Instrument Appears Dead (2; Fan Runs Slowly, All Leds On; Fan - HP 8340B Manual

All
LEDs Off.
Fan is Operating.
If all
annunciators and LEDs are off (but
the
instrument's fan is operating), check
that the fan is
supplying proper airflow to the interior of the instrument.
Ensure that the fan
filter
is not blocked.
If
the airflow
is
good, suspect
a
failure
in the instrument's
power
supply section.
Fan is Not Operating. Refer
to the FAN section, below.
Some LEDs
Off
If
some LEDs that should be on are
off,
the front panel section
is
probably faulty.
All LEDs On
If all
of
the LEDs and annunciators are on, instrument processor, memory, or power supply is
proba¬
bly faulty.
Character March
If the four display windows have strings of characters marching across them, the instrument
pro¬
cessor or memory
is
probably faulty.
INSTRUMENT APPEARS DEAD (2)
Fan is
not Operating, LEDs
Off
at Power
On
If all
instrument LEDs are off and the fan is
not operating, suspect
a
problem in
the instrument
causing complete
loss of line
power
(line
filter
module, fuse, transformer, or
wiring, related
problems).
Check the line
fuse and
line filter module
voltage select cam (see
POWER SUPPLIES
—
FAN
functional group).
FAN RUNS SLOWLY, ALL LEDS ON (But
are dim)
Check that the proper voltage has
been selected on the line
module (see POWER SUPPLIES
—
FAN
functional group).
FAN
(3)
Fan Does Not Turn On
When the
power
switch is
turned on, the instrument fan should start.
If
not,
the fan, power supply,
or
K1
relay (inside the instrument, near the rear panel) is
probably faulty.
If
the instrument has run
for
some
time with the fan not running, the interior
temperature may have
risen to the point
that the A62S1
thermal switch has turned the instrument off.
If
so,
all
front panel
LEDs
will have gone
off.
The switch will reset itself
when the instrument cools down.
HP 8340B/41B
Assembly-Level Service Overall Instrument Troubleshooting
A-37