Fujitsu M255XK Installation and operation manual

M255XK
51 ;4" Mini-Flexible Disk Drive
Customer
Engineering Manual
FUJITSU
TS021-013087 ... 01
70221
Rev. A

REVISION RECORD
Edition
Date Published Revised Contents
01 April 1987 Initial
Fujitsu America Release
Direct your comments on this publication to:
FUJITSU AMERICA, INC.
3055 Orchard Drive
San Jose, CA 95134 USA
TEL: [phone]
FAX: [phone]
TLX: 230-176207
TWX: [phone]
The
contents of this manual are subject to change without prior notice.
Copyright 1987 FUJITSU AMERICA, INC.
All
Rights Reserved
ii TS-021-013087 ••• 01
70221
Rev. A

LIST OF PAGES WITH REVISION LEVEL
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TS-021-013087 ••• 01
iii

SECTION 1 INTRODUCTION
1.1 Scope
1.2 General Description
1.3 Key
Features •
TABLE OF CONTENTS
1.4 Options and Accessories
SECTION 2 SPECIFlCATIONS
Physical Dimension
Storage Capacity •
Disk Mechanism
Track Access Mechanism
INDEX
Pulse. • • • • •
Read/Write Head and Track Specifications
Power
Requirements
Environmental Conditions
Reliability
Regulatory Agency
Certification
Write Protect Mechanism
Page
1-1
1-1
1-2
1-3
2.1
2.2
2.3
2.4
2.5
2.6
2.7
2.8
2.9
2.10
2.11
2.12 I/o Signal
Interface ..
2-1
2-2
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2~3
2-4
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2-5
2-5
2-6
2-6
2-6
SECTION 3 Tl-EORV OF OPERATIONS
3.1
3.2
3.3
Construction and Functions
3.1.1
Frame Assembly • • • • • • •
3.1.2 Door Opening/Closing and Disk Clamp Mechanism
3.1.3 Spindle Mechanism • •
3.1.4
Read/Write Head and Carriage
3.1.5 Seek Mechanism
3.1.6 Write
Protect Detection •
3.1.7
Track 00 Detection
3.1.8 Index Detection •
3.1.9
Diskette Inserted Detection
3.1.10 Head Load Mechanism
3.1.11 Door Lock Mechanism
Circuit Operations •
3.2.1
Read/Write Circuits •
3.2.2
Control Circuits
3.2.3 Spindle Motor
Test Points
3.3.1 TP1 and TP2 Pre-Amp
•
3.3.2 TP3 Ground •
3.3.3 TP4 and TP5 Di
fferential Amp
3.3.4 TP6
Erase Gate
3.3.5 TP7 Track 00 Sensor
iv
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3-12
3-13
TS-DZI-OIJ087 ••• 01

TABLE OF CONTENTS
SECTION 4 MAINTENANCE
4.1 Periodic Maintenance
4.1.1 Inspection and Adjustment
Items •
4.1.2 Field Replaceable Items
4.1.3 Tools Required
for Maintenance
4.2 Maintenance
Precautions
4.2.1 Screw Torque
4.2.2 Screw Lock
4.2.3 Handling Connectors
4.2.4 Additional Maintenance
Precautions
4.3 -Head Cleaning.
4.4 Inspection and Adjustment Procedures
4.4.1
Collet Assembly Centering Adjustment
4.4.2 Bail Inspection and Adjustment
4.4.3 Disk-in Sensor Inspection
4.4.4 Write
Protect Sensor
4.4.5 Disk
Rotational Speed
4.4.6 Head
Contact Inspection and Adjustment
4.4.7 Asymmetry
4.4.B Read Level
4.4.9 Resolution
4.4.10 T
rack Alignment
4.4.11 Track 00 Sensor Inspection and Adjustment
4.4.12 Index Burst Timing Inspection and Adjustment •
4.4.13 Head Load Inspection and Adjustment •
4.4.14 Door Lock Inspection
4.5 Removal and
Replacement Procedures
4.5.1 Head
Carriage Replacement •
4.5.2 Stepping Motor and
Steel Band Replacement
4.5.3 Spindle Motor Replacement •
4.5.4
Collet Assembly Replacement
4.5.5 Sensor Block Replacement
4.5.6 Main Circuit Card Replacement
4.5.7 Write
Protect Sensor Replacement
4.5.8 Bezel Replacement •
4.5.9
Front Lever Replacement
4.5.10 Clamp Cam Replacement
4.5.11 Head Load Replacement
4.5.12 Door Lock Solenoid Replacement •
SECTION 5 MAINTENANCE DRAWINGS AND PARTS LISTS
5.1 Construction •
5.2
Structural Parts Listing
5.3 Screws and Washers
5.4 Main
Circuit Card Components •
5-5
Circuit Card Layout and Schematic Diagrams •
TS-017-082786
••• 01
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FIGURE
2-1
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4-25
4-26
4-27
LIST OF ILLUSTRATIONS
External Outline Drawing of Disk Drive
Overall Block Diagram • • •
Tunnel Erase Type Read/Write Head
Read/Write
Circuits •
Typical Read
Circuit Waveforms
Typical Write
Circuit Waveforms •
Control Circui
ts •
Typical Stepping Motor Control
Circuit Waveforms
Location
of Connectors and Test Points
TP1/TP2 Typical Pre-Amp Waveform • •
TP4/TP5 Typical
Differential Amp Waveform
TP6 Typical Erase
Gate Waveform
TP7 Track 00
Detect Waveform
M2553K/54K Revision 2
Circuit Card - Jumper Locations
M2553K Revision 3
Circuit Card - Jumper Locations
M2552K Revision 1
Circuit Card - Jumper Locations
Disk Drive
Orientation During Maintenance
Collet
Shaft Adjustment •
Bail Height Adjustment
Bail Adjustment
Write
Protect Sensor
Head
Contact Inspection •
Asymmetry Measurement • •
Average Read Level Measurement (2F)
Resolution Measurement •
Lobe
Pattern for Track Alignment
Track Alignment Adjustment •
Track 00 Sensor Adjustment
Index Burst Timing
Index Sensor Adjustment •
Head Load SignalllAII
Head Load Signal
IIBII
Head Load Adjustment Screw
Head Unload Signal
II All
Head Unload Signal liB"
Door Lock Solenoid Activated
Door Lock Solenoid Deactivated
Head Carriage Assembly Replacement
Head Cable Routing •
Clamp
Cam Assembly
Head Load Height Adjustment
Door Lock Solenoid
.
Page
.2-1
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vi TS-017-082786
••• 01

FIGURE
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TABLE
LIST
OF ILLUSTRATIONS (Continued)
Top View
of Disk Drive (View 1)
Top View
of Disk Drive (View 2)
Bottom View of Disk Drive
Rear View of M255XK
Exploded View Drawing
M2552K Revision 1
Circuit Card Layout
M2553/54K Revision 2 Circuit Card Layout •
M2553 Revision 3
Circuit Card Layout •
Interconnec t Diagram
M2552K Revision 1 Schematic Drawing
M2553/54K Revision 2
Schematic Drawing
M2553K Revision 3
Schematic Drawing
UST OF TABLES
2-1
2-2
2-3
2-4
2-5
2-6
2-7
2-8
2-9
2-10
MFM Recording Storage Capacity
Disk Mechanism
Track Access Mechanism
INDEX
Pulse. • • • • •
Read/Write Head and Track Specifications
Power Supply Requirements
Environmental Conditions
Reliabili
ty
Regulatory Agency Certification
Interface Signal -Pin Designation
4-1 Inspection and Adjustment Items
4-2 Field Replaceable Items
4-3 Maintenance Tools
4-4 Screw Size and Torque •••••••
4-5A M2553K/54K Revision 2 Circuit Card Jumper Definitions
4-5B M2553K Revision 3 Circuit Card Jumper Definitions
4-5C M2552K Revision 1 Circuit Card Jumper Definitions
5-1 M255XK Assembly Chart
5-2 Listing of Structural Parts •
5-3 Listing of Screws and Washers • •
5-4 Listing of Main Circuit Card Components
TS-017-082786 ••• 01 vii
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5-10

1.1 SCOPE
SECTION 1
INTRODUCTION
This manual explains
the service procedures for the FUJITSU M255XK Family of
51" Mini Flexible Disk Drives.
This Section gives
an overview of the Disk Drives.
Section 2 provides
specifications.
Section 3 explains the drive's operations
Section 4
details maintenance procedures
Section 5 contains
parts lists and mechanical and schematic drawings.
1.2 GEI\ERAL DESCRIPTION
M255XK disk drives
offer superior performance, reliability and construction in
Half-Height 5i" Flexible Disk Drive technology.
Industry
standard 51" (130mm) diskettes are used as the storage medium. These
drives have an independently addressed Read/Write head
for each side of the
diskette.
FM (Frequency Modulation) or MFM (Modified Frequency Modulation) recording
methods
are acceptable.
There are three Models in the M255XK Family:
M2552K -This model
records 5,922 flux transitions per il1ch and has a per disk
unformatted storage capacity of 1 Mbyte with MFM Encoding or 500
Kbytes with
FM Encoding.
With a 16
sector format (256 bytes per sector), the M2552K emulates a
double density/double sided, 96
track per inch 51" industry standard
disk drive.
M255JK -This model
records 9,646 flux transitions per inch and has a per disk
unformatted storage capacity of 1.604 Mbytes with MFM Encording or
802 Kbytes with FM'Encording.
With a 15
sector format (512 bytes per sector) the M2553K emulates a
double density/double sided, 96
track per inch (1.2 MByte) industry
standard 51" disk drive.
M2554K -This model
has a host system controlled interface line (pin-2) that
allows operation at either 300 RPM, or 360 RPM.
TS-021-013087
••• 01 1-1

M2554K (Continued)
When
set at 300 RPM the M2554K records 5,922 flux transistions per
inch (similar to a M2552K) and has a per disk unformatted storage
capacity of 1 Mbyte with MFM Encording or 500 Kbytes with FM
Encording.
When
set at 360 RPM, the M2554K records 9646 flux transitions per
inch (similar to the M2553K). and has a per disk unformatted storage
capacity of 1.604 Mbytes with MFM Encording or 802 Kbytes with FM
Encoding.
With
MFM recording methods, the data transfer rate is:
M2552K -250 Kbi
ts per second
M2553K -500 Kbi
ts per second
M2554K -250
Kbits per second at 300 RPM
-500
Kbits per second at 360 RPM
Spindle
motor speed is:
M2552K 300 RPM
M2553K -360 RPM
M2554K -Host
system selected (via an interface signal line) for 300 or 360 RPM
On all Models,
Track density is 96 TPI and there ere 80 cylinders/160 tracks per
disk. Track to track access time is 3 milliseconds, plus a 15 millisecond settling
time. Average access time, including settling time, is 94 milliseconds.
Except for the di fferences .listedabove, performance of the units is identical.
Refer to the M255XK Product Description Manual for an overview of the M2552K,
M2553K, and M2554K Mini
Flexible Disk Drives.
1.3 KEY FEATURES
o
Half-Height (1.625 inches)
o Industry
standard flexible disk drive mounting
o Industry
standard flexible disk drive interface
o Vertical clamping mechanism
o
Up to 1.604 Mbytes of unformatted storage capacity
o The M2554K may be set by the host computer to function as a 1.6 Mbyte
or 1.0 Mbyte capacity disk drive (allowing a single source for two
products)
o High quality and
reliability
o FUJITSU AMERICA support
1-2 TS-021-013087
••• 01