Compaq 420C 486 DX4/75 MHZ 350 MB 4 MB 10.4 Personal Computer User Manual


 
Chapter 4. Running POST and Test
Introduction
This chapter covers troubleshooting information for the computer. The
basic steps in troubleshooting include:
1. Follow the preliminary steps listed in Section 4.1.
2. Run the Power-On Self-Test (POST) as described in Section 4.2.
3. Run Computer Checkup (TEST) as described in Section 4.3.
4. Follow the recommended action described in the diagnostic tables in
Chapter 5, Section 5.1, 5.2, and 5.3 if you are unable to run POST or
Computer Checkup, or if the problem still persists after they are run.
When taking the recommended actions given in Section 5.2, 5.3, and 5.4,
take them one at a time in the given order until the problem is solved and
no error messages occur. Refer to Chapter 3 for any recommended removal
and replacement procedures.
NOTE: If a problem only occurs when an external device is connected to the
computer, the problem may be with the external device or its cable.
Verify this by running POST with and without the external device
connected.
Chapter 4.1 Preliminary Steps
IMPORTANT: Use AC power when running POST, Computer Setup, and Computer
Checkup. A low battery condition could initiate Standby and
interrupt the program.
Before running POST and Computer Checkup, complete the following
preliminary steps:
1. If a power-on password has been established, type the password and
press the Enter key.
NOTE: If the key symbol (ohm) appears on the screen when the computer is
turned on, a power-on password has been established. If the password
is unknown, it must be cleared (refer to "Clearing the Power-On
Password" in this chapter).
2. Verify that Computer Setup has been run. If not, run Computer Setup.
3. Simultaneously press the Fn+F9 keys to adjust the brightness and the
Fn+F8 keys to adjust contrast on the MSTN and CSTN displays.
4. Turn off the computer and external devices.