Laptop User Manual

98
7521
7521
Plus / N N/B MAINTENANCE
Plus / N N/B MAINTENANCE
7. Maintenance Diagnostics
7.1
7.1
Introduction
Introduction
Each time the computer is turned on, the system bios runs a seri
Each time the computer is turned on, the system bios runs a seri
es of internal
es of internal
checks on the hardware. This power
checks on the hardware. This power
-
-
on self test (post) allows the computer to
on self test (post) allows the computer to
detect problems as early as the power
detect problems as early as the power
-
-
on stage. Error messages of post can alert
on stage. Error messages of post can alert
you to the problems of your computer.
you to the problems of your computer.
If an error is detected during these tests, you will see
If an error is detected during these tests, you will see
an error message
an error message
displayed on the screen. If the error occurs before the display
displayed on the screen. If the error occurs before the display
is initialized,then the
is initialized,then the
screen cannot display the error message. Error codes or system b
screen cannot display the error message. Error codes or system b
eeps are used to
eeps are used to
identify a post error that occurs when the screen is not availab
identify a post error that occurs when the screen is not availab
le.
le.
The value for the diagnostic port
The value for the diagnostic port
(378H)
(378H)
is written at the beginning of the test.
is written at the beginning of the test.
Therefore, if the test failed, the user can determine where the
Therefore, if the test failed, the user can determine where the
problem occurred by
problem occurred by
reading the last value written to port
reading the last value written to port
378H
378H
by the
by the
378H
378H
port debug board plug at
port debug board plug at
PIO PORT.
PIO PORT.