The Speaker Selector Switch; Monaural Recording On Ch. 1 Or Ch. 2 - TANDBERG 12 Service Manual

5.2.2 lhe speaker selector switch
The fig. 52 shows the speaker selector switch in play-
b a c k p o s i t i o n . T h e s w i t c h h a s f i v e p o s i t i o n s .
E X T : E x t e r n a l s p e a k e r s o n l y . C h . I : l e f t s p e a k e r ,
ch. 2: right speaker.
E X T * I N T : E x t e r n a l a n d i n t e r n a l s p e a k e r s . C h . I :
l e f t s p e a k e r s , c h . 2 . r i g h t s p e a k e r s .
I N T : f n f e r n a l s p e a k e r s o n l y . C h . l : l e f t s p e a k e r , c h . 2 ,
r i g h t s p e a k e r .
C H l , E X T , C H 2 , I N T : T h e o u i p u t f r o m c h . I i s c o n -
nected to both external speakers. The output from
c h . 2 i s c o n n e c t e d t o b o t h i n t e r n a l s p e a k e r s .
C H 2 , E X T , C H l , I N T : T h e o u t p u t f r o m c h . 2 i s c o n -
nected to both gxternal speakers. The output from
c h . I i s c o n n e c t e d t o b o t h i n t e r n a l s p e a k e r s .
Nole:
T h e r e s i s t o r s R 2 1 0 -
8 2 o h m s ( c h . l ) a n d R 2 l I -
8 2 o h m s ( c h . 2 ) a r e c o n n e c t e d i n s e r i e s w i t h t h e o u t -
p u t o f t h e p o w e r a m p l i f i e r s , w h e n t h e f u n c t i o n s e l e c -
f o r s w i t c h i s i n R E C O R D p o s i t i o n . T h e p r o g r a m m e t h a f
is being recorded will be monitored with a reduced
o u t p u t t h r o u g h t h e i n t e r n a l s p e a k e r o r e x t e r n a l
s p e a k e r t e r m i n a l s , d e p e n d i n g o n t h e p o s i t i o n o f t h e
s p e a k e r s e l e c t o r s w i t c h . R 2 l 0 a n d R 2 l I a r e s h o r t -
circuited by the mode switches, Nl-2-3 and Nll-2-3
when fhe funciion selecfor switches are moved to
P L A Y B A C K o r A M P p o s i t i o n .
F R O M
P O W E R O U T P U T
A M P L i F i E R
c H . l
R 3tz
8 2
N I P O S i T i O N S
R 210
d t
I = K t
L
2 = P L A Y B
3 = A M P
R 1 6
3 2
3 , 9
5 w
L E F T
C HANN EL
F
?
S P E A K E R
c H l
:
C E N T E R
C H A N N E L
S P E A K E R C H 2
:
R I G H T
C H A N N E L
R 1 7
, 5
Z = 4 n
=
N I I P 0 5 l T l O N S : ' l = f t g g
2 = P L A Y B
3 = A M P
R 2 1 1
8 2
(
5.2.3 Monaural recording on ch. I or ch.2
R e f . b l o c k d i a g r a m f i g . 3 9 .
W e p r e s u m e t h a i w e a r e r e c o r d i n g o n c h . I ( u p p e r
t r a c k ) . T h e i n p u t s i g n a l i s f e d t o t h e m i c r o p h o n e i a c k
c h . l . T h e f u n c t i o n s e l e c t o r s w i t c h c h . I i s i n p o s .
R E C O R D a n d t h e f u n c t i o n s e l e c t o r s w i t c h c h . 2 i s i n
position AMP. The speaker selector is set to pos. lNT.
The signal passes through the record pre-amplifier
c h . I a n d v i a t h e v o l u m e c o n t r o l o f t h e r e c o r d e q u a l i z -
ing amplifier via the record current potenfiomeier to
the record head. The record level indicator and the
erase head ch. I are both activated.
T h e r e s i s t o r R 2 l O ( B 2 o h m s ) i s c o n n e c t e d i n s e r i e s
with the internal speaker ch. I and the recording sig-
n a l w i l l b e m o n i t o r e d w i t h a r e d u c e d o u t p u t t h r u q h
t h i s s p e a k e r .
T h e i n p u t o f t h e e q u a l i z i n g a m p l i f i e r c h . 2 i s c o n -
nected to the output from the record pre-amplifier
c h . l . T h e p o w e r o u t p u t a m p l i f i e r c h . 2 i s c o n n e c t e d
t o t h e i n t e r n a l s p e a k e r c h . 2 . C h . 2 i s o p e r a t e d a s a n
a m p l i f i e r c o n t r o l l e d b y t h e v o l u m e c o n t r o l c h . 2 .
The procedure for monaural recording on ch. 2 is
exactly the same as explained above except that ihe
function selector switch ch. i is sef to AMp position
and the function selector switch ch. 2 is set to posi-
t i o n R E C O R D .
32
(
R 4 1 7
8 2
o--.-
F R O M
P O W E R O U T p U T - .
A M p L i F i iR
Fig. 52. The speoker selecfor switch, schemotic.
c H . 2
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N I I ,
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N O 6 3 1 8 - 3
1 2 1
S P E A X E R
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