Sony DVP-S7000 (serv.man2) Service Manual ▷ View online
– 102 –
(2) CD tracking servo
Figure 5-16.
CD tracking servo
Figure 5-17.
Trv (TE at tracking servo
OFF) waveform at CD disc,
IC717
@¶
P
Figure 5-18.
TE (enlarged Trv) waveform
at CD disc, IC717
@¶
P
CDTRK+
To CD Pickup
Tracking Coil
Tracking Coil
CDTRK–
TE
TFDR
TRDR
7
27
20
IC002
CXA1791M
TT-701 BOARD
CDE
CDTE
From
Optical Block
Optical Block
CDF
14
AMP
6
1
IC768
TC74HC4053
IC717
CXD2545Q
DSP
IC890
Tracking
Drive
MB-75 BOARD
15
2
27
4
6
4
6
11
12
Figure 5-19.
1TJ (track jump) waveform
at CD disc, IC717
@¶
P
– 103 –
The CDE and CDF signals output from the CD optical pickup are converted into CD
tracking error signal (CDTE!¢P) in the IC002 (CXA1791M) on the TT-701 board.
The CDTE signal is entered to the switch IC (IC768, 74HC4053) on the MB-75 board.
During CD playing, it is entered to the @¶P TE of IC717 (DSP CXD2545Q) via the
switch IC (IC768).
The tracking error signal is adjusted in gain and modulated in PWM, same as in DVD
playing.
The DSP tracking drive signals (TFDR4P, TRDR6P) are amplified in voltage,
transformed in voltage, and amplified in current by the tracking drive IC (IC890
BA5970FP) to drive the tracking coil of CD pickup.
The track jump control including CD search operation is made by the IC717 (DSP
CXD2545Q), same as in DVD searching.
Thus, if one track jump or N track jump (jump of many tracks) is executed, the IC717
generates tracking pulses, detects tracking zero-cross timing, controls tracking brake,
and measures the number of tracks jumped.
– 104 –
Figure 5-20.
CD sled control
5-3-2.
Sled Control
In the sled control during CD playing, a difference from sled control in DVD playing is that
the sled error signal detection is done with the tracking error signal (TERR).
The tracking error signal (TERR) is entered from the switch IC (IC983) 2P and output
from !∞P as a sled error signal (SLERR).
The sled error signal (SLERR) is entered to the IC717 (DSP: CXD2545Q) @•P (SE).
The sled control by DSP IC, and various controls including searching by sled drive IC are
made in the same manner as that for DVD.
MB-75 BOARD
SRDR
28
IC717
CXD2545Q
IC983
TC74HC4053
27
1
SLERR
15
2
10
SLD MODE
SE
TE
TERR
100
2
SFDR
Hence,
Same as DVD
Same as DVD
– 105 –
Figure 5-21.
CD spindle control
5-3-3.
Spindle Control
SPERR
Hence,
same as DVD
same as DVD
IC983
TC74HC4053
AMP
IC982
NJM3404
MB-75 BOARD
CN980
AMP
IC002
CXA1791M
IC717
CXD2545Q
TT-701 BOARD
3
PD1
PD2 4
12
12
CN005
CDRF
17
EFM
Frame
Sync
Protect
CLV
Process
DSP
36
96
5
MDP
7
5
3
4
This section describes the control signal flow in the spindle servo during CD playing. The
disc information read signals PD1 and PD2 (TT-701 board CN001: @• and @ªP) output
from CD optical pickup are converted into CDRF signal !¶P in the IC002 (CXA1791M) on
the TT-701 board.
The CDRF signal is output from CN005!™P on the TT-701 board, and entered to the DSPIC
(IC717: CXD2545Q) #§P from CN980!™P on the MB-75 board.
In the DSP IC, the spindle control signal is output as MDP ((§P) through EFM frame sync
protect and digital CLV control circuits.
The spindle control signal (MDP) passes through IC982 (OP AMP NJM3404), and it is
converted into ternary-valued signal in the center of +2.5V, then it is selected to the DVD
playing spindle control signal (DMO) in the switch IC (IC983: 74HC4053).
The spindle error signal SPERR output from the switch IC (IC983, 4P) is entered to the
spindle drive IC (IC887: LB1896).
The spindle drive IC (IC887) executes spindle motor control in the same manner as that for
DVD playing.
Gain switching to 12cm or 8cm disc is done with SPGC1 signal (!¡P), same as DVD.
Disc size (CD/DVD)
SPGC1 level
12 cm
H
8 cm
L
At the start and stop of disc playing, the forced acceleration and deceleration (pulse width)
control is executed, same as DVD.
Control mode
SPCTRL0 (9P)
SPCTRL1 (8P)
Acceleration
H
L
Deceleration
H
H
No control
L
H
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