Duet Wifi Dead ?



  • Hello,

    Last Sunday i have printed the last Time and all was fine! after this print i have switch off my Printer.
    On Sunday night i wantet start a New Print but i can't reach the Duet by Web 😞 The same Problem with USB no connection
    So i have try to change the SD-Card but without suxess.
    After that i have checked the Powersupply this is stable with 24 Volts.

    Normaly if i switch on The printer the Fans will start and stop after view seconds this don't work now the next Problem i have found is that the hotend and the head Bed will power on when i switch on The printer !

    In the last day I have checked all the Cable but i don't find some error.

    When i switch on the Printer all LED's are on and nothing else happens i can Press the Reset or The erase Button without any reaction here is a picture you can see the Board

    https://photos.app.goo.gl/K27brzMQEDzCa80O2

    is there any thing what i can do ?

    regards

    Andy


  • administrators

    If the heaters turn on when you apply power, then unfortunately it sounds as though there has been a severe over voltage event on the 5V or 3.3V rail that has blown the mosfet driver chip and probably the processor too. Is the processor or any other chip getting hot? What type of Z probe do you use?



  • Hello

    this sounds not good 😞 on the board is nothing what is hot. I think you mean the z endstop ? this is a mechanical micro switch.



  • hi,

    now i have controlled the Board Power on the 5 V i have 4.88V and on the 3.3 V i Have 3.1 Volts


  • administrators

    That's an odd failure mode. I've seen a couple of boards where the 5V or 3.3V rail appears to have been shorted to +12V or +24V, and in both cases the heaters turned on all the time AND some chips were getting hot (usually the 3.3V regulator, processor, and sometimes the 74HCT02 or 74HC125). If the 3.3V rail is only at 3.1V, that does suggest that the 3.3V rail is overloaded, in which case I would expect at least the 3.3V regulator to get hot.



  • Today i have checked again all the kable in the hope to find a blank or lose connection which can cause a short circuit something must have happened but i can't find it.
    The only part of the printer which are supplied with 24 V and 3.3V is the hot end but even there I found nothing I'm going crazy.

    I'm an electronics technician myself and this makes it twice bad that i can't find any error

    At one point we agree that the board seems to be defective what may have ever happened is there a way to get this board repaired? if yes how? this board is 2 months old



  • so far so good the printer works with a new Duet (except Y port) now is only the question what hav i to do to get the first board repaired ? can i send it directly or should i go to my German Seller?


  • administrators

    @SIam:

    Today i have checked again all the kable in the hope to find a blank or lose connection which can cause a short circuit something must have happened but i can't find it.
    The only part of the printer which are supplied with 24 V and 3.3V is the hot end but even there I found nothing I'm going crazy.

    I'm an electronics technician myself and this makes it twice bad that i can't find any error

    It's not uncommon for the cartridge heater in a hot end to develop a short between the element and the case, sometimes only when is hot. This puts the entire hot end metalwork at +12V or +24V. So you only need a short from the metalwork to something else on the hot end assembly to feed +12V or +24V to somewhere that it shouldn't be. The thermistor connections on the Duet are protected against this, but not the 3.3V pin on the Z probe connector that provides power to the Z probe. What type of Z probe do you have, and is there any possibility that it could have shorted against the hot end metalwork?



  • i don't use a z Probe i only have an Z-endstop switch.

    here are some photos from the hotend : https://photos.app.goo.gl/GfxbeygkryZRTKCE2


  • administrators

    So is there any 3.3V wiring on the hot end apart from the thermistor wires?



  • Looks like a large DSUB connector, perhaps a stray wire inside that connector shorted +24v to +3.3v?



  • on the first photo you see a gray flat cable this is the only 3.3V to the optical x endstop This cable goes directly to the Duet the other cable (fan/hotend and Thermistor) goes to the sub D connector and then to the Duet.
    All used pins in The sub D case are isolated with shrinking tube


  • administrators

    Please put in a warranty claim to your supplier.



  • ok Thank You i will contact my supplier


 

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