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    Shorted circuit for hot end fan

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    Duet Hardware and wiring
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    • Phaedruxundefined
      Phaedrux Moderator
      last edited by

      The damage isn't always visible.

      You can test them with a multimeter. Be careful with the probe tips.

      https://www.google.com/search?q=testing+mosfet+with+multimeter&oq=testing+mos&aqs=chrome.3.69i57j0l9.4510j0j7&sourceid=chrome&ie=UTF-8

      Z-Bot CoreXY Build | Thingiverse Profile

      gpermanundefined 1 Reply Last reply Reply Quote 0
      • gpermanundefined
        gperman @Phaedrux
        last edited by gperman

        @phaedrux digikey kept sending me the wrong components.

        I resoldered in a new mosfet but that didnt change any symptoms. Took the hot fan off and tested, works good. heated the hot end up past the threshold fo rthe fan and only see 3v at the pins off the duet2 wifi board.

        I replaced the mosfet at TR5 (Fan0) I believe that's the correct fan for the hotend. No effect.

        I suppose I could switch the fan to pwm fan2 but that doesn't fix my board.

        dc42undefined 1 Reply Last reply Reply Quote 0
        • Phaedruxundefined
          Phaedrux Moderator
          last edited by

          Can you show a photo of the repair job?

          Z-Bot CoreXY Build | Thingiverse Profile

          gpermanundefined 1 Reply Last reply Reply Quote 0
          • gpermanundefined
            gperman @Phaedrux
            last edited by

            @phaedrux alt text

            gpermanundefined 1 Reply Last reply Reply Quote 0
            • gpermanundefined
              gperman @gperman
              last edited by

              @gperman sorry for the poor camera quality. That was the best I could do. These are very small.

              1 Reply Last reply Reply Quote 0
              • gpermanundefined
                gperman
                last edited by

                @gperman i didnt touch anything but TR5

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                • dc42undefined
                  dc42 administrators @gperman
                  last edited by

                  @gperman said in Shorted circuit for hot end fan:

                  @phaedrux Thank you!

                  Also, does anyone know of a wire strain relief apparatus that goes on the two main in connectors for a smart effector? The movement of the effector keeps breaking my wires art the crimp.

                  I tie the cables to the Bowden tube. It doesn't completely eliminate flexing, but it does reduce it.

                  Duet WiFi hardware designer and firmware engineer
                  Please do not ask me for Duet support via PM or email, use the forum
                  http://www.escher3d.com, https://miscsolutions.wordpress.com

                  gpermanundefined 1 Reply Last reply Reply Quote 0
                  • dc42undefined
                    dc42 administrators @gperman
                    last edited by

                    @gperman said in Shorted circuit for hot end fan:

                    @phaedrux digikey kept sending me the wrong components.

                    I resoldered in a new mosfet but that didnt change any symptoms. Took the hot fan off and tested, works good. heated the hot end up past the threshold fo rthe fan and only see 3v at the pins off the duet2 wifi board.

                    I replaced the mosfet at TR5 (Fan0) I believe that's the correct fan for the hotend. No effect.

                    I suppose I could switch the fan to pwm fan2 but that doesn't fix my board.

                    Check that you still have VIN voltage on the positive output pin of the fan connector. Also measure the gate to source voltage of the mosfet. It should be 3.3V when the fan is supposed to be on, and 0V when it is supposed to be off.

                    Duet WiFi hardware designer and firmware engineer
                    Please do not ask me for Duet support via PM or email, use the forum
                    http://www.escher3d.com, https://miscsolutions.wordpress.com

                    gpermanundefined 1 Reply Last reply Reply Quote 0
                    • gpermanundefined
                      gperman @dc42
                      last edited by gperman

                      @dc42 i measured the V+ Header pin on the duet2wifi board (multimeter between v+ and - ) when the fan is supposed to be on and it outputs 3.something volts. Forgot to write it down.

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                      • gpermanundefined
                        gperman @dc42
                        last edited by

                        @dc42 performed a mosfet continuity test as per:
                        https://www.google.com/search?q=testing+mosfet+with+multimeter&oq=testing+mos&aqs=chrome.3.69i57j0l9.4510j0j7&sourceid=chrome&ie=UTF-8#kpvalbx=_6gCnYJmFE-yj_Qb_xKjgBg17

                        Realllllly difficult to get my finger in there to short out all 3 pins but i think I did......maybe.

                        When I short out all 3 then probe source to drain I get temporary continuity that slowly dissipates to open circuit. Then probe source to gate and get the same thing......light continuity 1900 or so that dissipates to 1.

                        pretty sure its a bad mosfet. Going to resolder one in and do it again I guess.....

                        gpermanundefined 1 Reply Last reply Reply Quote 0
                        • gpermanundefined
                          gperman @gperman
                          last edited by

                          Using that test from that link, I cant seem to turn on any of my mosfets. I tried 4 so far. Held probes to source and gate then source and drain, nothing. No continuity

                          gpermanundefined 1 Reply Last reply Reply Quote 0
                          • gpermanundefined
                            gperman @gperman
                            last edited by gperman

                            yea this circuit is dead. I ripped the copper trace off the board for the source terminal.

                            I cant even get the hotfan to work with the fan2 circuit. I am way out of my depth here. All I've managed to print is benchies after 2 year of owning this predator. I think it's time to toss this whole thing in the trash and buy a prusa.

                            dc42undefined 1 Reply Last reply Reply Quote 0
                            • dc42undefined
                              dc42 administrators @gperman
                              last edited by

                              @gperman said in Shorted circuit for hot end fan:

                              yea this circuit is dead. I ripped the copper trace off the board for the source terminal.

                              I did that once. I repaired it by adding a fine wire between the mosfet source terminal and a nearby component that was connected to ground.

                              Duet WiFi hardware designer and firmware engineer
                              Please do not ask me for Duet support via PM or email, use the forum
                              http://www.escher3d.com, https://miscsolutions.wordpress.com

                              gpermanundefined 1 Reply Last reply Reply Quote 0
                              • gpermanundefined
                                gperman @dc42
                                last edited by

                                @dc42 I bought the genuine duet2 wifi board from you. can I send it back to you for repair? how much would that cost?

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                                • Phaedruxundefined
                                  Phaedrux Moderator
                                  last edited by Phaedrux

                                  Where are you located? May find a local option here: https://forum.duet3d.com/topic/13875/community-repairs?_=1622215254328

                                  Z-Bot CoreXY Build | Thingiverse Profile

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