Service manual

Diagnostic Video Tests: Dell Latitude CP
The following sections describe each of the tests in the Video test group.
Video Memory Test
The Video Memory Test verifies the integrity of the video memory on the system board. When
a test is complete, a message indicates whether the video memory has passed or failed the
test. This test does not require any interaction on your part.
Video Hardware Test
The Video Hardware Test verifies the operation of the cursor registers and the horizontal and
vertical retrace bit registers. When a test is complete, a message indicates whether these
registers have passed or failed the test. This test does not require any interaction on your part.
Text Mode Character Test
The Text Mode Character Test consists of a group of subtests that display printable characters
and character attributes. The subtests check character quality and the ability of the display or
monitor to show the characters correctly. A prompt at the bottom of each screen asks you to
decide whether the display is satisfactory and to respond by typing y or n.
If you respond affirmatively to each subtest, the Text Mode Character Test passes. A negative
response to any subtest causes the test to fail.
The following subsections describe the subtests of the Text Mode Character Test in the order
in which they appear.
Character Attributes Subtest (80 x 25)
The 80-column x 25-line character attributes subtest displays four lines of text that
demonstrate normal-intensity video, reverse video, intensified video, and blinking video.
Character Set Subtest (80 x 25)
The 80-column x 25-line character set subtest displays all 256 characters in the American
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