Light Path Diagnostics - IBM x3850 X6 Planning And Implementation Manual

For details about this technology, see the Trusted Computing Group (TCG) TPM Main
Specification at the following website:
http://www.trustedcomputinggroup.org/resources/tpm_main_specification

3.19.4 Light path diagnostics

Light path diagnostics is a set of LEDs located on server's components that help to determine
failed component. If server's component failed or has error, then appropriate LEDs light up on
the front operator panel, the light path diagnostics panel and on the failed component. By
checking the LEDs, you can locate the failed component.
If an error occurs, check the LEDs on the front operator panel first. If the check log LED is lit,
check IMM event log or system-event log. If the system-error LED is lit, find the appropriate
component with lit LED. Figure 3-33 shows the location of LEDs on the front operator panel.
Power button LED
Figure 3-33 Front operator panel LEDs location
For example, if a Compute Book error occurs, the Error LED located on the appropriate
Compute Book should light up. Figure 3-34 shows the LED locations on the Compute Book.
Error
LED
Power
LED
Figure 3-34 Compute Book's LEDs location
If the Compute Book has a memory error, appropriate LEDs located on the Compute Book's
system board can help to determine the failed DIMM. To use this feature, you have to
disconnect the server from power, remove the Compute Book from the server, press the Light
path button located on the front panel of the Compute Book, and find the lit LED on the
system board. The DIMM LED that is lighted up points to the failed memory module.
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IBM System x3850 X6 and x3950 X6 Planning and Implementation Guide
Locate button LED
DDR3
compute book
Light path
button
Fan
LED
Fan
LED
Check log LED
System error LED
PCIe slot 11 error LED
PCIe slot 12 error LED
Board error LED