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RADIO ALIGNMENT INSTRUCTIONS
32.
33.
34.
35.
36.
37.
38.
36.
37.
38.
39.
40.
41.
ALIGNMENT INSTRUCTIONS-READ CAREFULLY BEFORE ATTEMPTING ALIGNMENT
Remove the plastic radio cover containing the dial scale and 45RPM record player.
Turn the tuning gang fully closed. Set the dial pointer to the calibration mark near the left hand end of the dial backplate.
Replace the plastic cover.
AM ALIGNMENT
Any adjusting done on the 455KC IP's will necessitate alignment of the 10. 7MC FM IF's.
Loop should be maintained in same relative position to chassis as when receiver is in cabinet.
Volume control should be at maximum position. Output of signal generator should be no higher than necessary to obtain an output reading. Use an
insulated alignment screwdriver for adjusting.
Alternate loading of the IF transformers is used.
Connect 47K£i resistor across the primary of each transformer while the secondary of the same transformer is being adjusted.
During secondary adjustment move the 47KS2 resistor to across the primary.
DUMMY
ANTENNA
.1MFD
SIGNAL
GENERATOR
COUPLING
High side to stator on
center "AM" section of
tuning gang. Low side
to chassis.
Loop
Loop
Loop
SIGNAL
GENERATOR
FREQUENCY
455KC
(4001, Mod.)
1620KC
1400KC
600KC
BAND
SWITCH
POS.
AM
(third
position
CW)
RADIO
DIAL
SETTING
Tuning gang
fully closed
Tuning gang
fully open
Tune for max.
output.
600KC
OUTPUT
METER
Across voice
coil
ADJUST
A39,
A40,
A41,
A42
A43
A44,
A45
A46,
A47
REMARKS
Adjust in the order given for maximum
output. Then adjust in reverse order
using alternate loading as described above.
Fashion loop of several turns of wire and
radiate signal into loop of receiver. Adjust
for maximum output.
Connect a lOKft resistor across the center
"AM" section of tuning gang. Rock tuning
gang while adjusting A46 for maximum
output. Remove lOKft resistor and adjust
A47 while rocking tuning gang. Repeat
steps 34 and 35 until no further improve-
ment can be made.
FM IF ALIGNMENT USING AM SIGNAL GENERATOR AND VTVM
Connect two matched lOOKSi (± 1%) resistors in series from point E to chassis. The junction of these two resistors is alignment point G as shown on
the schematic.
Alternate loading is used on lall FM transformers except the discriminator transformer L36. Connect a 680 ohm resistor across the primary of each
transformer while the secondary of the same transformer is being adjusting. During primary adjustment move the 680 ohm resistor to across the
secondary.
DUMMY
ANTENNA
. 01MFD
. 01MFD
470O
carbon
res.
SIGNAL
GENERATOR
COUPLING
High side to pin 1 (Grid) of
6AU6 (V24). Low side to
chassis.
High side to stator on
center of "FM" section of
tuning gang. Low side to
chassis.
SIGNAL
GENERATOR
FREQUENCY
10. 7MC
(Unmod. )
BAND
SWITCH
POS.
FM
(fourth
position
CW)
RADIO
DIAL
SETTING
Tuning gang
fully open
CONNECT
VTVM
DC Probe to
to Point<£\n to
chassis.
DC Probe to Point
F . Common to
PoinS^>.
DC Probe to Point
^K>. Common to
chassis..
ADJUST
A48
A49
A50,
A51,
A52,
A53
REMARKS
Adjust for maximum deflection.
Adjust for zero reading. A positive and
negative reading will be obtained on
either side of the correct setting.
Adjust for maximum deflection. Use alter-
nate loading as described above.
FM IF ALIGNMENT USING FM SIGNAL GENERATOR AND OSCILLOSCOPE
Use frequency modulated signal with 60 ^ modulation and 450KC sweep. Use 120% sawtooth voltage in scope for horizontal deflection.
DUMMY
ANTENNA
. 01MFD
. 01MFD
. 01MFD
SIGNAL
GENERATOR
COUPLING
High side to pin 1 (Grid) of
6BA6 (V24). Low side to
chassis.
High side to pin 5 (Grid) of
616 (V23). Low side to
chassis.
DUMMY
ANTENNA
Two 120£!
carbon
res.
"
SIGNAL
GENERATOR
COUPLING
Across FM antenna termin-
als with 120ft in each lead.
SIGNAL
GENERATOR
FREQUENCY
10. 7MC
(450KC
SWP)
SIGNAL
GENERATOR
FREQUENCY
90MC
(Unmod. )
106MC
90MC
BAND
SWITCH
POS.
FM
(fourth
position
CW)
fl
BAND
SWITCH
POS.
FM
"
RADIO
DIAL
SETTING
Point of non-
interference
A RF ALIGNMENT
RADIO
DIAL
SETTING
90MC
Tune for max.
deflection.
CONNECT
SCOPE
Vert. Amp. to
PolnKgX Low
side to chassis.
Vert. Amp. to
Point<^>. Low
side to chassis.
ADJUST
A48,
A50,
A51
A52,
A53
A49
CONNECT
VTVM
€
Probe to Point
Common to
LSSis.
ADJUST
A 54
A55,
A56
A57,
A58
REMARKS
Disconnect stabilizer capacitor C106.
Adjust for maximum amplitude and
symmetry as per figure 7.
Reconnect capacitor C106. Adjust A49 so
10. 7MC occurs at center of crossover lines
as per figure 8. SLIGHTLY retouch A48
for maximum amplitude and straightness
of crossover lines.
REMARKS
Expand or compres s coil turns for max-
imum deflection.
Adjust for maximum deflection.
Expand or compress coil turns for maxi-
mum deflection.
FIG. 7
FIG. 8
PAGE 12
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