IBM x3550 Problem Determination And Service Manual page 155

2. To view the light path diagnostics panel, slide the latch to the left on the front of
the light path diagnostics drawer. This reveals the light path diagnostics panel.
Lit LEDs on this panel indicate the type of error that has occurred.
The following illustration shows the light path diagnostics panel.
OVER SPEC
REMIND
Note any LEDs that are lit, and then close the drawer.
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
LEDs" on page 138 can often provide enough information to diagnose the error.
3. Remove the server cover and look inside the server for lit LEDs. A lit LED on or
beside a component identifies the component that is causing the error.
The following illustration shows the LEDs on the system board.
Light Path
Diagnostics
PS1 PS2
CPU VRM CNFG
MEM NMI S ERR
SP DASD RAID
FAN TEMP BRD
PCI
137
Chapter 5. Diagnostics