Dell Latitude CPi User Guide - Page 125

Video Test Group, Why Run a Video Test?, Subtests

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Video Test Group The subtests in the Video test group verify the proper operation of the video controller and the video control circuitry installed in the computer. These subtests check for the correct operation of the readable registers in the video circuitry and the controller. They write, read, and verify data patterns in the cursor registers of the controller. The Video test group also provides additional subtests to test the color features of the color display or an external color monitor. Why Run a Video Test? Many of the symptoms that would prompt you to run a subtest in the Video test group are obvious, because the display is the visual component of the computer. Before you run the Video test group or any of its subtests, you should make sure that the problem is not occurring in the software or caused by a hardware change. If the following symptoms still occur, run the appropriate test(s) as follows: If your display or external monitor shows a partially formed or distorted image, run all of the subtests in the Video test group. If the alignment of text or images is off, regardless of the program you are running, run the Text Mode Character Test, Text Mode Pages Test, and Graphics Mode Test. If the color on the display or external monitor is intermittent or not displayed at all, run the Text Mode Color Test, Color Palettes Test, and Solid Colors Test. If your display or external monitor malfunctions in one mode but works fine in another (for example, text is displayed correctly, but graphics are not), run the Text Mode Character Test, Text Mode Color Test, Text Mode Pages Test, and Graphics Mode Test. Subtests The eight subtests in the Video test group confirm the following video functions: Video Memory Test Checks the read/write capability of the video memory in various video modes Video Hardware Test Checks the cursor registers and the horizontal and vertical retrace bit registers in the video controller Text Mode Character Test Checks the video subsystem's ability to present data in text modes Text Mode Color Test Checks the video subsystem's ability to present color in text modes Text Mode Pages Test Checks the video subsystem's ability to map and present all available video pages on the screen, one page at a time

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Video Test Group
The subtests in the Video test group verify the proper operation of the video controller and the video control
circuitry installed in the computer. These subtests check for the correct operation of the readable registers in
the video circuitry and the controller. They write, read, and verify data patterns in the cursor registers of the
controller. The Video test group also provides additional subtests to test the color features of the color display
or an external color monitor.
Why Run a Video Test?
Many of the symptoms that would prompt you to run a subtest in the Video test group are obvious, because
the display is the visual component of the computer. Before you run the Video test group or any of its
subtests, you should make sure that the problem is not occurring in the software or caused by a hardware
change.
If the following symptoms still occur, run the appropriate test(s) as follows:
If your display or external monitor shows a partially formed or distorted image, run
all
of the subtests in
the Video test group.
If the alignment of text or images is
off
, regardless of the program you are running, run the Text Mode
Character Test, Text Mode Pages Test, and Graphics Mode Test.
If the color on the display or external monitor is intermittent or not displayed at all, run the Text Mode
Color Test, Color Palettes Test, and Solid Colors Test.
If your display or external monitor malfunctions in one mode but works fine in another (for example, text
is displayed correctly, but graphics are not), run the Text Mode Character Test, Text Mode Color Test,
Text Mode Pages Test, and Graphics Mode Test.
Subtests
The eight subtests in the Video test group confirm the following video functions:
Video Memory Test
Checks the read/write capability of the video memory in various video modes
Video Hardware Test
Checks the cursor registers and the horizontal and vertical retrace bit registers in the video controller
Text Mode Character Test
Checks the video subsystem's ability to present data in text modes
Text Mode Color Test
Checks the video subsystem's ability to present color in text modes
Text Mode Pages Test
Checks the video subsystem's ability to map and present all available video pages on the screen, one
page at a time