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geekhack Projects => Making Stuff Together! => Topic started by: Tye on Mon, 02 May 2016, 22:02:45
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I am assembling a Falbatech Ergodox. Unfortunately, they sent me a counterfeit Teensy which was total junk and wouldn't work with Ergodox firmwares. They sent me a new one, but the counterfeit was already soldered onto the headers. During removal, one of the pads on the Ergodox PCB fell off. Argh!!!
I think I have come up with a solution but I could really use some verification first since hardware just isn't my thing.
This is the detached pad. See the pad just above the 'e' in "Laminate"
[attach=1]
[attach=2]
I think, based on what I can see from the trace that I can run a jumper like the picture below. Then I can use the jumper wire to attach to the Teensy in place of the broken header. But I still don't fully understand how PCB design works. If I solder below the jumper to the hole below the '8', will this connect to the same spot that the Teensy header would have connected before the rip?
Back side/Ripped side proposed repair:
[attach=3]
Front side/Teensy side proposed repair:
[attach=4]
If this isn't a good solution, can somebody recommend a solution? Also, if it matters, I actually want to mount the Teensy as close to the board as possible so I won't install headers again. I'll just use Kapton tape between the Ergodox PCB and the Teensy.
Thanks! (please help!!!)
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in your place I would do the same
about the kapton tape, looks a good idea
hope it works :thumb:
where did you bought the teensy?
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Thanks, ineph. I appreciate the input. I got everything from Falbatech, based in Poland. http://falbatech.pl/prestashop/index.php .
If anyone can back up or add to ineph's thoughts I'd still appreciate it. I've spent a lot of time and money on this mod and I'd like to make it work without sinking much more money.
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Looks like the pad is still present on the front and that's what needs to be connected as it's the link to the rest of the board - your jumper is not wrong but I don't think it will fix it.
I would solder a short wire straight through the damaged hole with the solder on top, then slot the Teensy over it :)
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suicidal_orange, can you confirm this:
Based on what you see, I could still keep the jumper on the back side of the board (so I can still mount the Teensy flush to the PCB). However, the pad that I ripped isn't important, so I need to make sure the pads on the Teensy side are the ones that get soldered? Is that correct?
If that is correct, why do we normally solder the header pins on the back side of the PCB? Is there copper running through the entire hole to make a connection to both sides of the PCB? If not, then soldering per the Ergodox docs suggests that the back side pad is most important. Sorry, I'm really trying to learn all this and not spend any more cash.
My Trackpoint mod was going so well until this issue popped up.
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You've got it - the holes are called Plated Through Holes (sometimes referred to as PTH) and they have copper connecting the front and back of the PCB. If they weren't on the side with the I/O expander that pin would only connect to the Teensy pin, not the switches etc. In the case of a Teensy you can't see the front of the PCB to solder to even if you wanted to, so the instructions say to solder to the back.
If you're mounting it flush I would still solder each pin/hole to ensure it has a good connection, a bit of diode lead is is ideal as you'll probably have some you cut off and it's easy to cut which is good when you need it really short.
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Thank you, suicidal_orange and ineph! That's exactly the information I needed to move forward with this portion of the mod.
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suicidal_orange says everything!
keep us updated of your project :))
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The repair seems to have worked. I was able to write QMK firmware to the Teensy and test every keyswitch point with a jumper. Thank you again.
I hope to post a build log or finished product within the month!
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Looking forward to it :)