Video Test Group; Why Run A Video Test; Subtests - Dell Latitude CP Reference And Troubleshooting Manual

•
PC Card Controller Test
Checks the functionality of the PC Card controller
on the system board.
•
USB Register Test
Checks the integrated registers of the USB interface.
This subtest does not test USB peripherals.
•
USB Memory Structure Test
Monitors the ability of a USB controller to process a
simple set of memory-resident instructions.
V
ideo 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 control-
ler. The Video test group also provides additional subtests
to test the color features of the color display or an exter-
nal 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 fol-
lowing video functions:
•
Video Memory Test
Checks the read/write capability of the video mem-
ory 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
•
Graphics Mode Test
Checks the video subsystem's ability to present data
and color in graphics modes
•
Color Palettes Test
Checks the video subsystem's ability to display all of
the available colors
•
Solid Colors Test
Checks the video subsystem's ability to show
screens full of solid colors and allows you to check
for missing color pixels
Many of these tests display characters or graphics on the
screen for you to verify. Samples of these screens are
shown in Appendix B, "Diagnostic Video Tests."
NOTE: The default limit for testing SVGA modes is No. If
you are testing an external monitor, change the limit to Yes.
Running the Dell Diagnostics 4-15