Display not working

hi

I have installed Angstrom linux on Beagle Board B7 and currently am
using a 19" Benq monitor with DVI input and i have set the resolution
as omapfb.mode=dvi:1280x720MR-16@60'
this works fine for me without any problem

but now i have changed the display to 12" Industrial made with
resolution 800x600 with DVI input
as my final application is going to use the 12" display

i am setting the resolution as above with 800x600 but after the beagle
board boots nothing comes up the screen..not even the initial startup
Beagle
logo.

is this to do anything with the refresh rate of display..
i checked the data sheet of the display its says frame rate 60 Hz
which
am giving

i checked the display with normal PC it works fine