Please help me. Owner of a handful

  • I have been a user of these really useful and amazingly supported 32-bit boards side the 0.8.5 iteration, and now have moved on to the WiFi boards and have really enjoyed the process…up until recently. So, I have two nearly identical MetalMax delta frames setup both with 24V, .9° steppers, top of the line extruder from E3D and, and I suppose the only real difference lies in the hotend configuration -- one has a the trusty E3Dv6 (volcano and regular type) while the other is the more experimental setup that currently has a Cyclops switching dual filament on it that I've been tinkering with. My problem is that now I'm the annoyed owner of approximately 5 or so Duet WiFi boards that are useless and all share the same problem -- the temperature sensing channels are all blown -- I think -- and I'm so frustrated I could cry. It began a little while back when I decided to equip my rigs with MakerHive quick change effector boards to facilitate quick hotend swaps. At one point, during resist operation of the printer, suddenly I noticed error readings on both hotend and heated bed on my paneldue display. Convinced that there must've been some kind of mistake or something, I spotted the effector onto the other further WiFi unit and powered on and it was contagious! That board began the symptoms described above. Upon closer inspection I noticed that one of the crimped wires in the 12-pin connector (hosting thermistor, fan, and power) came frayed and I suppose must have contacted another adjacent pin and short circuited something and blown the temp channels. So there's two boards down. Replaced them and then couple weeks ago I was rewiring one of the quick change connectors and didn't realize there was power to the printer since the display was not connected at the time, and pulled a real amateur move when I took my snips and cut the bunch of wires simultaneously when a spark lit up and thereafter, again, errors top and bottom of paneldue temperature readings. Replaced board again, then vowed to be super extra careful from that point forward to avoid any such mishaps until today, while simply adjusting my mini it sensor, I honestly don't know what could've caused this SAME issue, but it has occurred yet again....AND I'M VERY upset about it. I can't f'ing believe it has occurred yet again. Now I have a handful of boards with the same issue and I'm so frustrated I can't verbalize it properly. HELP PLEASE Tony or David or Ian or someone...WTF?!?!?!?

    Hope everyone is having a a better day than I.


  • Most likely the VSSA fuse has blown.

  • administrators

    I agree, check the VSSA fuses on the boards. With power off, measure the resistance between the VSSA pin of any of the thermistor connectors and the ground pin of any endstop connector. It should be just a few ohms. If it is a lot more, the VSSA fuse has blown. If you replace it, the board may work again.

  • Is there an equivalent SMT part number for that same sized fuse that someone can get to replace it when its blown? I've seen some people modify their boards for a larger fuse and that seems sub optimal.

  • administrators

    Spare part numbers are listed at However, there is a Littlefuse part that is easier to solder than the AVX part so I'll add that part number to that page later today.

  • thanks for the replies and the potential fix, I'll look into it first chance i get tomorrow afternoon and post back my results. As an added bit of potentially useful troubleshooting info, I purchased a Duex5 expansion board and at one point prior to one of the multiple replacements I kept buying, I figured quite likely i could bypass the problems onboard and simply offload the thermistor and heaters to the expansion board. Despite the sound logic that would appear in this notion, I was unsuccessful in getting that method to pan out. Only thing there is that there exists the possibility that I simply misconfigured the expansion board by maybe incorrect syntax, but IIRC it involved adding the term X(followed by the number of channelyou wish to remap the original one to, in a fashion analogous to how you'd enter X200 to tell it that you're using PT100 channel 0 on addon board). Not certain thats all that was needed, but in short, it didn't work out for me – that way. I'm curious why simply moving my thermistor to E1 input and changing config accordingly also resulted in a not working workaround for the time being just to be able to still play around. Any wise words for this issue guys?

    Very much appreciated. Thanks to all who've read this and more thanks to everyone who's pitched in to assist. I love this forum.


  • administrators

    The VSSA line (analog ground) is common to all thermistor channels, including the ones on the DuetX5. So if the VSSA fuse blows, all of the thermistor channels will read open circuit.

    The good news is that replacing the VSSA fuse will probably get most of your Duet WiFi boards working. The one that was connected when you cut through a bundle of live wires may have other damage as well.

  • Many many thanks…for everything you do, really. Bravo. That is definitely a relief.

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