Universal
Serial
Bus
(USB)
port
problems
v
Follow
the
suggested
actions
in
the
order
in
which
they
are
listed
in
the
Action
column
until
the
problem
is
solved.
v
See
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.
Symptom
Action
A
USB
device
does
not
work.
1.
Run
USB
diagnostics
(see
2.
Make
sure
that:
v
The
correct
USB
device
driver
is
installed.
v
The
operating
system
supports
USB
devices.
v
A
standard
PS/2
keyboard
or
mouse
is
not
connected
to
the
server.
If
it
is,
a
USB
keyboard
or
mouse
will
not
work
during
POST.
3.
Make
sure
that
the
USB
configuration
options
are
set
correctly
in
the
Configuration/Setup
Utility
program
menu
(see
the
User’s
Guide
for
more
information).
4.
If
you
are
using
a
USB
hub,
disconnect
the
USB
device
from
the
hub
and
connect
it
directly
to
the
server.
Video
problems
See
Light
path
diagnostics
Light
path
diagnostics
is
a
system
of
LEDs
on
various
external
and
internal
components
of
the
server.
When
an
error
occurs,
LEDs
are
lit
throughout
the
server.
By
viewing
the
LEDs
in
a
particular
order,
you
can
often
identify
the
source
of
the
error.
The
server
is
designed
so
that
LEDs
remain
lit
when
the
server
is
connected
to
an
ac
power
source
but
is
not
turned
on,
provided
that
the
power
supply
is
operating
correctly.
This
feature
helps
you
to
isolate
the
problem
when
the
operating
system
is
shut
down.
Any
PCI-X,
memory,
microprocessor,
and
VRM
LED
can
be
lit
again
without
ac
power
after
you
remove
the
microprocessor
tray
so
that
you
can
isolate
a
problem.
After
ac
power
has
been
removed
from
the
server,
power
remains
available
to
these
LEDs
for
up
to
24
hours.
To
view
the
PCI-X,
memory,
microprocessor,
and
VRM
LEDs,
press
and
hold
the
light-path-diagnostics
button
on
the
PCI-X
board,
memory
card,
or
microprocessor
board
for
30
seconds
to
light
the
error
LEDs.
The
LEDs
that
were
lit
while
the
server
was
running
will
be
lit
again
while
the
button
is
pressed.
Many
errors
are
first
indicated
by
a
lit
information
LED
or
system-error
LED
on
the
operator
information
panel
on
the
front
of
the
server.
If
one
or
both
of
these
LEDs
are
lit,
one
or
more
LEDs
elsewhere
in
the
server
might
also
be
lit
and
can
direct
you
to
the
source
of
the
error.
50
IBM
System
x3950
Type
8878
and
System
x3950
E
Type
8879:
Problem
Determination
and
Service
Guide
