Compaq SLT 386s/20 Maintenance And Service Manual page 9

Chapter 2 - Power On Self Test (POST)
INTRODUCTION
This chapter lists the subassemblies checked by the Power On Self Test (POST)
and briefly describes the types of error codes that can occur.
also includes problem isolation procedures and a flowchart for quick
reference.
Chapter 2.1 POST
POST is a series of diagnostic tests that runs automatically on the
COMPAQ SLT 386s/20 and COMPAQ SLT/286 Personal Computers when the computers
are turned on.
POST checks the following subassemblies to ensure that the computer system is
functioning properly:
o System Board
o System Memory
o Memory Boards
o Keyboard
o Controller Circuitry
o VGA Backlit Display (Monitor)
o Fixed Disk Drives
o Diskette Drives
POST also detects the type of mass storage devices installed in the computer.
If POST finds an error in the computer, an error condition is indicated by an
audible and/or visual message.
an explanation of the error codes and a recommended course of action.
Chapter 2.2 PRELIMINARY STEPS
If you encounter an error condition, complete the following steps before
starting the problem isolation procedures:
1. Turn off power to the computer.
2. Disconnect any external devices (leave the AC Adapter attached). Do not
disconnect the printer if you want to test the printer or use it to log
error messages.
3. Install all appropriate loopback plugs and terminating plugs for complete
testing.
4. Clear the power on password, if it is preset by the user.
NOTE: The COMPAQ SLT 386s/20 has a power on password feature.
know that the power on password is set when a key icon (o--m) appears
See Chapter 3, "Error Messages and Codes," for
Do not remove the battery pack.
The chapter
You will