Display Test - Toshiba A20-S259 - Satellite - Pentium 4 2.66 GHz Maintenance Manual

3.7 Display Test

3.7 Display Test
To execute the Display Test, select 4 from the DIAGNOSTIC TEST MENU, press Enter and
follow the directions on the screen. The Display test contains seven subtests that test the display in
various modes. Move the highlight bar to the subtest you want to execute and press Enter.
Subtest 01 VRAM Read/Write for VGA
This subtest writes constant data AAh and 55h and address data to video RAM
8MB. This data is then read from the video RAM and compared to the original
data.
Subtest 02 Gradation for VGA
This subtest displays four colors: red, green, blue and white from left to right across
the screen from black to maximum brightness. The display below appears on the
screen when this subtest is executed.
To exit this subtest and return to the DISPLAY TEST menu, press Enter.
Subtest 03 Gradation for LCD
This subtest displays several horizontal bands of multiple color, followed by red,
green and blue bars. Each bar displays black on the top and the brightest color at
the bottom.
Next, this subtest displays full screen of eight colors: red, semi-red, green, semi-
green, blue, semi-blue, white, and semi-white.
Each color displays for three seconds.
Satellite A20 Maintenance Manual (960-444)
3 Tests and Diagnostics
3-19