Blown MCU Boards in Whirlpool Duet Washers

I’m seeing more and more of these Duets with funky MCU (motor control unit) boards. Often the washer will not even lock – just gives 3 beeps. When you disconnect the MCU at the CCU then at least the door will lock and you know you have a MCU problem. In this case, when I pulled the board out of the plastic housing, you can see that there has been soapy condensation dripping down the back of this board. I will keep checking these as I replace them to see if this soap residue is common to all these. FTR – this customer did have HE detergent in the laundry room. That does not mean they’ve always been using it, but right now they are.

EDIT Aug 15/11: Here is another one. You can see the soapy drip trail heading right at the burnt out spot on the board.   EDIT Aug 15/11: Here is another one.

Edit Sept 30/11: Another one. Multiple trails of soap residue.

Edit May 8/13: More residue trails.

MCU

6 Responses to Blown MCU Boards in Whirlpool Duet Washers

  1. Anuj October 10, 2013 at 2:07 am #

    Having the same issue with the mcu. I took it out and the residue is there but no burnt out spots. How did you go about cleaning the board to make it work again? Did any of you fix the board without soldiering anything? Thanks in advance for the help

  2. Jim August 31, 2013 at 1:08 pm #

    I had the same problem. I replaced the CCU and things still didn’t work properly until I came across this site. One of the legs of the bridge rectifier on the MCU had a burnt out solder point. I re-soldered it and it works again. Strange how this seems to be a common problem. I don’t have any wetness or dirt inside the machine (where the parts are) so I don’t see how this is happening. Thanks again for posting this information!

    Jim

  3. vince July 16, 2013 at 12:31 am #

    Ibid to what John Ellis said. I stumbled on your website and after reading about the soap residue on the Duet MCU decided to clear the codes and give it one more try ensuring my wife uses only HE detergent. Machine is only 2 years old and looks reasonably well built. Thanks again for your excellent web presentation.

    Vince
    Boston

  4. john ellis January 6, 2013 at 5:27 pm #

    I just paid $133 for a lesson that directed me toward the MCU being faulty. Of course it was fine while the tech was here then immediatly died once he left. The option of replacing a $250 MCU only 3 yrs old did not sit well with me so i started to dig and found your web page. The 3 pix you show was what led me to the solution – the soap (or whatever the white trails are) was the culprite, which actually ate through one of the fine board traces that are seen near the top left corner of your last pic. So, I cleaned up the board, soldered a new trace wire and bingo all is well.
    I can’t quite get my head around how the soap (if it is soap) gets in the MCU housing in the first place, since it seems sealed to contaminates on the trace side of the board. The other odd bit is that even in your pix the soap trails seem to defy gravity. If the boards you show are the same as mine, with the board sitting in a landscape position when installed, how does the soap leave trails as if the board is installed in a portrait position? Makes no sense.
    Irregardless your web page saved me $250. It’s refreshing, and rare now a days, to find some one like your self that wants to know why a problem has occured and share your findings with people that wish to FIX the item rather than just replace parts.
    My hats off to you mate!

    • Head Wrench January 6, 2013 at 8:47 pm #

      You’re very welcome! Glad it helped you and thanks for the kind words!

  5. shawn September 4, 2011 at 7:57 pm #

    i have this problem. after seeing this post i removed my mcu and it had soap residu all over it………no burn marks though. did you replace the mcu in the top picture with success. i have an f70 error which says nothing about the mcu, but when i remove the mi3 the washer powers up, which i believe points to the mcu. any ideas on how much this part is and should i bother replacing it, if yes how can i prevent this problem from happening in the future.

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