Toshiba A20-S259 Maintenance Manual - Page 131

3.7 Display Test 3 Tests and Diagnostics 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. Subtest 03 To exit this subtest and return to the DISPLAY TEST menu, press Enter. 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, semigreen, blue, semi-blue, white, and semi-white. Each color displays for three seconds. Satellite A20 Maintenance Manual (960-444) 3-19