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How to Fix the dim LCD backlight or not showing an image

Posted: Sat Jul 22, 2017 5:10 pm
by Helder
So I ran into the same issue some people had with the LCD turning on where the back light was very dim then no image showed. I tested voltage and it was 2.5v where it needed to be 3.3v and it ended up being a bad Ground on the 8pin connector on the PCB. If you have this issue a simple fix is to link the 2nd pin to the GND pad below the connector like the image below.

Image

Re: How to Fix the dim LCD backlight or not showing an image

Posted: Sat Jul 22, 2017 6:38 pm
by Orangebuster
Thanks for this solution Helder. I was having this issue and I linked the second pin to ground, but nothing still shows up on the screen

EDIT: okay, so it had something to do with the ribbon cable being in juuuuusst right.

Re: How to Fix the dim LCD backlight or not showing an image

Posted: Sat Jul 22, 2017 6:57 pm
by Robochris
Maybe off topic but is there a test pad for the gpio pin labeled "D/C"?

Re: How to Fix the dim LCD backlight or not showing an image

Posted: Sat Jul 22, 2017 7:12 pm
by Orangebuster
Yeah it's in the middle of the line of test pads, next to rst and sdi

Re: How to Fix the dim LCD backlight or not showing an image

Posted: Sat Jul 22, 2017 7:16 pm
by Robochris
Oh shit. Thanks.

Re: How to Fix the dim LCD backlight or not showing an image

Posted: Mon Jul 24, 2017 1:58 am
by L51
I am also having this problem. I just solder some wire to join the pin correct?

Re: How to Fix the dim LCD backlight or not showing an image

Posted: Mon Jul 24, 2017 2:55 am
by Helder
Yes just like the image on the first post.

Re: How to Fix the dim LCD backlight or not showing an image

Posted: Mon Jul 24, 2017 3:43 am
by abrugsch
Is that bad ground likely to be on the prototype board I have?
Cheers

Re: How to Fix the dim LCD backlight or not showing an image

Posted: Mon Jul 24, 2017 5:55 am
by Helder
No that one has some changes made around that area from the final version. I looked at the board files and the gnd there shouldn't have had an issue but little faults are bound to happen in a large production run. I'm just glad it happened to me so I could document it and the fix.

Re: How to Fix the dim LCD backlight or not showing an image

Posted: Tue Jul 25, 2017 5:04 am
by L51
Will there be a second revision where the screen works straight outta the box because mine going in the bin