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.
Remove
the
adapters
and
disconnect
the
cables
and
power
cords
to
all
internal
and
external
devices
until
the
server
is
at
the
minimum
configuration
that
is
required
for
the
server
to
start
(see
for
the
minimum
configuration).
4.
Reconnect
all
ac
power
cords
and
turn
on
the
server.
If
the
server
starts
successfully,
replace
the
adapters
and
devices
one
at
a
time
until
the
problem
is
isolated.
If
the
server
does
not
start
from
the
minimum
configuration,
replace
the
components
in
the
minimum
configuration
one
at
a
time
until
the
problem
is
isolated.
Solving
Ethernet
controller
problems
The
method
that
you
use
to
test
the
Ethernet
controller
depends
on
which
operating
system
you
are
using.
See
the
operating-system
documentation
for
information
about
Ethernet
controllers,
and
see
the
Ethernet
controller
device-driver
readme
file.
Try
the
following
procedures:
v
Make
sure
that
the
correct
device
drivers,
which
come
with
the
server
are
installed
and
that
they
are
at
the
latest
level.
v
Make
sure
that
the
Ethernet
cable
is
installed
correctly.
–
The
cable
must
be
securely
attached
at
all
connections.
If
the
cable
is
attached
but
the
problem
remains,
try
a
different
cable.
–
If
you
set
the
Ethernet
controller
to
operate
at
100
Mbps,
you
must
use
Category
5
cabling.
–
If
you
directly
connect
two
servers
(without
a
hub),
or
if
you
are
not
using
a
hub
with
X
ports,
use
a
crossover
cable.
To
determine
whether
a
hub
has
an
X
port,
check
the
port
label.
If
the
label
contains
an
X,
the
hub
has
an
X
port.
v
Determine
whether
the
hub
supports
auto-negotiation.
If
it
does
not,
try
configuring
the
integrated
Ethernet
controller
manually
to
match
the
speed
and
duplex
mode
of
the
hub.
v
Check
the
Ethernet
controller
LEDs
on
the
rear
panel
of
the
server.
These
LEDs
indicate
whether
there
is
a
problem
with
the
connector,
cable,
or
hub.
–
The
Ethernet
link
status
LED
is
lit
when
the
Ethernet
controller
receives
a
link
pulse
from
the
hub.
If
the
LED
is
off,
there
might
be
a
defective
connector
or
cable
or
a
problem
with
the
hub.
–
The
Ethernet
transmit/receive
activity
LED
is
lit
when
the
Ethernet
controller
sends
or
receives
data
over
the
Ethernet
network.
If
the
Ethernet
transmit/receive
activity
light
is
off,
make
sure
that
the
hub
and
network
are
operating
and
that
the
correct
device
drivers
are
installed.
v
Check
the
LAN
activity
LED
on
the
rear
of
the
server.
The
LAN
activity
LED
is
lit
when
data
is
active
on
the
Ethernet
network.
If
the
LAN
activity
LED
is
off,
make
sure
that
the
hub
and
network
are
operating
and
that
the
correct
device
drivers
are
installed.
v
Check
for
operating-system-specific
causes
of
the
problem.
Chapter
2.
Diagnostics
105
