HP Contura 400 Compaq Contura 400 Family of Personal Computers Maintenance and - Page 273

2. Clean trackball. 3. Ensure trackball connector is seated properly. 4. Replace the trackball assembly. 5. Replace the system board Chapter 5.3 Troubleshooting without Error Messages This section contains troubleshooting information that provides a quick reference for diagnosing problems that cannot be identified by running POST or Computer Checkup (such as a non-functional display that does not allow viewing error messages). For additional information refer to the tables 5-12 through 5-27 in Section 5.3. Since symptoms can appear to be similar, carefully match the symptoms of the computer malfunction against the problem description in the troubleshooting tables to avoid a misdiagnosis. WARNING To avoid a potential shock hazard during troubleshooting procedures, disconnect all power sources before removing the keyboard assembly or the display bezel. Before Replacing Parts When Troubleshooting When troubleshooting a problem, check the following list for possible solutions before replacing parts: o Verify that cables are connected properly to the suspected defective parts. Try reseating the cables even if they appear to be properly connected. o Run Computer Setup after connecting external devices. o Verify that all required device drivers are installed. o Verify that all required changes have been made to the CONFIG.SYS file. o Verify that all required changes have been made to the AUTOEXEC.BAT file. o Verify that printer drivers have been installed for each application. Table 5-12. Solving Power Problems Problem Probable Cause Solution(s) Computer will not turn AC Adapter may be 1. Replace AC Adapter. on when plugged in and defective. 2. Remove battery pack; battery pack is insert another battery inserted. pack and try to turn on computer again.