Tandy 1000 SL Technical Reference Manual page 282

which i n c l u d e s s p i n d l e .
The
DD
motor i s a n o u t o r - r o t o r t y p e DC b r u s h l e s s motor which h a s t h e
l o n g l i f e o f
30,000
h o u r s o r more i n c o n t i n u o u s r o t a t i o n . R o t a t i o n a l
speed i s 300rpm f o r
B
and
F
models o r 360rpm f o r
G
model.
I t
1s
m a i n t a i n e d a t a s t a b l e c o n d i t i o n a g a i n s t l o a d v a r i a t i o n s and e n v i r o n -
mental changes by a feedback s i g n a l from
AC
tachometer i n t h e r o t o r .
The c o l l e t and t h e s p i n d l e a r e combined p r e c i s e l y t o m a i n t a i n t h e
c e n t e r p o s i t i o n c o r r e c t l y w i t h o u t damaging t h e c e n t e r h o l e of a d i s k
and so a s t o make t h e head be i n c o n t a c t w i t h t h e d i s k a t a c o r r e c t
p o s i t i o n .
(4) Magnetic head and c a r r i a g e
E r a s e g a p s
-Rotational d i r e c t i o n
o f d i s k
E r a s e c o r e s
Read/write c o r e
Read/write gap
(Fig.202) E x t e r n a l view o f magnetic head c o r e
The magnetic head assembly (head c a r r i a g e A s s ' y ) o f t h i s
FDD
h a s two
heads.
One i s f o r s i d e 1 s u r f a c e o f t h e d i s k and t h e o t h e r f o r s i d e 0
s u r f a c e of t h e d i s k (down s u r f a c e when t h e
FDD
i s s i t u a t e d h o r i z o n t a l l y ) .
Both o f t h e s i d e 0 and s i d e 1 heads a r e s u p p o r t e d by s p e c i a l l y d e s i g n e d
f l e x u r e . The two magnetic heads a r e mounted a c c r o s s t h e d i s k on one
head c a r r i a g e , and t h e i r s u r f a c e s a r e d e s i g n e d f o r minimum d i s k
wear
and
maximum r e a d o u t p u t .
The head i t s e l f i s a long l i f e t y p e f o r improved
head wear.
The c o r e o f t h e head i s c o n s t r u c t e d w i t h r e a d / w r i t e gap which i s used
f o r d a t a w r i t e and d a t a r e a d o p e r a t i o n s and two e r a s e gaps which a r e
used t o e r a s e t h e edges o f t h e r e c o r d e d t r a c k immediately a f t e r t h e
r e c o r d i n g ( t u n n e l erase).
The head c a r r i a g e Ass'y forms t h e
most
-
203
-