Light Path Diagnostics; Viewing The Light Path Diagnostics Leds - IBM LS20 - BladeCenter - 8850 Service Manual

Light path diagnostics

Light path diagnostics is a system of LEDs on the control panel and on various
internal components of the blade server. When an error occurs, LEDs are lit
throughout the blade server. By viewing the LEDs in a particular order, you can
often identify the source of the error.
Some internal components contain LEDs that can be lit for a short time after you
remove the blade server from the BladeCenter unit. After you remove the blade
server, you can press and hold the light path diagnostics switch for a maximum of
25 seconds to light the LEDs that were lit before you removed the blade server
from the BladeCenter unit. Power remains available to light these LEDs for up to 24
hours after the component is removed from the server. The following components
have this feature:
v Microprocessors
v Memory modules (DIMMs)
v Light path diagnostics panel

Viewing the light path diagnostics LEDs

Before working inside the server to view light path diagnostics LEDs, read the
safety information that begins on page v and "Handling static-sensitive devices" on
page 60.
If an error occurs, view the light path diagnostics LEDs in the following order:
1. Look at the control panel on the front of the server (see "Blade server control
2. To view the light path diagnostics panel and LEDs, complete the following steps:
40
AMD Opteron LS20 Type 8850 for IBM BladeCenter: Problem Determination and Service Guide
panel buttons and LEDs" on page 4).
v If the information LED is lit, it indicates that information about a suboptimal
condition in the server is available in the BMC log or in the
management-module event log.
v If the blade-error LED is lit, it indicates that an error has occurred; go to step
2.
a. Remove the blade server from the BladeCenter unit.
b. Place the blade server on a flat, static-protective surface.
c. Remove the cover from the blade server.
d. Press and hold the light path diagnostics switch to relight the LEDs that
were lit before you removed the blade server from the BladeCenter unit. The
LEDs will remain lit for as long as you press the switch, to a maximum of 25
seconds.