Solving Power Problems - IBM System x3550 Type 7978 Problem Determination And Service Manual

v Follow the suggested actions in the order in which they are listed in the Action column until the problem
is solved.
v See Chapter 3, "Parts listing, Type 7978 and 1913 server," on page 89 to determine which components are
customer replaceable units (CRU) and which components are field replaceable units (FRU).
v If an action step is preceded by "(Trained service technician only)," that step must be performed only by a
trained service technician.
System event/error log message
CPU n non-critical over temperature warning
n = the microprocessor number
CPU n non-recoverable over temperature fault
VRD 1 critical over voltage fault
VRD 1 critical under voltage fault
VRD 2 critical over voltage fault
VRD 2 critical under voltage fault
Microprocessor VTT Power Fault.

Solving power problems

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:
1. Turn off the server and disconnect all ac power cords.
2. Check the power-fault LEDs on the system board. See ("Power problems" on
3. Check for loose cables in the power subsystem. Also check for short circuits, for
4. Remove the adapters and disconnect the cables and power cords to all internal
84
IBM System x3550 Type 7978 and 1913: Problem Determination and Service Guide
Action
1. Make sure that the fans are operating, that there are no
obstructions to the airflow, that the air baffles are in place and
correctly installed, and that the server cover is installed and
completely closed.
2. (Trained service technician only) Make sure that the heat sink
for microprocessor n is installed correctly.
1. Make sure that the fans are operating, that there are no
obstructions to the airflow, that the air baffles are in place and
correctly installed, and that the server cover is installed and
completely closed.
2. (Trained service technician only) Make sure that the heat sink
for microprocessor n is installed correctly.
3. (Trained service technician only) Replace microprocessor n
4. (Trained service technician only) Replace the system board.
1. (Trained service technician only) Reseat microprocessor 1.
2. (Trained service technician only) Replace the system board.
1. (Trained service technician only) Reseat microprocessor 1.
2. (Trained service technician only) Replace the system board.
1. (Trained service technician only) Reseat microprocessor 2.
2. (Trained service technician only) Replace the system board.
1. (Trained service technician only) Reseat microprocessor 2.
2. (Trained service technician only) Replace the system board.
1. (Trained service technician only) Reseat microprocessor 1.
2. (Trained service technician only) Replace the system board.
page 52).
example, if a loose screw is causing a short circuit on a circuit board.
and external devices until the server is at the minimum configuration that is
required for the server to start (see "Solving undetermined problems" on page
86 for the minimum configuration).