Electrical Adjustments - Sony LBT-N600AV Service Manual

SECTION 3
ELECTRICAL ADJUSTMENTS
Note:
1, 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 10MQ 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 iS:
a
TP(RF) O«—0
o<—o-
vc
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+0.3 Vp-p
S Curve Check
oscilloscope
BD board OC
a"
TP(FEO) o«—-o
TP(VC)
O<—0-
Eas
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
3.841.1 Vp-p.
S-curve waveform
symmetry
within 3.8 + 1.1 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 Se
"—
TP(RF) o«—po¥
TP(VC) be.
(VC)
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.
RF signal waveform
\
Y
VOLT/DIV : 200mV
TIME/DIV :500nS
OAK
TR
AHI
AS
level : 1.3 + 0.3 Vp-p