John Public
Posts: 90
Joined: Thu Jan 16, 2014 2:16 pm

Monitor not showing anything

Fri May 11, 2018 6:59 pm

I have a Samsung LE23R86BC which according to specs can handle 1368x768
So I edited /boot/config.txt to have
hdmi_group=2
hdmi_mode=39

Now when I boot RPi my monitor says "Mode not supported" and a blank screen. However, the lights blinking on RPi indicate that it has booted.
Is there a key combo or something that I could use to set the resolution to a default so I can fix my monitor settings on /boot/config.txt?

fruitoftheloom
Posts: 25802
Joined: Tue Mar 25, 2014 12:40 pm
Location: Delightful Dorset

Re: Monitor not showing anything

Fri May 11, 2018 7:23 pm

John Public wrote:
Fri May 11, 2018 6:59 pm
I have a Samsung LE23R86BC which according to specs can handle 1368x768
So I edited /boot/config.txt to have
hdmi_group=2
hdmi_mode=39

Now when I boot RPi my monitor says "Mode not supported" and a blank screen. However, the lights blinking on RPi indicate that it has booted.
Is there a key combo or something that I could use to set the resolution to a default so I can fix my monitor settings on /boot/config.txt?

If you are using the TV HDMi Input and a known good HDMi cable the resolution should be auto-detected as it is a 720p Screen:

http://www.backoffice.be/prod_uk/Samsun ... n_720p.asp
The information is out there....you just have to let it in.

My other Linux machines are a ChromeBox & Intel CoreDuo Desktop

John Public
Posts: 90
Joined: Thu Jan 16, 2014 2:16 pm

Re: Monitor not showing anything

Fri May 11, 2018 7:32 pm

Thanks for the reply. I managed to get the setting back to normal this way:
- I hard-shutdown rpi (pulled the power cord)
- took the SD card to another Windows computer and edited the config.txt to a better value.
It started OK with no data loss, Whew!

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