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Adjustnent
Procedure
-
4g4A/4g4Ap
Servtce
Vot.
1
Figure
5-9.
Sweep
board
tlming
adiustment
and test
point
locations.
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The
Spectrum
Analyzer
has
a
procedure
in firmware
for
calibrating
the
frequency
control
system.
However,
it
is
possible
that
some
adjustments
may
be
misad_
justed
enough
to
cause
the microcomputer
io
display an
€rror
message.
lf
this occurs,
bypass
the step
then
return
to the
calibratlon
routine.
Test
equipment
required
for
this
step
are
a
Voltmeter,
Time
Mark
Generator,
and
Fiequency
Counter.
Set
the
following
Spectrum
Analyzer
controls:
FREQUENCY
0.0 MHz
FREQ
SPAN/D|V
5
MHz
TRIGGERING
FREE
RUN
b. Connect
a
shorting
strap
from
Tplogs.
on
the
Span Attenuator
board,
to
chassis ground
(Figure
5-10).
Monitor
TP1073
on
the Span
Attenuator
board
with
the
voltmeter.
- --c:
Adjust
Sweep
Offset
R1063 (Figure
S-10) for
0.00
v.
d. Remove
the shorting
strap
from
Tp1035.
press
<BIUe.SHIFT>
PULSE
STRETGHER
and
select
item
1
(FREOUENCY
LOOPS
CAL),
then
item
0
(OVERALL
SYSTEM)
from
the menus.
perform
the
calibration
steps
as
directed
('CONNECT
A
DVM
TO
Tp105g
ON
THE 1ST
LO DRTVER
BOARD
AND
GROUND,),
etc.
(1)
lf
a
"CAL|BRATION
STEP
CANNOT
BE
COM-
PLETED"
message
is
displayed,
bypass
the
step,
perform
the
other adjustments
then return
to the
adjustment
and
try
to
bring
the
adjustment
in
range.
lf
the
problem
persists,
refer
to Troubleshooting
the
Frequency
Control
System,
in
the
Maintenance
sec_
tion.
e. Adjust
1st
LO
Sweep
as
follows:
(1)
Apply the
CAL
OUT signal to the RF tNpUT,
set
the FREQUENCY
to 600 MHz,
FREQ
SPAN/DIV
to
100 MHz, and
set
the REF
LEVEL
to display
the
mark€rs,
(2)
Adjust'Tune
Coil
Swp
R1065, on
the
Span
Attenuator
board
(Figure
5-10)
for one
marker
per
division
over
the center eight
divisions of
the
grati-
cule.
Reset
the
CENTER FREQUENCY
as neces-
sary
to
align
the
markers.
(3)
Remove
the
Calibrator signal
and
apply
0.2
ps
time
marks from
the Time
Mark
Generator to
th€ RF
INPUT.
(4)
Set
the
FREQ
SpAN/Dtv
to 5
MHz,
REF
LEVEL
to
+10
dBm,
and
FREQUENCY
to about
10 MHz.
(5)
Adjust
the lst LO FM
Coil
Swp R1071 (Figure
5-10) for 1 marker/division
over the center eight
divi-
sions of
the
display.
(6)
Set
th€ FREQ
SPAN/DIV to
20 KHz and appty
50
ps
markers from
the Time
Mark Generator.
n
Adjust
the 2nd LO
Sweep,
R1067,
for one
marker/division
over
the center
eight
divisions.
f.
Adjust Dot Marker
position
as follows:
(1)
Press
<Blue-SHIFT>
RESET.
(2)
Adjust
Dot Position R1052 on
the Sweep
board
to
position
the
dot
marker over the start spur.
5-1
0