Light Path Diagnostics - IBM System x3750 M4 Installation And Service Manual

v Troubleshooting by symptom

Light path diagnostics

This information describes the light path diagnostics support.
Light path diagnostics is a system of LEDs on various external and internal
components of the server that leads you to the failed component. When an error
occurs, LEDs are lit along the path of the front panel, the light path diagnostics
panel, then on the failed component. 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 "Safety" on page vii and "Handling
static-sensitive devices" on page 37.
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, press in on the blue release button on
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System x3750 M4 Types 8722 and 8733: Installation and Service Guide
3. Light path diagnostics panel
4. Memory modules
5. Microprocessors
6. Optical devices (CD or DVD)
7. SAS or SATA drives
See "Running the DSA Preboot diagnostic programs" on page 187 for more
information on running the DSA Preboot program on the server.
These tables list problem symptoms and actions to correct the problems. See
"Troubleshooting by symptom" on page 190 for more information.
v If the check log LED is lit, it indicates that information about an un-isolated
fault 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.
Light path
diagnostic
LEDs
Operator information
panel
the operator information panel and pull forward on the panel until the hinge of
Release
button