Power On Self Test/Problem Isolation; Power On Self Test; System Problem Isolation - Compaq Portable II Maintenance And Service Manual

Chapter 2. Power On Self Test/Problem Isolation

2.1 Power On Self Test

The Power On Self Test (POST) is a series of diagnostic tests performed
automatically when the system is turned on.
computer system is operating properly.
code appears on the screen.
To start POST, follow these steps.
1. Turn off the computer.
2. Disconnect the signal cables of any peripheral devices (printers, modems,
and so on) from the computer.
3. Remove the outer access casing to expose the system LED located on the
system board (see Chapter 7 for this procedure).
4. Install a loopback plug connector at each location from which a
peripheral signal cable was removed.
NOTE: To test your printer during the printer test or to log errors to a
printer, reconnect the printer now.
5. Verify that the AC power cable is connected to a usable, grounded, three
pronged AC power outlet.
6. Insert the DIAGNOSTICS diskette into drive A.
7. Turn on the computer.
Section 2.2, "System Problem Isolation," for information on handling
system problems.
Chapter 2.2 System Problem Isolation
This section contains problem isolation procedures for identifying and
correcting system related problems.
To isolate system problems, perform the following steps:
1. Verify that the AC power switch is on.
2. Listen for the sound of the fan.
YES: Proceed to step 3.
NO: Turn off the computer and check the condition of the AC power fuse.
Is the fuse good?
YES: Return the AC power fuse to its fuse holder and turn on the system.
Proceed to step 3.
These tests verify that the
If a subassembly fails POST, an error
The system automatically runs POST.
Did you hear the fan?
See