PWM fan controller possibly destroyed - advise requested



  • @dc42:

    Hi Sethipus, I'm sorry to hear of your misfortune. It sounds likely that you have blown the FAN0 mosfet. This is not difficult to replace. Do you know anyone who has hot air desoldering equipment?

    Yes you can map fan 0 to fan 2 in the M563 commands.

    Thanks for your response David.

    I have a soldering station that has a hot air gun for doing surface mount stuff, but I've never done any. I even have a tube of solder paste I bought once when I thought I might do some surface mount stuff, but it never happened. I've only used the normal soldering gun part of the station. I wouldn't mind having a look at the mosfet that would need to be replaced if you don't mind telling me what it is, and I'll make an informed decision on whether it's worth the risk having me actually try to do that. 🙂

    In the meantime, after my fanless PETG print finished, I edited config.g and added F2 to the T0 and T1 definitions. I've got a print going right now, and the fan kicked in at the appropriate time. The fan slider in the web interface no longer works, but that's not that big a deal. I can make a macro to turn it on if I need to, for testing purposes or whatever.

    So, honestly, I might well be better advised to just leave well enough alone. I'm down a PWM header, but I've got a fully functioning printer at the moment with what's actually on it right now. I'll still have a look at the mosfet though.

    I had no idea how weak that Noctua fan was for cooling PLA. Naturally I don't use much cooling for PETG, but I've been trying out Hatchbox wood-filled PLA lately, and it's runny as hell, and apparently needs all the cooling it can get. The Sunon fans will be here in a couple days. It will be annoyingly loud, but hopefully will get the job done.


  • administrators

    See https://duet3d.com/wiki/Connector_and_spare_part_numbers#Fan_mosfet for info on replacing the PWM fan mosfets.



  • Thanks David! I just ordered some mosfets. We'll see if I end up actually doing it, or whether I decide to cut my losses and just the the Duet Wifi as presently configured, since it is in fact working now.



  • I just wanted to say that I just replaced my fan1 mosfet as I must have shorted some wires during installation. I don't have a hot air station and I'd never done any surface mount soldering before, but I did get it replaced and with no collateral damage. Had I known the package with the mosfets was getting delivered that day, I would have waited until afterwords for my normal coffee break as the hands were a bit jittery after that caffeine injection.



  • Fabulous, had the same problem, ordered the part, question though.

    I still measure 24v coming from the wire .

    Would you still measure voltage if its the mofset blown?



  • Im not bad at soldering with an iron, but dont have a hot air gun solder station is it going to be possible to change the mosfet with a temp controlled iron, magnifyer, a steady hand and nerves of steel?


  • administrators

    The tricky part is removing the old mosfet without lifting the PCB traces. I've never tried that without using hot air to heat all 3 joints at the same time. I found this video on removing SOIC ICs without hot air: https://www.youtube.com/watch?v=tlSY1uaw0GA. Maybe it would work for small mosfets too.

    The new mosfet can be soldered in place using tweezers and a soldering iron with a fine-tipped bit.



  • that video makes it look too easy, We will see I guess possibly this week end then I get get my Printer to be quiet again, Thanks Admin Great board.



  • Did it in 20 min with my intermediate soldering skills. Fan started working right away. Thanks guys for the clear info on what , where , and making possible the components to be replaced.

    Cheers
    Stav



  • @dc42:

    The tricky part is removing the old mosfet without lifting the PCB traces. I've never tried that without using hot air to heat all 3 joints at the same time. I found this video on removing SOIC ICs without hot air: https://www.youtube.com/watch?v=tlSY1uaw0GA. Maybe it would work for small mosfets too.

    The new mosfet can be soldered in place using tweezers and a soldering iron with a fine-tipped bit.

    I cut the legs and de-soldered each one. I was not comfortable using my hot air station there as it's pretty dense.


  • administrators

    My worry has always been that if I try to cut the legs, the PCB pads would lift. I guess it's OK if your cutters are sharp enough!


 

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