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Thread: Teensy 4.0 DOA?

  1. #1

    Teensy 4.0 DOA?

    I just received my OSHpark edition Teensy 4.0 in the mail today, and unfortunately it seems DOA. The 5V rail is at 5.0V, the 3.3V rail is at 3.3V, the On/Off, Program, and Vbat rails are all at 3.3V as well. The Vbat rail is 3.238V, and the other pins and the 3.3V rail are at exactly 3.294V, I highly doubt that matters but I figured I'd mention it anyways. Both of the LEDs do not illuminate whatsoever, and the teensy draws 0.03a from the USB port. I'm thinking dead microcontroller? Is there anything else I can test or try?

    Thanks!

  2. #2
    Senior Member+ KurtE's Avatar
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    Check/try different cable

  3. #3
    Senior Member+ defragster's Avatar
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    New out of package with no pins soldered? Never programmed? Just the bare board plugged into USB with no button press and no orange LED flash?

    Not sure what the 'rail' in ref to "other pins and the 3.3V rail are at exactly 3.294V" ?

    The other pins on power up should be at GND - unless plugged into something or reprogrammed?

    Gotten a couple OSH purple Teensy's - all fine - they go through the PJRC test and package process and are seen to work and left with the No_USB Blink sketch installed.

  4. #4
    Ah sorry, I should have specified. The Vbat pin is down from the 3.3V rail and the On/Off & Program rail.

    I have tried a different cable, 5 in fact.

    Yeah, it's a brand new board, fresh out of the ESD bag, no headers soldered, never programmed, no blink program from the manufacturer, or at least it's not working, the program is probably there, on the flash. My PC does not recognize it at all. lsusb turns up nothing. I have tried my desktop and two laptops, one laptop running windows 10 with the latest arduino and teensyduino installed, the other laptop and desktop running linux, also latest software.

  5. #5
    Senior Member+ defragster's Avatar
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    Out of ESD pack it will not by design present any USB connect, only blink given 5V/GND.

    But when it gets GND and 5V to VIN from USB ( data or power only ) even from a battery pack - it should Orange LED Blink. Blink will stop in any case the Program Button is pressed - or if the PGM pin is set to GND.

    If the On/Off pin gets GND it will sleep the Teensy until all power removed - or GND released and then pressed again - but that is not an initial test - just to say it could be set OFF and will hold that while vBat has power.

    Assuming 'rail' just means that pin? Seeing rail gave the image of a breakout board with rails on.

  6. #6
    Oh I should add, the programming button does nothing. I have tried pressing it, holding it down for 15 seconds, and holding it down while plugging the teensy in, all to no avail. No device detected in Arduino, no new devices listed in lsusb, no change in current draw from the usb port, no LEDs.

  7. #7
    Ah yes, perhaps I am using an old term, sorry. I mean rail as in a common power supply connection, or common ground connection. I believe the term comes from when there were literal copper rails, or bus bars as they're known now, inside your device for a common point to get power from.

  8. #8
    AHA! I may have found the issue. There are three tiny SMD components, broken off. Damn FedEx, fast shipping but at a cost. The ESD bag is in rough shape, holes and dents too. Anyone know what components they are? I have a rather expansive hoard of SMD components, I'll just solder in some new ones.
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  9. #9
    Senior Member PaulStoffregen's Avatar
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    Those are these 3 parts on the schematic.

    Click image for larger version. 

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    The part closest to pins 7, 8 and pad 33 is the inductor. You can use a wire or any ferrite bead rated for 100 mA or higher. The other 2 do need to be X7R or X5R ceramic capacitors, since they are providing the input pulses of current for the 3.3V to 1.15V step down switcher.

    The pads near pins 6 & 5 are meant to be empty.

  10. #10
    Senior Member+ defragster's Avatar
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    Quote Originally Posted by Burdalfis View Post
    Ah yes, perhaps I am using an old term, sorry. I mean rail as in a common power supply connection, or common ground connection. I believe the term comes from when there were literal copper rails, or bus bars as they're known now, inside your device for a common point to get power from.
    Cool, my understanding similar - but as noted involves external rails of that would imply connection - versus the untouched pins.

    Any signs it was damaged in transit? Photos?

    Opps - time distracted - cross posted ...

  11. #11
    Paul and Defragster, you guys are awesome. Thanks so much for helping me. If I may ask, which part is which? I could probably buzz out what goes where with a multimeter but asking is easier.

    And yeah, definitely some signs. I'd attach a photo of the bag but I seemingly cannot. Rescaling the image, increasing JPG compression, and just taking a new photo altogether haven't worked, I've always had issues on my phone. If you really want to see I can just link it to my Google drive, I really don't mind.

  12. #12
    Also no sign of the components in the ESD bag or the bag the boards and the ESD bag came in, but I'm not about to go really looking for something that's as small as dust particles. :P

  13. #13
    Senior Member PaulStoffregen's Avatar
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    Quote Originally Posted by Burdalfis View Post
    If I may ask, which part is which?
    The part closest to pins 7, 8 and pad 33 is the inductor.

    The one above it is the 10 uF capacitor and the smaller one to the right is the 4.7 uF capacitor.

  14. #14
    Beautiful. Thanks again! Excited to give the new 4.0 a go, the benchmarks are insane. I'll update tomorrow after work on whether it worked or not.

  15. #15
    Senior Member PaulStoffregen's Avatar
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    Whatever happens, please do send some feedback to OSH Park. Maybe they'll consider more durable packaging material?

  16. #16
    Absolutely. I already put a ticket in with them, I'll send a link to this thread.

  17. #17
    Das Blinkenlights! It's alive! Turns out I didn't have a ~4.7uf cap big enough to fit the footprint, so a X7E low esr low L 10uf cap will do. And no ferrite bead. I wouldn't be surprised if it wasn't too stable, especially at higher clocks. But hey, it works!

    Looks like a few pads lifted too. And by lifted I mean cratered the board, those OSHpark boards really are high quality. My guess is that a board edge in the bag caught and sheared off the components during packing or shipping, since it's just the ESD bag with the teensy tossed in with a bunch of loose boards in a bag.
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