Light Path Diagnostics - IBM System x3850 X6 Installation And Service Manual

Light path diagnostics

This topic provides an overview of the light path diagnostics LEDs.
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 on the front operator panel on the front of the of the server,
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 46.
If an error occurs, view the light path diagnostics LEDs in the following order:
1. Look at the front operator panel (see "Front operator panel" on page 27) on the
2. The modules in the server (on the front and rear) have LEDs that are lit to
In addition to the light path diagnostic LEDs, the server LCD system information
display panel also displays a current list of errors reported by the system and other
information. The following is an illustration of the LCD display panel. See the
"LCD system information display panel" on page 28 for more information about
the LCD display panel.
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System x3850 X6 and x3950 X6 Types 3837 and 3839: Installation and Service Guide
front of the server.
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.
Note: Reset button: Press this button on the front operator panel to reset the
server and run the power-on self-test (POST). You might have to use a pen or
the end of a straightened paper clip to press the button.
indicate the location of a problem.