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Weird display flicker issue

Posted: Thu Nov 17, 2016 11:16 am
by spacedementia87
So I have had my screen and controlls working well for the fast few days, just been struggling with audio.

Got it wired uo, found a few issues, fixed them. Then discovered that audio was disabled in boot/config.txt.

Ok so that enabled. Boot up, fine choose super Mario and I get this screen flicker on the intro screen. It stops when I start the game properly.

https://vimeo.com/192005626

Any ideas what might be causing this?

Power issue maybe?

Incidentally the sound is very quiet. Any ways of boosting it?

Re: Weird display flicker issue

Posted: Thu Nov 17, 2016 11:52 am
by ABH

Re: Weird display flicker issue

Posted: Thu Nov 17, 2016 12:48 pm
by spacedementia87
ABH wrote:Check it may that will help you
http://www.sudomod.com/forum/viewtopic. ... ker#p19268
I will give that a go but seems unlikely considering the screen is fine when the audio output is disabled and once the game gets going.

Re: Weird display flicker issue

Posted: Sat Nov 19, 2016 8:25 am
by chaosratt
That looks like a power problem, my screen did something similar:

https://dl.dropboxusercontent.com/u/646 ... creen.webm

You need to perform the 5v mod for your screen. Check the wiki for the different models and procedures for each.

Re: Weird display flicker issue

Posted: Sat Nov 19, 2016 10:07 am
by spacedementia87
chaosratt wrote:That looks like a power problem, my screen did something similar:

https://dl.dropboxusercontent.com/u/646 ... creen.webm

You need to perform the 5v mod for your screen. Check the wiki for the different models and procedures for each.
I have performed the 5v mod.

This problem only started happening once connecting the audio up. Even then it only happens on that one scene. Once the game starts it works fine.

Re: Weird display flicker issue

Posted: Sat Nov 19, 2016 1:10 pm
by chaosratt
Interesting, whats your power source? How is it wired, what awg wire?

Do you have a DMM (digital multi meter)? I'm curious to see what the voltage is across the display's power input is when it spazzes out like that. My screen specifically would do it at less than 5.1V (from the powerboost's 5.2 source) until I did the 5V mod to it.

Re: Weird display flicker issue

Posted: Sat Nov 19, 2016 5:40 pm
by kirestus
i am having a simular problem but my display doesnt cut out, it just has lines going through it. the lines only kick in once retropie boots up the pwm audio so i think its a power issue but im not sure

Re: Weird display flicker issue

Posted: Tue Nov 22, 2016 10:56 am
by spacedementia87
Ok even weirder!

So the voltage across the pins seems fine. No worries there but in testing i found that simply holding the wires was enough to make the screen stay on. I then just tried pushing on various bits with a plastic implement

It is clearly some kind of dodgy connection then. I am going to stry a complete rebuild with new wires. Hopefully that will fix it.

Re: Weird display flicker issue

Posted: Tue Nov 22, 2016 11:01 am
by chaosratt
kirestus wrote:i am having a simular problem but my display doesnt cut out, it just has lines going through it. the lines only kick in once retropie boots up the pwm audio so i think its a power issue but im not sure
Kind of like this?
https://dl.dropboxusercontent.com/u/646 ... screen.mp4

This went away for me when I did the 5v mod to the display.

Re: Weird display flicker issue

Posted: Tue Nov 22, 2016 6:52 pm
by kirestus
chaosratt wrote:
kirestus wrote:i am having a simular problem but my display doesnt cut out, it just has lines going through it. the lines only kick in once retropie boots up the pwm audio so i think its a power issue but im not sure
Kind of like this?
https://dl.dropboxusercontent.com/u/646 ... screen.mp4

This went away for me when I did the 5v mod to the display.
yeah simular but it was after the 5v mod was done, it seemed to be cased by interference on the video "yellow" cable. i resoldered that on and insulated the wire with heat shrink and it went away