Technical Product Specification

Intel® Light-Guided Diagnostics Intel® Server Board S5520UR and S5520URT TPS
Intel order number E44031-012 Revision 1.9
124
8.5 Post Code Diagnostic LEDs
Eight amber POST code diagnostic LEDs are located on the back edge of the server board in
the rear I/O area of the server board by the serial A connector.
During the system boot process, the BIOS executes a number of platform configuration
processes, each of which is assigned a specific hex POST code number. As each configuration
routine is started, the BIOS displays the given POST code to the POST code diagnostic LEDs
on the back edge of the server board. To assist in troubleshooting a system hang during the
POST process, the diagnostic LEDs can be used to identify the last POST process to be
executed. See Appendix C for a complete description of how these LEDs are read, and for a list
of all supported POST codes.
A
Status LED
F
Diagnostic LED #4
B
ID LED
G
Diagnostic LED #3
C
Diagnostic LED #7 (MSB LED)
H
Diagnostic LED #2
D
Diagnostic LED #6
I
Diagnostic LED #1
E
Diagnostic LED #5
J
Diagnostic LED #0 (LSB LED)
Figure 45. POST Code Diagnostic LED Location