Zenith Y504B - Page 16

RF
AND
IF
ALIGNMENT
PROCEDURE
FOR
CHASSIS
18YT20,
18YT20Z,
20YT20
AND
20YT20Z
PURPOSE
Adjust
Primary
and
secondary
of
ratio
detector
for
maximum
amplitude
and
symmetry
as
shown
in
Scope
Pattern
“
B
”
Align
I.F.
transformers
for
maximum
output
and
symmetry.
This
pattern
is
not
necessarily
identical
to
the
overall
Scope
Pattern
“
A
”
Align
I.F.
transformers
for
maximum
output
and
symmetry
as
indicated
in
Scope
Pattern
“
A
”
Set
oscillator
to
Dial
Scale
Align
FM
Detector
stage
for
maximum. Align
AM
IF
for
maximum.
Set
oscillator
to
dial
scale.
Align
antenna
stages.
ADJUST
IRON
CORES
T — <
1-1
L12
o
t —4
J
08
o
U
00
h !
o3
L5
&
L6
Readjust
L5,
L6,L7,L8
L4
CN
J
08
V — I
CN
4
i — (
4
LO O
i-l CM
U J
C39D
C39A
For
A,
B,
C
See
Pages
13
and
14
SET
DIAL
TO
88
MHz
88
MHz
88
MHz
88
MHz
88
MHz
88
MHz
98
MHz
98
MHz
600
KHz
1600
KHz
1400
KHz
INPUT
SIGNAL
FREQUENCY
10.7
MHz
400
KHz
Deviation
10.7
MHz
400
KHz
Deviation
10.7
MHz
400
KHz
Deviation
10.7
MHz
400
KHz
Deviation
10.7
MHz
400
KHz
Deviation
10.7
MHz
400
KHz
Deviation
98
MHz
400
KHz
Deviation
98
MHz
400
KHz
Deviation
455
KHz
400
Cycle
Modulated
1600
KHz
400
Cycle
Modulated
1400
KHz
400
Cycle
Modulated
DUMMY
ANTENNA
47
ohm
in
shunt
with
gen.
output.
Then
from
hot
lead
a
27
ohm
in
series
with
a
.001
MFD
capaci

tor.
300
ohm
300
ohm
.05
in
series
with
hot
lead
of
gen.
CONNECT
GENERATOR
TO
Term.
#3
of
T3
3rd
IF
Trans.
Term.
#3
of
T3
3rd
IF
Trans.
Term.
#3
of
T2
2nd
IF
Trans.
Test
Point
“
F
”
Term.
#1
of
T1
1st
IF
Trans.
Test
Point
“
E
”
Connect
to
Test
Point
#D
Connect
to
Test
Point
#D
FM
Antenna
Post
(Remove
Antenna)
Test
Point
“
A
”
FM
Antenna
Post
(Remove
Antenna)
Test
Point
“
A
”
Test
Point
#L
Two
turn
loop
loose

ly
coupled
to
wave

magnet Two
turn
loop
loose

ly
coupled
to
wave

magnet
OPERATION
<
v — I
2
A
PQ
CO
4
B
5
B
6
B
7
B
8
B
O
10
c
11
c
16