IBM x3655 Service Guide - Page 193

Solving, problems, power

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Solving SCSI problems Note: This information also applies to Serial Attached SCSI (SAS) problems. For any SCSI error message, one or more of the following devices might be causing the problem: v A failing SCSI device (adapter, drive, or controller) v An incorrect SCSI termination jumper setting v Duplicate SCSI IDs in the same SCSI chain v A missing or incorrectly installed SCSI terminator v A defective SCSI terminator v An incorrectly installed cable v A defective cable For any SCSI error message, follow these suggested action in the order in which they are listed until the problem is solved. v Make sure that SCSI devices are turned on before you turn on the server. v Make sure that the cables for al external SCSI devices are connected correctly. v If an external SCSI device is attached, make sure that the external SCSI termination is set to automatic v Make sure that the last device in each SCSI chain is terminated correctly. v Make sure that the SCSI devices are configured correctly. 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 example, if a loose screw is causing a short circuit on a circuit board. 3. If a power-channel error LED on the system board is lit, perform the following steps; otherwise, go to step 4. See "System-board LEDs" on page 15 for the location of the power-channel error LEDs. Table 6 identifies the components associated with each power channel, and the order in which to troubleshoot the components. a. Disconnect the cables and power cords to all internal and external devices. Leave the power-supply cords connected. b. Remove each component that is associated with the LED, one at time, in the sequence indicated in Table 6, restarting the server each time, until the cause of the overcurrent condition is identified. Table 6. Components associated with power-channel error LEDs Power-channel error LED Components A Fan 4, fan 6, fan 8, fan 9, microprocessor 1, system board (integrated voltage regulator) B Fan 1, fan 2, fan 3, fan 5, VRM, IDE CD/DVD cable, IDE CD/DVD media backplane, microprocessor 2, system board Chapter 5. Diagnostics 175

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Solving
SCSI
problems
Note:
This
information
also
applies
to
Serial
Attached
SCSI
(SAS)
problems.
For
any
SCSI
error
message,
one
or
more
of
the
following
devices
might
be
causing
the
problem:
v
A
failing
SCSI
device
(adapter,
drive,
or
controller)
v
An
incorrect
SCSI
termination
jumper
setting
v
Duplicate
SCSI
IDs
in
the
same
SCSI
chain
v
A
missing
or
incorrectly
installed
SCSI
terminator
v
A
defective
SCSI
terminator
v
An
incorrectly
installed
cable
v
A
defective
cable
For
any
SCSI
error
message,
follow
these
suggested
action
in
the
order
in
which
they
are
listed
until
the
problem
is
solved.
v
Make
sure
that
SCSI
devices
are
turned
on
before
you
turn
on
the
server.
v
Make
sure
that
the
cables
for
al
external
SCSI
devices
are
connected
correctly.
v
If
an
external
SCSI
device
is
attached,
make
sure
that
the
external
SCSI
termination
is
set
to
automatic
v
Make
sure
that
the
last
device
in
each
SCSI
chain
is
terminated
correctly.
v
Make
sure
that
the
SCSI
devices
are
configured
correctly.
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
example,
if
a
loose
screw
is
causing
a
short
circuit
on
a
circuit
board.
3.
If
a
power-channel
error
LED
on
the
system
board
is
lit,
perform
the
following
steps;
otherwise,
go
to
step
4.
See
“System-board
LEDs”
on
page
15
for
the
location
of
the
power-channel
error
LEDs.
Table
6
identifies
the
components
associated
with
each
power
channel,
and
the
order
in
which
to
troubleshoot
the
components.
a.
Disconnect
the
cables
and
power
cords
to
all
internal
and
external
devices.
Leave
the
power-supply
cords
connected.
b.
Remove
each
component
that
is
associated
with
the
LED,
one
at
time,
in
the
sequence
indicated
in
Table
6,
restarting
the
server
each
time,
until
the
cause
of
the
overcurrent
condition
is
identified.
Table
6.
Components
associated
with
power-channel
error
LEDs
Power-channel
error
LED
Components
A
Fan
4,
fan
6,
fan
8,
fan
9,
microprocessor
1,
system
board
(integrated
voltage
regulator)
B
Fan
1,
fan
2,
fan
3,
fan
5,
VRM,
IDE
CD/DVD
cable,
IDE
CD/DVD
media
backplane,
microprocessor
2,
system
board
Chapter
5.
Diagnostics
175