Dell 4100/180, 4100/200 Appendix B Diagnostic Video Tests, Video Memory Test, Video Hardware Test

Appendix B Diagnostic Video Tests

The Video Test Group of the system diagnostics con- sists of the following seven tests, each of which verifies a particular 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.

Video 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.

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 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