Solving Power Problems - IBM System x3650 M4 Type 7915 Problem Determination And Service Manual

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 for loose cables in the power subsystem. Also check for short circuits, for
3. Check the LEDs on the operator information panel (see "Light path diagnostics"
4. If the check log LED on the light path diagnostics panel is lit, check the IMM2
example, if a loose screw is causing a short circuit on a circuit board.
on page 124).
event log for faulty Pwr rail and complete the following steps. Table 10 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 194). Leave the
power-supply cords connected.
b. For Pwr rail A 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 A error, see the step above), remove each
component that is associated with the faulty Pwr rail, one at a time, in the
sequence indicated in Table 10, restarting the server each time, until the
cause of the overcurrent condition is identified.
Table 10. Components associated with power rail error
Pwr rail error in the IMM2 event log
Pwr rail A error
Pwr rail B error
Pwr rail C error
Pwr rail D error
Pwr rail E error
Pwr rail F error
Pwr rail G error
Pwr rail H error
d. Replace the identified component.
Components
Microprocessor 1
Microprocessor 2
Optional adapter (if one is present) installed
in PCI riser-card assembly 1, PCI riser-card
assembly 1, Fan 1, and DIMMs 1 through 6
Optional dual-port network adaptor, fan 2,
DIMMs 7 through 12
Optional DVD drive (if one is installed), hard
disk drives, DIMMs 13 through 18
Optional adapter (if one is present) installed
in PCI riser-card assembly 1, PCI riser-card
assembly 1, fan 4, DIMMs 19 through 24
Optional PCI adaptor power cable (if one is
present), Fan 3, hard disk drives, hard disk
drive backplane assembly
Optional PCI adaptor power cable (if one is
present), optional adapter (if one is present)
installed in PCI riser-card assembly 2, PCI
riser-card assembly 2
Chapter 3. Diagnostics
175