RF,
IF, MPX AND AUDIO ALIGNMENT PROCEDURE
FOR MODELS
MC7031,
MC7041
STEP
CONNECT
GENERATOR
TO
DUMMY
ANTENNA
CONNECT
VTVM/
SCOPE TO
INPUT
SIGNAL
FREQ.
SET DIAL
TO
ADJUST
PURPOSE
AUDIO OUTPUT IDLE CURRENT ADJUSTMENT
CAUTION:
Be Certain That The Output Stages Have Been Adjusted For Proper Idle Current Under No Signal Input Conditions Before Perform-
ing Other Adjustments Or Alignment.
1
VTVM
Across R 1422
No Signal
I nput
R1412
Adjust Controls For 4mV Across
Corresponding Resistors. This
Would Be Approximately 15mA.
2
Across R1472
No Signal
I nput
R1462
AM ALIGNMENT - PREFERRED METHOD - WITH AM SWEEP GENERATOR
NOTE:
For AM IF Alignment Use AM Sweep Signal Generator Of 10 KHz Deviation, 60 Hz Modulation For Full Bandpass Display. Bandswitch
In AM. Also Connect Modulation Frequency To Scope Horizontal. (If AM Sweep Not Available, See Steps 17 Through 31.)
3
Short Test Point "L" (AM Gang Antenna Section) To Chassis Ground.
4
Test Point "K"
AM IF Input
Generator
Output
Probe "A"
Scope
Detector
Output
Across R1 23,
Term.#104
+ 455 KHz
Gang
Closed
-
Adjust Generator To Center
Frequency Of Ceramic
Filter.
5
Test Point "K"
AM IF Input
Generator
Output
Probe "A"
Scope
Detector
Output
Across R1 23,
Term.#104
Tune Generator To Center Total Bandpass
Waveform. Do Not Change Generator Frequency
For Remainder Of AM IF Alignment.
Adjust Generator To Center
Frequency Of Ceramic
Filter.
6
Test Point "K"
AM IF Input
Generator
Output
Probe "A"
Scope
Detector
Output
Across R1 23,
Term.#104
Center
Freq.
Of Ceramic
Filter In T102
Gang
Closed
L104,
L105
(T102)
Adjust For Maximum Gain And
Symmetry.
7
Test Point "K"
AM IF Input
Generator
Output
Probe "A"
Scope
Detector
Output
Across R1 23,
Term.#104
Center
Freq.
Of Ceramic
Filter In T102
Gang
Closed
T103
Adjust For Maximum.
8
Test Point "K"
AM IF Input
Generator
Output
Probe "A"
Scope
Detector
Output
Across R1 23,
Term.#104
Center
Freq.
Of Ceramic
Filter In T102
Gang
Closed
T104
Adjust For Maximum.
9
Test Point "K"
AM IF Input
Generator
Output
Probe "A"
Scope
Detector
Output
Across R1 23,
Term.#104
Repeat Steps 6, 7 & 8 For Minimum Change.
Adjust For Maximum.
1
0
Remove Short Between Test Point "|_" And Chassis Ground.
1
1
One Turn Loosely
Coupled To AM
Wavemagnet
Antenna
None
Scope
1400 KHz
1400 KHz C1 K
Set Oscillator To Dial Scale.
12
One Turn Loosely
Coupled To AM
Wavemagnet
Antenna
None
Detector
Output
Across R
1
23,
Term.
#104
600 KHz 600 KHz T101
Set Oscillator To Dial Scale.
13
One Turn Loosely
Coupled To AM
Wavemagnet
Antenna
None
Detector
Output
Across R
1
23,
Term.
#104
Repeat Steps 11 & 12 For Minimum Change.
Set Oscillator To Dial Scale.
14
One Turn Loosely
Coupled To AM
Wavemagnet
Antenna
None
Detector
Output
Across R
1
23,
Term.
#104
1400 KHz
1400 KHz
C1
G
Align Antenna Stage.
15
One Turn Loosely
Coupled To AM
Wavemagnet
Antenna
None
Detector
Output
Across R
1
23,
Term.
#104
600 KHz 600 KHz
L111 If Necessary
Align Antenna Stage.
16
One Turn Loosely
Coupled To AM
Wavemagnet
Antenna
None
Detector
Output
Across R
1
23,
Term.
#104
Repeat Steps 14 & 15 ForMinimum Change.
Align Antenna Stage.
AM ALIGNMENT - ALTERNATE METHOD - IF AM SWEEP GENERATOR IS NOT AVAILABLE
NOTE:
For AM IF Alignment Use A Signal With 400 Hertz Modulation. Bandswitch in AM.
17
Short Test Point "L" (AM Gang Antenna Section) To Chassis Ground.
18
Test Point "K"
AM IF Input
Generator
Output
Probe "A"
VTVM
Detector
Output
Across R123,
Term.
#104
+ 455 KHz Gang
Closed
-
19
Test Point "K"
AM IF Input
Generator
Output
Probe "A"
VTVM
Detector
Output
Across R123,
Term.
#104
Rock Generator While Adjusting L104
(T102 Primary) For Maximum.
Adjust For Maximum.
20
Test Point "K"
AM IF Input
Generator
Output
Probe "A"
VTVM
Detector
Output
Across R123,
Term.
#104
Rock Generator While Adjusting L105
(T102 Secondary) For Maximum.
Adjust For Maximum.
21
Test Point "K"
AM IF Input
Generator
Output
Probe "A"
VTVM
Detector
Output
Across R123,
Term.
#104
Repeat Steps 19 & 20 For Minimum Change.
Adjust For Maximum.
22
Test Point "K"
AM IF Input
Generator
Output
Probe "A"
VTVM
Detector
Output
Across R123,
Term.
#104
Equal Output Should Be Found If Generator
Is Detuned Equal Frequency Each Side
Maximum.
Adjust For Maximum.
23
Test Point "K"
AM IF Input
Generator
Output
Probe "A"
VTVM
Detector
Output
Across R123,
Term.
#104
Center
Freq.
Of
Ceramic Filter
In T102
Gang
Closed
1 1 03
Adjust For Maximum.
24
Test Point "K"
AM IF Input
Generator
Output
Probe "A"
VTVM
Detector
Output
Across R123,
Term.
#104
Center
Freq.
Of
Ceramic Filter
In T102
Gang
Closed
T104
Adjust For Maximum.
25
Remove Short Between Test Point "L" And Chassis Ground.
26
One Turn Loosely
Coupled To AM
Wavemagnet
Antenna
None
VTVM
1400 KHz 1400 KHz
C1
K
Set Oscillator To Dial Scale.
27
One Turn Loosely
Coupled To AM
Wavemagnet
Antenna
None
Detector
Output
Across R123,
Term.
#104
600 KHz
600 KHz T101
Set Oscillator To Dial Scale.
28
One Turn Loosely
Coupled To AM
Wavemagnet
Antenna
None
Detector
Output
Across R123,
Term.
#104
Repeat Steps 26 & 27 For Minimum Change.
Set Oscillator To Dial Scale.
29
One Turn Loosely
Coupled To AM
Wavemagnet
Antenna
None
Detector
Output
Across R123,
Term.
#104
1400 KHz 1400 KHz
C1G
Align Antenna Stage.
30
One Turn Loosely
Coupled To AM
Wavemagnet
Antenna
None
Detector
Output
Across R123,
Term.
#104
600 KHz 600 KHz
L111 If Necessary
Align Antenna Stage.
31
One Turn Loosely
Coupled To AM
Wavemagnet
Antenna
None
Detector
Output
Across R123,
Term.
#104
Repeat Steps 29 & 30 For Minimum Change.
Align Antenna Stage.
FM ALIGNMENT
NOTE:
For FM IF Alignment Use A Signal Of 250 KHz Deviation, 50 Hertz Modulation For Full Bandpass Display. Bandswitch In FM. Mute OFF. AFC
OFF.
Preset R208, R211, R303 And R313 To Mid Rotation Before Connecting Generator. Connect Generator Cable Ground To Gang Frame.
32
Shunt C1D To Ground With A .001 MF Capacitor.
33
Test Point "D"
FM IF Input
At Q2 Base
Generator
Output
Probe "A"
Scope
Detector
Probe "C"
Test Point
"G"
At IC201
Pin 1
± 10.7 MHz
Gang
Closed
-
Align I.F. Transformer For Maxi-
mum Output And Symmetry As
Indicated In Scope Pattern "A".
34
Test Point "D"
FM IF Input
At Q2 Base
Generator
Output
Probe "A"
Scope
Detector
Probe "C"
Test Point
"G"
At IC201
Pin 1
Tune Generator To Center Total Bandpass
Waveform. Do Not Change Generator Frequency
For Remainder Of FM IF Alignment.
Align I.F. Transformer For Maxi-
mum Output And Symmetry As
Indicated In Scope Pattern "A".
35
Test Point "D"
FM IF Input
At Q2 Base
Generator
Output
Probe "A"
Scope
Detector
Probe "C"
Test Point
"G"
At IC201
Pin 1
Center
Freq.
Of Ceramic
Filters Y201,
Y202,
Y203.
Gang
Closed
T201
Align I.F. Transformer For Maxi-
mum Output And Symmetry As
Indicated In Scope Pattern "A".
12
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