Ubuntu 11.04 fresh install - "Input signal out of range" or "Mode not supported..."

Question

I recently installed Ubuntu 11.04 using a CD .iso. Installation went fine. Upon completion I rebooted and after a second or two I got a black screen with the message "Input signal out of range". And there it sits...

Read a few things about how this could be related to screen resolution, refresh rate, etc. For the heck of it I tried a different monitor. The result is the same but the message provides some clues - "Mode not supported - H:92.7kHz, V:58.3Hz" (the latter is Hz; not kHz).

So my thought is that I should probably be able to use the 11.04 install disc to "Try out Ubuntu", find and edit some file that was created by the install with the correct values. Problem is, I am not too sure what I am supposed to edit. Looked at the xorg.conf file but this is so minimal at this point I am not sure it is where I want to go.

By the way, the monitor is an I-Inc ix191a. Anyone have any ideas on how to get around this?

Solution

I had a machine running Kubuntu 11.04 that suddenly started to do this last week - the fix was:

1. Wait for the invisible grub menu to timeout and the PC should eventually boot - or try pressing ENTER on the 'blank' screen and wait for Linux to boot

2. Open a terminal window and sudo vi /etc/default/grub (or use your favourite editor)

3. Find the line that starts #GRUB_GFXMODE=640x480 (or similar)

4. Insert the following on the next line: GRUB_GFXMODE=1024x768

5. Save your changes

6. Enter the command sudo update-grub

7. Reboot and see what happens!

If you want you could try another resolution such as 1280x1024, but 1024x768 gave me a suitable display.

PS: if this turns out to be more than just the boot menu, have a look at this Ubuntu Wiki page: https://wiki.ubuntu.com/X/Config/Resolution#Resetting_an_out-of-range_resolution

Comments

[Dennis]

Hi. A bit more information here. I found a copy of the specs for the montior and they show H-Frequency range = 31kHz - 80kHz and V-Frequency range 55Hz-75Hz. So the information that the second monitor is showing looks to be correct as far as the H-Frequency (92.7kHz).

[Dennis]

Hi. Thanks for that. Problem is the thing never boots. The only thing that I can ever do to change behavior is hit Shift repeatedly during boot and at some point I can see 'Grub Loading' flash on the screen and then back to the Input signal... But I suppose I could manage to modify the /etc/default/grub with a correct H-Frequency somehow?

[Linker3000]

Hmm - bummer! You could boot off the install disk and start rescue mode - that would let you mount the installed OS and edit the file.

[Dennis]

Actually, a big thank you is in order. After you initially responded, I considered that I might have been a little impatient. So after I got that ISOoR and the black screen, I waited a bit and hit the ENTER like you suggested and, lo and behold, it booted. I remembered a post I read over the weekend (ubuntuguide.net/…) that talked about a couple of easy steps that might also work and they did work. I guess I was just being too impatient.

[obecalp]

+1 ... I'd give you a hundred upvotes if I could, this saved me a ton of time