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9. TROUBLESHOOTING
9.6 Digital LEDs for Status Indications
The digital LEDs for status indications are used to display POST codes at system startup (for the period of time
from when the BIOS starts to when the OS starts). They are also used to display a hardware status code when an
error occurs in the hardware during system operation.
The digital LEDs for status indications and the status indication LEDs might remain lit even after the equipment is
shutdown and put into standby mode. They remain lit until the main power is shutdown or the power is turned on
again.
It should be noted that the digital LEDs for status indications might display a code even when there is no error.
(For example, when the BIOS screen is displayed (1F) or when the POST code is displayed from turning on the
power supply unit to OS startup.)
As shown here, the numerical value lamp shows the digits from 0 to F in hexadecimal.
0
1
9.6.1 POST messages
Power On Self Test (POST) is a feature whereby the system BIOS makes routine checks for hardware failures when
the power of the computer system is turned on. If any failure is found, the POST code corresponding to the location
of the failure is displayed on the digital LEDs for status indications on the front of the equipment. The user is then
notified via means such as having a message appear on the display or sounding a beep several times.
When a POST code is displayed, the BIOS status lamp in the status indication LEDs is lit in orange.
The following table shows the POST codes that are indicated when the system stops during startup and the
respective actions for resolving them.
Table 9-5 POST codes, reasons for stopping, and actions (1/2)
POST
Reasons for stopping and actions
code
There might be a problem with the main memory
A3
or CPU.
A5
Verify that the main memory is installed properly.
There might be a problem with the keyboard or
61
mouse.
83
Verify that the cables are connected correctly and
the keyboard and mouse are operating properly.
2
3
4
5
6
7
8
9
A
B
POST
Reasons for stopping and actions
code
1E
21
There might be a problem with the main memory.
57
Verify that the main memory is installed properly.
F8
9-30
C
D
E
F
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