Sony DVP-S7000 (serv.man2) Service Manual ▷ View online
– 94 –
Figure 5-8.
Trv (TE at tracking servo
OFF) waveform at DVD
disc, IC717
@¶
P
Figure 5-9.
TE (enlarged Trv) waveform
at DVD disc, IC717
@¶
P
Figure 5-10.
1TJ (track jump) waveform
at DVD disc, IC717
@¶
P
– 95 –
5-2-2.
Sled Control
Figure 5-11.
DVD sled control
HYCNTR
To Sled Motor
3
IC892
TC74HC4053
IC890
BA5970FP
5
24
TFDR
TRDR 23
4
22
9
CD/DVD
1
IC983
TC74HC4053
IC717
CXD2545Q
DSP
SFDR
SRDR
HA+
HA–
HB+
HB–
100
2
3
2
15
10
SLDE
SLD MODE
SLDE output to !∞P
when SLD MODE is “H"
28
IC888
NJM3404AM
MIX AMP
IC889
LA6527N
Sled Drive
From IC501,502
on LM-51 Board
on LM-51 Board
Feedback control by
Hall element
SLDMT+
SLDMT–
1
12
8
25
34 33 30 29
2
5
DAXLD
CPCK
CPDT0
IC722
MB88347
From periphery of
IC136 Drive Control
SDCNTR
12 13 14
3
2
2
(1) Sled control during playing
During disc playing, namely, when the focus servo and tracking servo are turned on,
the sled servo controls the sled motor so that an objective lens of optical pickup positions
always in the center of movable range of tracking actuator.
As for the sled error signal of sled servo, the signal of @™P (differentially amplified
TFDR and TRDR) of tracking drive IC (IC890: BA5970FP) is entered to the switch IC
(IC892, 74HC4053), where a switching is made for the input signal from the CD tracking
drive.
The sled error signal (SLDE) output from the switch IC IC892, 4P passes through the
switch IC (IC983: 74HC4053), then it is entered to the IC717 (DSP CXD2545Q) @•P
(SE).
– 96 –
The DSP IC provides the following controls in the sled servo system.
(a) Sled error amplification
The sled error signal is amplified by LPF (Low Pass Filter) comprising a digital
filter, and amplifier.
(b) Sled servo ON/OFF
At normal playing, the sled servo is turned on, and the sled servo is turned off
while the tracking servo is turned off at the start of play or during searching.
The sled error signal is output from SDP as sled drive signals (SFDR, !‚‚ P, SRDR, 2P)
after PWM modulation in the IC717 (DSP).
The SFDR and SRDR signals are differentially amplified in the IC888 (OP AMP
NJM3404), then entered to the DVI (!™P) of sled drive IC (IC889: LA6527N).
The sled drive IC contains the motor speed feedback controller that utilizes Hall elements.
Two Hall elements (HA, HB) are used for speed detection, and the sled motor board
outputs differential signal between (HA+, HA–) and (HB+, HB–) as a detection output.
The sled drive IC provides the speed feedback by detecting the tilt of Hall element
output waveform (differential value in the vicinity of zero-cross) when a sled motor is
running.
The sled drive IC converts a sled error signal into sled motor speed signal, then it
amplifies voltage and current and drives the sled (DC) motor with output signals
(SLDMT+, SLDMT–).
(2) Sled motor forced drive control
To drive the sled motor except for playing, that is, to execute direct searching operation,
the sled control signal is entered from 3P SDCNTR of IC722 (DA converter:
MB88347PFV) to the sled motor driver IC889 (LA6527N) 8P. Serial data to the IC722
(DA converter) are sent from the microcomputer IC136.
SDINIT7P of IC722 (DA converter) is an offset adjusting signal of IC889, and it is
used for adjustment so that the voltage applied between motor terminals becomes zero
when the sled motor stops.
– 97 –
5-2-3.
Spindle Control
This section describes the control signal flow in the spindle servo during DVD playing. The
IC770 (CXD8599Q) converts RF signal output from optical pickup into binary-valued RF
DATA signal (IC770, !™P), and supplies it to the the data processor IC (IC181: CXD8663Q).
The IC181 generates two servo error signals for disc rotation speed servo (AFC) and rotation
phase servo (APC) using the frame sync signal (PFCK) generated from the RF DATA signal.
The spindle control signal (DMO%¢P) is output after addition of these error signals and
PWM modulation.
The DMO signal is amplified in the IC982, then it is selected for the spindle control signal
(MDP) for CD playing in the switch IC (IC983: 74HC4053).
The spindle error output signal SPERR of the switch IC (IC983, 4P) is entered to the
spindle drive IC (IC887: LB1896).
The IC887 is a 3-phase brushless motor drive IC, and it contains a spindle error signal
amplifying circuit, gain switching circuit, and motor forced acceleration and deceleration
control circuit.
Gain switching is done with the SPGC1 signal (!¡P).
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 control is
executed.
Control mode
Input signals
SPCTRL0 (9P)
SPCTRL1 (8P)
Acceleration
H
L
Deceleration
H
H
No control
L
H
Figure 5-12.
DVD spindle control
V OUT
W OUT
To Spindle Motor
33
IC181
CXD8663Q
DATA Process
AFC
APC
PWM
IC770
CXD8599Q
RF Process
RFDATA
RFCLOCK
26
54
3
IC983
TC74HC4053
IC887
LB1896
MODE
Select
Matrix
SW
SPERR
SPGCI
SPCTRL0
SPCTRL1
5
3
DMO
4
9
CD/DVD
H:
L:
L:
12cm
8cm
8cm
Gain switching
IC982
NJM3404
AMP
From IC136
Drive Control
MB-75BOARD
U OUT
12
13
1
13
11
9
8
22
23
19
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