DP-1100B II
1. CIRCUIT DESCRIPTION
1 - 2 - 7 T r a y motor driver
3-state o u t p u t s i t u a t i o n in pin 9 of I C 1 5 is used f o r d r i v i n g t h e
tray m o t o r . T h e signal at " H " is i n v e r s i o n - a m p l i f i e d in IC3
( 1 / 2 ) t o drive Q 1 6 t o m a k e pin 3 of C N 4 n e g a t i v e so t h a t t h e
tray m o t o r r o t a t e s in t h e d i r e c t i o n in w h i c h t h e tray is c l o s e d .
C o n v e r s e l y , t h e signal at " L " is also i n v e r s i o n - a m p l i f i e d in
IC3 ( 1 / 2 ) t o t u r n O N Q 1 5 so t h a t t h e t r a y m o t o r rotates in t h e
d i r e c t i o n in w h i c h t h e t r a y is o p e n e d .
In a d d i t i o n , w h e n pin 9 of I C 1 5 is o p e n e d , pin 2 of IC3 is at
zero v o l t a g e so t h a t t h e t r a y m o t o r s t o p s since no v o l t a g e is
a p p l i e d .
1 - 2 - 8 T r a c k i n g error d e t e c t o r control
(This c i r c u i t is e f f e c t i v e o n l y at kick o p e r a t i o n . )
Both I C 1 2 ( 2 / 2 ) a n d I C 1 3 ( 1 / 2 ) o u t p u t " H " signals in nor
m a l o p e r a t i o n . T h e r e u p o n , w h e n t h e t r a c k i n g error v o l t a g e at
pin TE o u t p u t g o e s u p m o r e t h a n a b o u t + 0 . 6 V , pin 2 of
I C 1 2 ( 2 / 2 ) b e c o m e s " L " a n d t h i s v o l t a g e is a p p l i e d t o TEG 1
i n p u t of I C 1 5 . See " 1 " in t h e table b e l o w .
State
T E Voltage
TEG1
T E G 2
1
> + 0 . 6
L
H
2
< - 0 . 6
H
L
Table-1
C o n v e r s e l y , w h e n t h e t r a c k i n g e r r o r v o l t a g e at TE o u t p u t g o e s
d o w n less t h a n - 0 . 6 V , pin 2 of I C 1 2 ( 2 / 2 ) b e c o m e s " H "
a n d pin 2 of I C 1 3 ( 1 / 2 ) " L " so t h a t this v o l t a g e is a p p l i e d t o
TEG 2 i n p u t o f I C 1 5 . See " 2 " in t h e t a b l e a b o v e . T h e s e a r c h
t i m e is s h o r t e n e d by t h i s c o n t r o l c i r c u i t . N o r m a l l y , in play
m o d e , this v o l t a g e is o f f s e t by signal TEP, t h e r e f o r e i n p u t s
TEG 1 a n d TEG 2 are i n v a l i d .
1 - 2 - 9 P e a k hold circuit
T h e peak h o l d c i r c u i t c o n s i s t s of Q 2 3 t o Q 2 6 , D 2 8 t o D 3 5 ,
I C 1 4 ( 1 / 2 ) , e t c . W h e n KGC b e c o m e s " H " o n kick s t a t e , Q 2 3
a n d Q 2 4 t u r n O N , a n d Q 2 5 a n d
:
Q 2 6 t u r n OFF. T h e r e b y , C 7 0
is c h a r g e d w i t h t h e positive peak v o l t a g e at t r a c k i n g error i n
p u t TE a n d C 6 9 is c h a r g e d w i t h t h e n e g a t i v e peak v o l t a g e .
D u r i n g k i c k , C 6 9 a n d C 7 0 are c o n t i n u o u s l y c h a r g e d w i t h
t h e s e peak v o l t a g e s . W h e n t h e u n i t r e t u r n s t o n o r m a l play
f r o m t h e kick s t a t e , Q 2 3 a n d Q 2 4 t u r n OFF a n d Q 2 5 a n d
Q 2 6 t u r n O N . T h e n , t h e a v e r a g e v a l u e o f t h e v o l t a g e s at C 7 0
a n d C 6 9 is i n p u t t o I C 1 4 ( 1 / 2 ) . H e r e , it is s u b j e c t t o s u b t r a c
t i o n w i t h t h e v a l u e of v o l t a g e T E , so t h a t t h e u n i t is restored t o
n o r m a l play f r o m t h e kick s t a t e .
1 - 2 - 1 0 T E noise limiter
T h i s noise limiter consists of I C 1 4 ( 2 / 2 ) a n d Q 2 7 t o Q 3 0 .
Q 2 9 is t h e limiter O N / O F F s w i t c h . W h e n signal TEP is " L "
( d u r i n g k i c k ) , no limiter o p e r a t i o n is possible. N o r m a l l y , Q 2 9
is OFF d u r i n g play.
T h e t r a c k i n g e r r o r (TE) v o l t a g e is a m p l i f i e d t o a b o u t 6 t i m e s in
I C 1 4 ( 2 / 2 ) a n d is a p p l i e d t o t h e bases of Q 2 7 a n d Q 2 8
t h r o u g h a n HPF c o n s i s t i n g of C 7 3 a n d o t h e r s . W h e n t h e
v o l t a g e g o e s u p m o r e t h a n a b o u t + 0 . 6 V , Q 2 7 t u r n s O N ,
w h i l e w h e n it g o e s d o w n less t h a n a b o u t — 0 . 6 V , Q 2 8 t u r n s
O N . D u r i n g t h a t O N p e r i o d , t h e peak noise of t h e v o l t a g e is
s u p p r e s s e d so t h a t t h e f o l l o w i n g stage gets free f r o m t h e
d i s t u r b a n c e c a u s e d by this noise. T h e r e b y , t h e p i c k u p is
p r e v e n t e d f r o m j u m p i n g off t h e c o r r e c t t r a c k t o a n o t h e r o n e
d u e t o n o i s e .
1-2-11 D i s c f l a w position m e m o r y circuit ( S e e F i g . 1 - 2 A . )
Signal RFES p r o d u c e d in I C 1 0 ( 2 / 2 ) b e c o m e s " H " w h e n t h e
RF signal level is d i s c r e a s e d by f l a w s or d u s t o n t h e disc. T h i s
signal at " L " is o u t p u t as signal DIN f r o m t h e d r o p o u t c o n t r o l
b l o c k in IC15 t o t h e disc f l a w p o s i t i o n m e m o r y c i r c u i t in
w h i c h positional data of f l a w is s t o r e d . A t t h e s a m e t i m e , t h i s
signal is also o u t p u t as signal D C O N w h i c h is t h e t r a c k i n g ser
v o gain r e d u c t i o n g a t e pulse. D r o p o u t c o n t r o l is t h u s m a d e .
Pin DIN of IC15 o u t p u t s a signal i n d i c a t i n g t h e RFES state at
t h e rising e d g e of signal DOCK. It also c h e c k s t h e o u t p u t of
t h e disc f l a w p o s i t i o n m e m o r y c i r c u i t (pin 8 of IC7) at t h e fall
ing e d g e of signal DOCK a n d t h e n o u t p u t s signal D C O N (pin
1 2 of I C 1 5 ) t o t r a c k i n g servo a m p c i r c u i t .
1 - 2 - 1 2 Relationship b e t w e e n s e r v o a n d control line
For play, t h e a c t u a t o r of t h e p i c k u p is m o v e d u p or d o w n by
t h e 2 Hz signal f r o m F.SRCH (pin 2 of C N 2 ) . A t this t i m e ,
w h e n t h e disc is in r o t a t i o n , t h e RF signal is o u t p u t f r o m t h e
p i c k u p o n l y at t h e m o m e n t t h e laser b e a m is f o c u s e d . W i t h
t h e RF s i g n a l , I C 1 0 ( 1 / 2 ) o u t p u t s an " L " signal (RFOK) to
t u r n O N Q 3 1 . Further, this signal is i n v e r t e d at IC16 a n d FOK
b e c o m e s — 1 2 V . Q 2 a n d Q 6 is t u r n e d off by " L " FOK s i g n a l ,
" H " LDC signal is i n v e r t e d t o " L " t o t u r n Q 4 off, so t h a t t h e
f o c u s s e r v o starts o p e r a t i o n . T h u s , a c o n t i n u o u s RF signal a p
pears at pins 6 a n d 7 of C N 6 f r o m t h e p i c k u p . T h e r e b y , pin
1 4 (FOKG) of IC15 o u t p u t s an " H " s i g n a l . T h i s signal is i n
v e r t e d at I C 1 6 . T h e v o l t a g e at pin 11 of IC15 b e c o m e s - 1 2
V . T h e r e f o r e , Q 1 2 t u r n s OFF so t h a t IC2 ( 2 / 2 ) c a n p e r f o r m
a m p l i f i c a t i o n . In a d d i t i o n , D C O N is " L " as l o n g as t h e level of
t h e RF signal d o e s n o t d r o p s u d d e n l y d u e t o f l a w s or dirt o n
t h e disc. A s t h e KGC line is at - 1 2 V in n o r m a l play ( e x c e p t
f o r t h e kick s t a t e ) , Q 7 , Q 8 , Q 9 a n d Q 1 2 are all OFF. T h u s ,
t h e t r a c k i n g servo w o r k s so t h a t t h e p i c k u p t r a c e s t h e pit se
q u e n c e o n t h e d i s c . T h e data o n t h e disc c a n t h e r e b y be read
o u t c o n t i n u o u s l y .
36
Summary of Contents for DP-1100 B
Page 3: ...D P 1 1 0 0 B II D P 1 1 0 0 B II I BLOCK DIAGRAM ...
Page 32: ...D P 1 1 0 0 B II 1 CIRCUIT DESCRIPTION Disc Scratch Dust RFES D C O N D O C K Fig 1 2A 3 5 ...
Page 112: ...2 IC OPERATION OF EACH CIRCUIT AND D P 1 1 0 0 B II PIN DESCRIPTION Fig 2 4 1 G 1 ...
Page 117: ...DP 1100B II I OPERATION OF MAIN MICROPROCESSOR Fig 3 1D Q data reading flow chart ...