Shugart SA455 User Manual

SECTION I
INTRODUCTION
1.1 GENERi\L DESCRIPTION
The SA455/465 Minifloppy Disk DrlvE!s are enhanced double~headed, half~helght versions of the ShuBarl SAIJOO
minifloppy drives. The SA455/46f> provides up to four Umes the on-line storage capacity, faster access time, nnd
improved reliability and maintainability'.
51\455/465 drives read and write in single and double density on standard 5.25 inch diskettes on both :sides of the
diskettes. The
new drives are: half the height of the Shugart SA400 and are plug compatible.
The compact
SA455/465 offers a reliable, low cost, high performance alternative to OEM data storage applica-
tions where tape cassette units
wOUild bave been previously considered.
SA455/465 drives have these standard features: compact size' ~ 1.62 Inches high x 5.75 inches wiele x 7.96
inches deep, and a weight of 3.3 pounds; low heat dissipation; de drive motor with precision servo speed control
(lnd integral tachometer; band positioner; same proprietary glass bonded ferrite/ceramic read/write head as used
in SIIllUml\ Imge floppy drives; Int,ernal write protect circuitry; activity light. and solid die eust chassis.
Typical applications for the SA455/465 are word processing systems, entry level micro-processor systems, in-
telligent calculators, program storagl:!,hobby computer systems, and other applications where low cost rilndoTl\ ac-
cess data storage is a requirement.
This
manual prOVides depot level maintenance Informatk:m necessary to maintain, trouble-shoot, and repair the
SA455/465. A separate OEM manual (PIN 39238) Is available which describes installation. interface. ,mel power
requirements useful for the applications of the drive.
Key Features
a. 0.5 Mbytes (SA455) or 1.0 Mbyte (SA465) storage capacity (unformatted)
b. Low power (12.5 wallts)
c. 125/250 kbits/second transfer rate
d. DC drive motor (eliminates ac requirements)
1.2 SPECIFICATION SUMM~lRY
1.2.1 Perfonnance Specifications
SA455 (40 Track)
Single Densit~1 Double Density
(PM) (MFM)
SA465 (80 Trad')
Single Denstiy Double Density
(FM) (MFM)
Capacity
(in bytes)
Unformatted
Per Disk
Per Surface
Per Track
250,000
125,000
3,125
1·1
500,000
250,000
6,250
500,000
250,000
3,125
1,000,000
500,000
6,250

Shugart SA455 Specifications

General

Brand	Shugart
Model	SA455
Category	Floppy Disk Drive
Language	English

Summary

SECTION I INTRODUCTION

1.1 GENERAL DESCRIPTION

Provides a general overview of the SA455/465 minifloppy disk drives.

1.2 SPECIFICATION SUMMARY

Summarizes the technical specifications of the SA455/465 drives.

1.2.1 Performance Specifications

Details the performance metrics like capacity, density, and transfer rates.

1.2.2 Functional Specifications

1.2.3 Physical Specifications

Covers environmental limits, power requirements, and mechanical dimensions.

1.2.4 Reliability Specifications

1.3 FUNCTIONAL CHARACTERISTICS

Explains the fundamental operational characteristics of the drive.

1.3.1 Read/Write and Control Electronics

Describes the components of the electronics package.

1.3.2 Drive Mechanism

Details the DC drive motor and spindle speed control.

1.3.3 Positioning Mechanics

Explains the band positioner and stepping motor for head positioning.

1.3.4 Read/Write Heads

Discusses the design and function of the read/write heads.

1.3.5 Recording Formats

1.4 FUNCTIONAL OPERATIONS

1.4.1 Power Sequencing

Describes the correct procedure for applying power to the drive.

1.4.2 Drive Selection

Explains how a specific drive is selected in a system.

1.4.3 Motor On

Details the process of turning the drive motor on and off.

1.4.4 Track Accessing

Explains how the read/write heads move between tracks.

1.4.5 Step Out

Describes the operation to move heads away from the disk center.

1.4.6 Step In

Describes the operation to move heads towards the disk center.

1.4.7 Side Selection

Explains how to select read/write heads for different disk surfaces.

1.4.8 Read Operation

1.4.9 Write Operation

1.4.10 Sequence of Events

Refers to timing diagrams for operational sequences.

SECTION II ELECTRICAL INTERFACE

2.1 INTRODUCTION

Introduces the division of the interface into signal and power lines.

2.2 SIGNAL INTERFACE

Details the signal interface, categorized into control and data lines.

2.2.1 Input Lines

Describes the input signals, distinguishing between multiplexed and non-multiplexed lines.

2.2.2 Input Line Terminations

2.2.3 Drive Select 1-4

Details the function of drive select lines for system configuration.

2.2.4 Motor On

Explains the control signal for the drive motor.

2.2.5 Direction Select

Describes the signal that determines head movement direction.

2.2.6 Step

Details the pulse signal for head stepping and its timing.

2.2.7 Write Gate

Explains the signal that enables writing.

2.2.8 Write Data

2.2.9 Side Select

Explains the signal for selecting the read/write head side.

2.2.10 Output Lines

Lists the electrical specifications for output signals.

2.2.11 Track 00

2.2.12 Index/Sector

Explains the signals generated by index and sector holes.

2.2.13 Read Data

Describes the signal carrying read data from the drive.

2.2.14 Write Protect

2.2.15 Ready

Describes the signal indicating the drive is ready for operation.

2.3 POWER INTERFACE

2.4 FRAME GROUND

SECTION III PHYSICAL INTERFACE

3.1 INTRODUCTION

Introduces the two connectors used for interface.

3.1.1 J1/P1 Connector

Details the 34-pin signal interface connector.

3.1.2 J2/P2 Connector

Details the 4-pin power connector.

3.2 FRAME GROUNDING

SECTION IV THEORY OF OPERATION

4.1 THEORY OF OPERATION

Lists the electronic components on the drive's PCB.

4.2 READ/WRITE OPERATIONS

Describes the fundamental read and write processes.

4.4 WRITE CIRCUIT OPERATION

4.5 READ CIRCUIT OPERATION

4.6 DRIVE MOTOR CONTROL

Explains the control functions for the drive motor.

4.7 INDEX DETECTOR

4.8 TRACK ZERO INDICATION

Explains the signal indicating the head is at track zero.

4.9 TRACK ACCESSING

Details the process of moving the heads between tracks.

4.9.1 Stepper Motor

Describes the stepper motor's role in track access.

4.9.2 Stepper Control

Explains the logic controlling the stepper motor.

4.10 DRIVE SELECT

4.11 WRITE PROTECT

4.12 READY

Explains the READY signal and its conditions.

SECTION V MAINTENANCE

5.1 MAINTENANCE EQUIPMENT

Lists necessary equipment for maintenance.

5.1.1 Alignment Diskette

Describes the specialized diskettes for alignment checks.

5.1.2 Exerciser PCB

Explains the function of the exerciser PCB for testing.

5.1.3 Special Tools

Lists special tools required for maintenance.

5.2 DIAGNOSTIC TECHNIQUES

Outlines methods for diagnosing drive problems.

5.2.1 Introduction

Introduces common causes of errors and diagnostic approaches.

5.2.2 "Soft Error" Detection and Correction

Details detection and recovery procedures for soft errors.

5.2.3 Write Error

Explains how write errors are detected and handled.

5.2.4 Read Error

Discusses read errors and their recovery.

5.2.5 Seek Error

Covers seek errors and methods for recovery.

5.3 TROUBLE-SHOOTING

Provides flowcharts for troubleshooting common issues.

5.4 ADJUSTMENTS

5.4.1 Head Radial Alignment

Explains the procedure for aligning the read/write heads radially.

5.4.2 Read/Write Head(s) Azimuth Check

Outlines the procedure to check head azimuth alignment.

5.4.3 Head Amplitude Check

Describes how to check the amplitude of read/write signals.

5.4.4 Track Zero Detector Assembly Adjustment

Details the adjustment procedure for the track zero detector.

5.4.5 Index/Sector Timing Adjustment

Explains how to adjust the index/sector timing.

5.4.6 Motor Speed Adjustment (Using a Frequency Counter)

Describes how to adjust motor speed using a frequency counter.

5.4.7 Write Protect Detector

Explains how to check the write protect detector.

5.4.8 Test Points On Drive PCB

Lists test points on the drive's printed circuit board.

5.5 REMOVALS AND REPLACEMENTS

5.5.1 Faceplate Latch

Details the procedure for removing and replacing the faceplate latch.

5.5.5 Clamp Hub

Details the removal and reinstallation of the clamp hub.

5.5.6 Write Protect Sensor and Index Detector

Explains how to remove and replace the write protect sensor and index detector.

5.5.7 Track Zero Photo Detector

Details the removal and replacement of the track zero photo detector.

5.6 RECOMMENDED INCOMING RECEIVING INSPECTION

5.6.1 Necessary Equipment

Lists the equipment required for incoming inspection.

5.6.2 Procedure

Provides the step-by-step procedure for incoming inspection.