Dell Latitude CP Reference And Troubleshooting Manual

Also see for Latitude CP: Service manual Service manual

Contents

Running the Dell Diagnostics 4-15• PC Card Controller TestChecks the functionality of the PC Card controlleron the system board.• USB Register TestChecks the integrated registers of the USB interface.This subtest does not test USB peripherals.• USB Memory Structure TestMonitors the ability of a USB controller to process asimple set of memory-resident instructions.Video Test GroupThe subtests in the Video test group verify the properoperation of the video controller and the video controlcircuitry installed in the computer. These subtests checkfor the correct operation of the readable registers in thevideo circuitry and the controller. They write, read, andverify data patterns in the cursor registers of the control-ler. The Video test group also provides additional subteststo 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 asubtest in the Video test group are obvious, because thedisplay is the visual component of the computer. Beforeyou run the Video test group or any of its subtests, youshould make sure that the problem is not occurring in thesoftware or caused by a hardware change.If the following symptoms still occur, run the appropriatetest(s) as follows:• If your display or external monitor shows a partiallyformed or distorted image, run all of the subtests in theVideo test group.• If the alignment of text or images is off, regardless ofthe program you are running, run the Text ModeCharacter Test, Text Mode Pages Test, and GraphicsMode Test.• If the color on the display or external monitor isintermittent or not displayed at all, run the TextMode Color Test, Color Palettes Test, and SolidColors Test.• If your display or external monitor malfunctions inone mode but works fine in another (for example,text is displayed correctly, but graphics are not), runthe Text Mode Character Test, Text Mode ColorTest, Text Mode Pages Test, and Graphics ModeTest.SubtestsThe eight subtests in the Video test group confirm the fol-lowing video functions:• Video Memory TestChecks the read/write capability of the video mem-ory in various video modes• Video Hardware TestChecks the cursor registers and the horizontal andvertical retrace bit registers in the video controller• Text Mode Character TestChecks the video subsystem’s ability to present datain text modes• Text Mode Color TestChecks the video subsystem’s ability to present colorin text modes• Text Mode Pages TestChecks the video subsystem’s ability to map andpresent all available video pages on the screen, onepage at a time• Graphics Mode TestChecks the video subsystem’s ability to present dataand color in graphics modes• Color Palettes TestChecks the video subsystem’s ability to display all ofthe available colors• Solid Colors TestChecks the video subsystem’s ability to showscreens full of solid colors and allows you to checkfor missing color pixelsMany of these tests display characters or graphics on thescreen for you to verify. Samples of these screens areshown in Appendix B, “Diagnostic Video Tests.”NOTE: The default limit for testing SVGA modes is No. Ifyou are testing an external monitor, change the limit to Yes.