NEC -FA150ATUA Service Manual page 4

1. Audio circuit (Circuit diagrams Main PWB) KT
2. Power supply (Circuit daigrams MAIN PWB)
7 . 1 7 . 1 S t a r t S t a r t : When power is turned on, Q801 conducts due to bias from C805 and R803. Q801 supplies a 17 volt : When power is turned on, Q801 conducts due to bias from C805 and R803. Q801 supplies a 17 volt
7 . 1 S t a r t : When power is turned on, Q801 conducts due to bias from C805 and R803. Q801 supplies a 17 volt
7 . 1 7 . 1 S t a r t S t a r t : When power is turned on, Q801 conducts due to bias from C805 and R803. Q801 supplies a 17 volt : When power is turned on, Q801 conducts due to bias from C805 and R803. Q801 supplies a 17 volt
a n d a s t a r t i n g c u r r e n t a b o u t 0 . 3 m A t o p i n 7 o f I 8 0 1 . I 8 0 1 s t a r t s t o o s c i l l a t e ( R 8 1 6 , C 8 1 3 ) a n d o u t p u t s a p u l s e a n d a s t a r t i n g c u r r e n t a b o u t 0 . 3 m A t o p i n 7 o f I 8 0 1 . I 8 0 1 s t a r t s t o o s c i l l a t e ( R 8 1 6 , C 8 1 3 ) a n d o u t p u t s a p u l s e
a n d a s t a r t i n g c u r r e n t a b o u t 0 . 3 m A t o p i n 7 o f I 8 0 1 . I 8 0 1 s t a r t s t o o s c i l l a t e ( R 8 1 6 , C 8 1 3 ) a n d o u t p u t s a p u l s e
a n d a s t a r t i n g c u r r e n t a b o u t 0 . 3 m A t o p i n 7 o f I 8 0 1 . I 8 0 1 s t a r t s t o o s c i l l a t e ( R 8 1 6 , C 8 1 3 ) a n d o u t p u t s a p u l s e a n d a s t a r t i n g c u r r e n t a b o u t 0 . 3 m A t o p i n 7 o f I 8 0 1 . I 8 0 1 s t a r t s t o o s c i l l a t e ( R 8 1 6 , C 8 1 3 ) a n d o u t p u t s a p u l s e
t r a i n t h r o u g h p i n 6 t o d r i v e Q 8 0 3 . t r a i n t h r o u g h p i n 6 t o d r i v e Q 8 0 3 .
t r a i n t h r o u g h p i n 6 t o d r i v e Q 8 0 3 . t r a i n t h r o u g h p i n 6 t o d r i v e Q 8 0 3 . t r a i n t h r o u g h p i n 6 t o d r i v e Q 8 0 3 .
7 . 2 7 . 2 OPP OPP : W h en Q803 turns on, C805 supplie s a li n ea rl y in cr ea si ng t ri an gl e cu rr en t th ro ug h th e pr im ar y in d uc - : W hen Q803 turns on, C805 supplie s a li ne ar ly i nc re as i ng tr i an gl e cu rr en t th ro ug h th e pr im ar y in du c-
7 . 2 7 . 2 7 . 2 OPP OPP OPP : W h en Q803 turns on, C805 supplie s a li ne ar ly i nc re as in g tr ia ng le c ur re nt t hr ou gh t he p ri ma ry i nd uc -
: W h en Q803 turns on, C805 supplie s a li n ea rl y in cr ea si ng t ri an gl e cu rr en t th ro ug h th e pr im ar y in d uc - : W hen Q803 turns on, C805 supplie s a li ne ar ly i nc re as i ng tr i an gl e cu rr en t th ro ug h th e pr im ar y in du c-
t a n c e o f T 8 0 2 t o t h e d r i v e r Q 8 0 3 , o n c e t h e p e a k v a l u e o f t h i s c u r r e n t m u l t i p l i e d b y R 8 1 t a n c e o f T 8 0 2 t o t h e d r i v e r Q 8 0 3 , o n c e t h e p e a k v a l u e o f t h i s c u r r e n t m u l t i p l i e d b y R 8 1
t a n c e o f T 8 0 2 t o t h e d r i v e r Q 8 0 3 , o n c e t h e p e a k v a l u e o f t h i s c u r r e n t m u l t i p l i e d b y R 8 1
t a n c e o f T 8 0 2 t o t h e d r i v e r Q 8 0 3 , o n c e t h e p e a k v a l u e o f t h i s c u r r e n t m u l t i p l i e d b y R 8 1 t a n c e o f T 8 0 2 t o t h e d r i v e r Q 8 0 3 , o n c e t h e p e a k v a l u e o f t h i s c u r r e n t m u l t i p l i e d b y R 8 1
train will be shut down immediately to protect Q803, T802 from being burned out. train will be shut down immediately to protect Q803, T802 from being burned out.
train will be shut down immediately to protect Q803, T802 from being burned out.
train will be shut down immediately to protect Q803, T802 from being burned out. train will be shut down immediately to protect Q803, T802 from being burned out.
7 . 3 7 . 3 Regulation Regulation
7 . 3 Regulation : I f o u t p u t v o l t a g e + 5 V g o e s u p , t h e R t e r m i n a l o f I 8 0 3 g e t s m o r e b i a s , a c c o r d i n g l y p h o t o t r a n s i s - : I f o u t p u t v o l t a g e + 5 V g o e s u p , t h e R t e r m i n a l o f I 8 0 3 g e t s m o r e b i a s , a c c o r d i n g l y p h o t o t r a n s i s -
7 . 3 7 . 3 Regulation Regulation : I f o u t p u t v o l t a g e + 5 V g o e s u p , t h e R t e r m i n a l o f I 8 0 3 g e t s m o r e b i a s , a c c o r d i n g l y p h o t o t r a n s i s -
: I f o u t p u t v o l t a g e + 5 V g o e s u p , t h e R t e r m i n a l o f I 8 0 3 g e t s m o r e b i a s , a c c o r d i n g l y p h o t o t r a n s i s - : I f o u t p u t v o l t a g e + 5 V g o e s u p , t h e R t e r m i n a l o f I 8 0 3 g e t s m o r e b i a s , a c c o r d i n g l y p h o t o t r a n s i s -
t o r a n d p h o t o d i o d e f l o w s m o r e c u r r e n t . T h e v o l t a g e o f p i n 2 g o e s u p t o o , m a k i n g t h e p u l s e w i d t h o f p i n 6 t o t o r a n d p h o t o d i o d e f l o w s m o r e c u r r e n t . T h e v o l t a g e o f p i n 2 g o e s u p t o o , m a k i n g t h e p u l s e w i d t h o f p i n 6 t o
t o r a n d p h o t o d i o d e f l o w s m o r e c u r r e n t . T h e v o l t a g e o f p i n 2 g o e s u p t o o , m a k i n g t h e p u l s e w i d t h o f p i n 6 t o
t o r a n d p h o t o d i o d e f l o w s m o r e c u r r e n t . T h e v o l t a g e o f p i n 2 g o e s u p t o o , m a k i n g t h e p u l s e w i d t h o f p i n 6 t o t o r a n d p h o t o d i o d e f l o w s m o r e c u r r e n t . T h e v o l t a g e o f p i n 2 g o e s u p t o o , m a k i n g t h e p u l s e w i d t h o f p i n 6 t o
become narrower. So the output voltage +5V will be pulled down to a stable value. become narrower. So the output voltage +5V will be pulled down to a stable value.
become narrower. So the output voltage +5V will be pulled down to a stable value.
become narrower. So the output voltage +5V will be pulled down to a stable value. become narrower. So the output voltage +5V will be pulled down to a stable value.
Circuit Description
NEC-FA150ATUA
1 e x c e e d s 1 v o l t , p u l s e 1 e x c e e d s 1 v o l t , p u l s e
1 e x c e e d s 1 v o l t , p u l s e
1 e x c e e d s 1 v o l t , p u l s e 1 e x c e e d s 1 v o l t , p u l s e