Sony HCD-EC68 / HCD-EC78 / MHC-EC68 / MHC-EC78 Service Manual ▷ View online
HCD-EC68/EC78
17
3
It indicates the on-going processing of optical pick-up system
(= optical unit + BD board) when the trouble has occurred.
01: The CD SHIP mode processing is in progress.
02: The POWER OFF processing is in progress.
03: The INITIALIZE processing is in progress.
04: The optical pick-up system (= optical unit + BD board) is
01: The CD SHIP mode processing is in progress.
02: The POWER OFF processing is in progress.
03: The INITIALIZE processing is in progress.
04: The optical pick-up system (= optical unit + BD board) is
in the stop state.
05: The STOP operation is in progress.
06: The startup processing is in progress.
07: The TOC read-in processing is in progress.
08: The SEARCH operation is in progress.
09: The PLAY operation is in progress.
0A: The PAUSE operation is in progress.
0B: The PLAY – MANUAL SEARCH operation is in prog-
06: The startup processing is in progress.
07: The TOC read-in processing is in progress.
08: The SEARCH operation is in progress.
09: The PLAY operation is in progress.
0A: The PAUSE operation is in progress.
0B: The PLAY – MANUAL SEARCH operation is in prog-
ress.
0C: The PAUSE – MANUAL SEARCH operation is in prog-
ress.
4
It indicates the operation that is being processed when the trou-
ble has occurred.
It indicates the step number of each processing specifi ed by 3.
Because the numbers of steps are different in each processing,
this number is different in each processing.
Because the numbers of steps are different in each processing,
this number is different in each processing.
CD FACTORY MODE
Note1: Do not enter the [CD FACTORY MODE] while any other test-
mode is in progress.
Note2: Do not enter any other test mode while the [CD FACTORY
MODE] is in progress.
Procedure:
1. Press the [
1. Press the [
I/1
] button to turn the power on.
2. Press the [FUNCTION] button to select CD function
3. Press three buttons of [CD N], [FUNCTION], and [DIS-
3. Press three buttons of [CD N], [FUNCTION], and [DIS-
PLAY] simultaneously.
4. It enters the CD factory mode and displays the following mes-
sage.
–X1ON
S character mode setting
Tracking servo setting
RF gain setting
Key Operation:
[DISPLAY]:
[DISPLAY]:
The display changes in the following order when-
ever the button is pressed.
ever the button is pressed.
(Initial display)
fcsAG ** (**: Focus AGC value)
trkAG ** (**: Track AGC value)
RF-AG ** (**: RF AGC value)
[DSGX]:
RF gain setting changes whenever the button is
pressed.
pressed.
“–”: No gain fi xation.
“AL”: Fix to the gain for AL disc.
“RW”: Fix to the gain for RW disc.
[EQ]:
Tracking servo setting changes whenever the but-
ton is pressed.
ton is pressed.
“ON”: Tracking servo ON.
“OFF”: Tracking servo OFF.
[FUNCTION]:
S character mode setting changes whenever the but-
ton is pressed.
ton is pressed.
“ ”: S character mode OFF.
“S”: S character mode ON.
5. To release from this mode, press the [
I/1
] button to turn the
power off.
HCD-EC68/EC78
18
SECTION 5
MECHANICAL ADJUSTMENTS
SECTION 6
ELECTRICAL ADJUSTMENTS
PRECAUTION
1. Clean the following parts with a denatured-alcohol-moistened
1. Clean the following parts with a denatured-alcohol-moistened
swab :
record/playback head
pinch roller
erase head
rubber belts
capstan
idlers
2. Demagnetize the record/playback head with a head demag-
netizer. (Do not bring the head magnetizer close to the erase
head.)
head.)
3. Do not use a magnetized screwdriver for the adjustments.
4. After the adjustments, appiy suitable locking compound to the
4. After the adjustments, appiy suitable locking compound to the
parts adjusted.
5. The adjustments should be performed with the rated power
supply voltage unless otherwise noted.
• Torque
Measurement
Mode
Torque Meter
Meter Reading
FWD
CQ-102AS
2.0 – 8.0 mN • m
(20 to 80 g • cm)
(0.28 – 1.12 oz • inch)
FWD
Back Tension
Back Tension
CQ-102C
0.15 – 0.6 mN • m
(1.5 to 6 g • cm)
(0.021 – 0.083 oz • inch)
FF
CQ-201AS
5 – 17.7 mN • m
(50 to 177 g • cm)
(0.7 – 2.48 oz • inch)
REV
CQ-201B
5 – 17.7 mN • m
(50 to 177 g • cm)
(0.7 – 2.48 oz • inch)
• Tape Tension Measurement
Mode
Tension Meter
Meter Reading
FWD
CQ-403A
more than 80 g
(more than 2.82 oz)
1. Demagnetize the record/playback head with a head demagne-
tizer.
2. Do not use a magnetized screwdriver for the adjustments.
TEST TAPE
Tape
Signal
Used for
P-4-A063
6.3 kHz, -10 dB
Azimuth Adjustment
RECORD/PLAYBACK HEAD AZIMUTH ADJUSTMENT
Note: Perform this adjustments for both decks.
Procedure:
1. Mode: Playback
1. Mode: Playback
set
JACK board
PHONES jack
(J492)
PHONES jack
(J492)
+
–
level meter
test tape
P-4-A063
(6.3 kHz,
P-4-A063
(6.3 kHz,
−10 dB)
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.
so that outputs match within 1dB of peak.
3. Mode: Playback
set
test tape
P-4-A063
(6.3 kHz,
−10 dB)
oscilloscope
V
H
waveform of oscilloscope
in phase 45
°
90
° 135° 180°
good
wrong
JACK board
PHONES jack
(J492)
PHONES jack
(J492)
4. After the adjustments, apply suitable locking compound to the
pats adjusted.
Screw
position
L-CH
peak
within
1dB
Output
level
L-CH
peak
R-CH
peak
within
1dB
Screw
position
R-CH
peak
DECK SECTION
(EXCEPT EC68: UK model)
0 dB = 0.775V
HCD-EC68/EC78
19
Adjustment Location: Record/Playback/Erase Head
CD SECTION
Note:
1. CD Block is basically constructed to operate without adjustment.
2. Use YEDS-18 disc (3-702-101-01) unless otherwise indicated.
3. Use an oscilloscope with more than 10 M
1. CD Block is basically constructed to operate without adjustment.
2. Use YEDS-18 disc (3-702-101-01) unless otherwise indicated.
3. Use an oscilloscope with more than 10 M
Ω impedance.
4. Clean the object lens by an applicator with neutral detergent when the
signal level is low than specifi ed value with the following checks.
5. Check the focus bias check when optical pick-up block is replaced.
FOCUS BIAS CHECK
+
–
–
CD board
oscilloscope
(DC range)
TP121 (RFI)
TP124 (VC)
Procedure :
1. Connect the oscilloscope to TP121 (RFI) and TP124 (VC) on
1. Connect the oscilloscope to TP121 (RFI) and TP124 (VC) on
the CD board.
2. Press the [I/
1
] button to turn the power ON, and press the [
Z
]
button to open the CD disc tray.
3. Set disc (YEDS-18) on the trey and press the [CD N] button
to playback.
4. Confi rm that oscilloscope waveform is as shown in the fi gure
below. (eye pattern)
A good eye pattern means that the diamond shape (
◊) in the
center of the waveform can be clearly distinguished.
VOLT/DIV: 200 mV
TIME/DIV: 500 ns
level:
1.2 ± 0.3 Vp-p
Checking Location:
TP124
(VC)
– CD Board (Conductor Side) –
TP121
(RFI)
IC101
HCD-EC68/EC78
20
[AM]
Setting:
FUNCTION: AM
Setting:
FUNCTION: AM
AM RF signal
generator
30% amplitude
modulation by
400 Hz signal
Output level: 54 dBuV
60 cm
set
loop antenna A loop antenna B
+
–
level meter
32
Ω
JACK board
PHONES jack (J492)
MAIN board
ANTENNA
CN801 pin
[FM]
Setting:
FUNCTION: FM
Setting:
FUNCTION: FM
FM RF signal
generator
75kHz frequency
deviation by 1K Hz
signal
Output level: as low as possible
(8dBuV)
+
–
level meter
set
32
Ω
0.01 F
JACK board
PHONES jack (J492)
MAIN board
ANTENNA
CN801 pin
MAIN board
ANTENNA
CN801 pin
digital voltmeter
100 k
Ω
MAIN board
IC801 pin XL (TUNER VT)
• Repeat the procedures in each adjustment several times.
TUNER SECTION
0 dB = 1
μV
AM FREQUENCY COVERAGE ADJUSTMENT
(EC68: Mexican, Argentina, Australian/
EC78: Mexican, Argentina models)
Adjustment Part
Frequency Display
Reading on Digital
Voltmeter
L801
530 kHz
1.5 ± 0.1 V
Confi rmation
1,710 kHz
8 ± 0.5 V
AM FREQUENCY COVERAGE ADJUSTMENT
(Except EC68: Mexican, Argentina, Australian/
EC78: Mexican, Argentina models)
Adjustment Part
Frequency Display
Reading on Digital
Voltmeter
L801
531 kHz
1.5 ± 0.1 V
Confi rmation
1,602 kHz
7.2 ± 0.5 V
AM TRACKING ADJUSTMENT
(Except EC68: Mexican, Argentina, Australian/
EC78: Mexican, Argentina models)
Adjust for a maximum reading on level meter
L805
530 kHz
AM TRACKING ADJUSTMENT
(EC68: Mexican, Argentina, Australian/
EC78: Mexican, Argentina models)
Adjust for a maximum reading on level meter
L805
531 kHz
FM FREQUENCY COVERAGE ADJUSTMENT
Adjustment Part
Frequency Display
Reading on Digital
Voltmeter
L803
87.5 kHz
1.75 ± 0.1 V
Confi rmation
108 kHz
6.2 ± 0.5 V
FM TRACKING ADJUSTMENT
Adjust for a minimum reading on level meter
L804
98 MHz
Adjustment Location: MAIN board (See page 21)
[FM DETECTOR ADJUSTMENT]
Setting:
Setting:
FUNCTION: FM
FM RF signal
generator
Carrier frequency: 98MHz
Modulation:
deviation by FM 75 kHz
Output level: 60 dBuV
+
–
level meter
MAIN board
JW801 (TUNER-GND)
MAIN board
IC801 pin RT
(TUNER OUT L-ch)
set
MAIN board
ANTENNA
CN801 pin
MAIN board
ANTENNA
CN801 pin
1. Turn the set to 98 MHz.
2. Adjust L802 so that modulation distortion may become the
2. Adjust L802 so that modulation distortion may become the
best in the vicinity of the maximum value where the tuner out
level becomes –15dBuV or more.
level becomes –15dBuV or more.
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