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Thread: I think i destroyed my Teensy 4.0

  1. #1
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    I think i destroyed my Teensy 4.0

    It seems like, altough Im pretty experienced with microcontrollers and embedded, i somehow burned my Teensy 4.0 away. Its not getting recognized by windows anymore + its not drawing power anymore. By inspecting the board visually, i recognized, that the one part on the board gets extremely hot, which is surely not normal.

    Can someone tell me, what the part exactly does and what could be the reason for it to break down and overheat extremely?

    Thank you guys very much in advance!Click image for larger version. 

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  2. #2
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    that is the 3.3 v regulator
    how very hot but no current ? - it normally takes LOTS of current to get real hot

    i have a thermal image to send you - how did you attach that photo?
    never mind - i seem to have done it after all

    image is T4 at 816 MHz center of cpu and center 3.3 v regulator both at 67 C
    drawing about 140 ma
    original png is 225k but if i save image from post it is only 98K ???


    Click image for larger version. 

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    Last edited by analog&RFmodels; 06-27-2020 at 11:49 PM.

  3. #3
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    Thank you very much Mr Analog! Is the 3.3 regulator easy to replace? What could be the reason for it to get so hot? I cant touch it with my finger, it hurts.

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    i would not say easy - depends on what kind of soldering/de-soldering tools you have. good news it only has six leads,
    bad news is it has a thermal pad center bottom that i bet is soldered down also. hopefully someone with more surface
    mount experience than i have can weigh in on that.

    but i think first you should feel the cpu - is it at least warm? also hold down the pgm button for 15 seconds and when
    the red led comes on dim let go of the button - then the red led will get bright for about 30 seconds and then the
    yellow led will blink at 1 second intervals. if all of that does not work, measure the 5v from your computer on the pin
    labeled 5v - if it is low then the blown regulator is dragging down your usb supply. if 5v is ok measure the 3.3 volt
    output of the board on the pin labeled 3v, if it is 3.3v regulator is ok, if it is 5v the regulator is shorted input to
    output and it likely fried cpu etc. if it is near zero volts then either the regulator is blown or it is being dragged
    down by a blown cpu or memory chip.

    if the yellow led does blink, unplug it, reboot your computer, plug it in and try to send it a known good program
    and see if the red led blinks when you either say upload or hit the program buttom on T4. sometimes you have
    to repeat that cycle a couple of times to get everybody synced up.

  5. #5
    Senior Member PaulStoffregen's Avatar
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    When the regulator gets too hot and the 3.3V line measure less than 3.3V, usually that's a sign something else is wrong and attempting to consume far too much power from the 3.3V line.

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    Quote Originally Posted by PaulStoffregen View Post
    When the regulator gets too hot and the 3.3V line measure less than 3.3V, usually that's a sign something else is wrong and attempting to consume far too much power from the 3.3V line.
    I dont know exactly what happens there Paul. When i take my lab voltage source and apply 3.3v onto the LDO out pin (for replacement) then the output exceeds more than 1 amp and the Cortex becomes hot pretty fast! For me it seems like that, if that Problem in General occurs, that the Chip is blown right?

    I also measured the 100k resistor near the 3.3 reg and it told me theres only 30k ohms resistance, not 100k. Could that also be a problem?

    Thank you guys!

  7. #7
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    Maybe it has to do with maximum current a teensy pin can provide? I drive some ws2812 channels through a 5v Level shifter buffer and some logiv Level mosfets n-chanmel for analog 12v leds.

    Could that cause the problems i have?

  8. #8
    I also had a problem with a Teensy 4.0 where the LDO was getting hot. I found out that the LDO was just fine, but the MIMXR was burned.
    Check to see if you have a short circuit between the 3V3 and GND pins. For me this was the problem.
    I made sure by desoldering the MIMXR chip. After removing the chip the short was gone.

  9. #9
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    Quote Originally Posted by guzu View Post
    I also had a problem with a Teensy 4.0 where the LDO was getting hot. I found out that the LDO was just fine, but the MIMXR was burned.
    Check to see if you have a short circuit between the 3V3 and GND pins. For me this was the problem.
    I made sure by desoldering the MIMXR chip. After removing the chip the short was gone.
    Okay thank you very much for your response! Could you also pin point out, whats the reason for this at all?

  10. #10
    Senior Member PaulStoffregen's Avatar
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    Quote Originally Posted by cr4nkz View Post
    I drive some ws2812 channels through a 5v Level shifter buffer and some logiv Level mosfets n-chanmel for analog 12v leds.

    Could that cause the problems i have?
    If the 12V power accidentally touched any pin on Teensy, or any wire connecting back to Teensy... even for a brief moment, that would explain this problem perfectly. 12V kills Teensy 4.0 instantly!

  11. #11
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    Quote Originally Posted by PaulStoffregen View Post
    If the 12V power accidentally touched any pin on Teensy, or any wire connecting back to Teensy... even for a brief moment, that would explain this problem perfectly. 12V kills Teensy 4.0 instantly!
    Okay Paul
    That means: if that occurs, the only Option would be to replace the Cortex Chip, right?

    What about the maximum current per pin?

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