Service manual
_
_________
1
4
-
15
DOUBLE-DENSITY
DISK
CONTROLLER
.
If
you have
hard
errors,
the
best
approach
is
to
exit
this
program (type E
at
the
option
menu), format
another
blank
diskette,
and
repeat
the
entire TEST procedure.
If
this
approach
is successful, it is probably because
the
first diskette
had
one
or
more
bad
sectors, possibly
caused
by
dust.
If
replacing
the
diskette corrects
the
hard
errors,
continue
through
the
other TEST options
and
then
use
"Switch"
to restart TEST.
Then
insert
the
bad diskette
and
perform
"Media
Check"
in
order
to
identify
bad
sectors.
If
the
diskette contains
bad
sectors,
put
it aside. Do
not
use
a defective diskette to store data or
programs.
Hard errors
on
the
inside
(high numbered) tracks will
usually
result
if
you
use
double-bit
density, double-sided, 80-track
operation
with
diskettes
not
certified for
such
use.
If
you are getting
both
hard
and
soft errors,
and
"Media
Check" finds
nothing
wrong
with
the
"bad"
disk,
you
may
have
hardware
problems.
If
changing
the
diskette does
not
correct
the
problem, or if
you
do
suspect
that
you have
hardware
problems, refer to
the
"In
Case of Difficulty" section, Page 5-5.
M - MEDIA
CHECK
The
Media Check
will
examine
the
diskette
under
test for defects
in
the
magnetic
oxide
recording
medium.
If
you
had
any
hard
or soft errors
during
the
General Drive Checkout,
defects
in
the
diskette
medium
could
be
the
cause.
If
the
Media Check finds
any
bad
sectors,
the
bad
sector
numbers
will
be
listed
at
the
end
ofthe
test.
Run
this
test
on
all
new
diskettes to confirm
the
quality of
the
medium.
The
Media Check
will
take
anywhere
from 20 to 45 minutes. At
the
end
of
the
test,
the
following message
will
be
printed:
nnnn
BAD
SECTORS
LOCATED
The
number
"nnnn",
which
can
range
from 0000
to
2879, tells
how
many
of
the
sectors
on
the
diskette
under
test are defective.
The
numbers
of
any
bad
sectors
will
also
be
listed. Record
the
numbers
for
future
reference.
If
the
Media Check discovers a
bad
sector,
put
the
diskette
which
contains
the
bad
sector aside. Do
not
use
it
to store data or
programs. However, disks
which
have errors
in
double-density or double-sided
use
may
still
be
suitable for single-density or single-sided use.
S-SEEK
TIME
This
test
will
vary
the
track seek
time
of
your
drive
in
order to
determine
its
highest
reliable speed.
The
drive assemblies are
guaranteed
to perform reliably
at
a seek
time
of
30 milliseconds
per
track.
The
maximum
seek
speed
may
change
as
the
drive
unit
becomes
"broken
in."
If
frequent
read errors occur
with
one of
your
drives,
you
should
re-run TEST to
check
for possible
changes
in
the
drive speed.