Zenith J584W - Page 14

Kt-, It-, AND MPX ALIGNMENT PROCEDURE FOR CHASSIS
1WJR55,3WJR50,50Z, 3WJR52, 52Z - Cont'd.
12
CERAMIC FILTERS
CHASSIS 1WJR55,3WJR50,50Z, 3WJR52, 52Z
PART NO.
COLOR CODE
NOMINAL CENTER
FREQUENCY
FREQUENCY
RANGE
224-2
Black 10.64 MHz
10.61 to 10.67 MHz
224-2-01
Blue
10.67 MHz
10.64 to 10.70 MHz
224-2-02
Red
10.70 MHz
10.67 to 10.73 MHz
224-2-03 Orange
10.73 MHz
10.70 to 10.76 MHz
224-2-04
White
10.76 MHz
10173 to 10.79 MHz
FIGURE 3 - CERAMIC FILTER TABLE
STEP
CONNECT
GENERATOR
TO
DUMMY
ANTENNA
CONNECT
VTVM/
SCOPE TO
INPUT
SIGNAL
FREQ,
SET DIAL
TO
ADJUST
PURPOSE
NOTE
: For FM Detector A
Scope Horizontal. /
Remainder Of IF /
From Generator, Or
ignment Use A Signal Of 75 KHz Deviation, 1 KHz Modulation. Also Connect Generator Modulation Frequency To
kdjust Generator IF Frequency To Center Total Bandpass Waveform. Do Not Change Generator IF Frequency For
Alignment. (If Your Generator Does Not Provide Output For Audio Modulation Frequency Use Horizontal Output
Scope Horizontal Sweep, And Follow Step 24C.) Minimum Distortion Can Only Be Achieved By Use Of Step 24A Below.
24
Test Point "D"
FM IF Input
47 Ohm in
shunt with
gen. output.
Then from
hot lead a
27 Ohm in
series with
a .01 MF
capacitor.
A. Distortion
Analyzer
(thru a 100
usee de 
emphasis
network)
and
Scope.
See Fig. 2.
Center
Frequency
of Ceramic
Filter Y201.
See Fig. 3
Gang
Closed
L204
(on 1WJR55),
L203
(on 3WJR50,
50Z, 3WJR52,
52Z)
A. Preferred Method: Distortion
Analyzer at Test Point "H" should
read minimum distortion, approx.
46 to 55 dB below 0 dB set level.
B.Scope
B. Alternate Method: Adjust for
linear scope trace - no curve at ends of
trace. Disregard meter reading.
C. Scope
C. Alternate Method: Adjust for
maximum length and symmetry,
similar to Scope Pattern "A".
25
Test Point
"H"
R211 Adjust for center reading on
Tuning Meter On Chassis 3WJR50,
50Z; Or For Null With VTVM
Connected Between Points "AFC ”
and "AFC REF" On Chassis 1WJR55,
3WJR52, 52Z.
26
Test Point “ A" 300 Ohm
106 MHz
106 MHz
C14
Set Oscillator to dial scale.
27
FM Antenna Post
90 MHz 90 MHz
L4
28
(Disconnect Antenna)
Repeat Steps 26 & 27 for minimum change.
29 106 MHz 106 MHz
C1C Align FM Detector stage for maximum.
30
90 MHz
90 MHz
L2 if necessary
31
106 MHz 106 MHz
C1A Align FM Antenna stage for maximum.
32
90 MHz
90 MHz L1 if necessary
33
Repeat Steps 31 & 32 for minimum change.
NOTE:
: Apply Sufficient Signal Level — Approx. 100 Microvolts — To Obtain Full Limiting At Point Near 98 MHz.
34
Frequency
Counter and/
or Scope
Test Point
"M"
Unmodulated
RF Carrier
R302
A. Frequency Counter should read
19 KHz, + 100 Hz.
B. Alternate Method: Connect Test
Point "M" Signal to scope vertical and
an accurate 19 KHz signal to scope
horizontal input. Adjust for one
square synchronized waveform.
35
Scope and/or
AC VTVM
98 MHz
10% Pilot
(L+R) (L-R)
(L Only)
—
Check for separation. Maximum
left output.
Left Tape
Output
36
Right Tape
Output.
Check for separation. Minimum
right output.
NOTE:
Do Not Readjust Control R302 After Step 34.