20
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:
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.
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.
SECTION 5
ELECTRICAL ADJSTMENTS
+
–
TP18 (RFOP)
GND
oscilloscope
DVD SERVO board
RFAC signal waveform
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:
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:
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.
[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
R38
DVD SERVO board
+
–
digital voltmeter
R37
+
–
digital voltmeter
DVD SERVO board
51.9 mA
IDP200A
1154181
D519C674
