HP 8340b User Manual

FAULT ANNUNCIATOR
(7)
NOTE:
After
performing
the
following
procedure,
use
the
SHIFT M4
diagnostic test to
help isolate
the
cause
of
an
FAULT
condition.
The
FAULT
light
monitors
the
status
of the five
internal functions
described
below.
1.
If
the
FAULT
light is
on,
press
[SHIFT]
[MANUAL].
FAULT:
CAL
KICK
ADC PEAK
TRK
appears
in
the
ENTRY
DISPLAY.
The
name
of
the
faulty
function
is
flashing.
CAL
Refers
to
the
calibration
constants
stored
in
memory.
The
calibration
constants
are
checked only
at
instrument
preset.
If
CAL is
flashing,
the
instrument
has
resorted
to
default
calibration
constant
data.
The
major
effect of
this
condition
is
that
RF
power
output
flatness and
accuracy
are degraded.
To
remedy
this
situation,
you
must
re-enter
the the
factory-determined
calibration
con¬
stants
(see
HOW TO
RESTORE
FACTORY-OPTIMIZED CALIBRATION
CONSTANTS).
KICK
Refers
to
the
kick
pulses used
to
reset
the
YO
(YIG
oscillator) and
SYTM
(switched
YIG-
tuned multiplier).
This
fault
is
can
be
caused
by
a
kick
pulse
that
is
too
wide.
suspect
a
problem
with
the
kick
pulse
caused
by
the
A54 YO
pretune,
ASS
YIG
oscillator driver
(in
the
sweep generator-YO
loop
functional
group),
or
the
A28
SYTM
driver
assemblies
(in
the
RF
section
functional
group).
ADC
Refers to
a
check performed
on
the
ADC
(analog-to-digital converter)
circuits
on
the
A27
level
control
assembly.
This
check
is
done at instrument
preset
or
at
power
on.
ADC
indicates
that the
POWER
dBm
display
may
indicate
a
different
power
than
the
instrument
is
actually
producing. Also, an
ADC
failure
does not
allow
the
PEAK
and
auto
tracking
(SHIFT
PEAK)
functions
to
operate
properly.
If
this
annunciator
is
on,
suspect
a
problem
on
the
A27
level control assembly (see
the
RF
section
functional
group).
PEAK
This
refers
to
an
instrument function
that
peaks
the
RF
output
power
at
a
CW
fre¬
quency
by
fine
tuning
the
SYTM
(which
is
tuned
to
the
YO
frequency).
This
fault
can
only
come
on
if
you
press
[PEAK].
If
PEAK
is
flashing,
something
is
wrong
with
the
circuitry
that
peaks
the
SYTM.
PEAK
indicates that the
instrument
is
not
able
to
optimize
its
output
power.
While
this
instru¬
ment
failure
requires
service
to
correct,
the
optimum
power
may
not
be
adversely
affected.
Suspect
the
A28 SYTM
driver
or
A27
level
control
assembly.
TRK
Refers to
an
instrument
function
that
peaks
the
RF
output
power
while
the
instrument
is
sweeping.
This
fault
can
only
occur
if
you press
[SHIFT]
[PEAK].
The
TRK
light
Indicates the
same
things
as
a
flashing
PEAK.
The
FAULT
LED
(located
on
the
A2
display driver assembly)
is
driven
by
the
A3
display
processor,
annunciator
latch/driver
circuit.
The
instrument
microprocessor
detects
an
error
from
the
circuitry,
outputs
the
appropriate
bits
to
turn
the
LED
on,
and
outputs
address
15:RO
to latch the
data
bits.
A-40
Assembly-Level Service Overall
Instrument
Troubleshooting
HP
8340B/41B

HP 8340b Specifications

General

Brand	HP
Model	8340b
Category	Inverter
Language	English