Read Sony CFS-B21L Service Manual online
SECTION 3
MECHANICAL ADJUSTMENTS
SECTION 4
ELECTRICAL ADJUSTMENTS
PRECAUTION
1.
Clean the following parts with a denatured-alcohol moistened
swab :
swab :
record/playback head
pinch roller
erase head
rubber belts
capstan
idlers
2.
Demagnetize the record/playback head with a head
demagnetizer. (Do not bring the head demagnetizer close to
the erase head.)
demagnetizer. (Do not bring the head demagnetizer close to
the erase head.)
3.
Do not use a magnetizer screwdriver for the adjustments.
4.
After the adjustments, apply suitable locking compound to
the parts adjusted.
the parts adjusted.
5.
The adjustment should be perfomed with the reted power
supply voltage unless otherwise noted.
supply voltage unless otherwise noted.
6.
Power supply voltage: 6V dc.
Torque Measurement
Tape Tension Measurement
Torque meter
CQ-403A
Meter reading
more than 100g
(more than 3.53 oz)
Torque
Forward
Forward
back tension
back tension
Fast
Forward
Forward
Rewind
Torque meter
CQ-102C
CQ-102C
CQ-201B
CQ-201B
Meter reading
30-70g•cm
(0.42-0.97 oz•inch)
1.5-5.5g•cm
(0.020-0.076 oz•inch)
more than 60g•cm
(more than 0.83 oz•inch)
more than 60g•cm
(more than 0.83 oz•inch)
4-1.
TAPE RECODER SECTION
Standard Output Level
Test Tape
Tape Speed Adjustment
Procedure :
Mode : playback
Mode : playback
Type
WS-48A
P-4-A063J
Used for
tape speed adjustment
head azimuth adjustment
Signal
3kHz, 0dB
6.3kHz, –10dB
Speed checker
–1% to +1%
Digital frequency counter
2,970–3,030Hz
output terminal
load impedance
output signal level
HP OUT
32
0.25V (–10dB)
SP OUT
12
0dB
tape speed adjustment
control inside motor
control inside motor
4-2.
RADIO SECTION
•
FM Section
Setting :
FUNCTION switch : RADIO
BAND switch : FM
FUNCTION switch : RADIO
BAND switch : FM
set
0.01
µ
F
FM RF signal
generator
generator
telescopic antenna
input
input
22.5kHz frequency
deviation by 400Hz signal
output level : as low as possible
deviation by 400Hz signal
output level : as low as possible
FM IF ADJUSTMENT
Adjust for a maximum reading on level meter.
L4
*
* : The FM IF adjustment specifications are different depending
upon the color code of CF1. See the following table.
CF1 color
Red
Blue
Orange
Black
White
frequency
10.70MHz
10.67MHz
10.73MHz
10.64MHz
10.76MHz
color code
CF1
AM RF signal
generator
generator
Put the lead-wire
antenna close to
the set.
antenna close to
the set.
30% amplitude
modulation by
400Hz signal
output level : as low as possible
modulation by
400Hz signal
output level : as low as possible
32
Ω
phones jack
set
level meter
(range : 0.5–5V ac)
(range : 0.5–5V ac)
+
–
AM RF signal
generator
generator
Put the lead-wire
antenna close to
the set.
antenna close to
the set.
30% amplitude
modulation by
400Hz signal
output level : as low as possible
modulation by
400Hz signal
output level : as low as possible
32
Ω
phones jack
set
level meter
(range : 0.5–5V ac)
(range : 0.5–5V ac)
+
–
( ) : EE1 model
•
MW Section
Setting :
FUNCTION switch : RADIO
BAND switch : MW
FUNCTION switch : RADIO
BAND switch : MW
•
LW Section
FUNCTION switch : RADIO
BAND switch : LW
BAND switch : LW
Adjustment Location : TUNER BOARD (COMPONENT SIDE)
FM VCO Adjustment
Procedure :
1.
Connect frequency counter as shown below.
2.
Tune the set to 98MHz.
3.
Adjust RV1 for 76kHz±50Hz reading on the frequency counter.
L12 : AM IF
CF2
CF1
RV1 : FM VCO
L4 : FM IF
L1 : FM
TRACKING
TRACKING
L3 : MW TRACKING,
LW TRACKING
LW TRACKING
CT10 : LW TRACKING
CT3 : MW TRACKING
CT2 : FM FREQUENCY
COVERAGE
COVERAGE
CT1 : FM
TRACKING
TRACKING
L5 : LW FREQUENCY
COVERAGE
COVERAGE
L2 : FM
FREQUENCY
COVERAGE
FREQUENCY
COVERAGE
CT5 : LW FREQUENCY
COVERAGE
COVERAGE
CT4 : MW FREQUENCY
COVERAGE
COVERAGE
L6 : MW FREQUENCY
COVERAGE
COVERAGE
Adjustment Location :
[TUNER BOARD] (conductor side)
set
0.01
µ
F
FM RF signal
generator
generator
telescopic antenna
input terminal
input terminal
Carrier frequency : 98MHz
Modulation : no modulation
Output level : 0.1V (100dB)
Modulation : no modulation
Output level : 0.1V (100dB)
•
Repeat the procedures in each adjustment several times, and
the frequency coverage and tracking adjustments should be
finally done by the trimmer capacitors.
the frequency coverage and tracking adjustments should be
finally done by the trimmer capacitors.
— 6 —
— 7 —
— 8 —
frequency
counter
counter
1
µ
F
33k
Ω
32k
Ω
phones jack
test tape
WS-48A
(3kHz, 0dB)
WS-48A
(3kHz, 0dB)
speed checker
LFM-30
or
digital frequency
counter
LFM-30
or
digital frequency
counter
set
Adjustment Value :
Frequency difference between the beginning and the end of the tape
should be within 1.5% (45Hz).
should be within 1.5% (45Hz).
Adjustment Location :
2-3.
DIAL POINTER SETTING
2
Insert the pointer into stopper
and set for tuning knob.
stopper
(stopper is a part of
dial pointer bracket,
and located at the
left end.)
(stopper is a part of
dial pointer bracket,
and located at the
left end.)
1
Turn tuning knob fully in the
direction of the arrow.
— 5 —
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