Sony CMT-EP303 / HCD-EP303 Service Manual ▷ View online
11
HCD-EP303
3-8. Cassette Lid
1
Push stop/eject key.
4
cassette lid
3
claw
3
claw
2
12
HCD-EP303
SECTION 4
MECHANICAL ADJUSTMENTS
SECTION 5
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 magnetizer close to the
erase head.)
demagnetizer. (Do not bring the head magnetizer close to the
erase head.)
3.
Do not use a magnetized screwdriver for the adjustments.
4.
After the adjustments, apply suitable locking compound to the
parts adjusted.
parts adjusted.
5.
The adjustments should be performed with the rated power
supply voltage unless otherwise noted.
supply voltage unless otherwise noted.
Torque Measurement
Tape Tension Measurement
Mode
Torque Meter
Meter Reading
FWD
CQ-403A
more than 100 g
(more than 3.53 oz)
PRECAUTION
1.
Setting
MEGA BASS switch : OFF
MEGA BASS switch : OFF
TAPE DECK SECTION
0 dB=0.775 V
Test tape
Mode
Torque Meter
Meter Reading
2.95 – 6.86 mN•m
FWD
CQ-102C
(30 – 70 g•cm)
(0.42 – 0.97 oz•inch)
(0.42 – 0.97 oz•inch)
0.15 – 5.39 mN•m
FWD
CQ-102C
(1.5 – 5.5 g•cm)
Back Tension
(0.021 – 0.076 oz•inch)
more than 5.89 mN•m
FF
CQ-201B
(more than 60 g•cm)
(more than 0.83 oz•inch)
(more than 0.83 oz•inch)
more than 5.89 mN•m
REW
CQ-201B
(more than 60 g•cm)
(more than 0.83 oz•inch)
(more than 0.83 oz•inch)
Type
Signal
Used for
WS-48A
3 kHz, 0 dB
Tape Speed Adjustment
P-4-A063
6.3 kHz, –10 dB
Head Azimuth Adjustment
Record/Playback Head Azimuth Adjustment
Procedure:
1.
1.
Mode: Playback
level meter
test tape
P-4-A063
(6.3 kHz, –10 dB)
P-4-A063
(6.3 kHz, –10 dB)
set
HEADPHONE board
PHONES jack (JK401)
PHONES jack (JK401)
32
Ω
+
–
–
2.
Turn the adjustment screw and check output peaks. If the peaks
do not match for L-CH and R-CH, turn the adjustment screw
so that outputs match within 1dB of peak.
do not match for L-CH and R-CH, turn the adjustment screw
so that outputs match within 1dB of peak.
3.
Mode: Playback
4.
After the adjustments, apply suitable locking compound to the
parts adjusted.
parts adjusted.
Screw
position
position
L-CH
peak
peak
within
1dB
1dB
Output
level
level
L-CH
peak
peak
R-CH
peak
peak
within
1dB
1dB
Screw
position
position
R-CH
peak
peak
test tape
P-4-A063
(6.3 kHz, –10 dB)
P-4-A063
(6.3 kHz, –10 dB)
L-CH
R-CH
HEADPHONE board
PHONES jack (JK401)
PHONES jack (JK401)
oscilloscope
V
H
+ +
–
–
screen pattern
in phase
good
wrong
45
°
90
°
135
°
180
°
32
Ω
32
Ω
set
13
HCD-EP303
Tape Speed Adjustment
Setting:
Function: TAPE
Function: TAPE
Procedure:
1.
1.
Playback WS-48A (tape center) in the FWD state.
2.
Adjsut the volume in CAPSTAN/REEL motor (M201) so that
the frequency counter reading becomes 3,000 Hz.
the frequency counter reading becomes 3,000 Hz.
Specified Value: 2,910 to 3,090 Hz
3.
Confirm that the frequency at the beginning and that at the end
of tape winding are between 2,955 to 3,045 Hz.
of tape winding are between 2,955 to 3,045 Hz.
Adjustment Location:
frequency counter
test tape
WS-48A
(3 kHz, 0 dB)
WS-48A
(3 kHz, 0 dB)
set
HEADPHONE board
PHONES jack (JK401)
PHONES jack (JK401)
–
+
32
Ω
CAPSTAN/REEL
motor (M201)
motor (M201)
Tape Speed
Adjustment
Adjustment
Adjustment Location: Record/Playback Head.
Note: Refer to “3-8. Cassette Lid” (see page 11)
adjustment screw
14
HCD-EP303
TUNER SECTION
0 dB=1 µV
[AM]
Setting:
Function
Function
: TUNER
Band switch : AM
[FM]
Setting:
Function
Function
: TUNER
Band switch : FM
• Repeat the procedures in each adjustment several times, and the frequency
coverage and tracking adjustments should be finally done by the trimmer
capacitors.
capacitors.
AM RF signal
generator
30% amplitude
modulation by
400 Hz signal
Output level: as low as possible
modulation by
400 Hz signal
Output level: as low as possible
Put the lead-wire
antenna close to
the set.
antenna close to
the set.
+
–
–
level meter
set
32
Ω
HEADPHONE board
PHONES jack (JK401)
PHONES jack (JK401)
FM RF signal
generator
22.5 kHz frequency
deviation by 400 Hz
signal
Output level: as low as possible
deviation by 400 Hz
signal
Output level: as low as possible
+
–
–
level meter
set
32
Ω
0.01
µ
F
MAIN board
FM ANT
FM ANT
HEADPHONE board
PHONES jack (JK401)
PHONES jack (JK401)
digital voltmeter
100 k
Ω
MAIN board
TP10 (FM VT)
TP11 (AM VT)
TP11 (AM VT)
no mark : Except AEP, UK models
< > : AEP, UK models
< > : AEP, UK models
AM FREQUENCY COVERAGE ADJUSTMENT
Adjustment Part
Frequency Display
Reading on Digital Voltmeter
Confirmation
530 kHz
1.5 ± 0.2 V
<531 kHz>
T102
1,710 kHz
7.7 ± 0.3 V
<1,602 kHz>
<7.3 ± 0.3 V>
AM TRACKING ADJUSTMENT
Adjust for a maximum reading on level meter
L110
600 kHz <603 kHz>
TC102
1,400 kHz <1,404 kHz>
FM FREQUENCY COVERAGE ADJUSTMENT
Adjustment Part
Frequency Display
Reading on Digital Voltmeter
L104
87.6 MHz
2.1 ± 0.2 V
Confirmation
108 MHz
7.0 ± 0.4 V
FM TRACKING ADJUSTMENT
Adjust for a maximum reading on level meter
L103
89.9 MHz
TC101
105.9 MHz
Adjustment Location: MAIN board (See page 15)
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