Light Path Diagnostics - Lenovo x3550 M4 Installation And Service Manual

Light path diagnostics

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 "Safety" on page vii and "Handling static-sensitive devices" on
page 36.
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.
Figure 85. Operator information panel
2. To view the light path diagnostics panel, press the blue release latch on the
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System x3550 M4 Type 7914: Installation and Service Guide
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.
operator information panel. Pull forward on the panel until the hinge of the
operator information panel is free of the server chassis. Then pull down on the
panel so that you can view the light path diagnostics panel information. This
reveals the light path diagnostics panel. Lit LEDs on this panel indicate the
type of error that has occurred.