92Solving ProblemsMore Problem Solving ProceduresThis section provides a more detailed approach to identifying a problem and locating its source.Preparing the System for Diagnostic TestingCAUTIONTurn off devices before disconnecting cables: Before disconnecting anyperipheral cables from the system, turn off the system and any externalperipheral devices. Failure to do so can cause permanent damage to thesystem and/or the peripheral devices.1.Turn off the system and all external peripheral devices. Disconnect all of them from thesystem, 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 the system.Turn on the video monitor. Set its brightness and contrast controls to at least two thirds of theirmaximum ranges (see the documentation supplied with your video display monitor).4.If the operating system normally loads from the hard disk drive, make sure there is no diskettein drive A. Otherwise, place a diskette containing the operating system files in drive A.5.Turn on the system. If the power LED does not light, see Power Light Does Not Light onpage 93.Monitoring POSTSee Chapter 3.Verifying Proper Operation of Key System LightsAs POST determines the system configuration, it tests for the presence of each mass storage deviceinstalled in the system. As each device is checked, its activity light should turn on briefly. Checkfor the following:qDoes the diskette drive activity light turn on briefly? If not, see Diskette Drive Activity LightDoes Not Light on page 95.qIf a second diskette drive is installed, does its activity light turn on briefly? If not, see DisketteDrive Activity Light Does Not Light on page 95.qIf there is a hard disk drive or SCSI devices installed in the system, does the hard disk driveactivity light on the control panel turn on briefly? If not, see Hard Disk Drive Activity LightDoes Not Light" on page 95.Confirming Loading of the Operating SystemOnce the system boots up, the operating system prompt appears on the screen. The prompt variesaccording to the operating system. If the operating system prompt does not appear, see InitialSystem Startup on page 89.