Smoke Smoke Smoke!



  • I have a rostock max v3 that i put a duet wifi in. It has worked great for about 300 hours and last night i was printing abs. Went good for about 2 hours and then the cooling fan kicked in for a bridge or something and smoke started coming off the board. Hit the power switch right away and had a look. Disconnected the cooling fan. (I use a berd-air with eswitch module) and tried the power. More smoke.

    I disconnected everything and took out the board and the mosfet seems to be ok. The smoke seems to have been coming from the always on fan port. Cleaned it up a bit with IPA and desoldered the connection and it is quite damaged underneath.
    i had 2 12v 0.1a 40mm fans connected in parallel to the always on fan port.
    Does anyone have any ideas?




  • Are the fans working normally? Are they shorted? Might a wire have been pinched somewhere?

    Looks nasty.



  • fans seem fine. Wires are not pinched. Definitely shorted but i think shorted on the board. There is only 45ohm resistance across the always on fan port


  • administrators

    I'm sorry to hear of your misfortune. It sounds to me that you have or had a short across the VIN rail, either in your always-on fan wiring or possibly a stepper driver. Is there any sign of damage to any of the stepper driver chips?

    Can you confirm that you are using 12V power?



  • @dc42:

    I'm sorry to hear of your misfortune. It sounds to me that you have or had a short across the VIN rail, either in your always-on fan wiring or possibly a stepper driver. Is there any sign of damage to any of the stepper driver chips?

    Can you confirm that you are using 12V power?

    I cannot see any visible problems with the stepper chips. I am using 12V.


  • administrators

    With everything disconnected from the Duet, do you also get 45 ohms resistance across the VIN terminal block connections? Is it the same whichever way round you connect the multimeter?



  • @dc42:

    With everything disconnected from the Duet, do you also get 45 ohms resistance across the VIN terminal block connections? Is it the same whichever way round you connect the multimeter?

    Yes that is with everything disconnected. It kinda jumps all over but the most stable, when i hold really still i get 45ohm. Same both ways.


  • administrators

    Thanks. We'll replace your board under warranty, but we'd like the old one back for investigation because it's such an unusual fault. Please contact your supplier.


  • administrators

    Thanks for getting in touch we will email you with replacement details.


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