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M722 N/B MAINTENANCE
M722 N/B MAINTENANCE
5.
5.
A.1 Introduction
A.1 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
es
of internal checks on the hardware. This power
of internal checks on the hardware. This power
-
-
on self test (post) allows
on self test (post) allows
the computer to detect problems as early as the power
the computer to detect problems as early as the power
-
-
on stage. Error
on stage. Error
messages of post can alert you to the problems of your computer.
messages of post can alert 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
an error
message displayed on the screen. If the error occurs before the
message displayed on the screen. If the error occurs before the
display
display
is initialized,then the screen cannot display the error message.
is initialized,then the screen cannot display the error message.
Error
Error
codes or system beeps are used to identify a post error that occ
codes or system beeps are used to identify a post error that occ
urs
urs
when the screen is not available.
when the screen is not available.
The value for the diagnostic port
The value for the diagnostic port
(3F8H)
(3F8H)
is written at the beginning of
is written at the beginning of
the test. Therefore, if the test failed, the user can determine
the test. Therefore, if the test failed, the user can determine
where the
where the
problem occurred by reading the last value written to port
problem occurred by reading the last value written to port
3F8H
3F8H
by the
by the
M722
M722
debug board plug at CD
debug board plug at CD
-
-
ROM CONNECTOR
ROM CONNECTOR
.
.
5.A Maintenance Diagnostics