Light Path Diagnostics - IBM System x3650 M3 4255 Service Manual

Light path diagnostics

Light path diagnostics is a system of LEDs on various external and internal
components of the server. When an error occurs, LEDs are lit throughout the
server. By viewing the LEDs in a particular order, you can often identify the source
of the error.
When LEDs are lit to indicate an error, they remain lit when the server is turned off,
provided that the server is still connected to power and the power supply is
operating correctly.
Before you work inside the server to view light path diagnostics LEDs, read the
safety information that begins on page vii and "Handling static-sensitive devices" on
page 171.
If an error occurs, view the light path diagnostics LEDs in the following order:
1. Look at the operator information panel on the front of the server.
2. To view the light path diagnostics panel, slide the latch to the left on the front of
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IBM System x3650 M3 Types 4255, 7945, and 7949: Problem Determination and Service Guide
v If the information LED is lit, it indicates that information about a suboptimal
condition in the server is available in the IMM event log or in the system
event log.
v If the system-error LED is lit, it indicates that an error has occurred; go to
step 2.
The following illustration shows the operator information panel.
Operator information
panel
Light path
diagnostics LEDs
Release latch
the operator information panel and pull the panel forward. This reveals the light
path diagnostics panel. Lit LEDs on this panel indicate the type of error that has
occurred.
Operator information
panel
Light path
diagnostics LEDs
Release latch
The following illustration shows the light path diagnostics panel.