No green 3.3volt LED on mainboard


    "Yes, the Duet series generally tolerates having +3.3V shorted to ground due to mis-wired endstops, whereas mis-wired endstop switches is one of two common causes of blown regulators on Arduino/RAMPS. Had you known where to look, you would have noticed that the green LED indicating +3.3V power was not lit."

    what green LED? I have no such LED lit on my duetwifi, never seen one.

    duetwifi works fine…......

  • administrators

    At the left hand end of the edge of the Duet WiFi with the SD card and USB connector, there are 5 LEDs: E1 heat (red), E0 heat (red), VIN (blue), +5V (red), and +3.3V (green). The +3.3V LED can be rather dim on white pre-production boards.

  • I have a blue batch5 board. Yeah I can see the writing with a magnifying glass but it isnt lit. I pulled the end stops, no difference. Board seems to work fine as far as I can tell.

  • Tested end stops that are NO. When I close them the LED at each stepper plug lights so there is 3.3v there, or some sort of voltage anyway.

  • I actually dont recollect ever seeing one so I'll assume for now it is a dud LED. Is there anything else to look at?

  • Found a pic of when I first turned it on with nothing connected, it had a green LED then, the Q is then why not now. The regulator must be OK or the duetwifi wouldnt work?

  • administrators

    Yes, the 3.3V supply must be present if the board is responding. I suspect that either the LED has been damaged, or one end of it is not soldered down properly.

  • One of the things that made me hesitate on buying the duetwifi was the possibility I'd destroy it. So I ummd and ahh'd for weeks, but "jetguy's" recommendation sealed it. I mean a complete with mega and screen cheap ramps 1.4 is $35US v 150US for the duetwifi, expensive if I use it as a fuse for a first time try.


    and yes i know a cheap ramps is utter crap. Kind of strange really, as an engineer I buy good tools. The best I can afford, yet people insist on buying the equiv of tools from the $2 shop and expect great results.

    Ive only printed two calibration tests so far but if the finish I am getting with the same g-code is a good indication the Duetwifi was worth every penny. Congrats on it.

  • I guess I can carefully put a voltmeter in there as one end should have 3.3volts?

    I assume I could be brave and de-solder the Led…..

    What I did with the original setup was buy 4 tiny voltmeters to monitor this stuff trying to trace a fault, probably OTT now.

  • administrators


    what green LED? I have no such LED lit on my duetwifi, never seen one.

    I know you now which LEd we are referring to now, however for other reference I have added to the documentation:

  • I have lost one too ((
    Is it necessary to remove the faulty LED or i can leave it as is?

  • administrators

    You can leave it as it is.

  • @dc42:

    You can leave it as it is.

    Thanks David!

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