Hotend heater shorted on



  • I have a a duet wifi and it has been working fine for a few months now but now all of a sudden. About half way through the first layer of a print i noticed smoke coming off my hotend. I then look and my extruder is around 320c and possibly Higher may have been max that thermistor could read. The firmware tried to shut it down but couldn’t. It would only cool down after i unplugged the power supply I had it plugged in through usb so i was able to see the thermistor was still working. Later with all power disconnected usb and 12volt i measured with a multi meter and found that the heater i terminal i was using was shorted to +12v. Im just glad i was able to catch it in time before it caught something on fire. If possible can i get i new one i can send my old one in if need be.



  • Usually caused by a short in the wiring; I'd go over the hotend wiring and remap E0 to E1 if its free.


  • administrators

    As @bearer says, one possible reason would be a short in the heater wiring, although if the short persisted then the 7.5A fuse would blow.

    Another possible cause is a transient on the +5V power rail that caused the mosfet driver IC to fail. However, in that case it's likely that all three heater outputs would be stuck on.

    How long have you had the Duet, and which country are you in?



  • @dc42 I purchased it on july 7th and I live I the usa.
    Also i just measured all fuses are good and the bed heater output is shorted also all though it wasn't used.


  • administrators

    @joshuamensch said in Hotend heater shorted on:

    @dc42 I purchased it on july 7th and I live I the usa.
    Also i just measured all fuses are good and the bed heater output is shorted also all though it wasn't used.

    It sounds like the mosfet driver chip has failed then. Is everything else working? Is the E1 heater LED on too? Are you using the internal 5V power, or external 5V?



  • I was using internal 5 volt unless usb 5volt counts both hotend heater leds are on as soon as i give it 12volt power and i can only get 12volts from e0 even though the e1 led is on. I am also getting 12volt from the bed heater output of which i never used. Other than the issues i just mentioned everything else it working and i can read temperatures and move motors.



  • @dc42 so am i able to get it replaced?


  • Moderator

    Where was the board purchased on July 7th? If it was from an authorized reseller, then it would be within the 6 month warranty.

    https://www.duet3d.com/GenuineResellers



  • It was bought from filistuder


  • Moderator

    Thanks. Please contact Filastruder to initiate a warranty exchange. Refer them to this thread as authorization.


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