Copal F-5006 User manual

MAINTENANCE MANUAL
5.25" Mini Floppy Disk Drives
F-5006·
F-5008
.COPAL COMPANY, LIMITED
Memory Products Div.
2-16-20, Shimura, ltabashi-ku, Tokyo, JAPAN

MAINTENANCE MANUAL
5.25" Mini Floppy Disk Drives
July, 1985
F-5006
F-5008
Rev. 1
This Maintenance Manual is subject to change without prior notice.

CONTENTS
SECTION 3 Expl'7-nation of Operation ············ ··· ··············· ······ ····················· 300
3-1 Outline of Construction and Functions ··· ············ ··· ·················· ......... 301
3-1-1 Overal 1 block diagram ···. ·· ··· ··· ··· ··· ······ · ··. ·· ·.. ········· ··· ·········...... ... 301
3-1-2 Outline of structural parts ··· ··· ······ ··· ··· ············ ··· ··· ······ ······ ···... 302
3-2 Circuit Operation ······ ··· ··· ··· ··· ··· ······ ··· ······ ········· ··· ··· ··· ······ ··· ··· ··· ··· ... 305
3-2-1 Read/Write circuit ··· ··· ··· ············ ······ ······...·················· ··· ··· ··· ··· 305
3-2-2
3-2-3
Control circuit
Servo circuit
310
313
3-3 Test Point Functions and Type of Connector . ······ ······ ··· ······ ··· ··· ········· 314
3-3-1 Test point functions ··· ··· ··· ··· ········· ··· ......... ········· ···...········· ...... 315
SECTION 4 Explanation of Maintenance ............ ······ ····················· ... ············ 400
4-1
Maintenance Outline
4-1-1 Periodic maintenance
4-1-2 Inspection and adjustment
401
401
402
4-1-3 Replacement of maintenance parts ··· ······ ············ ··· ...... ············ ··· 403
4-1-4 Tools required for maintenance ······ ··· ··· •·· ········· ··· ··· ··· ··· ··· ···... ··· 406
4-2 Maintenance Cautions
407
4-2-1 Screw torque and screw lock ··· ···...··· ... ··· .................. ··· ··· ......... ··· 407
4-2-2 Handling the connectors ··· ......................................................... 408
4-2-3 Head cable treatment ..................... ············ ............... ······ ······ ··· 410
4-2-4 Others ··· ··· ··· ···...··· ·•· ······... ··· ··· ... ··· ··· ...... ··· .................. ··· · ..... ··· 412
4-3 Periodic Maintenance
414
4-3-1 Cleaning the magnetic heads with a cleaning disk ······ ............... 414
4-4 Inspection and Adjustment Methods ··· ··· ··· ··· ··· ··· ··· ··· ··· .................. ······ 415
4-4-1 Collet assembly centering adjustment ··· ··· ··· ··· ···... ······ ···... ··· ··· ··· 415
4-4-2 Front lever position adjustment ··· ··· ··············· ...··· ···•·· ··· ···...······ 417

4-4-3 Bail inspection and adjustment ....................•..•........................
4-4-4 Fi le protect sensor inspect ion ...•.. ·..·················· ·. · ................. .
4-4-5 Disk rotation speed inspection and adjustment ··· ··· ······ .............. .
4-4-6 Head touch inspection and adjustment ········· ··· ··· ··· ··· ··· ··· ........... .
4-4-7 Asymmetry inspection ··· ······ ··· ········· ··· ······ ··· ··· ··· ··· ··· ······ ........... .
4-4-8 Read level inspection ··· ............... ··· ··· .................. ··· ................. .
4-4-9 Resolution inspection ··· ··· ··· ··· ··············· ········· ······ ··• ······ ··· ........ .
4-4-10 Track alignment inspection and adjustment ...··· ······ ··· ................. .
4-4-11 Track 00 sensor inspection and adjustment ··· ······ ··· ··· ... ······ · ....... .
4-4-12 Track 00 stopper inspection and adjustment ··· ··· ··· ·················· ...
4-4-13 Index burst timing inspection and adjustment · ··. ·· · ................... .
4-5 How to Rep lace Parts ··················· ...··. ··· ... ·· .. · ..... · .......................... .
4-5-1 Head carriage assembly replacement ······ ········· ······ ···... ··· ........... .
4-5-2 Stepping motor and steel belt replacement ...... ······ .................... .
4-5-3 Disk Drive motor {spindle motor} replacement
4-5-4 Collet assembly replacement ············ ......................................... .
4-5-5 Track 00 block assembly replacement ··· ··· ......... ··· ··· ............ ··· ..... .
419
421
423
424
426
428
430
432
438
440
441
443
443
449
451
453
454
4-5-6 Main PWB assembly replacement ··· ······ ··· ········· ··· ··· ··· ··· ········· ··· ·... .. 455
4-5-7 Sensor block assembly replacement ··· ...... ······ ···. ·· ··· ...... ··· ............ 456
4-5-8 Front bezel replacement ······ ··· ········· ··· ··· .•.··•·•· ··· ··· ...··· ··· ...... ······ 457
4-5-9 Front lever assembly replacement ··· ... ··· ...······ ··· ... ······... ··· ··· ··· •·· 458
4-5-10 Cramp cam assembly replacement ··· ...··· ······ ··· ······ ··· ··· ...... ··· ··· ··· ··· 459
SECTION S Drawings and Parts Lists •·· ········· ······ ······ ··· ··· ··· ··· ••· ··· ·•· ·•· ··· ······ 500
5-1 Construct ion · ·· ···· ·· ··· ···· ·· · ·· · ·· ···· ·· · ·· · ·· ·········· ·· · ·· · ·· · ·· ··· ············· ·· ···· ·· .5()1
5-2 Structural Parts Exploded Drawing, Parts List ••· ··· ·•···· ······ •·· ···... ······ .5()7
5-2-1 Floppy Disk Ori ve chassis · ··. ········••·.··· •· · •·. •· • ··. ··· ... ··· ... ·· ...... ·..... .5()7
5-2-2 Screws and washers
................................. ... ..................... ......... 510
5-3 PWB Assembly Parts & Drawing No. List ...... ··· •·• ··· ··• ··· ··· ··· ...... ··· ··· ...... 511
5-3-1 Main PWB assembly ..................................................................... 511
5-4 Circuit Diagram ··· ...··· ...······ ...······ ······ ...... ············ ··· ··· •·· ······ ··· ··· ...... 516

SECTION 3
Explanation of Operation
-300-

3-1 Outline of Construction and Functions
3-1-1 Overall block diagram
REAO OATA
SIDE ONE SELECT
WRltE DAIA
DRIVE SELECT
0-3
WRITE GATE
HOTOR ON
STEP
DIRECTION
SELECT
IN USE
TRACK 00
INDEX
RF.ADY
WRITE PROTECT
+12V, •SV, OV
Read
Write
circuit
~
bl
..J
~
Control
circuit
Indicator
Hagnetic head
Irack 00 sensor
Stepping motor
File protect sensor
File protect sensor LED
Disk
Index sensor
Index sensor LFD
Spindle 110tor
Fig. 301 Overall Block Diagram
-301-

3-1-2 Outline of stn.ictural parts
This Floppy Disk Drive uses painstakingly assembled high-precision
parts because it uses flexible disks based on mylar film as the record-
ing medium and requires the ability to interchange data with other Flop-
py Disk Drives. For that reason, we request that only specially trained
maintenance personnel be allowed to touch the internal mechanisms and
that the unit be handled carefully, taking care to avoid strong shock.
The components include the frame, door opening and closing mechanism,
disk clamp mechanism, disk drive mechanism, magnetic head and carriage,
head seek mechanism and various detectors.
(1) Frame
The frame is the skeleton on which the various mechanisms and PWB
boards are mounted. It is based on a sheet steel chassis in order to
ensure the strength, accuracy, weather resistance and expansion
ratio required for stable Floppy Disk Drive reliability.
(2) Door opening and closing mechanism, disk clamp mechanism
The door opening and closing mechanism includes the clamp spring
(flat spring), front lever, set arm, etc. The disk clamp mechanism
(clamp assembly) is moved vertically by the end of the clamp spring.
When a disk is inserted and the front lever closed, the end of the
collet enters the central window of the disk, then presses against
the spindle so that the disk is accurately clamped in the correct
position along the collet.
(3) Disk rotating mechanism
The disk rotating system comprises the Disk Drive motor (spindle
motor} including the spindle.
Ihe Disk Drive motor (spindle motor) is a direct spindle coupled
outer rotor type DC brushless motor with an extra long service life
of 20,QCX) hours or more of continuous operation. Ibis servo motor
rotates at 3CX>rpm and maintains a constant speed even with load and
temperature fluctuations using feedback signals from the AC tacho-
meter built into the motor.
The collet and spindle are prec1s1on assembled at exactly the
•
right angle. This prevents injuring the edge of the center window of
the disk and accurately centers the disk so that the head and disk
come into contact at the correct position.
-302-

(4) Magnetic bead and carriage
Read/\Jrite core
Read/\Jrite gap
~ Direction of
disk rotation
Erase core
Tunnel erase type head
Fig. 302 External
Appearance of Magnetic Head Core
With both-side type Floppy Disk Drive units, both the side 0 and
side 1 heads are of a special flat shape supported by a gimbel con-
struction. The beads straddle the disks from the outside and are
mounted on one carriage.
In order to keep wear of the surf aces of the beads from contacting
the disks to a minimum, they are designed to obtain the maximum
playback from the disks. As shown in Fig.302, the heads used in this
Floppy Disk Drive can use tunnel erase type cores.
The center parts of tunnel erase type heads have a Read/Write gap
used to record and playback data and a tunnel erase type gap for
erasing the edges of tracks directly after recording.
(5) Head seek mechanism
The head seek mechanism is built around a stepping motor with a
capstan (pulley) and includes a steel band, guide shaft and car-
riage. The carriage slides along two guide shafts and is connected
to the capstan of the stepping motor via the steel band.
The stepping motor has a flat, 4-phase construction and rotates
one step (l.8° ) to shift the head one track. It is driven by sin-
gle-phase excitation.
The parallelism and distance between the shaft and disk center-
1 ines, as well as the shaft and capstan, are high-precision pro-
cessed. Temperature expansion of the chassis, st~el band, carriage
etc., have been carefully studied and designed to counteract the
expansion of the disk itself.
-303-

(6) Various detectors
(a) File protect detector
This detector comprises the LED and photo transistor used to
detect the presence or absence of the write enable notch on the
disk jacket. When a disk with this notch is loaded, the detec-
tion light path is interrupted and the operation of the write
circuit is prevented. Previously written data is protected from
erasure even if a record command is given by mistake. The LED is
on the Disk Drive motor (spindle motor) servo PWB and the photo
transistor is on the sensor block assembly.
(b) Track 00 detector
This detector comprises a photo interrupter used to detect the
outermost position (track 00) of the head gap and a track 00
stopper.
The tracks inside of track 00 are used but the head cannot
move outside of the range where it can self-reset when the power
is turned on, even if the head should move outside due to a
shock, because it strikes the track 00 stopper. Also designed to
ignore, at the discretion of the circuitry inside the Floppy
Disk Drive, the command to step out from the track 00 position.
In case a step out command is input at the innermost track,
margin is provided so the head does not strike the head window
edge of the disk but, rather, the head moves farther inward. Io
recalibrate (return to track 00) the track from this position,
it is necessary to input a step out conunand for several tracks
beyond the maximum number of tracks.
(c) Index detector
An index bole or center hole detector LED and photo transistor
are located at the position of the index window in the disk
jacket. The LED is on the Disk Drive motor (spindle motor) servo
PWB and the photo transistor is on the sensor block assembly.
The holes in the disk are detected in accordance with the speed
the disk is rotating.
-304-

3-2 Circuit Operation
The circuit section comprises three parts: the Read/Write circuit, the
control circuit and the servo circuit. The Read/Write and control circuit
are on the main PWB' while the servo circuit is on the Disk·Drive motor
(spindle motor) PWB.
3-2-1 Read/Write circuit
The Read/Write circuit comprises the read section, write section and
low voltage detector section. It is mainly in the Read/Write LSI (one-
chip bi-polar LSI). The block diagram is shown in Fig.303.
-305-