heated bed not turning on



  • hi i have just installed my new 3d printer and the heated bed don't seem to be powering up

    the thermistor is registering ok and when i click to turn the heated bed on i get no power from the 2 terminals that are supposed to power up

    I've tested the bed on a 12v power supply

    the board is powered by 24v supply and i step it down to 12v once it comes to the bed but I'm getting nothing from the duet board at all from the heated bedside. everything else seems to work ok
    my heater settings are below its a delta printer

    ; Heaters
    M305 P0 T100000 B4725 C7.060000e-8 R4700 ; Set thermistor + ADC parameters for heater 0
    M143 H0 S120 ; Set temperature limit for heater 0 to 120C
    M305 P1 T100000 B4725 C7.060000e-8 R4700 ; Set thermistor + ADC parameters for heater 1
    M143 H1 S300 ; Set temperature limit for heater 1 to 300C


  • administrators

    How are you stepping the voltage down to 12V? Please post a wiring diagram.



  • @dc42 said in heated bed not turning on:

    How are you stepping the voltage down to 12V? Please post a wiring diagram.

    im not stepping anything down as i don't have it wired in yet im just testing the voltage coming out from the heated ped pins once i turn the heated bed on and there is no voltage coming from the heated bed pins.

    but once i get a voltage i will be sending it to a 24 to 12 voltage stepper then out to the bed


  • administrators

    1. How are you trying to turn the bed heater on?

    2. Are you sure that the bed heater is on in the Fault state?

    3. Does the red LED near the bed heater turn on when you command the bed heater on?



  • The bed is working. I tried it on an external voltage.
    I'm turning the bed on via the web control

    And I fitted an external temp sensor from an hot end so it don't go in to a failed state

    And I'm getting no voltage using a volt tester



  • Also on board fuse intact



  • anyone ??? do i have a faulty board ????


  • administrators

    What state does DWC show the bed heater to be in? It should start in the Off state, then when you try to heat it, it should go to the Active state; then after a while (30 seconds by default AFAIR) if the bed temperature isn't rising it should go into the Fault state.



  • @dc42 said in heated bed not turning on:

    What state does DWC show the bed heater to be in? It should start in the Off state, then when you try to heat it, it should go to the Active state; then after a while (30 seconds by default AFAIR) if the bed temperature isn't rising it should go into the Fault state.

    that means cabling it all up and i dont see the point if there is no voltage coming from the terminals in the first place


  • administrators

    No it doesn't mean cabling up the heater. The point is that if the firmware has put the heater in the Fault state, it will refuse to turn it on.



  • @dc42 said in heated bed not turning on:

    The point is that if the firmware has put the heater in the Fault state, it will refuse to turn it on.

    the state is fine it's not showing a fault its ready to be turned on and the temp stays at 25 for a while then it goes to fault after a few seconds. but there's still no voltage coming from the terminals when i turn it on


  • administrators

    @dmkmedia said in heated bed not turning on:

    @dc42 said in heated bed not turning on:

    The point is that if the firmware has put the heater in the Fault state, it will refuse to turn it on.

    the state is fine it's not showing a fault its ready to be turned on and the temp stays at 25 for a while then it goes to fault after a few seconds. but there's still no voltage coming from the terminals when i turn it on

    Please run M140 without parameters to check that the bed heater is correctly configured. It should respond something like this:

    Bed heater 0 (slot 0) is currently at 28.4°C

    The "Slot 0" means it is configured to use heater 0, which is the bed heater output. if you do get a response similar to this, then it looks as if your Duet may be defective and you should ask your supplier to replace it.



  • yes it is i just fitted a new board i had spare and it all works now


  • administrators

    @dmkmedia said in heated bed not turning on:

    yes it is i just fitted a new board i had spare and it all works now

    In that case, please ask your supplier to replace the other one under warranty. If you bought it direct from duet3d.com, see https://www.duet3d.com/warranty.


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