Clothes dryer repair: AKO 742336 control unit type EDR0692XAX

Repairs of household appliances aren’t generally my field of expertise, but in some cases, it can be a very rewarding activity. Some particular models of clothes dryers (“AEG”, “Whirlpool”) common in Europe use a control board, and this is not designed up to standard. The design flaw, it renders the machine inoperative in the very sense, you can’t switch it on, and it doesn’t show anything on the display. Typically, this occurs after roughly 3 years of service….

This is the control unit:
dryer control

dryer control board

dryer control board detail

edr0692xax board

After a quick inspection, it is fully clear that the defect rests with the control board, model EDR0692XAX. Easy fix, just get a spare! Well, easy, but outrageously expensive.

ako 742336 edr0692xax

The defect, it is related to a DC switch mode regulator converting mains voltage down to some useful voltage to run the controller. This is a step-down converter, NOT mains insulated!

lmk304 application

Two dead parts were found, the LNK304 switch mode converter circuit, and a 47 Ohms resistor.

dryer control lnk304gn 47r resistor

The LNK304GN is easily found, and replaced. The resistor: WATCH OUT! This is a fusible resistor, NEVER replace with just a common resistor – it will potentially set your house on fire, when the next switch mode failure happens.
The 47 Ohm resistor, it’s a 3 Watt resistor, and the ULW3 series, available from all major suppliers, should be a good replacement.

ulw3 fusible resistor

This is the failure charcteristics of the ULW3 resistors – it will go open circuit if overloaded, without release of any flames or particles. It a hybrid, partly fuse, partly resistor.

ulw3 fusing characteristics

8 thoughts on “Clothes dryer repair: AKO 742336 control unit type EDR0692XAX”

  1. Hi,
    I have the same problem with my dryer.
    I have two questions:
    1. how can you tell it’s a 47 ohm resistor?
    2. do you know if there is a datasheet for this board?

    thanks for the help,
    Alphred

  2. Hi,
    Very useful article! Most likely also seems to be the issue with my Dryer. Where online can I buy these two parts in Europe? Where on the circuit board do I find the LNK304 switch (on the topside or down side of the PCB; if you can indicate the two parts in your picture?)

    Thank you for the help!
    CM

    1. Hi, You can find these on ebay or other supplieres no problem. They are widely available. The resistors need to be flame proof. Normal resistor will be a fire hazard!! The part is easy to find on the board otherwise just send a picture of the board.

      1. Hi Simon,
        Thanks a lot for the reply.
        My circuit board looks exactly like yours (EDR0692XAX). So if you can point the IC on your control board picture, then that should suffice.
        Otherwise, I couldn’t find any IC on the front side of the board with 7 pins. LNK304GN in your schematic shows 7 pins, the 6th one is missing.
        Thank you again for helping out.
        Regards,
        CM

        1. Hi, the IC actually on the other side, so you can’t see it on the picture. But it is easy to find. You have to take out the board from the holder by pushing back the white plastic tabs on the holder/case. This may differ slightly from dryer to dryer. Simon

  3. Hi – hoping you can help me ! My Mum’s Bosch dishwasher failed, no power to panel etc. I suspect a LNK304 failure and can see the subsequent AC input resistor failure. The resistor obviously heated up and has discoloured the bands so I can’t see what value it was. I am suspecting either 22 Ohm or 47 Ohm. We are on 240VAC over here if that makes any difference.

    https://dl.dropboxusercontent.com/u/973862/bosch/IMG_0299.JPG

    https://dl.dropboxusercontent.com/u/973862/bosch/IMG_1176.jpg

    Any help appreciated !

    1. Hi, I assume it is a 27 Ohm resistor. Make sure to use a fameproof resistor, 2 or 3 Watts. You might also want to check the big capacitor close to the LNK304. Simon

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