I have connected my rbp3 to an old PAL/SECAM CRT television and have issues getting colors working. I edited the /boot/config.txt file and set the sdtv_mode=2 flag and tweaked some settings.

As the machine boots I see the rainbow splash image and also some lines from Raspbian booting in colour (also the 4 berries on top). Then the berries disappear, the screens turns black and white the over/underscan settings are gone.

Something is overwriting my settings from the boot/config file and I don't know what, I sincerely thought that raspbian didn't had access to the actual sdtv settings.

I made a short video to show the issue: https://youtu.be/zbzejiEh_-Y

  • Is there anything in the video that you didn't describe in the question? – Dmitry Grigoryev Jul 18 '19 at 9:40

Is that TV trying to set its own resolution? It looks like it changes after a few seconds. I'd suggest reviewing the settings on the TV to make sure it's not tying to be clever...

| improve this answer | |
  • 1
    I went for work now, as I am back home I'll test with another screen. But as far as I know my tv is everything but intelligent and I feel like the issue occurs always in the same moment (as the 4 berries disappear) – Pivetta Jul 17 '19 at 11:38
  • Sure - but the issue appearing at the same point in the cycle could still be caused by the TV changing resolutions... don't forget the berries always disappear the same time after boot. Please let us know how you get on. – Jonathan Jul 17 '19 at 11:52

Im really sorry, Johnatan was right and it was my tv changing setting because the overscan was too high (I did never experience that and always thought my device was pretty basic) I have used a more primitive tv where the signal was working, and after changing the overscan settings I moved back to the other tv. Now everything is working and is calibrated. Thanks for the support!

| improve this answer | |
  • Very glad it helped! – Jonathan Jul 19 '19 at 11:38

Stock Raspbian does not overwrite /boot/config.txt file. It must be an issue with some software you have installed (example). You'll have to find out which one it is, perhaps by installing programs one by one. Googling for bug reports related to the issue may be another idea.

| improve this answer | |

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.