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3 Gearbest Screens not working!?!?

Posted: Thu Dec 01, 2016 8:46 pm
by JohnFreeman
Hello all,

So I bought some Gearbest screens for my GBZ but something really weird seems to be happening. So I've added the 5v mod to two boards and no matter what I've tried I can't get them to display. Hell, even one of the screens is an old one that was working before (although it was super fuzzy) and now I can't get any of them to display at all. Now I have it hooked up to test pad 24 on my Pi2 for video, then power and ground hooked up to a seperate micro usb connection. When I connect power to the pi and the screen I get nothing. I have already tested the pi2 running a fresh copy of retropie via hdmi and it worked fine. I have also tried this setup on my pi zero obviously connecting the tv out connection rather than a test pad. I will include some pictures below of how I have it setup currently. Does anyone have any clue why this won't work?

Pictures: http://iob.imgur.com/uYGg/HQdyc7iFLy

Re: 3 Gearbest Screens not working!?!?

Posted: Fri Dec 02, 2016 4:35 am
by nuneberg
Try powering the screen PCB from the raspberry PI. And do not use 2 seperate power supply sources.

Re: 3 Gearbest Screens not working!?!?

Posted: Fri Dec 02, 2016 5:41 am
by Camble
Am I right in saying that you have a composite connection to the Pi, but no ground connection to the Pi?

Re: 3 Gearbest Screens not working!?!?

Posted: Fri Dec 02, 2016 9:38 am
by JohnFreeman
Camble wrote:Am I right in saying that you have a composite connection to the Pi, but no ground connection to the Pi?
Yes. Should I always be doing that? I'm pretty inexperienced with electronics.

Re: 3 Gearbest Screens not working!?!?

Posted: Fri Dec 02, 2016 10:00 am
by Camble
There is a ground pin right beside the composite pin on the Pi. Try wiring your ground to that and keep both wires as short as possible, and the same length.

Re: 3 Gearbest Screens not working!?!?

Posted: Fri Dec 02, 2016 12:06 pm
by JohnFreeman
Camble wrote:There is a ground pin right beside the composite pin on the Pi. Try wiring your ground to that and keep both wires as short as possible, and the same length.
Alright. I'm currently at work but I will try and post an update when I done.

Re: 3 Gearbest Screens not working!?!?

Posted: Sat Dec 03, 2016 4:44 am
by JohnFreeman
It worked! I can finally start documenting my GBZ build

Re: 3 Gearbest Screens not working!?!?

Posted: Sat Dec 03, 2016 8:37 am
by Camble
JohnFreeman wrote:It worked! I can finally start documenting my GBZ build
Good stuff!