Page 1 of 3

Bad screen / ribbon cable

Posted: Sat Aug 18, 2018 9:55 pm
by TechIsAmazing
Hi all!

I just finished my soldering of the PCB to the pi and connected the screen to test. When I boot it up however, it starts off fine. As soon as I touch the ribbon cable or the screen I get all these rainbow lines on the screen and I loose picture. I'm assuming it's a bad screen or ribbon cable (since the pi worked fine when connecting to an HDMI).. (I'm using all stock parts purchased from sudomod)

Sidenote: I also have no sound...


Any help would be greatly appreciated!!

Thanks guys!! :)

Re: Bad screen / ribbon cable

Posted: Sun Aug 19, 2018 7:34 am
by KonnorJ
Reseat the ribbons

Re: Bad screen / ribbon cable

Posted: Sun Aug 19, 2018 7:50 am
by Helder
Which RIBBON? The white one? I would try adding a little extra solder to the white ribbon connector pins on both boards. Could well be a weak solder joint, also pictures of your work is helpful to determine things that could be the issue.

Re: Bad screen / ribbon cable

Posted: Sun Aug 19, 2018 9:12 am
by TechIsAmazing
Thank you for your response!!!

Here are some pictures!!

Working fine - https://imgur.com/a/8GfJHUT
Touched / moved the screen / ribbon cable - https://imgur.com/a/p8htUwg https://imgur.com/a/QYpvXBg
My setup - https://imgur.com/a/6Xlfbml https://imgur.com/a/1c7vxG0

Re: Bad screen / ribbon cable

Posted: Sun Aug 19, 2018 6:17 pm
by KonnorJ
Did you reseat the ribbon like I said? It looks crooked

Re: Bad screen / ribbon cable

Posted: Sun Aug 19, 2018 6:52 pm
by TechIsAmazing
Yes, mutiple times... Everytime it does the same thing... :(

Re: Bad screen / ribbon cable

Posted: Sun Aug 19, 2018 8:31 pm
by Helder
I haven't had time to look at the links but take the ribbon out completely and do a continuity test on each pin on both sides of the ribbon and bend it slightly to rule out the ribbon or not.

The other likely issue could be the ribbon connector pins having a weak joint so add a little extra solder to each to reinforce them. Use flux to make it an easy clean job.

Re: Bad screen / ribbon cable

Posted: Mon Aug 20, 2018 10:41 am
by TechIsAmazing
Just finished the continuity test on each pin on both sides of the ribbon and it appears as if the ribbon is functioning.

I will try to add some extra solder to it, and see if that works...

Thanks again for all of your help!!!

Re: Bad screen / ribbon cable

Posted: Mon Aug 20, 2018 10:57 am
by TechIsAmazing

Re: Bad screen / ribbon cable

Posted: Mon Aug 20, 2018 3:22 pm
by Helder
Yea loose pin on the connector is likely, add the solder like I said then test.