Lenovo x3550 M4 Installation And Service Manual page 188

About this task
Power problems can be difficult to solve. For example, a short circuit can exist
anywhere on any of the power distribution buses. Usually, a short circuit will
cause the power subsystem to shut down because of an overcurrent condition. To
diagnose a power problem, use the following general procedure:
Procedure
1. Turn off the server and disconnect all power cords.
2. Check for loose cables in the power subsystem. Also check for short circuits, for
3. Check the lit LEDs on the light path diagnostics panel (see "Light path
4. If the check log LED on the light path diagnostics panel is lit, check the IMM
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System x3550 M4 Type 7914: Installation and Service Guide
example, if a loose screw is causing a short circuit on a circuit board.
diagnostics LEDs" on page 132).
event log for faulty Pwr rail and complete the following steps. Table 17
identifies the components that are associated with each Pwr rail and the order
in which to troubleshoot the components.
a. Disconnect the cables and power cords to all internal and external devices
(see "Internal cable routing and connectors" on page 193). Leave the
power-supply cords connected.
b. For Pwr rail 1 error, complete the following steps:
1) (Trained technician only) Replace the system board.
2) (Trained technician only) Replace the microprocessor.
c. For other rail errors (Pwr rail 1 error, see step 4b), remove each component
that is associated with the faulty Pwr rail, one at a time, in the sequence
indicated in Table 17, restarting the server each time, until the cause of the
overcurrent condition is identified.
Table 17. Components associated with power rail errors
Pwr rail error in the IMM event log Components
Pwr rail 1 error
Pwr rail 2 error
Pwr rail 3 error
Pwr rail 4 error
Pwr rail 5 error
v Microprocessor 1
v Microprocessor 2
v Optional adapter (if one is installed) in PCI
riser-card assembly 1
v PCI riser-card assembly 1
v ServeRAID SAS/SATA adapter
v DIMMs 1 through 6
v PCI adapter power cable (if one is installed)
v Fan 1
v Fan 2
v Hard disk drives
v DIMMs 7 through 12
v DVD drive (if one is installed)
v Fan 3
v Fan 4
v Hard disk drives
v DIMMs 13 through 18