Hi

A couple of days ago the hotend wouldn’t heat up and i got a couple of errorcodes/warnings in the display. The bed heats up just fine, so i ordered a new hotend parts (heater, thermistor and a new aluminum block). Changed all of this, but still the same error. I can se that the thermistor works because it changes values in the display when touching the thermistor-end. Any good ideas why the heater doesn’t heat?

  • UncleStewart@sh.itjust.worksOPEnglish
    1·
    3 months ago

    Yeah, i have ohm’ed the heater. It actually was the same resistance as the one i thought was dead… I don’t remember the value (I’m at work right now)

    • papalonian@lemmy.worldEnglish
      2·
      3 months ago

      You don’t want to read the resistance of the heater. You want to find the voltage being sent to the heat cartridge.

      When you’re able to, disconnect your heat cart and stick your multimeter probes in the socket (or touch the top of the cable screws), and heat the nozzle. Should read 24v IIRC. Based on your answer to my other comment, my assumption is the number will not change when you turn on the heater, implying board or mosfet failure.

      • UncleStewart@sh.itjust.worksOPEnglish
        1·
        3 months ago

        Home, and done some measuring.

        1. measurement:
          Just started the printer: 1,24 VAC
          Preheating the nozzle: 0,00 VAC
          After error beep: 1,24 VAC
        2. measurement:
          Just started the printer: 1,57 VAC
          Preheating the nozzle: 0,00 VAC
          After error beep: 1,57 VAC

        Old heater: 13,6 Ohm
        New heater: 14,6 Ohm

        So, no power to the nozzle heater. Now, how to verify the mosfet?

      • UncleStewart@sh.itjust.worksOPEnglish
        1·
        3 months ago

        I will measure the voltage when I get back home later today. It probably will show no volts, so which board is defect? The little one in the hotend or the board on the other side of the USB-C cable? How to verify the mosfet?

        • papalonian@lemmy.worldEnglish
          2·
          3 months ago

          so which board is defect? The little one in the hotend or the board on the other side of the USB-C cable?

          My money is on the main board inside the printer. The “board” on your hotend (if it’s like others) doesn’t really have any computers or controllers on it, it’s more like a fancy cable connector between the main board and those components.

          If you test the voltage and get nothing, it’s either the main board or the mosfet for the heater. If you test it and it gives you a stable 24v, the problem lies somewhere between the main board and the heat cartridge (cable, connector, the hotend board, cartridge itself).

          Can’t say for sure without looking up your board and pin out chart but I’m pretty confident you’re probing one of these guys

          • UncleStewart@sh.itjust.worksOPEnglish
            1·
            3 months ago

            1. Power from PDU = OK
            2. Power to bed heater = OK
            3. Looks like power to the nozzle heater = same results as when checking volts directly on the hotend.
            4. Empty

            #3 goes up to a board back on the printer. This board has multiple outlets, and one USB-C that goes up to the hotend.

                • papalonian@lemmy.worldEnglish
                  2·
                  3 months ago

                  So that little board is simply connecting all the cables from the main board into one cable (the USB C cable). If you’re getting nothing from the main board, either the board itself or the mosfet for the heater is dying.

                  Honestly, I don’t know how you’d go about testing board vs mosfet, if it were me I’d just replace the board, but somebody else might be able to tell you if there’s a better route to take

                  • UncleStewart@sh.itjust.worksOPEnglish
                    1·
                    3 months ago

                    Yes, that little board connects many of the cables from the main board to one USB-C, the the black and the white connectors. The USB-C is the only one going to the hotend.
                    Anways, thank you, kind internet stranger, for trying to help me out with this. Looks like I’m gonna have to replace the mainboard.