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Thread: teensy 4 cap ID

  1. #1
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    teensy 4 cap ID

    i just bought a teensy 4 and as i was soldering the back side pads to attach wires, i hit a capacitor and it came off and got lost instantly, but from the schematic i cant easily tell what value it should be... hoping some one can help.

    i have attached a picture with the capacitor circled in red

    Thanks

    Click image for larger version. 

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  2. #2
    welcome to the club. you probably won't be the last, either. Paul will probably be along soon. I hit a different one when soldering the back side connector. Just got my package with the chip so will be giving it a try soon.

  3. #3
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    hi @PhilB, yes i noticed your thread hope you get yours fixed.

    i was just coating the pads with mine but because i already soldered in pin headers i soldered from a certain angle and it must have been some excess on the underside of my iron as i tinned pad 31 that just whipped it clean off, i didnt even notice something move which usually i do which makes me believe it happened under my iron as i pulled back, and its so small i bet the excess solder completely covered it and removed it in one go

    i was just starting a project i wanted to use this for as well, and my t3.6 is tied up right now. i have a box full of 3.2's but i wanted this beast

  4. #4
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    no one know this cap value? or is it going to be quicker to just order another?

  5. #5
    Senior Member+ defragster's Avatar
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    Another cap by pin #22 ID's here : Help-me-resurrect-a-T4-Cap-value-and-other-details

    Note sure if that helps read the schematic to ID the pad #31 cap?

    The caps are known - maybe only decipherable by Paul - and he's "on a Quest" it seems.

    Ordering fresh would be a sure bet for function in known time.

  6. #6
    Yeah, the schematic doesn't really help cause there are no part numbers on the boards or schematic.

    FWIW, it was my dead Teensy on the other post and it lives!

    and, FWIW-the-2nd, I ordered 2 extras!

  7. #7
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    Thanks, but there is no way for certain for me to tell what value that cap should be and pad 31 does not have a cap on it as per the schematic.

    honestly all other times i always buy at least 2, but this time, ya know, it just had to happen to me.

  8. #8
    Senior Member PaulStoffregen's Avatar
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    I can confirm it's 0.22uF. This one on the schematic:

    Click image for larger version. 

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    It's "only" a decoupling capacitor between 3.3V and GND. There are several others, so the board should (probably) work without it.

    If you replace it, the exact capacitor value isn't critical. Any ceramic capacitor from 10nF to 1uF should probably work fine, as long as it's the same 0402 size.

  9. #9
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    thanks for the reply/confirmation. based on the size/count of caps and number of caps for that size (the 4.7s look just slightly fatter to me) i would have guessed 0.22uF, but i wanted to be sure.

    i have just been sat with the DMM trying to trace things and deduct from the schematic what i could find... i hadn't crossed that cap off yet but i had my bets further up to be honest, around NVCC/VDD_SOC ... but... i hadn't finished yet lol

    thanks again

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