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Gomez
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Location: Porto, Portugal

Display malfuctioning on a 4.3" composite video

Wed Sep 30, 2015 12:10 pm

Hello,

I have a problem with my 4.3" display, I got a TRRS to RCA cable and I though I was good to go but I seem to be getting a few problems.

I am trying to build a retropie portable console, here's a video of whats happening with the display: https://youtu.be/Omk4kGXj-TY

After the video I tried to go on /boot/config.txt and change the framebuffers to 480 x 272, enabled sdtv_mode=2 and added hdmi_ignore_hotplug=1 but I still get the same thing, can this be a cable related issue?

Thanks

fruitoftheloom
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Location: Delightful Dorset

Re: Display malfuctioning on a 4.3" composite video

Wed Sep 30, 2015 12:21 pm

Gomez wrote:Hello,

I have a problem with my 4.3" display, I got a TRRS to RCA cable and I though I was good to go but I seem to be getting a few problems.

I am trying to build a retropie portable console, here's a video of whats happening with the display: https://youtu.be/Omk4kGXj-TY

After the video I tried to go on /boot/config.txt and change the framebuffers to 480 x 272, enabled sdtv_mode=2 and added hdmi_ignore_hotplug=1 but I still get the same thing, can this be a cable related issue?

Thanks
Did you check that it is a TRRS4 cable correctly wired :?:

http://www.raspberrypi-spy.co.uk/2014/0 ... video-jack

http://www.modmypi.com/raspberry-pi/acc ... 3-x-rca-3m
Rather than negativity think outside the box !
RPi 4B 4GB (SSD Boot)..
Asus ChromeBox 3 Celeron is my other computer...

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Gomez
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Joined: Mon Dec 15, 2014 3:42 am
Location: Porto, Portugal

Re: Display malfuctioning on a 4.3" composite video

Wed Sep 30, 2015 12:28 pm

fruitoftheloom wrote:
Gomez wrote:Hello,

I have a problem with my 4.3" display, I got a TRRS to RCA cable and I though I was good to go but I seem to be getting a few problems.

I am trying to build a retropie portable console, here's a video of whats happening with the display: https://youtu.be/Omk4kGXj-TY

After the video I tried to go on /boot/config.txt and change the framebuffers to 480 x 272, enabled sdtv_mode=2 and added hdmi_ignore_hotplug=1 but I still get the same thing, can this be a cable related issue?

Thanks
Did you check that it is a TRRS4 cable correctly wired :?:

http://www.raspberrypi-spy.co.uk/2014/0 ... video-jack

http://www.modmypi.com/raspberry-pi/acc ... 3-x-rca-3m
Oh yeah, I am pretty sure that's the problem, I don't have a multimeter with me atm so I can't check if its wired correctly, can I rewire it if its not correct or do I have to buy one that is compatible? I'm new to building projects so I am sorry if this questions sound stupid ahah

Thanks

edit: I mean, if I connect ANY cable to either white or yellow plug from the display, as long as there is any cable in both of them as it is on the youtube video then I get this weird signal on the display... any cable at all gives me this video so I am pretty sure it is not wired correctly and I either need a new cable or rewire it if its possible.. il test it later when i get my hands on a multimeter at school

drgeoff
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Joined: Wed Jan 25, 2012 6:39 pm

Re: Display malfuctioning on a 4.3" composite video

Wed Sep 30, 2015 2:02 pm

The crooked, unstable white bar is a 100% positive indicator that your cable is wired incorrectly. It is swapping video and ground. Your display is getting an inverted signal. That white bar is the horizontal sync pulse which should be blacker than black.

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Gomez
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Location: Porto, Portugal

Re: Display malfuctioning on a 4.3" composite video

Wed Sep 30, 2015 2:21 pm

drgeoff wrote:The crooked, unstable white bar is a 100% positive indicator that your cable is wired incorrectly. It is swapping video and ground. Your display is getting an inverted signal. That white bar is the horizontal sync pulse which should be blacker than black.
Thanks for the information sir, is the cable possible to be rewired manually or is it better to buy a proper one for raspberry pi?
Thanks

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Burngate
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Re: Display malfuctioning on a 4.3" composite video

Wed Sep 30, 2015 5:08 pm

Gomez wrote:Is the cable possible to be rewired manually or is it better to buy a proper one for raspberry pi?
Thanks
Certainly possible, provided you have the tools and dexterity.
But the end result would probably be unsightly and fragile.

"Better" depends on your circumstances, but for most people, buying the correct cable would be better

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Gomez
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Location: Porto, Portugal

Re: Display malfuctioning on a 4.3" composite video

Wed Sep 30, 2015 5:43 pm

Burngate wrote:
Gomez wrote:Is the cable possible to be rewired manually or is it better to buy a proper one for raspberry pi?
Thanks
Certainly possible, provided you have the tools and dexterity.
But the end result would probably be unsightly and fragile.

"Better" depends on your circumstances, but for most people, buying the correct cable would be better
Do you think I can solder the wires directly into the raspberry pi board? which means removing the 3.5mm socket itself? I assume that is possible, not sure, on the final design the screen is supposed to be directly above on the raspberry pi so the cable can't even be long, the shorter it is the better it fits into this case I made on Fusion 360.

image

Can I solder it directly on the board or do I just buy a new cable that works properly and then shorten the cable and just connect usually? I assume this last one is safer but less space-efficient in the case..

Thanks

drgeoff
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Re: Display malfuctioning on a 4.3" composite video

Wed Sep 30, 2015 11:25 pm

You can solder directly to the underside of the board without removing the 3.5 mm socket.

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Gomez
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Location: Porto, Portugal

Re: Display malfuctioning on a 4.3" composite video

Thu Oct 01, 2015 1:52 pm

drgeoff wrote:You can solder directly to the underside of the board without removing the 3.5 mm socket.
I fixed the jack, I'll try it when I get home but I'm pretty sure it's working, it is looking good at least.

http://m.imgur.com/4h9e4KL,GnXKQgB

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Gomez
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Location: Porto, Portugal

Re: Display malfuctioning on a 4.3" composite video

Thu Oct 01, 2015 6:40 pm

It is working, I will maybe solder the wires directly to the bottom of the board later, but in testing stages where I am still configuring gpio buttons and other kinds of stuff this is good enough, here's a video ^^

https://www.youtube.com/watch?v=R9VEwJh ... e=youtu.be

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Burngate
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Re: Display malfuctioning on a 4.3" composite video

Fri Oct 02, 2015 9:09 am

Better than I expected. :) To quote someone else: Not just Good, but Good Enough!

Next time you upload a video, could you clean the lens? There's a splodge of muck just right-of-centre, which annoys the ... out of an ex-broadcast TV engineer :(

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Gomez
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Re: Display malfuctioning on a 4.3" composite video

Fri Oct 02, 2015 2:05 pm

Burngate wrote:
Better than I expected. :) To quote someone else: Not just Good, but Good Enough!

Next time you upload a video, could you clean the lens? There's a splodge of muck just right-of-centre, which annoys the ... out of an ex-broadcast TV engineer :(
It is on the inside of the phone's lens, nothing I can do tbh, getting a meizu soon so my next videos will be fine ahah

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