5-6 Problem SolvingDiagnostic TestingThis section provides a more detailed approach to diagnostic testing and identificationof a problem and locating its source.Error CheckingEach time you turn on the system, POST (Power-On-Self-Test) runs automatically andchecks the system boards, processors, memory, keyboard, and most installed peripheraldevices.If POST finds an error, it displays an error message. Refer to the Error Message sectionin this chapter for an explanation of each error message.Troubleshooting GuideUse the following troubleshooting procedures to help you identify a problem. Thesegeneral procedures lead you through the following:! Preparing the system for diagnostic testing! Monitoring POST while it is running! Verifying proper operation of key system LEDs! Confirming loading of the operating system.Preparing the System for Diagnostic TestingTo prepare the system for diagnostic testing, perform the following:Note: Before disconnecting any peripheral cables from thesystem, turn off the system and any external peripheral devices.Failure to do so can cause permanent damage to the system and/orthe peripheral devices.1. Turn off the system and all external peripheral devices. Disconnect all devices fromthe system except the keyboard and video monitor.2. Make sure the system power cord is plugged into a properly grounded AC outlet.3. Make sure your video display monitor and keyboard are correctly connected to thesystem. Turn on the video monitor. Set its brightness and contrast controls to at leasttwo-thirds of their maximum ranges (refer to the documentation supplied with yourvideo display monitor).4. If the operating system normally loads from the hard disk drive, make sure there isno diskette in drive A. Otherwise, place a diskette containing the operating systemfiles in drive A.5. Turn on the system. If the power indicator LED does not light, refer to “PowerLight Does Not Light” found later in this chapter.
