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I have just installed Ubuntu (12.0.4 TLS for Servers) on a DELL poweredge 2850. During the installation, the process goes OK. However, as soon as I start the system normally (and the text font is changed) it starts continuously blinking: 4 seconds I can see the screen, 4 seconds is black, and so on and so forth. This annoying behaviour does not happen during installation or if I run x-windows. Any ideas of what could be happening?

PS: I have asked in Ask-Ubuntu ( and have been redirected here

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It looks like you might have an issue where your monitor's autodetection is kicking in inappropriately. Many monitors will second-guess themselves and do things like constantly switch the active input for no reason or display "input out of range" overtop of an otherwise properly displayed image when they receive a signal or EDID data that confuses them.

Try explicitly passing the vga option to your kernel. For instance, for 1280x1024 24bpp, specify vga=795. Alternatively, replace the monitor.

Occasionally I have also seen this problem caused by a bad video card or display cable.

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mmm.. I am trying to do this but with any parameter I pass on to vga on grub I got a "xxx vga mode is deprecated". I do not have time to read the rest... – Kiara Jul 3 '13 at 1:30

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