IBM System x3950 E Installation Manual page 87

2. To view the light path diagnostics panel, press the release latch on the front of
the operator information panel to the left; then, slide it forward. This reveals the
light path diagnostics panel. Lit LEDs on this panel indicate the type of error that
has occurred.
OVER SPEC
REMIND
Look at the system service label on the top of the server, which gives an
overview of internal components that correspond to the LEDs on the light path
diagnostics panel. This information and the information in "Light path diagnostics
panel" on page 77 can often provide enough information to correct the error.
3. Remove the server cover and look inside the server for lit LEDs. Certain
components inside the server have LEDs that will be lit to indicate the location
of a problem. For example, a VRM error will light the LED next to the failing
VRM on the microprocessor tray.
The following illustration shows the LEDs and connectors on the microprocessor
tray.
Light Path
Diagnostics
PS LINK
CPU VRM LOG
MEM NMI PCI
SP DASD RAID
NONRED TEMP FAN
PCI CPU I/O
BRD BRD BRD
Chapter 6. Solving problems
75