Sony DVP-S7000 (serv.man2) Service Manual ▷ View online
– 98 –
5-2-4.
Tilt Control
Figure 5-13.
Tilt control
(1) Tilt servo by tilt sensor
At the start of DVD or CD playing, the tilt control is made using the tilt sensor of
optical pickup.
The optical pickup’s tilt sensor output signals (TT-701 Board CN001, $¡P SKEW IN
(TIA), $™P SKEW OUT (TIB) are entered to the tilt amplifier (@º, @¡P) of IC001
SSI33P3720.
The signals are integrated and amplified there, then output as a tilt error signal
(TIERR@§P).
The tilt error signal (TIERR) is entered to the switch IC, IC8922P (74HC4053) on the
MB-75 board, and used for servo ON/OFF control.
If the tilt error signal (TIE) level becomes lower than the specified value VC1 (+2.5V),
the window comparator output signal TILTIN (7P) of the IC777 (OP AMP µPC393)
becomes “H” level, and consequently the tilt error output (!∞P) of switch IC (IC892) is
switched to the IC892 “1” pin voltage level VC1 (+2.5V) ± 50mV.
Thus, the tilt servo is turned off.
The tilt error output signal (!∞P) of the switch IC passes through IC888 (OP AMP
NJM3404), then it is entered the tilt drive IC891 (BA6295AFP).
The IC891 amplifies voltage, transforms voltage, and amplifies current, then drives the
tilt motor (DC brush motor) with its output signals (TIMT+ 3P, TIMT– 2P).
IC888
NJM3404AM
IC136 Periphery
Drive
Control
IC770
CXD8599Q
RF
Process
AMP
To Tilt Motor
1
VC
(2.5V)
TIERR
IC777
µ
PC393G2
“H” when TIE is below
Vc (+2.5)
±
50mV
IC892
TC74HC4053
IC001
SSI33P3720
TT-701 BOARD
MB-75 BOARD
2
15
5
20
TIA
TIB
Tilt
AMP
Drive
21
10
TILTIN
26
6
13
DAXLD
CPCK
CPDTO
14
12
DAC
7
IC891
BA6295
26
3
TIMT+
TIMT–
2
72
70
CPDTI
SOEN
CPCK
59
IC722
MB88347
MB88347
TIE
23
7
Comparator
– 99 –
(2) Tilt servo to minimize a jitter
During DVD playing (except searching), the jitter value (JITTER: time axis variation
in RF signal output from optical pickup) is used as a tilt error signal.
The jitter value of RF signal is measured by IC770 (CXD8599Q), the signal lines for
serial data (CPDTI&ºP), enable (SOEN&™P), and clock (CPCK%ªP) are connected to
the drive control microcomputer IC136 (HD6413002F) and its peripheral circuits.
Serial data (CPDTI) of jitter value is entered to the IC136!¢P, and the IC136 outputs
the tilt control data CPDTO, clock CPCK, and load DAXLD signals to the IC722 (DA
converter: MB88347PFV).
The output signal for tilt servo (TI DRIVE6P) of the IC722 (DA converter) is entered
to the tilt drive IC, IC891 to drive the tilt motor.
Thus, the IC136 controls the tilt servo so that the jitter value becomes minimum.
– 100 –
5-3.
Servo Operation at CD and Video CD Playing
5-3-1.
Optical Pickup Control
(1) CD focus servo
Figure 5-14.
CD focus servo
Buffer
AMP
IC890
BA5970FP
Level
Shift
MB-75 BOARD
CN980
CDFCS–
To CD Pickup
Focus Coil
Focus Coil
AMP
IC002
CXA1791M
CD
Optical
Pickup
Pickup
TT-701 BOARD
OPTICAL
BLOCK
CDFCS+
3
4
IC768
TC74HC4053
IC717,
IC886, 892
DSP
Level Shift
SW
Same route as
DVD servo
3
5
28
29
28
14
14
29
CN001
CN005
CDFE
PD1
PD2
16
4
2
FE
14
13
20
9
CD/DVD
+5V
Q887
UN5113
SW
D886
MA111
MA111
Figure 5-15.
S waveform at CD disc (focus error),
IC717
@ª
P
– 101 –
The RF signals (PD1, PD2) output from the CD optical pickup are converted into focus
error signal (CDFE, !§P) in the IC002 (CD RF AMP CXA1791M) on the TT-701
board.
The CD focus error signal (CDFE) is entered to the switch IC, IC768 (74HC4053) on
the MB-75 board through a flexible flat cable. During CD playing, it is entered to @ªP
FE of IC717 (DSP: CXD2545Q) via switch IC (IC768). The focus error signal is adjusted
in gain and focus bias, and modulated in PWM in the DSP, in the same manner as in
DVD playing.
The focus drive signals (FFDR, 8P, FRDR, !ºP) output from the DSP IC are entered
to the focus drive IC (IC890 BA5970FP), same as in DVD playing. The IC890 is a 4-
channel driver IC, and it drives coils for each pickup by switching over the level of
MUTE pins (9, @ºP) to H or L between CD play and DVD play.
Play mode
MUTE signal
9P
@ºP
DVD
“H”
“L”
CD, Video CD
“L”
“H”
The IC890 amplifies voltage, transforms voltage, and amplifies current, then drives the
focus coil of CD pickup with its output signals (CD FCS+, CD FCS–).
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