Technics SL-PS900 Service Manual

¢ 1C801 (MN6474): Digital filter & D/A converter
pea AVOOD1 a Power supply (connected to +4.8V)
| 23 | DVOD1 Pas Power supply (connected to +4.9V)
Ea Ovss1 aa GND terminal (digital system)
ee a
[ape | [eee
a ee Co
| 28 | DOvbDDd2 pi ae = Power supply (connected to + 4.9V)
| 20 | Ovss2 as 24 GND terminal (digital system)
Sub-strate terminal
(Not used, connected to +4.9V)
Zero input detector terminal
fae [eam [0 | ett ceren isnt
LR clock selector (Not used,
Ea LRPOL vit | connected to +4.9V)
Ea LRCLK cals 4 LR discrimination signal input
} 35 | BCLK fet Serial bit clock input
| 36 | SRDATA a Serial data input (MSB first)
Ce
ec
aC a Ce
[4 fre | — | TEST terminal
Pete J
eee
a [rere [ 1 [rete cea
a
a
re [avoor [1 [pone emacs a
Pe Tomer [2 [examen came
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a
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¢ 10103 (AN8377N): Traverse motor drive
v0 Fie)
Division Division
pt fieve fo | ee — Pree pe} me | oo | aver <4 i piu
river
pat aie a | Power supply terminal fo] e- | 0 | Inverting output of focus driver
TB External transistor base driving 11 To+ Non-inverting output of tracking
output driver
VMON Voltage output Tp- Inverting output of tracking
driver
psf ono fo | ore ae ae ag pa fnor | oo | aver seid " ahs
pe fom fo | Tracking error signal input fu] mo- foo | Inverting output of driver
Rees Focus error signal input ras | /RST fee | Reset signal output
a VREF Pe Reference voltage input pe] ro fot | PC input (connect to GND)
Power supply (connected to +4.9V)
i DIGITAL SERVO SYSTEM
The newly-developed digital servo system is adopted in the servo circuit of the unit’s CD player instead of the
ordinary analog servo system.
1. The diagrams shown below represent differences between the analog servo and digital servo systems. The HEAD AMP. output signals (i.e., foct
error and tracksing error output signals) are analog. These analog signals are converted to the 8-bit digital signals through the MN6650. The
MN6650 performs the following adjustments automatically; focus offset, tracking offset, focus gain, tracking gain, and tracking balance adjustme
The outputs from the MN6650 such as the focus coil driving signal, tracking coil driving signal, and traverse motor driving signal are converted to
analog signals again and sent to the coils and motor to perform proper servo control for a disc.
ANALOG SERVO SYSTEM
SYSYSgg
6
VRs
require
adjustment
r
: To EMF demodulation Digital audio
RF
signal
&
D/A
conv.
—————=_
playback
=
auePD
AN8374 (Analog processing) Pa
AN8373
pea
So
5
ae
7
?
Focus
coil
FOCUS SERVO
Focus error
output signal
TRACKING
SERVO
Tracking
error
TRAVERSE
Traverse coil
'
i
output signal | SERVO
os aes ae at a ah J
DIGITAL SERVO SYSTEM
S
Only 1 VR requires adjustment (best eye adjustment) Ph
, To EMF demodulation Digital audio
Gineignel & D/A conv. playback -
AN8800 MN6650 (Digital servo processor) o
: its Gen rads ST bare q
!
Focus error |
output signal | Tracking coil Y
|
1 | Soft |
|_| microprogram areal
- | | processing
Tracking
error!
|
Traverse
coil
output signal
baeioes 24
Microcomputer

Technics SL-PS900 Specifications

General

Brand	Technics
Model	SL-PS900
Category	CD Player
Language	English