Dell Latitude XPi Reference Guide - Page 85

• Coprocessor Error Exception Test Verifies the math coprocessor's ability to handle errors and to send IRQs to the microprocessor. • PC Card Controller Test Checks the functionality of the PC Card controller on the system board. • Thermal Control Test Checks the functionality of the thermal-monitoring and microprocessor speed-switching device on the system board. This test does not apply to the Dell Latitude LM. 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 the 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, the Color Palettes Test, and the 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 the 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 • 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 Running the Dell Diagnostics 4-15