Instruction manual
Checking
and
Adjusting
Drive
Motor
Speed
and
Head
Stop
Position.
1541
Drive
(SX·&4)
Drive
motor
speed
and
head
stop
position
are
fully
adjustable
on
the
1541
drive.
However,
routine
adjustments
to
these
are not
recommended.
Both
the
Drive
Speed
and
Head
Stop
adjusting
screens
are
accessed
from
the
Alignment
Screen.
Before
selectIng
either
of
these options,
use
the
[I)
command
to
Initialize
the
calibration
disk.
Drive
Speed:
The
Check
Drive
Motor
Option
uses
a
system
of
averaging
to
calculate
the
actual
drive
speed.
With
this
method,
adjustment
process
is
much
smoother.
If
the
screen
display
Indicates
a
'TOO
lOW
drive
speed,
increase
speed
by
turning the
small
potentiometer
on
the upper
circuit
board
a
small
amount, then walt
for
the
program
to complete another
averaging
pass.
(Adjustments
for
the
SX-64
are
made
from
the underside
of
the
drive
chassis.)
Make
sure
that
a
full
averaging
pass
In
conducted
between
adjustments.
If the
drive
active
light
flickers,
you
have
Increased
(or
decreased)
speed
too
much.
Continue
adjustments
until
the
Speed
Analysis
display
indicates
EXCELLENT
or
SATISFACTORY.
Remember,
electric
motors
don't
slow
down
by
themselves.
If
your
drive
motor
Is
running too
slow,
it
is
probably
caused
by
a
loose
or
worn
drive
belt,
worn
Idler
hub
bearings
or
a
binding
floppy
disk.
Head
Stop
Position:
Checking
head
stop
position
on
the
1541
should
be
done
as
infrequently
as
possible.
The
routine
to
check
head stop
position
is
the
same
ROM
routine
that
causes
all
the
drive
alignment
problems
to
start
with.
If
the
screen
display
Indicates
adjustment
Is
necessary,
loosen
the
head
stop
retaining
screw
and
move
the
head
stop out
(away
from
the
stepper motor
hub)
In
VERY
small
increments,
then retest.
(The
Ideal
position
of
the
head
stop
is
just
past
the
point that the
display
changes
from
'TRACK
l'
to
'TRACK
0'.)
Contlnue
this
procedure
until
the
screen
display
indicates
a
satisfactory
head
stop
position
with a
TRACK
of '0'.
After
checking
or
adjusting
head
stop,
always
recheck
drive
alignment.
1571
Drive
Drive
Motor
Speed
and
Head
stop
position
are
not adjustable
on
the
1571
drive.
A
fixed,
electronic
method
is
used
to
limit
head movement
If
drive
speed
indicates
'TOO
LOW'
the
cause
is
probably
a
loose
or
worn
idler
hub
bearings
or
a
binding
floppy
disk.
The
Head
Stop
Check
will
return
an
'Unsatisfactory',
'TRACK:
l'
display.
This
Is
due to the head
limiting
electronics
that
will
not
allow
the
1571
head
to
move
to
track
'0'.
Hud
SlOp A.uembly
Circuit,
B~rd