Bosch dishwasher starts and stops SMU50E05AU

Bosch dishwasher starts and stops SMU50E05AU

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Thread: Bosch dishwasher starts and stops SMU50E05AU

  1. #1
    Join Date
    Mar 2017
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    4

    Default Bosch dishwasher starts and stops SMU50E05AU

    Hi

    I have a Bosch Dishwasher, model SMU50E05AU.
    It is about 4 years old and was bought and used in Australia.

    Yesterday I turned it on and started a normal cycle, but then it cut out after running for maybe 3 minutes.
    There is no numerical display but there are usually LEDs lit while running.
    When it stopped the LEDs went off too.
    Some time later, after maybe 5-10 minutes, it starts up again and continues the cycle with the LEDs lit.
    I think it also stops and then starts again part way through the cycle, though it is hard to be sure since a normal cycle takes 1.5-2 hours so I didnt watch it the whole time.

    After reading around on the internet I removed the filters and ensured they were cleaned.
    I also removed the white clip under the filters that exposes the impeller (i think thats what it is called) its the white plastic bit that spins around. I ensured that was clean and moved unobstructed, which it did.

    I then tried running a normal cycle again and it still did the stop start thing.
    I did notice that when it was running it was able to fill up with water, and was then able to drain the water.
    Mid way through running I opened it and the water was hot and steamy so it seems heating is working too.

    I was not able to get into any test mode to get diagnostic feedback from it.
    It only has power, start and half load buttons.
    (and well 2 unlabelled buttons once I took apart the control panel and looked inside).
    No combination of these when turning it on appeared to get it to any mode other than normal.
    I have included a picture of the front so you can see its layout.

    Any ideas what the issue might be?
    Any help is greatly appreciated.
    I am quite happy to take apart whatever needs to be taken apart and test stuff with a multimeter and solder anything required.

    Bosch dishwasher starts and stops SMU50E05AU-img_7850_sm-jpgBosch dishwasher starts and stops SMU50E05AU-img_7851_sm-jpg

    (And yes the blue is the protective coating that comes on the door. We decided we liked it so left it on ehehe)

  2. #2
    Join Date
    Mar 2017
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    I captured some videos of the dishwasher cutting out.

    The normal behaviour is:
    No lights when off.
    Blinking red light when turned on but not washing.
    Steady red light when washing.

    This first video shows a few minutes into the wash cycle.
    There is currently no water inside, so it's like it's about to fill up in the next stage.
    You can see the red light on steady.
    Then at about 18 seconds in you see it cut out and all lights go off.
    This is abnormal behaviour.
    Bosch Dishwasher cutting out - YouTube


    This second video shows the dishwasher sitting there with a blinking light, which usually means it is not currently in a wash.
    This was after running overnight start/stopping and I think finally completing its cycle.
    At about the 40 second mark you again see it cut out and all lights go off.
    The interesting thing here is that it wasn't doing a wash, so the cut out shouldnt be due to any new part of the cycle kicking in.
    Dishwasher cutting out when not washing - YouTube


    Looking at the available parts from the bosch page there is a small control board that they call the "operating module" in the top of the door. I took the door apart to check it out. It looks very simple, only a couple of small chips as well as the buttns and leds. It looks almost too simple to be the only control board in it. There was no obvious damage to it, there were no high power stuff on the board like relays etc, so I guess there is at least a second power board probably underneath the machine. There was also no roach poo, dirt, dust, liquid etc on this board in the door.
    Spare Part Finder Detailpage

  3. #3
    Join Date
    Feb 2012
    Location
    Canada
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    Default

    Hi,

    I have a Bosch Dishwasher, model SMU50E05AU.
    It is about 4 years old and was bought and used in Australia.
    We are not going to be familiar with UK style appliances. We have only seen Canadian and US appliances.

    Yesterday I turned it on and started a normal cycle, but then it cut out after running for maybe 3 minutes.
    There is no numerical display but there are usually LEDs lit while running.
    When it stopped the LEDs went off too.
    Might suspect a loose/burnt main power wire where the wires enter the d/w....might heat up and quit, cools down and closes again.
    UK Appliance Resources | Appliance Aid
    Some appliance repair, service and part links specifically for European style-made appliances...

    jeff.
    http://www.applianceaid.com/
    Appliance Repair Aid

  4. #4
    Join Date
    Mar 2017
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    Default

    Ok thanks Jeff.

    I found the real control board kind of underneath and to the side.
    From the part number on that I found a place that sells replacements so I will try getting a new one.
    There was no obvious issue with it from looking at it, but the fact that it cuts out even when not washing and when just sitting there makes me think it is probably a control board issue.

    There were no obvious issues with wiring between power supply and the board either.

  5. #5
    Join Date
    Feb 2018
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    1

    Default

    Hi Zac, did you find a solution to the stop start issue? We have the same model going through the same problem so interested to know what the issue was.

  6. #6
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    You could try sending Zak a private message to see if he can tell us what he found...
    https://www.ez-forums.com/members/4747.html

    jeff.
    http://www.applianceaid.com/
    Appliance Repair Aid

  7. #7
    Join Date
    Mar 2017
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    Hi Tanzie, I replaced the main control board and it is still working ok now almost a year later.

    After watching it fail for a while I noticed that it would fail even when it was at stages of its cycle where it didn't really use any other parts of the washer. Based on that I assumed that the only part in use at those times was the control board, so I replaced it and it did indeed fix it.

    I am in Australia, so I ordered a part from BigWarehouse Spare
    For my model dishwasher, SMU50E05AU07, the part number I ordered was 1748722.
    It cost me AUD$340 delivered.

    There was a bit of wrestling with the dishwasher to get it apart and follow the wiring to find out where the control board goes, but actual install of the part was just a matter of unclipping the old part and clipping in the new part, then reassemble.

    Protip: When ordering be sure to order a pre-programmed control board. You need the board programmed to be able to use it, and it is only like $10 more for preprogrammed. The unprogrammed ones assume you have the various hardware and software that repair people use to program it themselves. I read about this somewhere when I was looking into buying the board. I don't remember where though.

  8. #8
    Join Date
    Feb 2012
    Location
    Canada
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    Thankx for the update Zak!

    jeff.
    http://www.applianceaid.com/
    Appliance Repair Aid

  9. #9

    Default

    I'm glad you replaced the right part the first time.

    Although not specific to Bosch dishwashers, sometimes it's a single defective component drawing too much power and shutting down the main PCB.

    *cough* vent fan in a KitchenAid dishwasher *cough*

    Sometimes you have to unplug all loads one by one to find out without which is stops stopping.

    Also, if you have access to the complete sequence of cycles or an accelerated mode for testing purposes, it can be much quicker to find out where it fails during the cycle and isolate that part.

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