However, if the computer fails the POST, the computer emits a series of LED codes during the start-up. The system LED is integrated on
the Power button.
The following table shows different light patterns and what they indicate.
Table 2. Power LED summary
Amber LED state
White LED state
System state
Notes
Off
Off
S5
Off
Blinking
S3, no PWRGD_PS
Previous State
Previous State
S3, no PWRGD_PS
This entry provides for the
possibility of a delay from
SLP_S3# active to PWRGD_PS
inactive.
Blinking
Off
S0, no PWRGD_PS
Steady
Off
S0, no PWRGD_PS, Code fetch
= 0
Off
Steady
S0, no PWRGD_PS, Code fetch
= 1
This indicates that the host BIOS
has started to execute and the
LED register is now writable.
Table 3. Amber LED blinking failures
Amber LED state
White LED state
System state
Notes
2,1
Bad MBD
Bad MBD - Rows A, G, H, and J
from table 12.4 of SIO Spec -
Pre-Post indicators [40]
2,2
Bad MB, PSU or cabling
Bad MBD, PSU or PSU cabling -
Rows B, C and D of table 12.4
SIO spec [40]
2,3
Bad MBD, DIMMS, or CPU
Bad MBD, DIMMS or CPU -
Rows F and K from table 12.4 of
SIO spec [40]
2,4
Bad coin cell
Bad coin cell - Row M of table
12.4 in SIO spec [40]
Table 4. States Under Host BIOS Control
Amber LED state
White LED state
System state
Notes
2,5
BIOS state 1
BIOS Post code (Old LED
pattern 0001) Corrupt BIOS.
2,6
BIOS state 2
BIOS Post code (Old LED
pattern 0010) CPU config or
CPU failure.
2,7
BIOS state 3
BIOS Post code (Old LED
pattern 0011) MEM config in
process. Appropriate mem
modules detected but failure has
occurred.
3,1
BIOS state 4
BIOS Post code (Old LED
pattern 0100) Combine PCI
device config or failure with
68
Troubleshooting
