Fisher RS-913 - Alignment Procedures; Caution on RF Adjustment; FM IF S-Curve Alignment; FM RF Frequency Cover Alignment (87.5 MHz)

- CAUTION ON RF ADJUSTMENT
This
model
uses
a
microprocessor
for
memory
preset
control
for
the
various
bands.
ay
in
aa
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,
press
the
POWER
STANDBY
button
fer
approximately
§
seconds
so
that
the
frequency
points
show
in
the
following
table
before
beginning
adjustment.
The
following
table
shows
the
initially
preset
frequencies.
To
el
Peep
ene
rg
eet
a
cr
[
arene
|
toawiiz
|
eemnz
|
sown
|
tosne
|
somne—
Fawr]
eoanre
|
14oantte
|
ooktie
|
veowre
|
s80mre
|
250nre
FM TUNER ALIGNMENT
FM ALIGNMENT — Band Selector switch to FM/ST(MUTE) position.
Note
Is
almost
unnecessary
to
adjust
coil
in
Front
End
as
pertectly
adjusted.
GENERATOR
DIAL
SETTING
INDICATOR
PROCEDURE
nnect
10.7MHz
Radio
Position
of
Connect
Radio
IF
|
Adjust
FM
DET
14
Coil
(F102)
and
S
CURVE
eGarcacane
output
to
non-interference
Genescope
input
FM
DET
2
(T1103)
so
that
S-wave
ALIGNMENT
Pin
tF
(Front
End)
and
Minimum
to
TP3
and
ground
from
becomes
symmetrical.
ground
lead
to
chassis.
Frequency.
lead
to
chassis.
Use
5pF
capacitor
in
series
with
generator
output
fead.
.
FM
REF
Do
not
connect
Set
Preset
Connect
DC
Voit-
|
Adjust
FM
OSC
Coll
(L6)
untll
FREQUENCY
Generator.
STATION
button
meter
to
Pin
B2
DC
Voltmeter
reads
1.5V
+0.05V.
~
COVER
to
“1°
position.
(Front
End)
and
nO
ALIGNMENT
Set
to
87.5MHz.
ground
lead
to
(87.SMHz) chassis.
Same as above. Change Preset Same as above.
STATION button
to “2” position.
Set to 108MHz.
Note:
Repeat
the
adjustments
in
Items
2
and
3.
Then,
confirm
that
each
voltage
becomes
1.5V
to
8.3V
at
receiving
frequency
of
87.5MHz
to
108MHz.
(See
Table
2)
4.
FM
RF
Connect
FM
RF
Signal
Set
Preset
Connect
AC
VTVM
|
Adjust
FM
RF
Coil
(2,
L4,
L5)
Check the OC Voltmeter reads
7V ~ OV.
i i i tput.
TRACKING
Generator
through
FM
STATION
button
and
Oscilloscope
|
for
maximum
gain
ou
ALIGNMENT
Dummy
Antenna
to
FM
to
“3”
position.
to
Tape
REC
OUT
|
Do
not
touch
the
Coil
(88MHz)
Antenna
terminals.
Set
to
88MHz.
-
Terminals.
(L1
and
L3)
Set Generator to 88MHz
or 108MHz. Modulate
with 1kHz to provide
+75kHz deviation.
Set Generator output
with attenuator as low
as possibile.
Adjust FM RF Trimmer (TC1, TC2,
TC3) for maximum gain output
Change Preset Same as above.
STATION button
to "2" position.
Set to 108MHz.
{108MHz)
Note: Repeat the adjustments in Items 4 and 5. Then, confirm there is no tracking error.
6. DETECTOR Set MODE switch Connect DC Voit-
ADJUSTMENT to FM MONO posi- | meter across
{MINIMUM tion and Preset TP1 and TP2.
T.H.D.) STATION button to
“4" posion.
Set to 98MHz.
Adjust FM DET 1 Coil {T102) until
DC Voltmeter reads OV +50mV.
Connect FM AF signal
generator through FM
Dummy Antenna to FM
Antenna terminals.
Set generator to 98MHz
+2kHz. Modulate with
Adjust FM DET 2 Coil (7103)
for minimum gain and best
Connect
Harmonic
1kHz to provide +40kHz Distortion linearity.
deviation. Setting gene- Analyzer to
rator with attenuator REC OUT.
output level for 60dByV.
Note:
Repeat
Step
1
(FM
DET
1
Coil
T102)
and
2
(FM
DET
2
Coil
T103)
until
optimum
alignment
is
reached.
FM TUNER ALIGNMENT (continued)
ITEM
GENERATOR
DIAL
SETTING
INDICATOR
PROCEDURE
7, FM STEREO Connect FM Stereo SG Same as above Connect AC VTVM
SIGNAL to FM Antenna terminals. | Set MODE switch | and Oscilloscope
SEPARATION 19kHz signa! ON. to FM ST/MUTE to REC OUT.
CONTROL Main channel, sub position.
channel signa! ON. _
Apply 1000Hz signal
from LEFT channel.
Adjust VR103 for minimum
output.
Same as above for
RIGHT channet.
Connect AC VTVM
and Oscilloscope
to REC OUT.
Front panel
TUNED Indicator
Display.
. FM MUTING
AUTO STOP
SENSITIVITY
ADJUSTMENT
Set generator to 98MHz.
Adjust attenuator output
Jevel to 18dByV.
Same as above.
Adjust VR101 until the TUNED
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
tevel
meets
the
specifications
sufficiently
when
the
wave
form
has appeared.
Use a screwdriver with plastic grip for ail adjustments.
FM
Frequency
Cover
Range
MW
Frequency
Cover
Range
LW
Frequency
Cover
Range
Tuning
Voltage
Value
at
B2
(Front
End)
Tuning
Voltage
Value
ai
TP
(R147)
Tuning
Voltage
Value
at
TP
(R147)
(Table
1}
(Table
2)
(Table
3)
seas [sore | [teense
Pwinimom [ory |_| [ winimam [ov]
TMaximum |__| 90v_| [maximum [| aov
AM TUNER ALIGNMENT
AM ALIGNMENT — Band Selector switch to MW or LW position.
Maintain generator output as fow as possible for suitable indication.
| rem | GENERATOR
Note: Perform this atignment after FM Tuner Alignment
DIAL SETTING INDICATOR PROCEDURE
1.
AMIF
Connect
450kHz
Radio
Position
of
Connect
Radio
IF
|
Adjust
AM
IFT
(1105)
for
maximum
ALIGNMENT
IF
Genescope
output
non-interference
Genescope
input
gain
and
best
symmetry.
to
Pin
W1
and
W2
Adjust
|
Minimum
to
TP4
and
ground
|
Keep
signal
low
enough
for
noise
output fevel to 70dByV. Frequency. jead to chassis. on response.
2.
MW
RF
Do
not
connect
Front
Panel
Connect
DC
Volt-
|
Check
DC
Voltmeter
for
Indication
FREQUENCY
generator.
DIGITAL
Counter
meter
to
TP
(R147}|
8.0V
~
9.0V.
COVER
Display
and
ground
lead
ALIGNMENT
Set
to
1641kHz.
_to
chassis.
(1611kHz)
3. Same as above.
(522kHz)
DIGITAL Counter
Display
Set to 522kHz.
Note:
Repeat
the
adjustments
in
items
2
and
3.
Then,
confirm
that
each
voltage
becomes
1.0V
to
8.0V
at
receiving
frequency
of
$22kHz
to
1611kHz.
(See
Table 2)
4. LWRF.
Same as above.
Gheck DC Voltmeter for indication
0.7V ~ 1.0V.
Do not connect Front Panel Connect DC Voit- Check DC Voitmeter for Indication
FREQUENCY generator. DIGITAL Counter meter to TP (A147); 7.5V ~ 9.0V.
COVER Dispiay and ground Jead to
ALIGNMENT Set to 360kHz. chassis.
(360kHz)