NEC -FA150ATUA Service Manual page 5

7 . 4 7 . 4 OVP OVP : If +5V goes up too much, the induced voltage on pin 4 of T802 becomes lar : If +5V goes up too much, the induced voltage on pin 4 of T802 becomes lar
7 . 4 OVP : If +5V goes up too much, the induced voltage on pin 4 of T802 becomes lar
7 . 4 7 . 4 OVP OVP : If +5V goes up too much, the induced voltage on pin 4 of T802 becomes lar : If +5V goes up too much, the induced voltage on pin 4 of T802 becomes lar
o v e r 2 2 v o l t s , Z D 8 0 3 c o n d u c t s , Q 8 0 6 i s t r i g g e r e d o n , p i n 1 o f I 8 0 1 i s p u l l e d d o w n t o g r o u n d , t h e p u l s e t r a i n o v e r 2 2 v o l t s , Z D 8 0 3 c o n d u c t s , Q 8 0 6 i s t r i g g e r e d o n , p i n 1 o f I 8 0 1 i s p u l l e d d o w n t o g r o u n d , t h e p u l s e t r a i n
o v e r 2 2 v o l t s , Z D 8 0 3 c o n d u c t s , Q 8 0 6 i s t r i g g e r e d o n , p i n 1 o f I 8 0 1 i s p u l l e d d o w n t o g r o u n d , t h e p u l s e t r a i n
o v e r 2 2 v o l t s , Z D 8 0 3 c o n d u c t s , Q 8 0 6 i s t r i g g e r e d o n , p i n 1 o f I 8 0 1 i s p u l l e d d o w n t o g r o u n d , t h e p u l s e t r a i n o v e r 2 2 v o l t s , Z D 8 0 3 c o n d u c t s , Q 8 0 6 i s t r i g g e r e d o n , p i n 1 o f I 8 0 1 i s p u l l e d d o w n t o g r o u n d , t h e p u l s e t r a i n
a t p i n 6 g o e s down to zero , shutting Q803 o f a t p i n 6 g o e s do wn to zero, shuttin g Q803 o f
a t p i n 6 g o e s down to zero, shutting Q8 03 o f
a t p i n 6 g o e s down to zero , shutting Q803 o f a t p i n 6 g o e s do wn to zero, shuttin g Q803 o f
7 . 5 7 . 5 SCP SCP
7 . 5 SCP : I f o u t p u t t e r m i n a l i s s h o r t t o g r o u n d , p h o t o t r a n s i s t o r d o e s n o t c o n d u c t , h e n c e Q 8 0 5 d o e s n o t c o n d u c t : I f o u t p u t t e r m i n a l i s s h o r t t o g r o u n d , p h o t o t r a n s i s t o r d o e s n o t c o n d u c t , h e n c e Q 8 0 5 d o e s n o t c o n d u c t
7 . 5 7 . 5 SCP SCP : I f o u t p u t t e r m i n a l i s s h o r t t o g r o u n d , p h o t o t r a n s i s t o r d o e s n o t c o n d u c t , h e n c e Q 8 0 5 d o e s n o t c o n d u c t : I f o u t p u t t e r m i n a l i s s h o r t t o g r o u n d , p h o t o t r a n s i s t o r d o e s n o t c o n d u c t , h e n c e Q 8 0 5 d o e s n o t c o n d u c t : I f o u t p u t t e r m i n a l i s s h o r t t o g r o u n d , p h o t o t r a n s i s t o r d o e s n o t c o n d u c t , h e n c e Q 8 0 5 d o e s n o t c o n d u c t
n e i t h e r n e i t h e r . T h e r e f e r e n c e v o l t a g e + 5 V a t p i n 8 b e g i n s t o c h a r . T h e r e f e r e n c e v o l t a g e + 5 V a t p i n 8 b e g i n s t o c h a r
n e i t h e r . T h e r e f e r e n c e v o l t a g e + 5 V a t p i n 8 b e g i n s t o c h a r
n e i t h e r n e i t h e r . T h e r e f e r e n c e v o l t a g e + 5 V a t p i n 8 b e g i n s t o c h a r . T h e r e f e r e n c e v o l t a g e + 5 V a t p i n 8 b e g i n s t o c h a r
pin 1 down to ground, shutting Q803 of pin 1 down to ground, shutting Q803 of
pin 1 down to ground, shutting Q803 of
pin 1 down to ground, shutting Q803 of pin 1 down to ground, shutting Q803 of
3. On-screen circuit (Circuit diagrams Main PWB 3/6)
f completely f completely
f completely
f completely f completely
f completely f completely
f completely
f completely f completely
LCD 1550M Power Board Block Diagram
. . . .
.
ge on C829 and activates Q806 to conduct, pulling ge on C829 and activates Q806 to conduct, pulling
ge on C829 and activates Q806 to conduct, pulling
ge on C829 and activates Q806 to conduct, pulling ge on C829 and activates Q806 to conduct, pulling
. . . .
.
NEC-FA150ATUA
g e a l s o . S u p p o s e t h a t i t i s g e a l s o . S u p p o s e t h a t i t i s
g e a l s o . S u p p o s e t h a t i t i s
g e a l s o . S u p p o s e t h a t i t i s g e a l s o . S u p p o s e t h a t i t i s
Circuit Description