I've installed Lubuntu 14.04 on an AsRock 775 VM 800 with a Pentium 4. It often boots to the Lubuntu splash screen for a few seconds and then displays what appears to be a black screen. After a while the monitor reports that there is no video signal. At this point the hard drive light flashes occasionally. The video does not respond to the keyboard and mouse. There is no response to power cycling the monitor (off then on). I even switched to PS/2 keyboard and PS/2 mouse to eliminate USB initialization problems but the problem happens regardless of whether the input devices are USB or PS/2.

This board is described as having the following video support: Integrated UniChrome Pro 3D Graphics. The BIOS seems to have a setting to specify AGP or PCI. Neither setting makes a difference and perhaps the setting applies to plug-in video cards, of which none are present.

I have swapped monitors, keyboards, mice, and installed a voltage regulator. The problem persists.

Very seldom does the Lubuntu login screen appear, but if it does, the unit is functional and was tested with Skype and Firefox, so I know the OS is present and common applications work.

How do I resolve this black screen problem?


1 Answer 1


If the information at the link My computer boots to a black screen, what options do I have to fix it? with relevance to Ubuntu does not get the job done then perhaps the advice there about using the install menu's F6 to change the nomodeset option was not sufficient or the recommendation about using GRUB to also apply nomodeset was similarly lacking.

The answer in this post is specific to Lubuntu and contains no screen shots of Ubuntu that are not exactly what the Lubuntu user will encounter. This answer is specific to Lubuntu 14.04.

The tested recommendation that did succeed for this particular hardware is:

  1. Reboot from the ISO image but highlight Try Lubuntu without installing. While it is highlighted notice that the cursor keys allow you to cursor (horizontally) through the list of configuration keywords. It might not be obvious. What is obvious is that if you can cursor through them you can edit them. Replace the words quiet and splash with the words nomodeset and xforcevesa. The nomodeset will cause the kernel not to set video parameters and leave it to other parts of Lubuntu. The xforcevesa has to do with forcing VESA configurations, probably in X support.
  2. It might not be obvious that Try Lubuntu without installing will provide a way to conveniently install, so to merely "try Lubuntu" is not a waste of time. Once the edits have been made proceed to invoke Try Lubuntu without installing. In a little while, the desktop will show an icon that allows you to actually install Lubuntu. Right click it and invoke it. (Note that the selection Install Lubuntu back in the install menu (not to be confused with the desktop icon for installing) also allows horizontal cursoring and option editing and so it probably is the alternative solution. However, as suggested, to merely "try" was not a terribly inefficient route.)

Perhaps it is not obvious but apparently the option edits that were done in step 1 will persist over shutdowns and reboots.

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