light source and a phototransistor, posi-
t ioned t o g e n er at e a s i g n a l w h e n a n
index hole on the diskette is
detected.
T he driv e ca n d e t e r m in e i f a s i n g l e -
sided
o r dou b l e - s i de d d i s k e t t e i s
installed. This output si gnal is present
at the interface.
O pening a n d c l o s in g t h e d i s k e t t e l e v e r i s
required to r epeat a t est t h a t h a s f a i l ed. The
diskette lever must be left open to complete
an error cycle.
1.5 P H YSICAL DESCRIPTION
3 . A
W r i t e P r o t ec t s e n sor d i s ables t h e
write electronics when a w r i t e - enable
tab is
removed from the diskette.
POWER ON SELF- TESTS
A representative drive is shown in F i g ur e 1-1.
The drive can be mounted in a vertical or hori -
zontal plane. However, the
logic circuit board
m ust be on the uppermost side when the driv e
i s mounted horizontall y .
The drive conducts a
power on self-test
as part
o f the normal p ower on sequence. Two of t h e
tests do not require a d i sk ett e t o be inserted.
These tests
are: the head carriage stepping in,
away from, Track 0, and the head carriage
stepping out toward Tr ack 0. Fail ure of either
of these tests is i n d i cated on th e f r on t p a n el
L.E.D. by the following flashing sequence:
3 flashes, then 2:
F a i l s t o s t e p i n f r o m
Track
0 or Tr a c k 0
s ensor is a l w ay s e q u al
to zero.
The spindle is
rotated by a direct drive,
brush-
less D. C. motor w it h a n i n t e g ral t a chometer.
T he c r y s t a l - c on t r o l l e d s e r v o c i r c u i t an d
tachometer control the speed of the spindle.
O perator a ccess for d i s k e tt e l o a d in g i s p r o -
vided via a horizontal
slot
located at the front
of the drive.
3 flashes, then 3:
F a i l s t o st e p o ut t o
Track
0 or Tr ac k 0
sensor is a l w ay s e q u al
to one.
The read/write double-head assembly is posi-
tioned by a split b and positioner mounted to a
microprocessor-controlled stepper motor. The
r ead/writ e h e a d s a r e g l a s s-bonded, f e r r i t e /
ceramic st r u ct u res w it h a l i f e e x p ectancy of
15,000 operating hours.
A third t est monit ors the index sensors when-
e ver th e d i s k e tt e l e v e r i s c l o sed, an d m u s t
have a diskette inserted into the drive.
If the
d iskette l ever i s c l osed wi t h ou t a d i s k e tt e i n
place, or
the spindle motor fails
to operate, an
error message flashes on the front panel
L.E.D. in the following sequence:
3 flashes, then 4:
N o in d e x pu l s e wi t h
The c o n t ro l
e l e c t r o n ic s o f t h e dri v e ar e
mounted on a printed circuit board located
above the chassis. Power and interf ace signals
a re r o u t e d t hr o u g h c o n n e c t or s p l u g g i n g
directly i nt o th e l o gic cir cui t b o ard. A second
circuit board, mounted under the drive,
oper-
ates the brushless D. C. spindle motor.
lever closed.
1-3
