Electrical Adjustments - Sony DVP-NW50 Service Manual

DVP-NW50
DVD SECTION
AUTO SERVO ADJUSTMENT
After parts related to the servo circuit (RF amplifier , servo control
(U2), motor driver (U4), EEPROM (U6) so on) are replaced, re-
adjusting the servo circuit is necessary.
1. RFOP Level /RF Waveform Check
[TEST DISC]
Use the following test disc on test mode.
TDV-520CSO (DVD-V SL) : Part No. J-2501-236-A
PATD-012 (CD) : Part No. 4-225-203-01
TCD-W082L (CD-RW) : Part No. J-2502-063-2
TDV-540C (DVD DL) : Part No. J-2501-235-A
Connection:
DVD SERVO board
TP18 (RFOP)
GND
Procedure:
1. Connect an oscilloscope to TP18 (RFOP) and GND on the
DVD SERVO board.
2. Turn the power on.
3. Set the test disc on the tray and press H button to playback
the number two track.
4. Confirm that oscilloscope waveform is clear and check RFAC
signal level is correct or not.
Note: A clear RFAC signal waveform means that the shape "◊" can be
clearly distinguished at the center of the waveform.
RFAC signal waveform
5. Procedure 4 is repeatedly confirmed from procedure 1 with
each TEST DISC.
Note: TEST DISC (TDV-540CSO), playback the number thirty two track,
too.
20
SECTION 5
ELECTRICAL ADJSTMENTS
oscilloscope
+
–
VOLT/DIV: 200 mV
TIME/DIV: 500 ns
level: 0.9 ± 0.25 Vp-p
2. Iop (CD) Check
[TEST DISC]
PATD-012(CD) :Part No. 4-225-203-01
Connection:
DVD SERVO board
R38
Procedure:
1. Connect an digital voltmeter across R38 (10 Ω) on the DVD
SERVO board.
2. Turn the power on.
3. Put the test disc (PATD-012) into playback the number two
track.
4. Measure the voltage across R38 (10 Ω) on the DVD SERVO
board.
5. Confirm the Iop value is less than 75 mA.
Iop value (mA) = The voltage across R38 (10 Ω)/10 Ω
3. Iop (DVD) Check
[TEST DISC]
TDV-520SCO (DVD) :Part No. J-2501-236-A
Connection:
DVD SERVO board
R37
Procedure:
1. Take note of the Iop value that is printed in the bottom of the
label on the rear of the optical pick up.
IDP200A
1154181
D519C674
[D***C***] The last three digits after the character "D"
indicates the Iop value.
2. Connect an digital voltmeter across R37 (10 Ω) on the DVD
SERVO board
3. Turn the power on.
4. Put the test disc (TDV-520SCO) into playback the number
two track.
5. Measure the voltage across R37 (10 Ω) on the DVD SERVO
board.
6. Confirm that the measured value is within specified range of
± 4 mA.
Iop value (mA) = The voltage across R37 (10 Ω)/10 Ω
digital voltmeter
+
–
digital voltmeter digital voltmeter
+
–
51.9 mA