Gearbest Screen Problems: Do I just suck at soldering?

[GMoney]

Can someone please take a look at the attached photos and give me some ideas on why my gearbest screen isn't doing anything?

Just a quick rundown: I have a slightly-modded RPi 3 (just cut down from 4 USB/ethernet to a single USB that will soon be removed). I know I have some cleanup to do on the board itself, but I intend to remove a bunch more components, so I'm not concerned about that right now.

I bought the 3.5" Gearbest Screen http://www.gearbest.com/development-boa ... 29447.html that everyone seems to suggest on here. To step it down from 12V to 5V, I soldered as suggested in the screen comparison thread.

IMG_20170131_230936.jpg (3.81 MiB) Viewed 3834 times

IMG_20170131_230954.jpg (3.22 MiB) Viewed 3834 times

IMG_20170131_231051.jpg (3.5 MiB) Viewed 3834 times

I couldn't find any instructions on where to wire directly onto the RPi 3, so I cut off the end of the composite cable the screen came with, removed the black covering on the wires, tinned them, and connected as follows:

Yellow (composite?) to PP24
Red (power?) to PP1
Black (ground?) to PP5
White I didn't touch.

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IMG_20170131_231013.jpg (4.6 MiB) Viewed 3834 times

Finally, as you can see in the below picture, everything is wired together, but nothing happens when I power on the Pi.

Troubleshooting:

I removed and resoldered every wire at least thrice.

I tried using the official 5V charger instead of the external phone battery I have in the attached photos.

I used two different SD cards with RetroPie images on them (that work perfectly in my Pi3 that is plugged directly into my TV).

Please help! Is it just the soldering? This is my first big project so I'm terrible at soldering (hence the re-doing). OR am I supposed to be messing around with config.txt? Drivers? Did I connect the wrong wires?

Thanks in advance

[Lphillimore]

Hi @GMoney

Looks like your 5v mod is wrong. Your wire runs from the ground pin on the connector.

See here for how it should be. (found elsewhere on forum)

IMG_2628.JPG (127.75 KiB) Viewed 3832 times

Screen should also run off of 5v out of the box but you've already started modding so no drama.

It's hard to see from your pics but make sure your wire is only touching Pin2, too.

[GMoney]

Hi @GMoney

Looks like your 5v mod is wrong. Your wire runs from the ground pin on the connector.

See here for how it should be. (found elsewhere on forum)
[image]

Screen should also run off of 5v out of the box but you've already started modding so no drama.

It's hard to see from your pics but make sure your wire is only touching Pin2, too.

Haha, you are right! I looked at that picture over and over and obviously messed up. I feel like that kid in The Royal Tenenbaums...

Thanks for your help - I will fix that tonight.