UNSOLVED How dead is my Duet 2 Maestro?



  • Long story short, I thought I would be fancy and try to replace my hot end umbilical cables (bltouch, part fan, hot end fan, y-end stop, and hot end thermistor) with a USBC cable connected via breakout boards. I got everything connected, turned on my printer, and there was a pop and a puff of smoke.

    Close inspection of the board reveals a small hole in the WIZnet W5500 networking chip alt text

    Based on my investigation of the incident, it would appear that I grossly underestimated the complexity of USBC wiring. alt text Through sheer bad luck, I wired the optical end stop (+3.3V) to A4, and the fan source (+12V) to A9 without realizing they are connected inside of the cable.

    I have some questions:

    • How might I go about troubleshooting the board to determine if this is the only damage done?

    • If I managed to only damage the ethernet controller, could the board still be controlled via USB (either a PC or octoprint)?

    • If I had access to the right facilities, could the ethernet controller chip be removed and replaced without having to do any SW/FW shenanigans?



  • @patrickwjoyce said in How dead is my Duet 2 Maestro?:

    How might I go about troubleshooting the board to determine if this is the only damage done?

    https://duet3d.dozuki.com/Wiki/What_to_do_if_your_Duet_won't_respond

    If I managed to only damage the ethernet controller, could the board still be controlled via USB (either a PC or octoprint)?

    sure, but i'd try to find away to use https://duet3d.dozuki.com/Wiki/Gcode#Section_M559_Upload_file so you can keep printing off the SD card with M23 & M24.

    If I had access to the right facilities, could the ethernet controller chip be removed and replaced without having to do any SW/FW shenanigans?

    if the damage is limited to the W5500 chip, yes. you could also see https://forum.duet3d.com/post/127089 but if I'm reading your post correctly you sent 12v to the 3.3v rail so i'd be concerned the cpu and sd card is also damaged, but see the first link


  • administrators

    If you are very lucky, the W5500 may have failed short circuit first and protected other components. If you have access to hot air rework equipment, you could try removing that chip and then see if the rest of the board works if you don't try to enable networking.



  • So the SD card appears to have also been fried. It does not register as being plugged in when using an external card reader on windows. That indicates that is likely other damage to the system.

    I do get the green 3.3v led, and red 5v led when connecting to usb power only. the red DIAG and reset leds are both staying lit. When connecting to windows, the device shows up as "Unknown USB Device (Device Descriptor Request Failed". Attempts to install the Duet driver are unsuccessful.

    I tried loading a new config + firmware on a new sd card, nothing seems to happen when connecting to USB power. Do I need the 12v power in order for the firmware to update from the SD card?


  • Moderator

    No usb power should be enough to flash the firmware just motors and heaters won't work.



  • @patrickwjoyce said in How dead is my Duet 2 Maestro?:

    I tried loading a new config + firmware on a new sd card, nothing seems to happen when connecting to USB power. Do I need the 12v power in order for the firmware to update from the SD card?

    no but the firmware could be corrupted; see https://duet3d.dozuki.com/Wiki/Installing_and_Updating_Firmware#Section_Fallback_procedure_Num_3

    long shot, if that works then go get a lottery ticket asap:)


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