INTERNAL TRIM ERASE
accuracy.
COMPACT SIZE
ACTIVITY INDICATOR
DIRECT DRIVE, BRUSHLESS D. C.
MOTOR
INDUSTRY STANDARD INTERFACE
CO MPATI B ILITY
DISKETTE LEVER LOCK SOLENO ID
The reduced size of the drive occupies only
o ne-half t h e m o u n t i n g s p ace r e qu i red f o r a
conventional drive.
T he spi n dl e m o t o r i s a cr y s t a l c o n t r o l l e d ,
direct drive, brushless D. C. motor for
improved m o tor start time, and speed
The drive provides the control signals neces-
sary for
proper trim erasure of
data.
T he drive is compati ble w it h c o n t r o l l ers t h a t
use an industry standard interface.
An activity indicator, located on the front
p anel, is aut om at i call y i l l u m i n a ted when t h e
d rive i s s e lected. T hi s f r on t p a n e l L . E .D . i s
also used as an indicator in the diagnostic
mode.
n ormal o p er a t i on . E ac h d r i v e c o n sists o f a
direct drive, spindle system, a head positioning
system, and a
read/write system.
T he T M 8 4 8-1E i s a s i n g l e -sided d r i v e . T h e
T M848-2E i s a d o u b l e-sided dr i ve . Th e o n l y
difference b e t w een
t h e t w o d ri v e s i s t h e
number of heads.
The circuit
board is
identical
for both models.
When th e d i s k ett e l e ver i s o p ened, access is
p rovided for t h e i n s er t ion o f a d i s k e t t e . T h e
diskette's j a c ket i s a c c u r at el y p o s i t i oned by
plastic gu ide r a i ls. It s l o cation i s ensured by
the back stop and disk
ejector.
C losing t h e di s k e t t e l e v e r ac t i v a t e s t h e
c one/clamp s y s t em , r e s u l t i n g in acc u r a t e
c entering and clamping of th e di sk ette to t h e
d rive hub. Th e d r iv e hu b i s d r i v e n a t a c o n -
s tant
s p e e d o f 360 RPM by a cry st a l -
controlled, direct dr i ve, brushless D. C. motor.
The h ea d i s l o a d e d i n t o c o n t a c t w i t h t h e
r ecording m e d i u m wh e n e ve r t he di s k e t t e
lever is latched.
The heads are positioned over the desired
track by m e ans of a stepper motor/band
assembly an d i t s a ssociated electronics. This
positioner uses a
3.6
degree rotation to
cause a
one track linear movement.
W hen a w r i t e - protected di sk ett e i s i n s e r t ed
i nto th e d r i v e , th e W r i t e P r o t ect sensor di s-
ables the write electronics of
the drive, and a
Write Protect status output signal is available
t o th e i n t e r f a ce. W he n p e r f o r m i n g a w r i t e
o peration, a 0 . 0 1 3-inch w i d e , n o m i n al , d a t a
t rack i s r e c orded. Then, t hi s t r a c k i s t u n n e l
erased to 0.012-inch, nominal.
Data recovery electronics in clude a l o w -level
r ead a m p l i f i e r , f i l t e r , d i f f e r e n t i a t or , z e r o
crossover detector, and dig i t i z in g c i r c u i ts. No
data-clock separation is
provided.
I n additi on, the dr ive is supplied wit h th e f ol -
lowing sensor systems:
The diskette l ever l ock solenoid is contr oll ed
by the host system.
1.4 F U NCTIONAL DESCRIPTION
1 . A
T r a c k 0 s e n s o r d e t e ct s w h e n t h e
Head/Carriage Assembly is positioned
over Track 0.
2. Th e T M 8 4 8 -2E has tw o i n dex sensors,
e ach consisting o f a n i n f r a r e d L . E . D .
The drives are fully self-contained, and
r equir e
n o ope r a t o r i n t e r v e n t i o n d u r i n g
1-2
