28
1
2
3
4
1
2
3
4
C
D
F
A
B
E
PD-M427
10. Focus Servo Loop Gain Adjustment
9. Focus Best Adjustment
Oscilloscope
DC Mode
CH1: 5mV/div
CH2: 20mV/div
H: 200ns/div
Prove (10:1)
Player
START
TP1
(CN201)
RF
VC
MAX
GND
Prove (10:1)
FE
6
1
4
GND
Readjust if
adjustment
is incorrect.
Adjust the RF level to maximum, with
the focus error voltage within
±
150mV.
MOTHER BOARD ASSY
VR153
MOTHER BOARD ASSY
Test mode
SPDL servo
FOCUS servo
TRKG servo
=
=
=
CLOSE
CLOSE
CLOSE
TEST DISC
PLAY
Innermost
circumference
(1 TRK)
UNDER
Oscilloscope
X-Y Mode
X: 20mV/div
Y: 5mV/div
GND
Prove (10:1)
Player
START
TP1
(CN201)
FI
VC
UPPER
JUST
Low-frequency
oscillator
1.2kHz
1Vp-p
GND
GND
Prove (10:1)
56k
Ω
0.001
µ
F
Low pass filter 2
100k
Ω
FE
6
5
4
Lissajous Waveform
MOTHER BOARD ASSY
Test mode
SPDL servo
FOCUS servo
TRKG servo
=
=
=
CLOSE
CLOSE
CLOSE
TEST DISC
PLAY
Innermost
circumference
(1 TRK)
VR152
MOTHER BOARD ASSY
Check