Motorola 17K1BE, Руководство по обслуживанию

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1. C o n n e c t the h ig h s id e o f the s ig n a l g e n e r a t o r th ru a 1000
m m f c a p a c i t o r to the g r id (p in 1) o f the v id e o a m p li f i e r tu be
V - 7 , and the lo w s id e to c h a s s i s .
2. C o n n e c t the v o lt m e t e r and g e r m a n iu m c r y s t a l r e c t i f i e r ,
a s s h o w n in F ig u r e 5, b e t w e e n th e c a t h o d e o f the p i c t u r e
tube ( y e llo w le a d ) and c h a s s i s . U se the lo w e s t v o lt a g e s c a l e
on the m e t e r .
4. 5 MC T R A P A L IG N M E N T
to c h a s s i s . S et the c e n t e r f r e q u e n c y o f the s w e e p to a b o u t
24 . 6 m e and a d ju s t i n it ia lly f o r a s w e e p d e v ia t io n o f a p ­
p r o x i m a t e l y 12 m e . H o w e v e r , a s w e e p o f f r o m 8 to 10 m e
m a y b e fou n d b e t t e r f o r o v e r a l l a lig n m e n t .
4 . U sin g R - 2 6 (1 00K ) a s a d e c o u p lin g r e s i s t o r , c o n n e c t the
s c o p e to p in 4 o f t e s t s o c k e t and c h a s s i s . If a s t r o n g e r o u t ­
put is r e q u i r e d , c o n n e c t the s c o p e b e t w e e n the p ic t u r e tube
c a t h o d e and c h a s s i s . T h e c u r v e s e e n at t h is p o s it io n w i l l b e
the r e v e r s e o f th e p o l a r i t y sh o w n in F ig u r e 6.
3. W ith the s ig n a l g e n e r a t o r a c c u r a t e l y s e t at 4 . 5 m e and
m a x im u m ou tp u t, a d ju s t t r a p L .-1 8 f o r m in im u m r e a d in g on
the m e t e r .
IF A M P L I F I E R A L IG N M E N T
5. S et th e c o n t r a s t c o n t r o l at m in im u m .
N O T E : If a d is t o r t e d o r u n s t a b le p ic t u r e is s e e n on the o s ­
c i l l o s c o p e d u r in g a lig n m e n t , it m a y b e n e c e s s a r y to s t o p the
o s c i l l a t o r b y d is c o n n e c t in g r e s i s t o r R - 9 (1500) f r o m the
p la te (p in 6) o f the o s c i l l a t o r tube V - 2 B (1 2 A T 7 ), o r b y s u b ­
s titu tin g a n o th e r tu b e w ith p in 6 r e m o v e d .
E q u ip m e n t R e q u ir e d :
C A U T IO N :
IF S w e e p G e n e r a t o r m e e t in g the fo llo w in g r e q u ir e m e n t s :
18 to 30 m e , a p p r o x im a t e ly 12 m e s w e e p w id th . O u tput
c o n s t a n t and a d ju s t a b le to at l e a s t . 1 v o lt m a x im u m
w ith a c c u r a t e l y c a l i b r a t e d , a d ju s t a b le m a r k e r s .
C a th o d e R a y O s c i l l o s c o p e : p r e f e r a b l y on e w ith a c a l i ­
b r a t e d in p u t a t te n u a to r .
N O T E : If t h e r e is n o b u i l t - i n m a r k e r in the s w e e p g e n e r a ­
t o r , l o o s e l y c o u p le the output o f an a c c u r a t e l y c a l ib r a t e d
A M s ig n a l g e n e r a t o r to the IF s t r ip . A t a ll t i m e s , k e e p the
m a r k e r outp ut lo w en o u g h to p r e v e n t the m a r k e r f r o m d i s ­
t o r t in g the r e s p o n s e c u r v e .
A . D o not r e d u c e the o s c i l l o s c o p e g a in and i n c r e a s e s ig n a l
in p u t s o that the t o p o f the c u r v e is fla t t e n e d , due to l i m i t ­
in g in th e v i d e o o r s c o p e a m p l i f i e r s .
B . T h e d r e s s o f p la te & g r id c o m p o n e n t s in the IF a f f e c t s
tu n in g . D o n ot m o v e i n d i s c r im i n a t e l y .
C . On the IF c o i l s and on the t r a p s , the r e s o n a n c e p o in t
w i l l b e fo u n d at tw o s e t t in g s o f the s lu g . T h e c o r r e c t s e t tin g
is the on e w h ic h is fo u n d w ith the g r e a t e r p a r t o f the a d ju s t ­
in g s c r e w out o f the c o i l .
N O T E : T h e 1st & 2nd IF t r a p s a r e tuned f r o m b o t t o m o f
c h a s s i s w h ile IF c o r e s a r e a d ju s t e d f r o m the t o p .
If a w id e ba n d s c o p e is u s e d , the m a r k e r w ill b e m o r e
d is t in c t if a c a p a c i t o r o f 100 to 1000 m m f is p la c e d a c r o s s
the s c o p e in p u t. U se the s m a l l e s t s i z e p o s s i b l e , s in c e t o o
la r g e a v a lu e w i l l a f f e c t the sh a p e o f the c u r v e .
1. R e m o v e the h ig h v o lt a g e g e n e r a t o r tube V -1 7 (6 B Q 6 G T )
f r o m it s s o c k e t to e lim in a t e h o r iz o n t a l p i c k - u p in the o s c i l ­
l o s c o p e . R e p la c e 6B Q 6 w ith 2 5 00 oh m 25 w a tt r e s i s t o r c o n ­
n e c t e d f r o m B p lu s s id e o f fu s e to c h a s s i s .
2. B y m e a n s o f an e x t e r n a l b a t t e r y , a p p ly a n e g a tiv e 3. 0
v o lt b ia s f r o m the b o t t o m o f the 1st IF tube g r id c o i l d a m p ­
in g r e s i s t o r , R -1 3 , to c h a s s i s .
3. U sin g le a d s a s s h o r t as p o s s i b l e , c o n n e c t the h ot s id e o f
the s w e e p g e n e r a t o r to the g r id (p in 1) o f the 1st IF tu be V - 3
th r o u g h a 5000 m m f c a p a c i t o r (d o n ot u s e the l o o s e o r
" s p r a y i n g " m e th o d o f c o u p lin g ). T h e lo w s id e is c o n n e c t e d
6. T u n e the lo w f r e q u e n c y t r a p L -1 4 l o c a t e d on the 2nd IF
c o i l f o r m a x im u m a tte n u a tio n on the c u r v e at 2 1 .9 m e ,
DIAG. NO 63A7912 7 2 -0
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FIGURE 5. ELECTRONIC VOLTMETER CONNECTIONS
21.9
27.3
2 1 .9
27.3
FIGURE 6. IF RESPONSE CURVE FIGURE 7. OVERALL RESPONSE CURVE FROM MIXER
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Scanned by mbear2k - Jan 2012