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10
,
D
isc
o
nnect the voltmeter
fr om capacit
r
C
2
7
a
and
co
nn
e
c
t
th
e
meter to
the input side of
capacitor
C4 l
,
located
on the
bottom d
ec
k
of
the
Model
416A.
The
input side of
C41
i
s
connected
to
terminal
strip TS2
,
also
identified in
Fig
.
21.
Note
the voltmeter
indication
and
record it
as
Voltage
B (this resultant
voltage corresponds to Voltage B as shown
in
F
ig
s. 3 and
5).
A
typical Voltage B reading might be
172
millivolts.
11
.
The Voltage A
reading
(obtained in step 9) and
the
Voltage
B read-
ing (obtained
in step 10) each should be within 5%
of
the
average of their
values
(
.
05
x
Voltage
A
+
Voltage B).
2
12
.
Disconnect the
voltmeter
from capacitor C41
.
13
.
With the
incoming resultant voltages within
the
limits
specified
in step
9, adjust
variable resistor
R96 to obtain an
indicati
on of
100
(full
-
scale)
on the
PERCENT
REFLECTION (REFLECTOMETER) scale.
The
R96
adjustment is located on the
top
deck of the Model
416A
,
and
is identified
in
Fig.
20
.
14
.
Adjust the SET TO FULL SCALE control
to
obtain
an
indication
of
90 on the PERCENT REFLECTION (REFLECTOMETER)
scale
.
15
.
Vary the power
input
to the Model 416A by
resetting the
variable
transformer
for
a
103
.
5V AC
input
and then a 126. 5V AC input.
The meter
indication should stay on 90
.
16
.
Readjust the SET TO FULL SCALE
control
to obtain an indication
of 100 on the
PERCENT REFLECTION (REFLECTOMETER)
scale
.
Tuning
Eye
(V9) Adjustment
-
-
1.
Unless it
is
known that the
instrument
is adjusted and functioning
properly
,
the
Electrical Zero and Electrical. Full Scale A
d
justments
should
be performed befo
re
the
t uni
n
g
eye
(RF POWER MONITOR)
is
adjusted
.
At
the
start of the tuning
eye adjustment, therefore
9
test equipment will
.be con-
nected
as shown
in
F
ig. 18,
and
c
ontrols
will
h
av
e the settings
obtained
as
a
result of
the calibration
a
djus tments
.
The
signal source
is
deli
vering 10 volts
at
1
kc to attenuator # 1
.
Attenuator
#
1
is
set at
-
40 db and attenuator
#2
is
set
at 0
db
.
The variable
transformer is set
so that line voltage to
the
Model
416A
is
115V AC
.
2.
With
the
input to
the
i
ncide
nt
and reflected channels as set
up by
the
calibration
proc
edure, adjust
va
r iable
resistor
R60 so that the tuning
eye closes
and overlaps
approxi
mately
1/32 in.
If it is known that the Model 416A
is
functioning
correctly
,
the tuning
eye may be
adjusted by
applying
100 millivolts at 1 kc to each channel,
(at
the
INCIDENT
/REFERENCE connector and the REFLECTED/PROBE
connector),
and adjusting
R60 so that the tuning eye closes and overlaps approximately
1/32
in
.
This
procedure for
adjusting
the tuning eye is
not
recommended
.
-5
4
-
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