How to configure the composite video output to a 7" LCD?

[RoboTrader]

Hello Pi-Fans,

I have a 7" LCD color monitor with 1440 x 234, PAL/NTSC, 16:9 in my camper and want to use it for my Raspberry Pi 3B+.
And I already have (the right) cable and connected it (composite video output of the pi to cinch input of the LCD).

First trial:
The blue stand-by screen changed to a black screen and I saw the boot lines with white letters but it was chaotic and blurred.

Second trial:
So, I decided to install the GUI (had only Stretch) and set the 16:9 option in /boot/config.txt but now I cannot see anything and it's just the blue stand-by screen like nothing is sent.

Could anyone help me with this wish?
Thank you!

[drgeoff]

Are you sure the RPi is now booting? Red LED steady and green one flashing randomly for circa 30 seconds?

What happens if you reinstall the OS you began with?

[RoboTrader]

I am sure because I have another monitor and there I can see the booting and I can use it.
And in the camper I can connect by ssh local. So, it runs. But I cannot see anything on the LCD but on another monitor.

[jamesh]

Is the Pi set to NTSC and the screen to PAL or vica versa?

[RoboTrader]

Hm, good question. In the specifications of the LCD it's written "PAL/NTSC automatic switch" ...

[cleverca22]

i believe the composite output is disabled if hdmi is detected

on he rpi4, composite remains off by default and you need to enable it in config.txt

[mikronauts]

fyi, it is 1440/3 pixels as they count r, g, and b separately.

Hello Pi-Fans,

I have a 7" LCD color monitor with 1440 x 234, PAL/NTSC, 16:9 in my camper and want to use it for my Raspberry Pi 3B+.
And I already have (the right) cable and connected it (composite video output of the pi to cinch input of the LCD).

First trial:
The blue stand-by screen changed to a black screen and I saw the boot lines with white letters but it was chaotic and blurred.

Second trial:
So, I decided to install the GUI (had only Stretch) and set the 16:9 option in /boot/config.txt but now I cannot see anything and it's just the blue stand-by screen like nothing is sent.

Could anyone help me with this wish?
Thank you!

[RoboTrader]

i believe the composite output is disabled if hdmi is detected
on he rpi4, composite remains off by default and you need to enable it in config.txt

I uncommented the line `hdmi_ignore_hotplug=1`.

fyi, it is 1440/3 pixels as they count r, g, and b separately.

Thanks. But I didn't set anything yet.

What makes me wonder is that I do not see anything?
And I did see anything before?

I have another SD and will set the clean Raspbian there to check it.
By the way, is there a clean way to uninstall the graphics installed before by:

- sudo apt-get install -y raspberrypi-ui-mods rpi-chromium-mods
- sudo apt-get install --no-install-recommends xinit

After remove those three packages, is everything like it was before?

Thank you all!

[cleverca22]

i believe the composite output is disabled if hdmi is detected
on he rpi4, composite remains off by default and you need to enable it in config.txt

I uncommented the line `hdmi_ignore_hotplug=1`.

that means it will ignore the lack of hdmi, and always force it into hdmi only mode!

you want to turn that off if you want composite

also, which model of pi are you on?, the 4 needs an extra setting to enable composite output

[RoboTrader]

that means it will ignore the lack of hdmi, and always force it into hdmi only mode!
you want to turn that off if you want composite

also, which model of pi are you on?, the 4 needs an extra setting to enable composite output

I tested all variations.
Nothing worked.
That's so curious.

So, I have to set the '#' before the `hdmi_ignore_hotplug=1`.

And the other parameters are not really important, am I right? I at least have to get any signal - even a bad one, haven't I?

(Raspberry Pi 3B+)

[cleverca22]

and youve confirmed the composite signal is present and works on a normal tv?

[drgeoff]

i believe the composite output is disabled if hdmi is detected

on he rpi4, composite remains off by default and you need to enable it in config.txt

The first line of the opening post contains "... and want to use it for my Raspberry Pi 3B+."

One "DL" is enough on these forums is sufficient, thank you.