Realistic STA-21 - Page 9

FM RF
&
IF
ALIGNMENT
EOUIPMENT
REOUIRED
3. AC Vottmeter
1.
FM
signal Generator
output Level:
1 mV
4.
oscilloscope
2.
Sweep Generator
S. Distortion
Meter
NOTE
o
Signal
Generator
output should
be no higher
than
necessary
to
obtain
an
output reading.
.
Set
SELECTOR
Switch to FM.
o
Maintain
Line voltage
at 12Q volts.
(UL,
C.S.A.)
1220/240
VAC
For European
& Australian
Models.)
a
Refer
to P.C.B.
illustrations
for
test
points,/adjustments.
STEP
GENERATOR
COUPLING
GENERATOR
FREOUENCY
RADIO
DIAL
SETTING
INDICATOR
ADJUSTMENT
REMARKS
1
Sweep Generator
to
"FM
ANT"
terminal
on
FM
Front
end
board
10.7 MHz
(1400
kHz
Sweep)
Any dial
setting
where no noise
or
interference
exists
Scope
to TP 7
at R 151
{MPX
input)
AM/FMIMPX
Board
T 101,
102
103,
104
(Primary)
FM IFT
Adjust
for
maximum
amplitude
and
proper
linearity
between
+ 150
kHz
markers.
Refer to Fig.
7.
2
Sweep
Generator to
FM
Antenna
Terminal
thru FM
Dummy
antenna
(300
ohm)
T101,
102
FM IFT
3
Same as above
T 104
FM
IFT.
(Primary
and
Secondary)
Ajust for
symmetri-
cal
"S"
curve
as
shown in
Fig.6.
4
Signal
Generator to
FM Antenna
Terminal thru FM
Dummy antenna
(300
ohm)
98 MHz
(400
Hz,
100o/o
MOD}
Tune for
Maximum
reading
on
meter
Distortion
Meter
to TAPE
OUT Jack
T 104
FM
Discrim.
(Secondary)
Adjust for
minimum
distortion.
5
Same as above
*86.5
MHz
See Note
in step 7
Tuning
gang
fully
closed
AC Voltmeter
and Scope
to
TAPE
OUT
Jack
L 105
(FM
OSC}
Adjust for
maximum
reading
on meter.
6
Same as
above
108.5 MHz
Tuning
gang
fully
opened
TC 103
(FM
OSC
Trimmer)
7
Repeat
STEPs
(5)
and
(6)
until
Tuning
Range
Covers exactly
from
86.5 MHz
to 108.5
MHz.
(*European
models
must
not be
able to
tune
below
87.8 MHz.)
8
Signal Generator
to
FM Dummy
antenna
(300
ohm)
90
MHz
90 MHz
Tune to
Signal
AC Voltmeter
and Scope
to
TAPE
OUT
Jack
L 101
(FM
ANT
Coil)
L
103
(FM
BF
Coil; stretch
or squeeze)
Adjust for
maximum
reading
on meter.
9
Same
as above
106 MHz
106 MHz
Tune
to
Signal
TC
101
(FM
ANT Trimmer)
TC 102
(FM
RF Trimmer)
10
Repeat
STEPs
(8)
and
(9)
until no
furt her improvement
is noticed.
11
Same
as
STEP
(8)
ANT. input:
1 mV
98 MHz
98 MHz Tune
to
Signal
T110
Adjust
for maximum
reading
on meter.
12
Same
as STEP
(8)
ANT. input: 100 mV
VR1Ol
Adjust
so the Meter
Pointer
on
Receiver
is full
scale.
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