Sony HCD-EC68P Service Manual - Page 22

Hcd-ec68p/ec78p, Electrical, Adjustments

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HCD-EC68P/EC78P SECTION 5 ELECTRICAL ADJUSTMENTS 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 MΩ impedance. 4. Clean the object lens by an applicator with neutral detergent when the signal level is low than specified value with the following checks. 5. Check the focus bias check when optical pick-up block is replaced. FOCUS BIAS CHECK CD board TP121 (RFI) TP124 (VC) oscilloscope (DC range) + - Procedure : 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. Confirm that oscilloscope waveform is as shown in the figure 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 TUNER SECTION 0 dB = 1 μV [AM] Setting: FUNCTION: AM 60 cm loop antenna A loop antenna B AM RF signal generator level meter 30% amplitude modulation by 400 Hz signal Output level: 54 dBuV 32 Ω set + - MAIN board ANTENNA JACK board PHONES jack (J492) CN801 pin  [FM] Setting: FUNCTION: FM FM RF signal generator 0.01 F MAIN board ANTENNA level meter CN801 pin  32 Ω set + - 75kHz frequency deviation by 1K Hz signal MAIN board ANTENNA CN801 pin  Output level: as low as possible (8dBuV) JACK board PHONES jack (J492) level: 1.2 ± 0.3 Vp-p digital voltmeter MAIN board 100 k Ω IC801 pin XL (TUNER VT) Checking Location: - CD Board (Conductor Side) - • Repeat the procedures in each adjustment several times. TP124 (VC) TP121 (RFI) IC101 22

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HCD-EC68P/EC78P
22
SECTION
5
ELECTRICAL
ADJUSTMENTS
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
Ω
impedance.
4.
Clean the object lens by an applicator with neutral detergent when the
signal level is low than speci
fi
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
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. Con
fi
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
[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
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
(TUNER VT)
•
Repeat the procedures in each adjustment several times.
TUNER
SECTION
0 dB = 1
μ
V