Zenith J584W - Page 16

RF, IF AND MPX ALIGNMENT PROCEDURE FOR CHASSIS 15WJR29
14
STEP
CONNECT
GENERATOR
TO
DUMMY
ANTENNA
CONNECT
VTVM/
SCOPE TO
INPUT
SIGNAL
FREQ.
SET DIAL
TO
ADJUST
PURPOSE
NOTE
For AM Alignment Use A Signal Wi
th 400 Hertz Modulation, Bandswitch In AM.
1
One Turn Loosely
coupled to AM
None
___ VTVM __
Speaker
Voice
Coil
455 KHz
Gang
Closed
L203, L204
(T202)
Align IF for maximum output.
2
Wavemagnet Antenna
L207, L208
(T203)
3 L209(T204)
4
1600 KHz
1600 KHz
C109 Set Oscillator to dial scale.
5
600 KHz
600 KHz
LI 05 (T102)
6
Repeat Steps No. 4 & 5 for minimum change.
7
1400 KHz
1400 KHz
C1H
Align RF stage.
8 600 KHz
600 KHz
L103 (T101)
9
Repeat Steps No. 7 & 8 for minimum change.
10 1400 KHz
1400 KHz
C1F
Align Antenna stage.
11
600 KHz
600 KHz
LlOlif necessary
12
Repeat Steps 10 & 11 for minimum change.
NOTE
: For FM IF Alignment Use A Signal Of 250 KHz Deviation, 50 Hertz Modulation For Full Bandpass Display. FM In MONO, AFC OFF,
Preset R213, R308 and R317 To Mid Rotation Before Connecting Generator. Connect Generator Cable Ground To Gang Frame.
13
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.
See Fig. 1.
Scope
Test Point
“ G ”
Thru
Diode
Detector
Probe,
See Fig. 2.
10.7 MHz
Gang
Closed
L201, L202
(T201)
Align I.F. transformer for maximum
output and symmetry as indicated
in Scope Pattern “ B ” .
NOTE: For FM Detector Alignment Use A Signal Of 75 KHz Deviation, 1 KHz Modulation. Also Connect Generator Modulation Frequency To Scope
Horizontal. Adjust Generator IF Frequency To Center Total Bandpass Waveform. Do Not Change Generator IF Frequency For Remainder
Of IF Alignment. (If Your Generator Does Not Provide Output For Audio Modulation Frequency Use Horizontal Output From Generator,
Or Scope Horizontal Sweep, And Follow Step 14C.) Minimum Distortion Can Only Be Achieved By Use Of Step 14A Below.
14
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/or
Scope.
See Fig. 3.
Center
Frequency
of Ceramic
Filters
Y201 and
Y202.
See Fig. 4.
Gang
Closed
L205
A. Preferred Method: Distortion
Analyzer at Test Point “ H ” should
read minimum distortion, approx.
50 to 55 dB below 0 dB set level.
B.Scope
B. Alternate Method: Adjust L205 for
linear scope trace-no curve at ends of
trace. Disregard meter reading.
C.Scope
Test Point
“ H ”
C. Alternate Method: Adjust L205
for maximum length and symmetry,
Similar to Scope Pattern “ A ” .
15
R213
Adjust for center reading on
Tuning Meter.
16
Test Point “ A ”
300 Ohm
106 MHz
106 MHz
C15
Set Oscillator to dial scale.
17
FM Antenna Post
90 MHz
90 MHz L4
18 (
Disconnect Antenna)
Repeat Steps 16 & 17 for minimum change.
19
106 MHz
106 MHz C1C
Align FM Detector stage for maximum.
20
90 MHz
90 MHz
L2 if necessary
21
106 MHz
106 MHz
CIA
Align FM Antenna stage for maximum.
22
90 MHz
90 MHz
LI if necessary
23
Repeat Steps 19 thru 22 for minimum change.