Light Path Diagnostics; Viewing The Light Path Diagnostics Leds - IBM BladeCenter HS20 7981 Problem Determination And 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 can be lit
throughout the blade server to help identify the source of the error.
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 and locate the
failing component. The following components have this feature:
v Hard disk drives
v Light path diagnostics panel
v Microprocessors
v Memory modules (DIMMs)

Viewing the light path diagnostics LEDs

Before working inside the blade server to view light path diagnostics LEDs, read the
safety information that begins on page vii and "Handling static-sensitive devices" on
page 56.
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 blade server (see "Blade server
2. To view the light path diagnostics panel and LEDs, complete the following steps:
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BladeCenter HS20 Type 7981: Problem Determination and Service Guide
controls, LEDs, and connectors" on page 4).
v If the information LED is lit, it indicates that information about a suboptimal
condition in the blade 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 light the LEDs of the
failing components in the blade server. The LEDs will remain lit for as long
as you press the switch, to a maximum of 25 seconds.