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    12V on the 5V rail

    Duet Hardware and wiring
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    • Haggan90
      Haggan90 last edited by

      How screwed am I if I manage to connect 12VDC on the 5VDC rail?

      DuetWifi...

      droftarts dc42 zapta 3 Replies Last reply Reply Quote 0
      • droftarts
        droftarts administrators @Haggan90 last edited by droftarts

        @Haggan90 Usually terminal. See https://duet3d.dozuki.com/Wiki/How_to_destroy_your_Duet_2

        Ian

        Cartesian bed-slinger with Duet 3 Mini 5+ WiFi : RRP Fisher Delta v1 with Duet 2 Maestro : TronXY X5S with Duet 2 Wifi (in progress)

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        • Haggan90
          Haggan90 last edited by

          ![alt text](ops.PNG image url)

          If I connected 12VDC there (beautiful red arrow), am I screwed then? 😃

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          • dc42
            dc42 administrators @Haggan90 last edited by

            @Haggan90 said in 12V on the 5V rail:

            How screwed am I if I manage to connect 12VDC on the 5VDC rail?

            Unfortunately, for every 3D printer controller board on the market except Duet 3, that will usually cause multiple components to fail. As it was 12V not 24V, there is a chance that one of the components on the 3.3V rail (most likely SD card or WiFi module) will have failed in such as way as to protect the rest. To test that you would need to remove the 3.3V regulator chip and the 74HCT02 mosfet driver chip, apply an external 3.3 supply to the 3.3V rail (or you could replace the 3.3V regulator chip and apply USB power), and see what gets hot. If the processor doesn't get hot, it's worth trying to connect to it over USB; and if that doesn't work, use the Erase jumper and see if you can get he Bossa port to appear (because I've heard of an over-voltage erasing the firmware but the processor still working afterwards).

            Duet 3 has been designed to survive that type of accident, although other devices powered from the 5V rail (e.g. RPi or PanelDue) would have been damaged.

            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

            Haggan90 2 Replies Last reply Reply Quote 0
            • Haggan90
              Haggan90 @dc42 last edited by

              @dc42 do you think mt duex2 got damage as well?

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              • Haggan90
                Haggan90 @dc42 last edited by

                @dc42 I can't find the 74HCT02 chip.
                The only component that seems off is this one.

                2020-3-20 19-15-25.jpg

                A Former User 1 Reply Last reply Reply Quote 0
                • A Former User
                  A Former User @Haggan90 last edited by

                  @Haggan90 said in 12V on the 5V rail:

                  I can't find the 74HCT02 chip.

                  and yeah, u2 is done for

                  6c948227-7cfa-435e-95bc-af7565fdcb31-image.png

                  Haggan90 1 Reply Last reply Reply Quote 0
                  • Haggan90
                    Haggan90 @Guest last edited by

                    @bearer Yeah, that's what I tought.. Could it be fixed if I just replaced U2? 😃
                    What does U2 do?

                    A Former User 1 Reply Last reply Reply Quote 0
                    • A Former User
                      A Former User @Haggan90 last edited by

                      @Haggan90 said in 12V on the 5V rail:

                      Could it be fixed if I just replaced U2?

                      Theoretically. It provides 3.3v to the system. U11 / 74HCT02 drives the heater mosfets. But there could be more damage as well. I'd remove U2 and apply an external, preferably current limited supply to test.

                      Haggan90 1 Reply Last reply Reply Quote 0
                      • Haggan90
                        Haggan90 @Guest last edited by

                        @bearer Ok!
                        I've removed U2, where can I connect 3.3V and what should I set the current limit to? 😃
                        Btw, I tried the SD card and it seems to work fine.

                        A Former User 1 Reply Last reply Reply Quote 0
                        • dc42
                          dc42 administrators last edited by

                          A current limit of 200mA should be enough if nothing else is damaged, until you turn the WiFi module on. With WiFi on you may need 600mA.

                          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

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                          • A Former User
                            A Former User @Haggan90 last edited by

                            @Haggan90 said in 12V on the 5V rail:

                            where can I connect 3.3V and what should I set the current limit to?

                            i've found that making a cable to connect to CONN_SD gives me convenient access to gnd, 3v3 and 5v connections. You can use single du-pont style wires as well. In general you can use any 3.3v pin shown on the wiring diagram. as dc42 said, 200mA is a good starting point; if it goes into current limiting mode try 300mA but if it takes more than a second or two to charge up capacitors and start up then start looking for what gets warm.

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                            • zapta
                              zapta @Haggan90 last edited by

                              @Haggan90, you can find the duet wifi schematics in the link below. It may help you understand what's is going on.

                              https://github.com/T3P3/Duet/tree/master/Duet2/Duet2v1.04

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                              • dc42
                                dc42 administrators last edited by

                                You can feed the 3.3V into any endstop connector.

                                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

                                Haggan90 1 Reply Last reply Reply Quote 0
                                • Haggan90
                                  Haggan90 @dc42 last edited by

                                  @dc42 I connected 3.3V and nothing got hot.
                                  When I connected USB I got 4.4V in the 3.3V rail...

                                  A Former User dc42 2 Replies Last reply Reply Quote 0
                                  • A Former User
                                    A Former User @Haggan90 last edited by

                                    @Haggan90 said in 12V on the 5V rail:

                                    When I connected USB I got 4.4V in the 3.3V rail...

                                    after removing the 3.3v volt regulator? strange, please post a picture of the board?

                                    Haggan90 1 Reply Last reply Reply Quote 0
                                    • Haggan90
                                      Haggan90 @Guest last edited by

                                      @bearer I connected 3.3V to where the regulater output was.
                                      20200322_073622.jpg

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                                      • dc42
                                        dc42 administrators @Haggan90 last edited by

                                        @Haggan90 said in 12V on the 5V rail:

                                        @dc42 I connected 3.3V and nothing got hot.
                                        When I connected USB I got 4.4V in the 3.3V rail...

                                        Remove the other blown chip too.

                                        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

                                        Haggan90 1 Reply Last reply Reply Quote 0
                                        • Haggan90
                                          Haggan90 @dc42 last edited by

                                          @dc42 You mean the U11 / 74HCT02?

                                          dc42 1 Reply Last reply Reply Quote 0
                                          • dc42
                                            dc42 administrators @Haggan90 last edited by

                                            @Haggan90 said in 12V on the 5V rail:

                                            @dc42 You mean the U11 / 74HCT02?

                                            Yes.

                                            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

                                            Haggan90 2 Replies Last reply Reply Quote 0
                                            • Haggan90
                                              Haggan90 @dc42 last edited by

                                              @dc42 aha ok! I have to do that at work where we have a hot air solder gun

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                                              • Haggan90
                                                Haggan90 @dc42 last edited by

                                                @dc42 Hi!

                                                Sorry for taking such long time for this, but now I have manage to replace the U2 and U11.
                                                When I connect the Duet to USB I get a warning of high current cunsumtion on the USB port, and U2 get's really hot.

                                                Do you have any slightest idea of what else could be broken?

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                                                • dc42
                                                  dc42 administrators last edited by dc42

                                                  What else is getting hot? Start by checking the processor, SD card (if it is in the socket), and WiFi module.

                                                  Are you certain that you used the correct chip to replace U2? Different hardware versions of the Duet WiFi use different chips in that position.

                                                  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

                                                  Haggan90 1 Reply Last reply Reply Quote 0
                                                  • Haggan90
                                                    Haggan90 @dc42 last edited by

                                                    @dc42 hi!
                                                    As far as I can nothing else get's hit then the U2. Here are the new components.
                                                    2020-4-26 10-27-58.jpg 2020-4-26 10-28-13.jpg

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                                                    • dc42
                                                      dc42 administrators last edited by

                                                      What part number did you use for the 3.3V regulator, and what hardware revision Duet board is it? I think you may have used the wrong regulator.

                                                      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

                                                      Haggan90 1 Reply Last reply Reply Quote 0
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