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  • AW23 completely dead

    Hi,
    I can't find any reference in the knowledge base or forums to this fault:
    M/C halfway through wash died. No lights, no display, no nothing. As if the fuse had blown. Mains power to main board good. Any idea what can make this M/C behave as if it's not plugged in?
    Thanks
    Kerrin

  • #2
    all boards need a low voltage supply to power the electronics. In most boards its 12volts. Their is a circuit that lowers the voltage and its likely this part of the main board has failed

    you say you have checked the mains voltage to the board. Have you checked for both live and neutral ?

    dave

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    • #3
      Hi Dave,
      Yes, the live and neutral are both sound.
      Situation update: I cannot find any low DC voltages on the PCB at all, so I suspected a mains to 12V or 5V converter failure, glad you you suspect the same. I notice all the relays are 12V so I think you're right about that, I'll stop looking for 5V.
      I am having trouble getting to the reverse of the PCB without damaging it (I can't find a switching converter chip on this side, so I guess there's a surface mount one on the other), the only other clue was a slight coating of soot below the switching transformer, which is not present on any other part of the PCB. I'll have another go at that when the light is better and my patience is not as frayed. I'd buzz out the transformer, but again, I've got to get to the other side to get on its pins.
      I'll let you know how I get on, but removing the PCB has been the big problem: the little white clips holding it in seem to want to break off and there's something retaining the lower centre of the board that I can't see. It's a shame I don't know what comprises the "control module" and what it looks like when removed, has any one got a picture of that? Preferably from both sides. The part number(s) on the PCB don't match any on your list, though I expect it is one of them.
      BTW I'm a recently retired senior electronic design engineer, so don't worry about the safety aspect of what I'm attempting :-)

      Thanks for the advice.
      Kerrin

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      • #4
        There is a very, very small torx screw you need to remove from the lower centre of the pcb.

        Just checked in in my old tool bag, itís an 08 torx bit.
        Last edited by iadom; 17-07-19, 09:19 PM.
        Nothing really matters much, and hardly anything really matters at all.

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        • #5
          the soot may not be a problem. the high voltages (300v +) seems to attract it

          there is normally fusible resistor approx. 3 watt under 100 ohms that feeds the whole power convertor. check this for resistance. if its blown its likely the chip has as well


          Dave

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          • #6
            Hi Dave,

            We've got guests arriving, so the Good Lady has made me put it back together. I'll get another chance at the weekend. Thanks for the tips, I'll hopefully have more of a clue by next week.

            Cheers,
            Kerrin

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            • #7
              Hi Dave,

              I finally got a moment to look at this, you're spot on, I changed a 47ohm 2W resistor and a a little off line switcher chip . Took all of 20 minutes. Job done. Thanks for you help.
              Best regards,
              Kerrin

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