Sharp FDD-412A User manual

SHARP
_
SERVICE
MANUAL
FLOPPY
DISK
DRIVE
mopeEL
FDD-412A/B
. GENERAL
_
PRINCIPLES
OF
OPERATION
_
MAIN
TENANCE
. TROUBLESHOOTING
. PARTS LIST & GUIDE
SHARP
CORPORATION

FDD412A/B
CONTENTS THIS MANUAL.
This
manual
provides
service
and
all
maintenance
and
service
information
to
support
the
slim,
2-side
double-density
floppy
disk
drive
FDD-412A
and
FDD-412B.
Before
attempting
any
service
or
repairs,
take
time
to
familiarize
yourself
with
this
manual to
make
your
servicing
easier
and
more
efficient.
Currently
this
floppy
disk
drive
use
as
bellow
mentioned
model.
Also
intentionaly
will
be use to other model.
UNIT
NAME
PARTS
CODE
APPLIED
PRODUCT
MODEL
FDD-412A DUNTK3010SCZZ Office computer
HAYAC-2900 SYSTEM
CO2900E
CO02902E
HAYAC-3900 SYSTEM
CO3906E CO3900E
CO3902E CO3903E
CO3904E CO3905E
CO3906E CO3907E
Personal computer
MZ1F05
POS system
OM18FD1
FDD-412B DUNTKS3011SCZZ HAYAC-2900 SYSTEM
CO2900E
Personal computer
MZ1F05
POS system
OM18F D2

GENERAL .........-2 eee
Overview ......eeeeeee
FOaATULES sce cca cee es
PRINCIPLES OF OPERATION
(Oy need 0 | = ee
Configuration: ..c.c6.%
.1 Drive Mechanism ....
.2 Control Electronics
SUSCTTLCALIONS eines
.l1 Performance Specific
.2 Power Requirements .
.3 Mounting Specificati
.4 Environment Specific
.5 Reliability Specific
Recording Media cea
.l Medium Type ........
.2 Handling of Recordin
.3 Recording Methods ..
-4 Data Format ........
Logic Operations .....
.l1 Sensor-Related Opera
-2 Seek Operations ....
.4 Data Write Operation
.5 Data Read Operation
CONTENTS
Pr
ee ee ed
re
woke atetlave, Gao witan bl etseb Boece ACR aerate. anda eae ate
sgh we dav esas sateen oo 8i-2h 8 vaysSiare a ole otiouel teres abel ent stevens
eB a ele ces eat OS aie ial a Seite eee 8 eae Boe
Se barea Sicha ate heNer Rca las eite se: MIRTe wide ais Sedelanac eters Shela
a elsekir lorie ton'o v's Swabia (lob: SiewiSre elergcontue a vershane tardies
a ave Nente Gey deviant, Crane hasanesereteyslaherane wasiev paemarens
SELONS tectos eens big Gesa tie Sane fore-aes
Ssidisal SC Sisce ete be ihe 8 Read Se SP SAS eee
OWS = os acces cetesiar es See ere te eee Se A os ese Ss
AC TOWS: ee vaca fovea: eleravete eerd ovelecwed’s eielale es
BEDLONSH “ove sevesel Bist wia te eee weil Sid? ae Sadak scar aires
bis whe Sg ahaa es ere, 6M ace cated ecereie dele elie svesial's
ica ile Saha re ob fore S. ook: Sud eh ae re ata alae Sie, «| Saree
GZ Media .. cece cee eee ec eee reer eees
Bi Dea ed BR Lave: Site 6 GA ie tak AS ONS APES RES TT
Sea aS oye ee te SBS Seca ie wo dds sw che Se ere See
Pe ee
EDOTIS© sieves faite esdesele nbven Sd: 6 anette er ee 8 ea 2 eee :
ed
.3
Magnetic
Head
Composition
and
Its
Related
Operations
..
ed
ee
FDD412A/B
10
11
11
12
12
13
13
14
15
15
17
19
20
22

FDD412A/B
2.5.6 Operations Related to Spindle Motor Drive Mechanism ...
2.5.7 Overall FDD Operations (Timing Charts) .............:..
Goes
SULCUS
ACE
sxe aca
pea
tae
wae
gel
wetee
ek
ee
Mawes
So
ok
2.6.1 Connection of Floppy Disk Controller (FDC) to FDD .....
2.6.2
Device
Configuration
in
Daisy
Chain
Connection
........
2.6.33 Inter hace. Siena lsc < sec veceteaswvenenel ovens vecte svaud. Salebate Gubboea vrei
26.4 Interface ‘Signal: ‘Timing: 25 ts. wei aiianis wed ob ob cw ieoeelees
3s. “HANDLING > secco5 5 eStats wee dalale aw eels Gree Deter Wave ews gaeies
8.0 Hand] ing. Procedures-a.. nity ssw ee eta awa wes Po ieateas: cae
3.1.1 Floppy Disk Not. in USE ose. ee ck es eee dee cee ee oe ean
3,14.2 Insertion of BLoppy: Disk ~ wesc S08 eres ob ese e eS SER! pass
3.1.3 Opening/Closing of Door; Floppy Disk in Use ...........
3.124 Removal’ of Floppy (Disk ..c.ccuiewio Ss Se Moe oes aie, aecateees
3.1.5 Handling of Floppy Disk ..... feet e eee ee eee Stee e eee eee
Be Tbs sRELOCAELGT tected t ace te Wate Wav eue te leceely Suayenepe alana betel srgaeca Boeie BG RAS
3.1.7 Packaging, Transit and Storage ...... eee ee ee ee ees
$72. “Setting of FORD Operation Mode... a qcted easton see es i rates
3.2.1
Operation
Mode
Changed
by
Shorting-Plugs
Seana
careers
lables
eae
s
3.2.2 Shorting-plug Presetting Position oe Shipment
EYTOM: PACCOLY: 25 Seiad g he nk seis wi ecte ete oes rereece sells Fae Bronese Sis arer loves oe
nc MAINTENANCE: onctead ieanadteanien Sane aria d aieae Aeeee ye laees
4.1] Maintenance Items ...... Be thle lets Meinatccen es eae ee
a.2 .Parts Replacement Procedures. is.siaswashae sven yenauwe ers
4.2.1 Common Work 1: Top Cover ...... ee ee
A. 2.2: Common; Work: 22 Pilate Opening/Closinge sss. denc-ee esas
4.2.3 eae Work 3: Wire Handling and Wire Routing ........
hy Oe PER Assembly “(PCCI4)) csi ancecod Ue daein he beam SS G4 dale es
Page
28
29
82
82
33
84
85
45
45
45
45
45
46
46
48
49
49
49
53
54
54
55
55
55
56
58

oO
. 10
il
sed
13
14
jab
. 16
17
18
.19
Motor (DD Spindle) .......
Head Load Solenoid .......
Head
Load
Bail
Assembly
...........--
ion
d
sae
wa,
ayectn
toes
Sua
arate
ely
O
Sensor
Assembly
LL...
eee
ee
ete
eee
ee
eee
teens
Protect
Sensor
Assembly
...
ec
cece
ee
eee
ete
eee
eet
e
eres
Index Sensor Assembly ....
Index LED Assembly .......
MiCroOSWIECH.. i. cd dsvcdeers ee
Center Cone Assembly ....
Plate Assembly ..........-.
Indicator Assembly .......
Door Lock Assembly .......
DOGY’ -BUETON: 63s cbreOee ae eats
FPH-H680T Assembly .......
Setp Motor ..ceeeeeseeeees
Adjustment
Procedures
......
TROUBLESHOOTING
.....--------
Troubleshooting
Flowchart
..
Media-Related Troubles .....
.
ho
Troubleshooting Procedure
Pr ee ee
Pe ee ee ee
ee ae ee
er er ee
wee tee eer meee eee nee erro eee ene
a er
Pe ee
Pe er ee SS
i a ae
a a ee ee
Pe ed
.1
Head
Position
(Tracking)
Adjustment
.......-e
eee
eeeeees
.2
0
Track
Sensor
Position
Adjustment
......-...-e-eeeeeee
.3
Bail
Stopper
Elevation
Adjustment
.......---eeeeeeeeeee
Pe ee
ee
er
Pe
Pictures
of
Normal/Abnormal
Readout
Waveshapes
........
Major Floppy Disk Failures
Pe a ee ee
FDD412A/B
60
61
62
62
63
64
64
65
66
67
67
68
70
71
71
74
75
77
77
85
85
85
85
93

FDD412A/B
for) a for) fo) for) for) for) jor) on > eo iw)
a
des
3 3ie
Medi
um
Management.
sticc2eat
4
fa
tea
weet
ek
aes
ee
eit
oe
1 Necessity of Medium Management
ee a
2>
TMe@
Pum:
Wie
is
fe
F
ents
obs
eb
sa
ee
afew
ee
Cae
oe
aieeee
ei
aes
te
CONTROL.
BOARD:
ssscstieecenttiesenneciect
ells
beh
th
weetestintins
feds
casseseeneeous
Control
Board
Schematic
Drawings
—
]
crcccesctecsseesecseeesseereeenes
Control
Board
Schematic
Drawings
—Q--cceece
ce
cteees
tects
cseeseeeaes
Control
Board
Schematic
Drawings
—
Q
errs
tec
teeeenecetes
Control
Board
Schematic
Drawings
—
deri
tet
eenies
FDD412
A/B
Operating
mode
Setup
Method
vrvcrcrc
cece
Parte
Layout
Chart
45
0.04
wine
wiaieiS
ele
Biel
Wl,
e
Sidin
wig
elt
O10
Sieg
deioletaie
Gide
oig
Gig
a
via
plaid
sy
baictoa
badd
Uae
daeeevanudes
101
102
108
104
105
107

bel
FDD412A/B
GENERAL
Overview
The FDD-412A/B floppy disk drive (FDD) is a slim, energy-saving,
lightweight FDD that accommodates 2-sided, double-density floppy disks,
based on the technologies implemented in the widely used FDD-101A/201/
401/102D/402D/403D FDD..
The FDD-412A (Model A) incorporates a VFO, while the FDD-412B (Model B)
has no VFO. The user can select either depending on whether there is a
controller VFO or not.
The standard specifications of the FDD are as follows:
Mae
(1)
(2)
(3)
(4)
(5)
(6)
File protection : Transparent
Top cover color .: . Black
Door lock : Electromagnetic door lock mechanism
Features
Slim lined
The body is only half as wide as conventional types. This makes
it possible to install 2 units in a space for a single conven-
tional type.
Lightweight
The FDD weights 3.5 kg or less.
This weight is about 70% of that of our existing models, making
handling procedures much easier.
Field-proven brushless direct drive system
Our field-proven brushless direct drive system is implemented in
a narrower enclosure.
This system is much more reliable than the belt system or brush-
based direct drive system. Without any parts to be replaced
periodically, the system is of a complete maintenance-free design.
‘There is no need to distinguish 50Hz and 60Hz in frequency.
Convenient VFO connecting interface
Up
to
4
FDDs
can
be
connected
to
the
controller.
If
a
system
con-
figuration
includes
one
model
A
FDD,
all
FDDs
can
be
connected
to
the
VFO interface
regardless
of
the
other
three
being
of
model
A
or
B.
This
promises
configurations
of
high
cost-performance.
2-DC power supply
A 2-DC power supply system has replaced the 3-DC power supply
system. This has reduced the average power consumption to about
57% of that of our existing models.
LSI-based circuitry
Dedicated LSIs constitute the greater part of circuitry. Without
any parts to be replaced periodically, higher reliability and much
better maintenability can be realized. .

FDD412A/B
(7) Electromagnetic door lock/umlock mechanism
The
controller
is
equipped
with
an
electromagnetic
door
lock/unlock
mechanism
that
prevents
an
inadvertent
opening
of
the
door
during
operation.
pene
Fig. 1.1 Outside View of FDD-412A/B Floppy Disk Drive
2. PRINCIPLES OF OPERATION
2.1 Outline
The FDD (floppy disk drive) is a device that writes and reads data to
and from the floppy disk.
As shown in Fig. 2.1, a floppy disk has 77 concentric "tracks" on either
surface (i-e., 154 tracks on both sides). Data is sequentially recorded
on each track. A carriage has.one magnetic head on each side respec-
tively, and read/write data. It moves radially, processing data on the
tracks.
To write or read data to or from a given location on the floppy disk,
the following steps are required:
(1) The magnetic head and recording medium are given a relative
velocity.
(2) The magnetic head is positioned over the target track.
(3) The target data is searched from among numerious data records
written on that track. :
(4) The data is read from or written onto the record.

FDD412A/B
.hese
operations
and
their
control
are
shared
by
the
FDD
and
FDC
(floppy
disk
controller).
Each
of
the
above
steps
is
further
explained
below.
(1)
(2)
(3)
Floppy disk
Track
Magnetic head
Fig. 2.1 Floppy Disk
The
magnetic
head
and
recording
medium
are
given
a
relative
velocity.
Data
is
sequentially
recorded
(i.e.,
in
bit-series)
on
floppy
disk.
For
data
processing,
it
then
becomes
necessary
to
move
the
mag-
netic
head
relative
to
the
medium.
This
is
achieved
by
rotating
the
floppy
disk.
The
motion
is
provided
by
an
FDD
spindle
motor,
which
rotates
at
a
constant
speed
for
correct
reading.
Applying
power
to
the
FDD
rotates
the
spindle
motor.
With
a
floppy
disk
inserted
and
the
door
closed,
the
disk
is
secured
to
the
spindle,
ready
for
revolutions.
The
magnetic
heads
are
fixed
to
the
FDD.
As
the
floppy
disk
rotates,
a
relative
velocity
is
pro-
duced
between
the
heads
and
the
disk.
The
floppy
disk
has
an
index
hole
to
determine
the
start
point
on
each
track.
The
FDD
senses
the
index
hole.
When
the
disk
rota-
tion
is
found
normal,
the
FDD
enters
a
ready
state
and
can
be
subject
to
control
from
the
FDC.
The
magnetic
head
is
positioned
on
the
target
track.
The
magnetic
head
is
then
positioned
on
the
target
track
among
many
concentric
tracks.
The
positioning
is
done
by
moving
the
head
radially.
How
far
the
head
should
move
is
calculated
by
the
FDC
as
the
positional
difference
between
the
current
track
and
the
target
track.
The
FDD
receive
pulses
indicating
the
amount
of
magnetic
head
relocation.
The
FDD
has
a
step
motor
to
which
the
magnetic
heads
are
secured.
One
pulse
causes
the
head
to
move
by
1
track.
In
this
manner,
the
head
is
positioned
on
the
target
track.
The target record is’ searched.
When positioned on the target track, the head reads out data from
the track.
To minimize wear, the FDD is designed so that the head comes in
contact with the disk surface only upon reading/writing. The FDC
issues a HEAD ENGAGE command to the FDD for contact between the-
head
and
the
disk.
:

FDD412A/B
(4)
Ze
The
The
FDD
reads
out
the
data
from
disk
and
sends
it
to
the
FDC.
The
FDC
searches
the
target
record
as
it
reads
data
on
the
track.
One
record
consists
of
an
ID
part
(identifier)
and
a
data
part.
Reading
the
ID
part
reveals
whether
or
not
the
record
is
what
is
needed.
Index : Index
VY V
IDO ! Data 0 | ID1 ! Data 1 | ID2 : Data 2
{ :
EL RCCOEE Soe
IDn ! Data n
Fig. 2.2 Data Arrangement on Track
The data is read out or written in.
When the target record is found, data is written to or read from
the data part.
The magnetic heads of the FDD are used for both heading and writ-
ing. When a write command is given by the FDC, a current flows in
the magnetic head and all readout operations are suppressed.
That is, the FDD performs either a write or readout operation at
any one time, not both simultaneously. The data read from disk is
of analog waveshapes, which are digitized by the FDD for trans-
mission to the FDC.
The model A FDD incorporates a VFO circuit, and is capable of
demodulating the data that was modulated by the so-called FM/MFM
magnetic recording method.
Configuration
FDD is composed of a drive mechanism and the control electronics,
as shown in Fig. 2.3 (on page 14).
Zerdee
The
reo)
(2)
(3)
1 Drive Mechanism
drive mechanism consists of the following:
Carriage
The carriage is equipped with 2 magnetic heads for side 0 and side
1.
For movement, the carriage receives step motor revolutions via a
steel belt.
Step motor
The step motor turns in response to the STEP-N signal from the
controller.
Step motor revolutions are transmitted via the steel belt to the
carriage which positions the magnetic head at a given location.
Spindle motor
The floppy disk medium is press-fit to the spindle motor by a
collet for rotation.