Fisher TAC-M82 - Caution on RF Adjustment; FM Tuner Alignment; FM Alignment

CAUTION ON RF ADJUSTMENT
This
model
uses
a
microprocessor
for
memory
preset
control
for
the
various
bands.
This
function
has
been
used
to
preset
frequency
points
for
the
different
bands
to
permit
adjustment
and
make
it
possible
to
check
the
function
of
the
microprocessor.
To
use
this
supplemental
function,
ground
initialize
test
point
TP7
for
1
second
before
beginning
adjustment.
The
following
table
shows
the
initially
preset
frequencies.
}
wang
|
Memon
ee
ee
ee
re
[Fut
_|
7
swri
|
Toawrie
|
eomie
|
oowhiz
|
voawniz
|
sowna
Fuwitw
[coakiiz
|
iaoawre
|
soontie
|
ve0nne
|
ostntiz
|
2sonrte
|
FM TUNER ALIGNMENT
FM
ALIGNMENT
—
FUNCTION
switch
to
FM/STEREO
position.
Note:
It
is
almost
unnecessary
to
adjust
coil
in
Front
End
as
perfectly
adjusted
ITEM
GENERATOR
DIAL
SETTING
INDICATOR
PROCEDURE
1.
FM
IF
Connect
10.7MHz
Radio
Position
of
Connect
Radio
IF_
|
Adjust
FM
DET
1st
Coil
(T106)
and
S-CURVE
IF
Generator
output
to
non-interference
Genescope
input
FM
DET
2nd
Coil
(T107)
so
that
ALIGNMENT
TP1
and
ground
lead
to
Minimum
to
TP5
and
ground
|
S-wave
form
becomes
symmetrical.
chassis.
Use
5pF
Frequency.
lead
to
chassis.
capacitor
in
series
with
generator
output
lead.
.
DETECTOR
Connect
FM
RF
signal
Set
Preset
Connect
DC
Volt-
Adjust
FM
DET
1st
Coil
(T106)
until
ADJUSTMENT
|
generator
through
FM
STATION
button
meter
across
DC
Voltmeter
reads
OV
+50mV.
(MINIMUM
Dummy
Antenna
to
FM
to
“4”
position.
TP3
and
TP4.
T.H.D.)
Antenna
terminals.
Set
to
98MHz.
Set
generator
output
Set
MODE
switch
|
Harmonic
Adjust
FM
DET
2nd
Coil
(T107)
for
level
to
60dByV
at
to
MONO.
Distortion
minimum
gain
and
best
linearity.
98MHz
+
2kHz.
Analyzer
to
SPEAKER
OUT.
Note:
Repeat
Step
1
(FM
DET
1st
Coil
T106)
and
2
(FM
DET
2nd
Coil
7107)
until
optimum
alignment
is
reached.
3.
FM
MUTING
Same
as
above.
Same
as
above.
Front
panel
Set
MODE
Switch
to
STEREO.
LEVEL
Adjust
attenuator
output
TUNED
Display
Adjust
P101
until
the
TUNED
ADJUSTMENT
|
level
for
18dBuV.
Indicator.
Indicator
partly
light
up.
Note:
Decrease
the
output
level
of
ATT
and
confirm
that
the
wave
form
disappears.
Increase
the
output
level
of
ATT
again
and
confirm
that
the
input
level
meets
the
specifications
sufficiently
when
the
wave
form
has
appeared.
4.
FM
STEREO
Connect
FM
Stereo
SG
Connect
AC
VTVM
SIGNAL
to
FM
Antenna
terminals.
and
Oscilloscope
SEPARATION
19kHz
signal
ON.
to
SPEAKER
OUT.
CONTROL
Main
channel,
sub
channel
signal
ON.
Adjust
P103
for
minimum
Apply
1000Hz
signal
output.
from
LEFT
channel.
Same
as
above
for
Connect
AC
VTVM
RIGHT
channel.
and
Oscilloscope
to
SPEAKER
OUT.
Use
a
screwdriver
with
plastic
grip
for
all
adjustments.
MW/LW Frequency Cover Range
Tuning Voltage Value at TP2
a
a
P
winimum
[ory
|
eov
[tov
|
rov_|
[Maximum
|
12v_
|
ov
|
1av
|
sov
|
(Table 1)