Read Sony HCD-M70 Service Manual online
HCD-M70
13
IC103
TP (RF)
TP (VC)
CD SECTION
Note:
1. CD Block is basically constructed to operate without adjust-
ment.
2. Use YEDS-18 disc (3-702-101-01) unless otherwise indicated.
3. Use an oscilloscope with more than 10 M
3. Use an oscilloscope with more than 10 M
1 impedance.
4. Clean the object lens by an applicator with neutral detergent
when the signal level is low than specified value with the fol-
lowing checks.
lowing checks.
5. Check the focus bias check when optical block is replaced.
Focus Bias Check
Procedure :
1. Connect oscilloscope to TP (RF) and TP (VC) on the CD board.
2. Press the
1. Connect oscilloscope to TP (RF) and TP (VC) on the CD board.
2. Press the
I/
1
button to turn the power on, and press
the
Z
CD
button to open the CD disc tray.
3. Put disc (YEDS-18) in and press the
CD
N
button to play-
back.
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.
A good eye pattern means that the diamond shape ( ) in the
center of the waveform can be clearly distinguished.
Checking Location:
– CD BOARD (Conductor Side) –
+
–
–
BD board
TP (RF)
TP (VC)
TP (VC)
oscilloscope
(DC range)
VOLT/DIV: 200 mV
TIME/DIV: 500 ns
TIME/DIV: 500 ns
level:
1.1
1.1
±
0.2 Vp-p
s
Note:
Confirm each contents of this section first of all. If the results are
not satisfied, do the adjustment.
not satisfied, do the adjustment.
1. The adjustments should be performed with the rated power sup-
ply voltage unless otherwise noted.
2. The adjustments should be performed in the order given in this
service manual.
3. The adjustments should be performed for both L-CH and R-
CH.
REC Bias Adjustment
Procedure:
1. Mode: REC
1. Mode: REC
FUNCTION: VIDEO
2. Mode: Playback
3. Confirm playback the signal recorded in step 1 become speci-
fied values as follows.
If these values are out of specification values, adjust the RV101
(L-CH) and RV201 (R-CH) on the TC board to repeat steps
1and 2.
If these values are out of specification values, adjust the RV101
(L-CH) and RV201 (R-CH) on the TC board to repeat steps
1and 2.
Specified values: Playback output of 315 Hz to playback
output of 10 kHz:
± 0.5 dB
Adjustment Location: TC board
attenuator
set
MAIN board
AUDIO IN (MD/VIDEO) jack (SJ302)
L-CH, R-CH
AUDIO IN (MD/VIDEO) jack (SJ302)
L-CH, R-CH
1) 315 Hz
2) 10 kHz
2) 10 kHz
50 mV (– 23.8 dB)
¬
®
600
1
blank tape
CN-123
CN-123
AF OSC
+
–
–
set
recorded
portion
portion
MAIN board
SPEAKER terminals (SJ301)
L-CH, R-CH
SPEAKER terminals (SJ301)
L-CH, R-CH
level meter
SECTION 5
ELECTRICAL ADJUSTMENTS
0 dB=0.775 V
DECK SECTION
RV101 (L)
RV201 (R)
¬
«
«
«
«
®
REC Bias
Adjustment
Adjustment
– TC BOARD (Component Side) –
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