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4. OUTLINE OF MAINTENANCE
•
The
following tools ate
required
for maintenance of
a
Floppy
Disk
Dri
ve.
(FOO)
4.1
Align
ment Diskette
Alignment
diskette
is
used
for
nead
actuator alignment
and
index
sensor adjustment
.
•
Ad;tiuments
(Refer
to
table
8.
1)
(1)
Specify an
appIJcable model
from
label 8.1. CInd make
a readlwrite
head radial adjustment
at
a specified
tracle
.
(SidesQ,l)
(2)
Make an
iodell
timing adjustment
at
a specified Irack
.
(Sides
O.
1)
(3)
Make
iHI
azimuth measurement at a specified
tracle
(Sides 0,
1)
CAU
TION
Do
not write when
using
alignment diskette.. Check
that
write protect
sensor
is properly
operating.
4.2
Exerciser
The
exerciser
enables you to make all
ad
justments
and
inspections necessary
for
an
FDD.
Its
functions
include
the
follow
ing:
(1)
Seek increment or
alternate
tracks
(2)
Read (but no
da ta compare)
(3) Write
1
F
or
2F
(AIIO'sor
"
s)
(4) Head
load (S.2S-inch
FDD
with optional
head
loader)
(5)
Recalibrat
ion
to track 00
The exerciser has
switches
and
indicators
to execute a
specified
function
.
5. DIAGNOSTIC PROCEDURES
5.1
Error
Symptom
Re<ognition
Erro
rs
that
occur
because of the wrong operating procedure, wrong programming, or
use of
a
defective
diskette,
or
soft
errors
due to external
causes, such as contaminated air and random electrical noise, are often attributed to a drive
failure or
maladjustment.
Unless
a visual
inspection
of the dri ... e reveals an evident auembly
fault
or
II
defect,
always
confirm errors
with
another
good
diskette, and another known good
dri
...
e.
5.2 Soft Error Detectio
n
and
Correction
Soft
errors
are normally
caused
by the
following
:
(1)
Contamination
between read
I
write heads
and
diskette.
This kind
of
cont.}:,lination can be easily ehminated by the liner
in
the diskette.
(2)
Random electrical
noise, normally
a few microseconds or less
.
(3)
Small defects in
written
data and
l
o
r
tfaclr.
not
detected du ring
write
operation may cause roft
errors during
read
.
(4) Faulty
grounding
of the
dr
.... e
or
host
system can also cause a
soft
error.
(5)
Wrong
motor speed
is another
cause
of
soft errors.
Take
the
following
steps
on
the controller side
to recover from the
soft
errors
mentioned above.
(1)
Read
the track again
ten times or
until
the
data
is
recovered.
(2) If
Step
(1) above fail
s
to recover
the
data
,
access the adjacent.
Then return
the
head
to
the
original track.
(3)
Repeat
Step (11
.
(4) Any
error that
cannot
be
corrected
by the
above procedure
is
irrecoverable
.
-
2 -
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