The Pressure Pad; The Automatic End Of Switch; The Revolution Counter; Assembling The Top Cover - TANDBERG 12 Service Manual

4.IO THE PRESSURE PAD
The pressure pad (59.27) is located in front of the
e r a s e h e a d a n d i s i n t r o d u c e d t o s e c u r e m a x i m u m
erasure, and to ensure constant friciion for the tape,
w h e n t h e r e c o r d e r i s o p e r a t i n g i n n o r m a l f o r w a r d
d r i v e . R e f . f i g . 1 1 a n d 3 5 . T h e p r e s s u r e p a d a r m
(59.2) is activated by the pressure wheel lever (5 1.5)
and the transfer bracket (59.24). The pressure pad
(59.27) is pressing against the tape and the erase head
i n n o r m a l f o r w a r d d r i v e , a n d i s c o m p l e t e l y d i s e n g a g e d
i n a l l o i h e r p o s i t i o n s o f t h e o p e r a t i n g l e v e r ( 5 4 ' 1 ) .
Adiustments
The pressure pad (59.27) should be cleaned occa-
s i o n a l l y , a s t h e a c c u m u l a t i o n o f d u s t a n d i r o n o x i d e
p a r t i c l e s m i g h t s e r i o u s l y a f f e c t t h e e r a s u r e a n d t h e
tape movement.
N o t e : D o n o t s o a k t h e f e l t p a d w i t h a n y l i q u i d .
T h e s p r i n g w i t h f e l t f o r t h e p r e s s u r e p a d ( 5 9 . 1 ) i s d e -
s i g n e d a s a s n a p - o n t y p e , a n d c a n e a s i l y b e p u l l e d o u t
b y b e n d i n g t h e t w o t a g s o n t h e h a r d b r a s s s p r i n g a w a y
from the slots in the pressure pad arm (59.2).
The tension of the pressure pad (59.27) against the
e r a s e h e a d , i n n o r m a l f o r w a r d d r i v e p o s i t i o n , s h o u l d
be 75-100 g (25/e-3Vz oz). This tension is corrected
b y a d i u s t i n g t h e t e n s i o n o f t h e s p r i n g ( 5 9 . 1 4 ) f o r t h e
p r e s s u r e p a d .
4.I I THE AUTOMATIC END STOP SWITCH
The actuating spring (79.17) for the end stop switch
i s l o c a t e d i n t h e s l o t o f t h e r i g h t i a p e g u i d e ( 7 9 . 1 4 ) '
T h e m i c r o s w i t c h ( 3 3 . 2 ) i s m o u n l e d u n d e r t h e u p p e r
m o u n t i n g p l a t e ( 7 1 . 2 ) r e f . f i g . 9 a n d 1 1 .
The microswitch (33.2) shuts off the motor when the
t a p e r u n s o u t o r i f t h e t a p e b r e a k s . T h e s w i l c h w o r k s
i n d e p e n d e n t u p o n t h e p o s i t i o n o f t h e o p e r a t i n g l e v e r
(54. r ).
Adiustments
The operating point of lhe microswitch (33.2) is adiust-
ed by bending the actuating spring (79.17) in point A.
Ref. fig. 36. The operaling point is set 0.5 mm (.02")
in f ront of the imaginary line x-x, when the actuating
spring (79.17) is moved from the rest position lowards
the front of the upper mounting plate (71.2).
T h e a c t u a t i n g s p r i n g s h a l l r u n f r e e i n s i d e t h e t a p e
g u i d e s l o t w i t h o u t s t i c k i n g . T h e w i d i h o f t h e s l o t i s
a d i u s t e d t o 2 m m ( . 0 8 " ) b y b e n d i n g t h e b r a c k e t i n
p o i n t B . R e f . f i g . 3 6 .
T h e v e r t i c a l p o s i t i o n o f t h e a c t u a t i n g s p r i n g ( 7 9 . 1 7 ) i s
a d l u s t e d a s s h o w n i n f i g . 3 7 . T h e v e r t i c a l p a r t o f t h e
s p r i n g s h o u l d c o v e r a p p r o x . 3 m m ( ' / u " ) o f t h e t a p e .
Misalignments could cause the tape to be squeezed
o u t o f t h e t a p e g u i d e .
Ascertain sufficient clearance between the upper part
of the actuating spring marked D and the front trim
c o v e r ( 7 3 . 1 ) w h e n t a p e i s i n s e r t e d .
/ D
,
rc
F i g , 3 7 . V e r t i c o l o d i u s f m e n t o f r h e e n d s t o P s w i t c h '
4.12 THE REVOTUTION COUNIER
The revoluiion counter (79.23) is located between the
u p p e r a n d t h e l o w e r m o u n t i n g p l a t e s ( 7 1 . 2 , 7 1 . 1 ) , b e -
h i n d t h e o p e r a t i n g l e v e r ( 5 4 . 1 ) . T h e c o u n t e r ( 7 9 . 2 3 ) i s
d r i v e n b y a r u b b e r b e l t ( 6 9 . 3 ) a n d a p u l l e y d i s c ( 6 9 . 1 )
a t t a c h e d t o t h e s h a f t o f t h e t a k e - u p t u r n t a b l e ( 6 5 . 1 ) .
R e f . f i g . 9 a n d 5 3 .
Adiustmenls
T h e p u l l e y d i s c f o r t h e r e v o l u t i o n c o u n t e r ( 6 9 . 2 ) i s
m o u n t e d f l u s h w i t h t h e c o u n t e r s h a f t . T h e p u l l e y d i s c
( 6 9 . . | ) i s m o u n t e d t i g h t u p a g a i n s t t h e l o c k s p r i n g
( 7 9 . 8 ) f o r t h e t a k e - u p t u r n t a b l e . M i s a l i g n m e n t o f t h e
v e r t i c a l p o s i t i o n o f t h e p u l l i e s m i g h t c a u s e t h e r u b b e r
belt (69.3) to fall off.
4.13 ASSEMBTING THE TOP COVER
The top cover is attached to the recorder as shown in
f i g . 3 8 .
Vertical alignment of the lop cover
Two thick rubber washers (74.5) have been introduced
between the top cover and the mounting brackets. By
t i g h t e n i n g l h e t w o s c r e w s ( M . l 3 0 ) s l i g h t l y , t h e r u b b e r
will be compressed and allow the necessary vertical
a d l u s t m e n t o f t h e t o p c o v e r . R e f . f i g . 3 8 .
The vertical position of the top cover should be adiust-
ed to ascertain sufficient spacing between the plastic
tape reels and the fop cover in all modes of operation.
f
z z
F i g . 3 6 . H o r i z o n i o l o d i u s t m e n t o f t h e e n d s t o p s w i t c h .