HP 8340b User Manual

If
the
OVERMOD
annunciator
comes
on
only
when
a signal
is
input
to the
FM
jack,
The
MODULATION
INDEX
(peak
deviation
in
MHz/modulation
rate
in
MHz) of the signal
is
significantly
greater
than
the
specified
maximum
(5).
The
OVERMOD
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:R3
to
latch
the
data bits.
SRQ
ANNUNCIATOR
(10)
What
is
a
Service
Request
(SRQ)
An
SRQ
is
used only
when
the
instrument
is
connected
to
an external
controller
(via
HP-IB).
The
controller
programs
the
instrument
to
send
an
SRQ
under
certain
conditions.
When
one
of
the
programmed
conditions
occurs,
the
HP
8340B/41B
sends out
an
SRQ
signal
and
activates
the
SRQ
annunciator.
When
the
controller
responds
to
the
SRQ (by
doing
a
serial
poll
command)
the
HP
8340B/41B
turns
the
SRQ
annunciator off.
This
entire
process
takes
a
fraction
of
a
second,
so
the
SRQ
annunciator
stays on
only briefly.
SRQ
Annunciator Stays
On
If
the
SRQ
annunciator
goes
on
and
stays
on
it
usually
indicates
one
of the
following
conditions:
If
the
HP
8340B/41B
is
Connected
to
an
External
controller.
The
computer
controller
is
not
able
to
service
the
SRQ
interrupt.
The
controller
is
probably
stuck
in
a
loop,
etc.
This
is
usually
not
caused
by
an instrument
fault.
If
the
HP
8340B/41B is
Programmed
by
an
External
Controller
and
then
Disconnected.
A
controller
can
be
an
external
computer
or
HP
8756A,
8757A,
or
8510A
network
analyzer.
The
SRQ
annunciator stays on
if
a
controller
has
programmed
the
instrument
to
send
an SRQ,
and
is
subsequently
disconnected.
To
clear
this
SRQ,
press
[INSTR]
[PRESET]
and
then
cycling
the
power
switch
to STANDBY
and
then
ON.
The
SRQ
(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:R3
to
latch the
data
bits.
UPPER
KEYBOARD,
LOWER
KEYBOARD,
DISPLAYS
(11,12,13)
Refer
to the front
panel
—
rear
panel
functional
group.
A-42
Assembly-Level
Service
Overall Instrument
Troubleshooting
HP 8340B/41B

HP 8340b Specifications

General

Brand	HP
Model	8340b
Category	Inverter
Language	English