AMSTRAD CPC664 - Page 7

Software
Errors
If
a
drive
fault is
reported
the fault
may be a
software
problem.
Before
investigating
the
drive
please
carry out
the
following
checks to
ensure
it is not a
software
problem.
Detection
and
Correction of
"Soft
Errors"
Soft
errors
are
usually caused
by
the
following
reasons.
1)
Random
external noise
of
several usee
or less.
2)
Minute
off-tracking
and
shifting
of
write
timing that
are not
detected
during the
write
operation
which can
cause
the
soft
error during
the read.
To
remedy
such
soft
errors,
take the
following
procedures
at
the
controller
side.
1)
Repetitive
reading on
the
track by
10 times
or
more
until the
data
is restored.
2)
When
the data
is not
restored
by step 1,
access
the
head to
the
adjacent
track
in the
same
direction
as
move
previously,
and
thereafter
return
the head
to
the
original
track.
3)
Repeat
the step
1.
4)
If the
data is
not
restored by
the above
steps,
the
error
cannot
be
remedied
Write
Error
When
an
error is
caused
during the
write
operation,
the
error is
usually
detected
during the
next
rotation
through
the read
operation
called
"Write
check".
To
correct
the
error,
repeat the
write
operation
again
and
carry
out
the Write
check.
If the
result
is still
incorrect
even
after the
write
operation
is
repeated
more
than
10
times,
either
the
disc
or the
drive
are
working
incorrectly.
To
find out
the
trouble
source,
carry out
the read
operations
with
another
track.
Should
the
error
still be
found,
change
the
disk
and
repeat the
above
procedures.
Should
error
still be
found,
the
drive
should be
considered
defective.
If the
error is
removed,
the
original
disk must
be
defective.
Discard
it.
Seek
Error
1)
Step
motor
or step
motor
drive
circuit
is
defective.
2)
The
torque
of the
carriage
is
not
correct.
Restoration
procedures
from
the
seek error.
Make
the
re-calibration
to
the
track
00.
Then, carry
out
the
re-seek to
the
original
track.
Notes:
1)
Always
ensure
the
head
is clean.
2)
Index/Sector
Factor (Ready
Defect)
As
the
unit has
Optional
Read
Output
It
is
normally
not ready
until 2
revolutions
are
made
after the
disk
insertion.