HP 8340b User Manual

Verifying
the
PLL2
Discriminator
19.
Turn
the
instrument's
power
switch to
STANDBY.
20.
Remove
all
coaxial
cables and
mounting
screws
from
the
A43 PLL3
discrimlnator
assembly.
Place
the
A43
assembly
on
a
36-pin
extender
board
and
reconnect
all
coaxial
cables.
21. Turn
the
instrument's
power
switch
on
and
press:
[INSTR
PRESET]
[START FREQ]
[2]
[.]
[3]
[GHz]
[STOP FREQ]
[7]
[GHz]
22.
Connect
an
oscilloscope
to
pin
1
of the
extender
board.
Set the
oscilloscope's horizontal
time
base to
2
ms
and
verify a
ramp
voltage from
0
to
approximately
9
volts.
If
the
ramp
is
not
present,
repair
or
replace
the
ASS
sweep
generator assembly.
23.
Connect
a
DVM
to A43TP1. Press
the
following
instrument
keys:
(INSTR
PRESET]
[CW]
[SHIFT]
[GHz]
[0]
[Hz]
[SHIFT]
[MHz]
[1]
[Hz]
[SHIFT]
[kHz]
[0]
[Hz]
Measure
0V
±0.005 on
the
DVM.
Press
[1] [0] [2] [3]
[Hz].
Measure
7.0V
±0.2V
on
the
DVM.
If
this
test fails,
repair
the
pretune
circuit
or
replace
the
PLL2
discnminator.
24.
The
other inputs to
this
assembly
have been
verified
in
previous
tests.
This
assemblies output
is
the
error
voltage
for the
PLL2
VCO.
If
the
loop
fails
to
lock,
troubleshoot
or
replace
this
assembly.
25.
Turn
the
instrument's
power
switch
to
STANDBY,
remove
the
extender
board and
replace
the
A43
assembly.
TROUBLESHOOTING
PHASE
LOCK LOOP
3
PLL3
is
fully
contained
on
the
A39
PLL3
upconverter
assembly.
Troubleshooting
this
assembly
con¬
sists
of
verifying
two
inputs
and
one output.
1.
On
the
instrument, press
[INSTR PRESET]
[CW],
2.
Connect
an
oscilloscope
to
A39J1
(PLL3
output)
and
check
for
a
CW
signal
between
160
and
166
MHz
at
approximately —20
dBm.
If
this
signal
is
present go
to
step
5.
If
the
signal
is
not
present,
first
check
the
inputs
to
the
A39
assembly
as
follows:
Verify the
100
MHz
Input
to
the
ASS
Assembly.
3.
Disconnect
the
coax
cable
from
A39J2
and
connect
the
spectrum
analyzer
to
the
cable.
Make
sure
a 100
MHz
CW
signal of
approximately
0
dBm
is
present.
If
not,
troubleshoot
the
reference
loop.
Refer
to
the
reference
loop
—
M/N
loop
section.
HP
8340B/41B
20-30
Loops Assembly-Level
TroubleshooHns
C-13

HP 8340b Specifications

General

Brand	HP
Model	8340b
Category	Inverter
Language	English