Sony HCD-D170 - Page 13

CD SECTION
Note :
1. CD Block is basically designed to operate without
adjustment. Therefore, check each item in order given.
2. Use YEDS-18 disc (3-702-101-01) unless otherwise
indicated.
3. Use an oscilloscope with more than 1OMQ 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. Adjust the focus bias adjustment when optical block is
_ replaced.
Focus Bias Adjustment
oscilloscope
(DC range)
BD board
_—_—
TP(RF) O<— 0}
VC O«—0o-
Procedure:
1. Connect oscilloscope to test point TP (RF). (GND terminal
: VC)
2. Turned Power switch on.
3. Put disc (YEDS-18) in and playback.
4. Adjust RV101 so that the waveform is clear.
(Clear RF signal waveform means that the shape “()” can
be clearly distinguished at the center of the waveform.)
5. After adjustment, check the RF signal level.
¢ RF signal
VOLT/DIV : 200 mV
TIME/DIV_ : 500 nS
level
1.3 40.3 Vp-p
S Curve Check
oscilloscope
BD board &
amen
TP(FE) O«——oF
TP(VC) o«—lo-
Procedure :
1. Connect oscilloscope to test point TP (FEO).
2. Connect between test point TP (FOK) and GND by lead
wire.
3. Turn Power switch on.
4. Put disc (YEDS-18) in and turned Power switch on again
and actuate the focus search. (actuate the focus search when
disc table is moving in and out.)
5. Check the oscilloscope waveform (S-curve) is symmetrical
between A and B. And confirm peak to peak level within
3.8+1.1 Vp-p.
S-curve waveform
symmetry.
within 2.4 + 0.7 Vp-p
°6. After check, remove the lead wire connected in step 2. .
Note : « Try to measure several times to make sure than the
ratio of A: B or B: A is more than 10: 7.
* Take sweep time as long as possible and light up the.
brightness to obtain best waveform.
RF Level Check
oscilloscope
BD board
mum
TP(RF) O«—oF
TP(VC) o«—to-
Procedure : ,
1. Connect oscilloscope to test point TP (RF) on BD board.
2. Turned Power switch on.
3. Put disc (YEDS-18) in and playback.
4. Confirm that oscilloscope waveform is clear and check RF
signal level is correct or not.
Note :
Clear RF signal waveform means that the shape “()” can be
clearly distinguished at the center of the waveform.
VOLT/DIV : 200mV
TIME/DIV : 500nS
RF
signal
waveform
AX
RET
YXY
XXX]
(XXV
XX)
level:
1.3
+
0.3
Vp-p
OX AXKAAAK ANAK)
OX AAA)
Vi
DANNY
NUNN
S43