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Thread: Teensy 3.1 Underside Pad Problems

  1. #1
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    Angry Teensy 3.1 Underside Pad Problems

    Has anyone had any problems with soldering pins to the 14 underneath pads on the Teensy 3.1?

    We've been working on 2 prototypes, one of which utilises all of the available I/O and as a result we've soldered pins onto the pads, the problem we've encountered is that on 3 of the 5 Teensy's, when we have tried to unplug them from the main board, some of the tracks have lifted away from the PCB.

    On closer examination on one of the boards, we removed the plastic carrier strip holding the pins together and pulled on a couple of the pins, and sure enough, they came away from the board without any real effort.

    This is worrying us, as most of the design work has been based on the 3.1 and the concern is if this is a general problem or just an isolated batch.

    At this moment in time, we dont know what to do, will there be a Teensy 3.1++ where all the I/O is taken to the edge like the rest??

    John

  2. #2
    Senior Member PaulStoffregen's Avatar
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    Those SMT pads on the bottom aren't strong enough to make the board pluggable with an ordinary header and socket. If you're using those 14 pins, you probably need to just permanently install Teensy 3.1.

    Yeah, it's not ideal. There are always a lot of trade-offs in the design of anything. Originally Teensy 3.0 was planned to have the 48 pin chip, but it was upgraded to the 64 pin chip at the last minute. I didn't want to have so many extra signals inaccessible, but the board really didn't want to grow bigger either.

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    Just a thought, perhaps on a future Teensy (if the form factor is to remain), the pins on the short edge could be replaced with an expansion "Edge connector", then Paul could sell an inexpensive expansion board to take the extra IO to some more pins

    Thinking about it, the short edge pins can remain, and simply have the expansion edge connector extend slightly further

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    This is an older thread, but I found it while doing some other reading and thought it might still be valuable to post.

    One option for prototyping is to use "pogo pins" to connect to the SMD pads, but you may have problems with the much less secure connection they would be making. Certainly limited current, mostly for signals. Sparkfun has a tutorial for how they make PCBs using the pogo-pins for quick-connections.

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    Senior Member pictographer's Avatar
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    How about a ribbon cable soldered to the bottom, secured with a big blob of epoxy and connected at the other end to pin header suitable for breadboarding? Will all due respect, it isn't reasonable to expect pcb pads to hold up to removal from a solderless breadboard or socket.

    One of the other posters here had a clever idea to remove pins from a pin header and run it across the pads anchored at either edge of the T3 by the through-hole connections. Not sure how to search for it and I'm not describing it well.

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    Senior Member MichaelMeissner's Avatar
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    Quote Originally Posted by MichaelMeissner View Post
    with a solderless breadboard?

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    Senior Member jimmayhugh's Avatar
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    Quote Originally Posted by stevech View Post
    with a solderless breadboard?
    My solution will not work with a solderless breadboard. Use this if you want to use a solderless breadboard for prototyping. I socket my TeensyNet boards to allow me to re-use the Teensy3.1 boards, and to break out all of the pins, such as on my TeensyGLCD board, and Version 14 of my TeensyNet board.

  9. #9
    Senior Member MichaelMeissner's Avatar
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    Quote Originally Posted by stevech View Post
    with a solderless breadboard?
    I tend to agree with Jimmayhugh, that if you want to use all pins on a solderless breadboard, that getting the Tall Dog board from Tindie, would be the way to go.

    Another way is to use this board, and connect the wires to the breadboard: https://www.tindie.com/products/fret...rd-and-shield/

    A third possibility is solder wires to the pads, and bring them out in 2 sets of 6 wires (plus one wire for A14, and 3 wires for A10/A11/VUSB) that you plug into the solderless breadboard.

  10. #10
    Senior Member PaulStoffregen's Avatar
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    Quote Originally Posted by MichaelMeissner View Post
    I tend to agree with Jimmayhugh, that if you want to use all pins on a solderless breadboard, that getting the Tall Dog board from Tindie, would be the way to go.
    Has anyone actually done this?

    Really, I'm just curious to see some pictures of so many wires connected to so much stuff on breadboards. Think "pics, or it didn't happen!"

  11. #11
    Senior Member jimmayhugh's Avatar
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    Quote Originally Posted by PaulStoffregen View Post
    Has anyone actually done this?

    Really, I'm just curious to see some pictures of so many wires connected to so much stuff on breadboards. Think "pics, or it didn't happen!"
    I did use the Tall Dog board from Tindie when I was breadboarding my TeensyGLCD, but once I got it working and made a pcb, I took it apart, so no pics.

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