Appendix B Diagnostic Video Tests; Video Memory Test; Video Hardware Test; Text Mode Character Test - Dell 6100 Installation And Troubleshooting Manual

Appendix B
Diagnostic Video Tests
T
he Video Test Group of the system diagnostics (see
Chapter 5, "Running the System Diagnostics") consists
of the following seven tests, each of which verifies a par-
ticular video function or group of functions:
•
Video Memory Test — Checks the integrity of char-
acters generated from data in the video memory.
•
Video Hardware Test — Checks the functions of the
cursor register and the horizontal and vertical retrace
bit registers.
•
Text Mode Character Test — Checks the video sub-
system's ability to present text mode data.
•
Text Mode Color Test — Checks the video sub-
system's ability to present color in text modes.
•
Text Mode Pages Test — Checks the video sub-
system's ability to map and present all available
video text pages on the monitor screen, one page at a
time.
•
Graphics Mode Test — Checks the video sub-
system's ability to present graphics mode data and
colors.
•
Color Palettes Test — Checks the video subsystem's
ability to display all available colors.
•
Solid Colors Test — Checks the video subsystem's
ability to show screens full of solid colors. Allows
you to check for missing color subpixels.
All of these tests, except the Video Memory Test and the
Video Hardware Test, are interactive. These interactive
tests display images on the monitor screen and require
the user to respond with the following steps:
1. Examine a displayed image for correctness.
2. If an image is correct, type y.
3. If an image is incorrect, type n.
The following sections describe each of the tests in the
Video Test Group.
V
ideo Memory Test
The Video Memory Test verifies the integrity of the
video memory either on the system board or on a video
expansion card. As the test runs, it describes which
64-kilobyte (KB) block of video memory is being tested.
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.
V
ideo 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.
T
ext Mode Character Test
The Text Mode Character Test consists of a group of sub-
tests that display printable characters and character
attributes. The subtests check character quality and the
monitor's ability to display the characters correctly on its
screen. A prompt at the bottom of each screen asks the
user 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.
Diagnostic Video Tests B-1