new, “related topics” feature with which I am quite impressed – it’s certainly better than the manual search at the moment) and try and persuade customer that I need more time.
Mike.

[leavemetogetonwithit]

Re: What’s this component on Miele W504 board?

Well, still no further with this one. No loom damage found. Replaced a couple of components on the board (the IGBT and the current sensing resistor) but to no avail.
I am getting a couple of volts back through the tacho connection at the board end when I revolve the drum by hand and I have made sure the pins in the plug are raised so they should be making contact.
Yet what happens is as follows: select spin/drain, press start, drum turns in one direction for a second or two then rinse light flashes rapidly (=no tacho signal received.) After a few seconds, the light stops flashing and the drum turns for a second or two in the other direction then rinse light flashes again. Rinse light goes out, one more time it tries then rinse light flashes again and then the machine goes to end and drains with rinse light continuing to flash.

This all indicates to me that something is not happening between the tacho pins on the board and the processor. I just don’t understand how such a low current portion of things could get damaged at all by just washing a bath mat.
Sorry, I see I didn’t mention that before. It was not rubber backed and I was told machine had made excessive noise (I presumed unbalanced) and customer had turned it off, got filter out and in so doing (I deduced) water had overflowed into base leading to original call to empty base.

Customer is ready to pay for a new board (£262 + del.) but I’m still hesitant. What could I have missed?
Long shot I know, but has anyone out there broken a Premier 500 series and has a secondhand board I could borrow? 🙂
Mike.

[BobHope]

Re: What’s this component on Miele W504 board?

Hi Mike,

just love your repair storys, and nice to here from someone who still repairs to componat level, without having a zoomed out picture of the pcb to see other componats around the red box i would say that its a pulse transformer, Used in SCR and TRIAC starting circuits of low, medium and high powers.

Bob.

[leavemetogetonwithit]

Re: What’s this component on Miele W504 board?

Hi Bob. Thanks for the reply. I’m not sure if I have a zoomed out pic or not, I’ll have a look in my PC and camera cards later and post it up if I do. Board is back in machine now as I was going to order new board. I stopped suspecting the red plastic doodah after finding something on the net about VOGT (?) being a classy manufacturer of chokes. So I decided it must be a choke; and as its only two connected legs (diagonally across component) have low ohms between them, I decided it was probably OK.
Trouble with working on Miele boards is that everything is soldered in to military spec. Which is great till it goes wrong and you want to desolder it to check it. So I have to practically destroy a component to get it out so unless it’s cheap and readily available (and not that many Miele components are) I avoid it if possible. Then there’s several diodes on there whose markings I cannot find any reference to anywhere on the web. Also some smd semiconductors which are blanked out 🙁 .
Mike.

[leavemetogetonwithit]

Re: What’s this component on Miele W504 board?

Have rung customer and explained that I am not going to order a new board. They wouldn’t save that much since it would be £262+£100 to get a Miele engineer to do it or £262+£50 should I do it. I don’t want that nightmare hanging over me. So they either go the Miele route or get a new washer. January sales coming up.
The Mrs customer has agreed and thinks she may go for a Bosch. When Mr customer gets home he’ll be allowed to have some input.
Mrs C has agreed that they will keep the dead Miele in the backyard so I can dismantle it and help them sell off the good parts on ebay.
Will update should there be any further developments.
Mike.

[gandh1]

Re: What’s this component on Miele W504 board?

can i have first dibs on the motor if i need it ?

[leavemetogetonwithit]

Re: What’s this component on Miele W504 board?

Sure but I very much doubt you’ll need it. I reckon’ yours is the board too. Aren’t the motors covered for 10 years anyway? Wonder if water got into the motor somehow.
Mike.

[gandh1]

Re: What’s this component on Miele W504 board?

any noticeable burn outs on them or is it internal failure of compents?

[leavemetogetonwithit]

Re: What’s this component on Miele W504 board?

Only the merest whiff of any visible problem on the board as I said in my first post. The boards look like they’re built to withstand an earthquake and a lightning strike at the same time. So really, I’m only pointing a finger in that direction for lack of any other culprit.
My customer is waiting for her Bosch to arrive. She told me on the phone that the gentleman at Currys had also advised her (without prompting) not to let the delivery guys take the old Miele away but to stick it on ebay!
I’m thinking I might take out the motor, loom and board and have a little play around in the lab before putting anything up for sale.
Mike.

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