HP 8340b User Manual

3.
If
any
of the
above
outputs
do not
meet
the
frequency
or
power
values
shown, repair or
replace
the
A40
PLL2
VCO.
4.
Disconnect
the
spectrum
analyzer.
Reconnect
the
five
cables
listed
in
step
1.
Verifying the
Operation
of
the
A42
PLL2
Divider
5.
Turn
the
synthesizer's
power
switch
to
STANDBY
and
remove
the
A41
PLL2
phase detector.
6.
Place
the
A42
PLL2
divider
on
a
36-pin
extender
board.
7.
Turn
the
instrument's
power
switch
on
and
press
[INSTR
PRESET].
8.
Connect
an
HP
1740A
oscilloscope
to A42TP4.
Set the horizontal
sweep
time
to
0.2
us/div.
20
cycles
should be
displayed
across
the
oscilloscope
display.
9.
Measure
A42TP5
with
the
oscilloscope.
Verify
one
cycle
of
a
pulsed
waveform.
10.
Set
a
frequency synthesizer
to
100
MHz
at
-20
dBm
and
connect
the
output
to
the
cable
marked
A40J1.
This
injects
the
signal
into the
N2
divider
on
the
A42 PLL2
divider.
11.
Connect an
oscilloscope
to
A42TP1
and set
the
horizontal
sweep
speed
to
0.5
us/div.
The pulsed
waveform
consisting
of
two
pules
should be
displayed.
12.
Set
the
frequency
synthesizer's
frequency
to several values
above and below
100
MHz.
As the
value approaches
75
MHz,
the
time
delay
between
the
pulses
will
increase.
As
the
value
approaches
150
MHz,
the
time
delay
between
the
pulses
should
decrease.
13.
If
the
waveforms
are incorrect,
replace
or
repair
the
A42 PLL2
divider.
If
the
waveforms are
correct,
turn
the
instrument's
power
switch
to
STANDBY. Disconnect
all
test
probes
and
replace
the
A41
phase detector,
the
A42
divider,
and related
hardware (screws). Reconnect
all
instrument
cables,
proceed
to
the
next
test.
Verifying
the
PLL2
Phase
Detector
14.
Turn
the
instrument's
power
switch to
STANDBY.
Remove
the
PLL2
discriminator and
turn
the
power
switch
on.
15.
Set
a
frequency
synthesizer
to
100
MHz
at
-20
dBm
and
connect
its
output to
the
cable
marked
A40J1.
16.
Connect
an
oscilloscope to
the
(p
detector test
point
of the
top
casting
of the
A41
PLL2
phase
detector.
Note
the
sawtooth
waveform.
17.
Remove
the
cable
from
A42J1,
then
replace
it. Note
that
the
oscilloscope
trace
changes
levels
and/or
the
sawtooth
waveform reverses
phase.
Repeat
this
step
with
the
cable marked
A40J1.
18.
Disconnect
the
frequency
synthesizer from
the
cable
marked
A40J1.
Remove
the
oscilloscope
probe
from
the
A40
phase
detector
test
point.
C-12
20-30
Loops Assembly-Level Troubleshooting
HP 8340B/41B

HP 8340b Specifications

General

Brand	HP
Model	8340b
Category	Inverter
Language	English