Sony dvp-s530d User Manual
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Sled Motor Drive - PB
Initially during disc search, just System Control IC202 data was used to
move the sled motor. During playback, IC202 data and tracking error are
used to handle the sled movement. The choice is dependent upon the
location of disc information. When the disc is played linearly requiring
smooth sled travel, the tracking error signal is used to follow the track.
When information must be retrieved at a different part of the disc, System
Control IC202 instructs the sled to momentary move the laser assembly
to another location.
move the sled motor. During playback, IC202 data and tracking error are
used to handle the sled movement. The choice is dependent upon the
location of disc information. When the disc is played linearly requiring
smooth sled travel, the tracking error signal is used to follow the track.
When information must be retrieved at a different part of the disc, System
Control IC202 instructs the sled to momentary move the laser assembly
to another location.
Following the Track
When playing a CD, and most of the time when playing a DVD, the sled is
periodically pulsed or “kicked” ahead so the tracking coil can remain within
operating range of the new disc information. These sled kick pulses origi-
nate from the linear tracking error signal taken from Tracking Coil Driver
IC801/pin 6. This error signal is amplified internally and output IC801/pin
7.
periodically pulsed or “kicked” ahead so the tracking coil can remain within
operating range of the new disc information. These sled kick pulses origi-
nate from the linear tracking error signal taken from Tracking Coil Driver
IC801/pin 6. This error signal is amplified internally and output IC801/pin
7.
The amplified tracking error signal is LPF by R707 and C705 before en-
tering IC702/pin 3. With C706 positioned between IC702/pins 1 and 2 for
negative feedback, IC702 is configured as an active LPF. These two low
pass filters remove the instantaneous tracking error “noise” component.
What is left is a DC voltage that increases when the tracking servo ap-
proaches its mechanical limit.
tering IC702/pin 3. With C706 positioned between IC702/pins 1 and 2 for
negative feedback, IC702 is configured as an active LPF. These two low
pass filters remove the instantaneous tracking error “noise” component.
What is left is a DC voltage that increases when the tracking servo ap-
proaches its mechanical limit.
The DC component of the tracking error signal is passed onto Servo IC701/
pin 66. IC701 makes a judgment about the input voltage level. When a
DC threshold is reached, IC701 “kicks” or rotates the sled motor forward
(laser outward) one step. The movement of the sled motor returns the
laser assembly to the center range of the tracking servo. This causes the
tracking error’s DC voltage component to drop below the sled movement
threshold.
pin 66. IC701 makes a judgment about the input voltage level. When a
DC threshold is reached, IC701 “kicks” or rotates the sled motor forward
(laser outward) one step. The movement of the sled motor returns the
laser assembly to the center range of the tracking servo. This causes the
tracking error’s DC voltage component to drop below the sled movement
threshold.
Sled Movement to Another Location
Supplemental information can be found in different locations on the DVD
disc. When this information is called for, the sled is asked to move to
approximately that location. The disc information is played to determine
how close the laser is to the target. IC202 then decides to make a smaller
jump or remain where it is.
disc. When this information is called for, the sled is asked to move to
approximately that location. The disc information is played to determine
how close the laser is to the target. IC202 then decides to make a smaller
jump or remain where it is.
This sled movement is controlled by System Control IC202 after receiving
disc information from ARP2 IC303. IC202 communicates with IC701 on
the parallel bus in order to have IC701 move the sled. Once the sled is
moved, System Control IC202 waits for disc information (from Processor
IC303) to determine if the laser is close enough to the target information
before requesting another sled movement. If no sled movement is called
for, the laser plays through the supplemental information. Afterwards
IC202 instructs the laser to return to where it originated to resume normal
playback.
disc information from ARP2 IC303. IC202 communicates with IC701 on
the parallel bus in order to have IC701 move the sled. Once the sled is
moved, System Control IC202 waits for disc information (from Processor
IC303) to determine if the laser is close enough to the target information
before requesting another sled movement. If no sled movement is called
for, the laser plays through the supplemental information. Afterwards
IC202 instructs the laser to return to where it originated to resume normal
playback.
IC Summary Chart
ICs involved in Sled Movement
Disc Identification
DVD Playback
CD Playback
IC202
IC001 (TK51 Bd)
IC001 (TK51 Bd)
IC601
IC303
IC701
IC701
IC202
IC702
IC802
IC601
IC801
IC701
IC802
IC702
IC801
IC802