Damaged Duet Wifi



  • I currently own a Duet Wifi and have been using it for a while now to control my homemade 3d printer. However recently I was attempting to wire up a laser driver so that I could use the printer as a laser etcher and something has happened to the Duet.

    If i connect the duet to a pc via USB then the board powers on and i can connect to the web interface as usual with the endstops working as expected. However whenever I power the board from my 24V supply like i normally would, the led next to the wifi module will flash on initially but the board does not connect to the wifi and i'm unable to connect to the web interface. Also the endstop leds (normally closed) turn on initially but then go off and the endstops are unresponsive. The only LEDs that stay on are the blue power LED and the red 5V LED.

    Do you have any suggestions as to what may have happened to my board? What i was attempting to do was power a 12V regulator from my 24V supply and use the output of that as power for the laser with the 5V output from the Fan3 header (I have the fan power jumper set to 5V not VIn) to the 5V TTL input of the laser driver.

    Obviously I've done something to it and i'm assuming it's something to do with the power delivery but it isn't completely dead so i'd rather not have to buy a brand new Duet if there's any chance of fixing it.

    Thanks


  • administrators

    My guess is that something attached to the 3.3V rail is drawing excessive current. Check whether the 3.3V regulator chip (U2, the one with 3 legs on one side and a tab on the other side) is getting hot. If it is, find out what other chip is getting hot.



  • Thanks for the response, U2 is indeed getting hot but nothing else seems to be and the issue still occurs with everything disconnected from the board.



  • I've just checked the voltages across U2 and Vin is coming up as 5.38V but Vout is only 0.92. Could U2 itself be the problem?


  • administrators

    @blocky82 said in Damaged Duet Wifi:

    I've just checked the voltages across U2 and Vin is coming up as 5.38V but Vout is only 0.92. Could U2 itself be the problem?

    It's possible, however the input shouldn't be as high as 5.38V. The output from the internal 5V regulator is normally close to 4.90V.

    Which country are you in?



  • I'm in Australia, the board is running off a Meanwell 24V power supply



  • I've just moved the power jumper to use external 5V, powered up with the 24V supply and USB and everything seems to work ok! I'll find a 5V supply and a relay and hook them up so i can control the 24V from the web interface.

    There's obviously something damaged with the VIn to 5V circuitry but I'm happy enough with this workaround.

    Thanks for all your help


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