As a disclaimer, I'm new to digital electronics and somewhat new to soldering.

I recently bought a standard GPIO header for my Raspberry Pi Zero, but in order to use both the camera part of my case and the pins, I soldered the pins up from underneath, rather than from above down. So the short pins are soldered on the top of the board instead of underneath like usual. However, I tried using a screen module on this, which only showed up black but showed up in full display on the other Pi Zero I soldered in the traditional way. My T Cobbler also works on the normal one, but not on the one soldered upside down.

What could be the possible cause of this? I tried reversing the orientation of the ribbon cable from the Pi to the T Cobbler and that showed power for a brief second before dying off.

Again, I'm extremely new to this sort of thing since my specialty is programming, so I'm not sure how to diagnose these sorts of issues -- I do have a multimeter, as well if need be.


  • 1
    What kind of screen did you attach? Are you aware that if you solder the pins on the other side, the numbering will be mirrored? You'll have to swap the even with the odd pins on your display connection.
    – PMF
    Nov 9, 2020 at 6:06
  • 2
    the odd and even pins became transposed when you did that ... you need a short cable with female ends and a pin header ... use it to extend the existing cable ... two ribbon cables joined with a pin header introduce a second flip into the circuit and resolve the problem
    – jsotola
    Nov 9, 2020 at 7:35
  • 1
    As @Millways says you will need a custom cable. In effect you have created a mirror image of the pins so you will need a mirror image cable.
    – joan
    Nov 9, 2020 at 8:44

1 Answer 1


If you are trying to access the Pi Header from the bottom the short answer is that this is IMPOSSIBLE

Technically it is not strictly impossible but you would either have to:-

  1. Make a gender-changing board
  2. or use a header on the bottom of whatever you are trying to connect. (I did something like this to connect a gertboard via a cable) - but this requires significant manual dexterity and soldering skill.
  • I don't understand. Why is the orientation matters?
    – daparic
    May 2, 2021 at 4:21

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