PCC D3400 Service manual

MODEL NO. V ~£f22-
MODELS 03300 AND D3400
DISK DRIVES
-_ ..... PSlTEC
COmpUT'EA
..... _ COAPOAATlOn
PERTEC DIVISION
9600 IRONDALEAVENUE, CHATSWORTH, CA91311
OPERATING AND SERVICE MANUAL NO. 104630
'2; 1978 by Partee Computer Corporation

__ O. o-nber1978
FOREWORD
This manual provides operating and service instructions for the 03000 Series Disk Drives
Models 03300
and 03400, manufactured by the Pertec Division of Pertec Computer
Corporation, Chatsworth,
Cal iforn ia.
The content includes a detailed description, specifications, installation instructions, and
checkout of the disk drive. Also included are theory of operation and preventive
maintenance instructions. Section
VII contains a recommended spare parts list, photo
parts Iists and schematics.
All graphic symbols used in logic diagrams conform to the requirements of ANSI Y32.14
and all symbols used in schematic diagrams are as specified in Y32.2.
The disk drive models covered by this manual are listed below.
Cartridge Type Load
Model Tracks per Inch Bits per Inch
Fixed Disk Spindle Speed (rpm)
Front Top
D331 X 100 2200 X 1500 or 2400
D332X 100 2200 X X 1500
or 2400
D334X 100 2200 X X 1500
or 2400
D342X 200 2200 X X 1500
or 2400
D344X 200 2200 X X 1500
or 2400
ii

SERVICE AND WARRANTY
This Pertec Computer Corporation (PCC) product has been rigorously checked out by capable Quality control personnel. The design
has been engineered with a precise simplicity which should assure a new level
of reliability. Ease of maintenance has been taken
into consideration during the design phase with the result that all components (other than mecnanical components) have been
selected wherever possible from manufacturer's off·the-shelf stock. Should a component fail, it may be readily replaced from
PCC
Peripherals Division or your local supplier. The unit has been designed for plug·in replacement of circuit boards or major
components which will ensure a minimum
of eQuipment down time.
The Peripherals Division of PCC warrants products of its manufacture to be free from defect in design, workmanship, and material
under normal use and service for a period twelve
(12) months, or in the case of flexible disk products 120 days, after the date of
shipment. PCC Peripherals DiviSion agrees to repair or replace at its authorized repair center, without charge, all defective parts in
systems which are returned for Inspection to said center within the applicable warranty period; provided such inspection discloses that
the defects are as specified above, and provided further the equipment has not been altered or repaired other than with authorization
from
PCC Peripherals Division and by its approved procedures, not been subjected to misuse, improper maintenance, negligence or
accident, damaged by excessive current orotherwise had its serial number or any part thereof altered, defaced or removed. All defective
items released hereunder shall become the property
of seller. THIS WARRANTY IS IN LIEU OF, AND BUYER WAIVES, ALL OTHER
WARRANTIES, EXPRESSED OR IMPLIED, INCLUDING THOSE OF MERCHANTABILITY OR FITNESS FOR PURPOSE.
Please read the instruction manual thoroughly as to installation, operation, maintenance, and component reference list.
Contact your local PeC Service Division office for serviCing and maintenance on all
PCC equipment except flexible disk drives.
Flexible disk drives must be returned to the Peripherals Division factory Repair Depot for servicing.
Please contact the following groups for assistance with your specific problem.
SERVICE DIVISION SUPPORT
For all servicing reQuirements on PCC Peripherals Division equipment, please contact your local PeC Service Division office.
Additionally, the Service Division offers maintenance contracts, service contracts, third party maintenance contracts, etc.
PERIPHERALS DIVISION SUPPORT
NORTH AMERICA: 21111 Erwin Street, Woodland Hills, California 91367, [phone]
Our Woodland Hills facility is staffed to provide assistance in the following areas.
ORDER ADMINISTRATION
• For submitting your equipment orders.
• For obtaining delivery schedules on your equipment.
• For any other information on your orders. (Note also that
your local sales office can answer these questions.)
TRAINING SUPPORT
• Contact the Training Coordinator for class schedules, for
classes
to be held at your facilities, or for having a
customized training program developed.
SPARES SUPPORT
• Spares Order Administration for submitting your spare
requests (except Emergency).
• Spares Logistics Administrators to answer any Questions
on spares (including assistance in determining part
numbers).
NORTH AMERICA: 9600 Irondale Avenue, Chatsworth, California 91311, [phone]
Our Chatsworth facilities are staffed to provide aSSistance in the following areas.
REPAIR DEPOT
• For all Questions related to eQuipment sent back or being
sent back to the Repair Depot. This includes schedules,
repair costs, or refurbishments.
• All eQuipment being returned for repair should be sent
to
PCC Peripherals Division Repair Depot, 20400 Plummer
Street, Chatsworth, California, 91311.
TECHNICAL SUPPORT
• For eQuipment troubleshooting assistance.
• For applications information.
• For any other information or questions, or if you need
assistance and you just
don't know who to call.
EMERGENCY
SPARES
• For spare parts that are reQuired immediately.
EUROPE: 10 Portman Road, Reading, Berkshire RG3 1DU. England
Phone Reading
(734) 5821151 TWX (851) 847·101
Users of PCC Peripherals Division equipment in Europe should direct all inquires on the subjects listed for North America to the
Reading office.
ServiCing of all PCC Peripherals Division equipment is coordinated through the Reading office, including U.S. OEMs that ship
systems to Europe. PACIFIC
Users of PCC Peripherals Division equipment in Australia, Japan, New Zealand, and South America should direct all inQuiries on the
sub;ects listed for North America to their local pce representatives.
iii
6179

/
PROPRIETARY NOTICE
Information contained in this document is copyright by Pertec Computer
Corporation and may not be duplicated
in full or in part by any person without
prior written approval of Pertec Computer Corporation. Its purpose is to
provide the User with adequately detailed documentation so as to
efficiently
install, operate, maintain, and order spare parts for the equipment supplied.
Every
effort has been made to keep the information contained in this
document current and accurate
as of the date of publication or revision.
However, no guarantee is given or implied that the document is error-free
or
that it is accurate with regard to any specification_
iv

TABLE OF CONTENTS
SECTION I - GENERAL DESCRIPTION AND SPECIFICATIONS
1.1 Introduction ..................................................... 1-1
1.1.1 Model Identification ............... " ...................... 1-1
1.2 Purpose of Equipment ............................................ 1-2
1.3 Physical Description of Equipment
................................. 1-2
1.4 Functional Description
............................................ 1-3
1.5 Mechanical and Electrical Specifications
............................ 1-7
1.5.1 Interface Specifications
.................................... 1-7
SECTION 11- INSTALLATION AND INITIAL CHECKOUT
2.1 Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . .. 2-1
2.2 Uncrating the Disk Drive ......................................... " 2-1
2.3 Power Connections. . . .. . .. . . .. . . . . . . . .. . . .. . .. . . . . . . . . .. .. . . . . . .. 2-6
2.4 Initial Checkout Procedure. . . . . . . . . . . . . . . . . .. . . .. . . . . . . . . . . . . . . . . .. 2-6
2.5 InterfaceConnections. . . . . . . . . . .. . . . . .. . . . . . . . . . . . . . . . . . . . . . . . .. .. 2-8
2.6 Rack Mounting the Disk Drive .................................... " 2-11
2.6.1 Slides. . . . . . . . . . . . . . . . . .. . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . .. 2-11
2.6.2 Installation of Slide Set Part NO.1 02731 ...................... 2-11
2.6.3 Installation of Slide Set Part No. 103670 ...................... 2-12
SECTION 111- OPERATION
3.1 Introduction ................................................... " 3-1
3.2 Cartridge Handling and Storage .................................... 3-1
3.3 Disk Drive Preparation ............................................ 3-2
3.4 Cartridge Loading
and Unloading ................................. " 3-2
3.4.1 Loading a Cartridge, Front Load Models ...................... 3-2
3.4.2 Unloading aCartridge, Front Load Models. . . . . . . . . . . . . . . . . .
.. 3-4
3.4.3 Loading a Cartridge, Top Load Models ..................... " 3-4
3.4.4 Unloading aCartridge, Top Load Models ..................... 3-5
3.5 Selecting Write Protection. .. . .. . . . . . . . .. . . . . . .. . . . . . . . . . . . . . . . . . .. 3-8
3.6 Starting the Disk Drive ............................................ 3-8
3.7 Stopping the Disk Drive ........................................... 3-8
3.8 Designating Unit Number. . . . . . . . .. . . . . .. . . .. . . . . . . . . . . . . . . . . . . . . .. 3-8
3.9 CE Alignment. . . . . . .. . . . . . . . . . . . . . . .. . . . . . . . . . .. . . . . . . . . . . . . . . . .. 3-9
3.10 Periodic Maintenance. . . . .. . . . . . . . .. . .. . .. . . . . . . . .. . . . . . . . . . . .. . .. 3-9
3.11 Interlock Protection. . . . . . . . . . . . . . . . . . . .. . . . . . . . . . .. . . . . . . . . . . . . . .. 3-9
3.12 SafeCondition ................................................... 3-10
3.13 Emergency and Fault Detection .................................... 3-11
3.14 Manual Controls ................................................. 3-11
3.14.1 ON/OFF ................................................. 3-11
3.14.2 RUN/STOP .............................................. 3-11
3.14.3 READy .................................................. 3-12
3.14.4 SAFE ................................................... 3-12
3.14.5 PROT (Protect) ........................................... 3-12
3.14.6 Unit NumberSelectorSwitch ............................... 3-12
3.14.7 Write Protect Sw itehes. . . . . . . . .. . . .. . . . . . . . . . . . . . . .. . . . . . .. 3-12
3.15 03000 Interfacing .............................................. '" 3-13
3.16 Interface Inputs (Controllerto Disk Drive) ............................ 3-13
3.16.1 UnitSeteet Lines .......................................... 3-13
3.16.2 Platter Select. . . . . .. . . . . .. . .. . . .. . . .. . . .. . . . . . . . . . . . . . . . .. 3-13
3.16.3 Head Select .............................................. 3-13
3.16.4 CylinderAddress Strobe ................................... 3-14
v

TABLE OF CONTENTS (Continued)
Page
3.16.5 Cylinder Demand Address
(9 Lines) .......................... 3-15
3.16.6 Restore Initial Cylinder .................................... 3-15
3.16.7 WriteEnable ............................................. 3-15
3.16.8 Erase Enable
............................................. 3-15
3.16.9 Write Data Signal
......................................... 3-16
3.16.10 Read Enable .............................................. 3-16
3.16.11 Track Offset .............................................. 3-16
3.16.12 Activate Emergency Unload ... " ........................... 3-17
3.16.13 Start/Stop Disk Drive ...................................... 3-18
3.17 InterfaceOutputs (Disk Drive toController). . . . . . . . . . . . . . . . . . . . . . . . . .. 3-18
3.17.1 Ready ................................................... 3-18
3.17.2 Busy Seeking
(4 Lines) ..................................... 3-19
3.17.3 SectorPulse
............................................. 3-19
3.17.4 SectorCount Lines . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 3-20
3.17.5 Index Pulse .............................................. 3-21
3.17.6 Read Clock. . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . .. 3-21
3.17.7 Read Data. . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 3-21
3.17.8 Illegal CylinderAddress. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 3-21
3.17.9 File Protected ............................................ 3-22
3.17.10 Malfunction Detected. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
.. 3-22
3.17.11 Dual Platter . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 3-23
3.17.12 Double Track Drive . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 3-23
3.17.13 Special Interface Signal. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 3-23
SECTION IV -THEORY OF OPERATION
4.1 Introduction ..................................................... 4-1
4.2 Organization of the Disk Drive ...................................... 4-1
4.2.1 Main Chassis Group. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 4-1
4.2.2 PositionerAssembly ...................................... 4-4
4.2.3 Power Supply Assembly
................................... 4-4
4.2.4 Read/Write, Servo, and Logic PCBAs ........................ 4-4
4.2.5 Temperature Compensation PCBA (200 tpi Models) .. . . . . . . . . .. 4-5
4.3 Functional Subsystems ........................................... 4-5
4.4 Positionerand Positioner Electronics ............................... 4-5
4.4.1 PositionerAssembly ...................................... 4-5
4.4.2 PositionerElectronics . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
.. 4-7
4.5 Read/WriteOperations
............................................ 4-10
4.6 Read/Write Electronics. . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 4-11
4.6.1 Head Select . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . .. 4-11
4.6.2 Write Electronics ......................................... 4-11
4.6.3 Read Electronics .......................................... 4-13
4.7 Logic Functions and Control ....................................... 4-16
4.7.1 Logie Arrangement ........................................ 4-16
4.7.2 Disk Drive Functional Control ............................... 4-17
4.7.3 Spindle Speed Control. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 4-22
4.7.4 Position Control Logic
..................................... 4-25
4.7.5 SectorElectronics ........................................ 4-27
4.8 MotorControl. .. . .. . . . . .. . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . .. 4-30
4.9 Power Supply. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 4-31
4.10 Temperature Compensation (200 tpi) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 4-33
vi

TABLE OF CONTENTS (Continued)
Page
SECTION V - DETAILED ELECTRICAL AND LOGIC DESCRIPTION
5.1 Introduction ...........................•........•................. 5-1
5.2 Logic Term Mnemonic Identification .. .. . .. . .. . . . . •• .... .. • .... .. ... 5·1
5.3 Servo PCBA ..................................................................... 5-1
5.3.1 Voltage Regulators. . . . . . . •. . . . . . .. . . . . . •. . . . . . . . •. . . . . •. .. 5-3
5.3.2 Positioner Servo Electronics. .. .. . . .. .. . . ••.. . . . . •. . .. .. . • .. 5-3
5.3.3 AC MotorControl Circuits. . •. •. . • •. •. . •. . ••. •. •••••. . . ••. .. 5-9
5.3.4 Cartridge Lock Solenoid Driver .............................. 5-11
5.3.5 Power Clear Control Circuit. ................................ 5-11
5.4 Read/Write PCBA .........•...........•.........•...••.•......... 5-13
5.4.1 Head Selection Matrix and Select Amplifier. . ••. . •. . . . . •. ••. .. 5-13
5.4.2 Writeand Erase Drivers ..•. .. . . . .. . .. . . . ••.. . .. . . .. . .. . •. .. 5-15
5.4.3 Read Switch ......•..............•...........••........... 5·18
5.4.4
Read Preamplifier ....••..••••..•.....•••••.•.........••.•. 5·16
5.4.5
Filter. •. . . . . . . . •. . •. . ••. .•.•. .••. . . .. . . . •. . •••••. . . . . . • .• 5-18
5.4.8 Variable Gain Amplifier ................................... 5-18
5.4.7 Peak Detector, Squarer, and Pulse Former .••.............•... 5-18
5.4.8 Data Decoder CI rcuitry •. . ••. ••. •••.. .•. . . •••••••••. . . . ••• .• 5·17
5.~.9 Emergency Condition Detection. .. . .•. .•. ••. . .. ••••••. ••. . .. 5-17
5.5 Logic
PCBA ...........•..............•......•.•....•.......••... 5-19
5.5.1 Sheet 2 (Schematic No. 102830) ............................. 5-19
5.5.2 Sheet 3(Schematic No. 102830) ............................. 5-25
5.5.3 Sheet 4(Schematic No.1 02830) .. . . .. .. . . . . .. ........ . . . .... 5-29
5.5.4 Sheet 5 (Schematic No.1 02830) . . •. .. . .. . . .. . .. . . .. .. . . . . . .. 5·35
5.6 MotorControl PCBA 5-43
5.7 Temperature Compensation PCBA . . .. . •. . •. .. . . .. . •. . . . . . . . . . . . . • .. 5-45
SECTION VI -MAINTENANCE AND TROUBLESHOOTING
6.1 Introduction . . . .. . .. . . .. . .. . .. .. . .. . . .. •. •. .. . .. . . .. ••••. . .. . . . .• 6-1
6.2 Fuse Replacement .. , ............................ " ............... 6-1
6.3 Scheduled Maintenance. .. . .. . .. . .•. .. . . . . .. . . •. . .. . .. . .. . .. . . .. .. 6-1
6.3.1 Maintenance Philosophy ................................... 6-1
6.3.2 General Maintenance. . . .. . .. . .. . .•. .. . . . . •. ••••. .. . . . ••• .. 6-3
6.3.3 General Precautions. .. . .. . .. . .. . . . . .. . . . . . . . . ••. .. . . .. . . .. 6-3
6.4 Cleaning the Disk Drive .................................•.......... 6-3
6.4.1 Cleaning the Heads ......•.....•..•.....••...••......•••.. 8-4
6.4.2 Cleaning the Fixed Disk.. . ........ . . .. . .. . .. . . .. • .. . .... . .. 6-5
8.4.3 Cleaning theSpindle . . .•. . . . . . . . . •.. . . .. . .. . . .. . .. . .. . .. .. 6-8
6.4.4 Cleaning the Positioner .•..•......•......•................. 6-8
6.4.5 Cleaning the Base Casting, Dust Cover. and Filters ..•......•.. 6-8
6.5 Part Replacement Adjustments ...•................................. 6-9
8.6 Electrical Adjustments. .. .. . . .. . .•.. . . . . . .. . .. . . .. . .. . . . •. . . . .. .
.. 6-9
6.6.1 Adjustment Philosophy.. . .. . .... . .. . . . •. . .. . .. •. •. . . . •. ... 6-10
6.6.2 10vand5vRegulators ...................................... 6-10
6.8.3 AC Motor Speed Control .. .. . . .. . .•. .. . . . . .. . . . . . . . . . . . . . .. 6-12
6.7 Positioner Servo Calibration ....................•.................. 6·14
6.7.1 Positioner Preparation forStaticTests .....•..•.............. 6·14
S.8 Static PositionerAdjustments ...........•..............•••......... 6-16
6.8.1 X + 0 Gal n and Balance. . .. . . .. . .. . .. . . . . . . . . . . . . . . . . . . . . .. 6·16
6.8.2 X + 90 Gain and Balance. . . •. . .. . .. . . . . . . . . . . . . . . . . . . . . . . .. 6-18
vii
!53DD

TABLE OF CONTENTS (Continued)
Page
6.8.3 X + 0and X + 90 Signal Polarity and Quadrature Check ........ 6-1S
6.8.4 Heads Retracted Signal Check . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 6-21
6.8.5 Index Balance ............................................ 6-22
6.S.6 Velocity Transducer Phasing. .. . . . . . . . . . . . . . .. . . . . . . . . . . . . .. 6-24
6.8.7 PositionerVoice Coil Polarity Check. . . . .. . . . . . . . . . . . . . . . . . .. 6-25
6.8.S Power-Down Procedure. . .. . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . .. 6-25
6.9 Dynamic Positioner AdJustments. . .. . . . . . . . . . . . . . . .. . . . . . . . . . . . . .
.. 6-26
6.9.1 Positioner Preparation, Dynamic Tests. . . . . . . . . . . . . . . . . . . . . .. 6-26
6.9.2 Dynamic Adjustments .. ; .................................. 6-26
6.9.3 Dynamic Reticle-to-Scale Phase Adjustments. . . . . . . . . . . . . . . .. 6-30
6.9.4 Current Adjustment .. . .. . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . .. 6-31
6.9.5 Seek-Time Adjustment ..................................... 6-32
6.9.6 Overshoot Test Procedure. . .. . . . . . . . . . . . . . .. . . .. . . . . . . . . . .. 6-33
6.9.7 Overshoot Adjustment Procedure
........................... 6-35
6.9.8 Index to Quadrature Clock Relationship ...................... 6-35
6.9.9 Overshoot and Settling Response Procedure. . . . . . . . . . . . . . . . .. 6-39
6.10 Performance Checks. : . . .. . . . . . . . . . . .. . . . . . . . . . . .. . . . . . . . . . . . . . . .. 6-41
6.10.1 Servo and PositionerTest . .. . . . . . . . . . . . . . . . .. . . . . . . . . . . . . .. 6-41
6.10.2 Spindle Speed Accuracy Test .. .. . . . . . . . . . . . . . .. . . . . . . . . . . .. 6-41
6.11 Sector Phase-Lock-Loop Adjustment. . . .. . . . . . . . . . . . . . .. . . . . . . . . . . .. 6-42
6.11.1 Test Configuration .. . .. . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . .. 6-43
6.11.2 Test Procedure ........................................... 6-43
6.11.3 Adjustment Procedure. .. . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . .. 6-43
6.12 Read DecodeCircuit Adjustments .................................. 6-44
6.12.1 Read Pulse Narrow (RPN) Pulsewidth Adjustment ............. 6-44
6.12.2 'Ones' Window Setting
..................................... 6-45
6.12.3 Data and Clock Pulsewidth ................................. 6-46
6.13 Temperature Compensation (200 tpi Only) ........................... 6-47
6.13.1 Temperature Compensation Tests
and Adjustments. . . .. . . . . . .. 6-47
6.13.2 Scaling ResistorVerification. . . . . . . . . . . . . . . . . . . . . . . . .. . . . . .. 6-48
6.13.3 Environment Temperature Adjustment . . . . . . . . . . . . . . . . . . . . . .. 6-48
6.14 CE Alignment Procedure .......................................... 6-51
6.14.1 Front Loading CE Disk Cartridge .. . . . . . . . . . . . . . . . . . . . . . . . . .. 6-51
6.14.2 Top Loading CE Disk Cartridge .............................. 6-52
6.14.3 CE Cartridge Stabilization .................................. 6-53
6.14.4 Test Configuration -All Models ............................ 6-53
6.14.5 Radial Alignment -Front Load
............................. 6-54
6.14.6 Circumferential Alignment -Front Load
..................... 6-60
6.14.7 Radial Alignment -Top Load .............................. 6-63
6.14.8 Circumferential Alignment -Top Load ...................... 6-67
6.15 Cartridge InterlockSystem -Front Load Models ..................... 6-69
6.15.1 Checking the Interlock System -Front Load Models ........... 6-69
6.15.2 Adjusting InterlockSystem ................................. 6-69
6.16 Cartridge InterlockSystem -Top Load Models ....... , ............... 6-71
6.16.1 Checking the InterlockSystem. . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 6-72
6.16.2 Adjusting the InterlockSystem .............................. 6-72
6.17 Bezel and PowerSwitch ........................................... 6-75
6.17.1 Removal of Bezel ......................................... 6-75
6.17.2 Installation of
Bezel .. .. . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . .. 6-75
6.17.3 Removal of Power Switch Bracket ........................... 6-75
viii

TABLE OF CONTENTS (Continued)
Page
6.18 Magnetic Transducer Gap ......................................... 6-76
6.18.1 Upper Transducer Test and Adjustment -Top Load Models ..... 6-76
6.18.2 LowerTransducer Alignment -Top Load Models ............. 6-77
6.18.3 LowerTransducer Alignment -Front Load Models ............ 6-77
6.19 Disk Drive Pulley System ... .. . . . . . . . . . . . . . .. . . . . . . . . . . . .. . . . . . . . .. 6-78
6.19.1 Belt Removal. . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . .. . . . .. 6-78
6.19.2 Belt Replacement .. . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . .. 6-78
6.20 Static Discharge Contact .......................................... 6-80
6.21 Care and Handling of Heads ....................................... 6-81
6.21.1 Load Pin Seating. . . .. . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . .. 6-82
6.22 Head Removal and Installation ..................................... 6-82
6.22.1 Head Removal Procedure ................................... 6-82
6.22.2 Head Installation Procedure
... .. . . . . . . . . . . . . .. . . . . . . . . . . . .. 6-85
6.23 Lamp/Lens Assembly Removal and Installation ....................... 6-87
6.23.1 Lamp/Lens Assembly Removal ............................. 6-87
6.23.2 Lamp/Lens Assembly Installation ........................... 6-87
6.24 Reticle Removal and Installation ........................ : . . . . . . . . . .. 6-87
6.24.1 Reticle Removal .......................................... 6-87
6.24.2 Reticle Installation . .. . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . .. 6..a8
6.25 Scale Assembly Removal and Installation ............................ 6-88
6.25.1 Scale Assembly Removal. .. . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . .. 6-88
6.25.2 Scale Assembly Installation ................................ 6-89
6.26 Air Filter. . . . .. . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . .. . . .. . . . . . . . . . .. 6-89
6.26.1 Pre-Filter Cleaning . .. . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . .. 6-90
6.26.2 Removal of Absolute Filter
................................. 6-90
6.26.3 Replacement of Absolute Filter ............................. 6-90
6.27 Power Supply. . .. . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . .. 6-90
6.27.1 Power Supply Removal .................................... 6-91
6.27.2 Power Supply Installation .................................. 6-91
6.28 Drive Motor. . .. . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . .. 6-92
6.28.1 DrIve MotorRemoval ...................................... 6-92
6.28.2 Drive MotorInstallation .................................... 6-92
6.29 MaintenanceTools ............................................... 6-94
SECTION VII - PARTS LISTS AND SCHEMATICIASSEMBLY DRAWINGS
7.1 Introduction ..................................................... 7-1
7.2 Illustrated Parts Breakdown (IPB) ................................... 7-1
7.3 Recommended Spare Parts ........................................ 7-1
7.4 Part NumberCross Reference List ... , .............................. 7-1
7.5 Integrated Circuit Pin Summary .................................... 7-1
7.6 PCBA Interconnections ........................................... 7-1
APPENDIX A - 03000 MNEMONICS
APPENDIX B - TROUBLESHOOTING
ix

Figure
1-1
1-2
1-3
1-4
1-5
1-6
1-7
2-1
2-2
2-3
2-4
2-5
2-6
2-7
2-8
2-9
3-1
3-2
3-3
3-4
3-5
LIST OF ILLUSTRATIONS
Page
Model Identification ., ............................................... 1-1
03000 Disk Drive, Top Load Model .................................... , 1-3
03000 Disk Drive, Front Load Model. . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . .. 1-3
Functional Block Diagram ............................................ 1-4
Mechanical Sectoring ......... , . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 1-5
Platter, Cylinder, Track Relationship ................................... 1-6
InterfaceConfiguration .............. , ................................ 1-9
Cartridge Receiver and Front Door Shipping Restraints
................... 2-2
Rack Mounting the 03000 Disk Drive
................................... 2-3
Component Identification, Logicand Servo PCBAs Extended
.............. 2-4
Component Identification ............................................ 2-4
Counterweight in Shipping
Position. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 2-5
Counterweight in Operation Position . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . .
.. 2-5
InterfaceConnector Board Installation .................................. 2-10
Mounting Bracket to EIA Cabinet; Hardware Orientation for
Use
with PIN 103670 ................................................. 2-13
Inside Measurement Between Slide Brackets ............................ 2-14
Cartridge Loading/Unloading, Front Load Models
........................ 3-3
Cartridge Loading/Unloading, Front Load Models ........................ 3-3
Cartridge Inserted, Front Load Models
..... , ............................ 3-3
Cartridge Loading, Top Load Models (Lock Arm Away from Disk Area)
...... 3-6
Cartridge Loading, Top Load Models (Release/Lock Down) ................ 3-6
3-6 Cartridge Loading, Top Load Models (Release/Lock Up)
.................. 3-6
3-7 Cartridge Loading, Top Load Models (Cartridge Positioned Over
Adapter Bowl . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . .. 3-6
3-8 Cartridge Loading, Top Load Models (Cartridge Loaded,
Release/Lock Down) ................................................. 3-7
3-9 Cartridge Loading, Top Load Models (Lock Arm Over Cartridge Cover)
...... 3-7
3-10 Cartridge Unloading, Top Load Models ................................. 3-7
3-11 Cartridge Unloading, Top Load Models ................................. 3-7
4-1 03000 Disk Drive Organization ......................................... 4-2
4-2 Positionerand Positioner Electronics, Functional Block Diagram
........... 4-35
4-3 Double Frequency Recording Flux and Pulse Relationship
................. 4-11
4-4 Read/Write Electronics, Functional Block Diagram .. , .................... 4-37
4-5 Peak Detector and SquarerWaveform
........ , . . . . . . . . . . . . . . . . . . . . . . . . .. 4-14
4-6 Double Frequency GeneratorTimi ng Relationship , . . . . . . . . . . . . . . . . . . . . . .. 4-14
4-7 Data DecoderTiming Relationship
..................................... 4-15
4-8 Digital Sequential Machine Block Diagram
.............................. 4-18
x

LIST OF ILLUSTRATIONS (Continued)
Figure
Page
4-9 Start/Stop Control, Functional Block Diagram .......................... , 4-39
4-10 SpindleSpeed Control, Functional Block Diagram ....................... 4-41
4-11
Position Control Logic, Functional Block Diagram ....................... 4-43
4-12 Sector Electronics, Functional Block Diagram ........................... 4-45
4-13 Power Supply, Functional Block Diagram. . .. . . . . . . . . . . . . . . .. . . . . . . . . . .. 4-32
4-14
Transformer Primary Connections ..................................... 4-33
4-15 Temperature Compensation, Functional Block Diagram ................... 4-47
5-1 Servo PCBA Test Point and Connector Placement ........................ 5-2
5-2 Position Transducer Output Signals. .. . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . .. 5-6
5-3
Position Transducer Signal AmplifierOutputs . . . . . . . . . . . . . . . . . . . . . . . . . .. 5-6
5-4 Fault Detection Waveforms ........................................... 5-12
5-5 Read/Write C PCBA, Test Point and Connector Placement ............... 5-14
5-6 Logic PCBA, Test Point and Connector Placement ....................... 5-20
5-7 MotorControl PCBA, Test Point and Connector Placement. . . . . . . . . . . . . . .. 5-43
5-8 Temperature Compensation PCBA, Test Point and Connector Placement. . .. 5-45
6-1 Slider Defects and Head Contamination which Require Cleaning Action ..... 6-6
6-2 Slider Defects and Head Contamination which Require Head Replacement ... 6-7
6-3
AC MotorSpeed Control Signal Pulsewidth ............................. 6-13
6-4 Position Transducer Signal Amplifier Outputs . . . . . . . . . . . . . . . . . . . . . . . . . .. 6-17
6-5 X + 0 Analog Signal Added to X + 90 Digital Signal. . . . . . . . . . . . . . . . . . . . .. 6-20
6-6 X + 0Waveform, One-Track Repetitive Seek ............................ 6-28
6-7 Balanced Waveform, One-Track Repetitive Seek ......................... 6-28
6-8 Analog Waveform Limits, One-Track Repetitive Seek ..................... 6-28
6-9 X + 0Waveform Crossover .. . .. . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . .. 6-29
6-10 Current Waveform After Adjustment of R111 ............................. 6-33
6-11 Velocity Feedback Waveform, TP16 . .. . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . .. 6-33
6-12 X + 0Waveform 000-001 Repetitive Track Seek .......................... 6-34
6-13 SPRCG, SPTIG, SPQCG Signals, Repetitive Restore Mode ................ 6-36
6-14 Correct Relationship Between SPQCG and SPTIG Signals, Extended ........ 6-37
6-15
Index Signal, TP3, Repetitive Restore Mode ............................. 6-38
6-16 X + 0 Overshoot and Settling Response Waveforms ...................... 6-40
6-17 X + 90 Waveform for Long Track Seeks ................................. 6-41
6-18 Quadrature Relationship Between Sector Phase-Lock-Loop Square Waves ... 6-42
6-19
Read Pulse Narrow1'0nes'Window . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . .. . .. 6-44
6-20
Read Clock/Read Data Pulsewidth ..................................... 6-46
6-21 CylinderAddress Temperature/Voltage Conversion at TP4 ................ 6-49
xi
83CD

LIST OF ILLUSTRATIONS (Continued)
F~u~ P~e
6-22 TP3 Temperature/Voltage Conversion .................................. 6-49
6-23 TP2 Temperature/Voltage Conversion. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 6-50
6-24 Approximately Aligned Front Load Disk Drive ............................ 6-54
6-25A Head Alignment (IBM CE Cartridge), Track100, Front Load DiskDrives .••... 6-56
6-25B Head Alignment (3M CE Cartridge), Track100, Front Load Disk Drives •..... 6-57
6-26 Radial Alignment, Heads Aligned. .. . . . . •. . . . . •. . . . . . . . . . . ••••••. . . ••
.. 6-58
6-27 Radial Alignment. . ••. •. . . . . . . . .. . . ••. •. . . . . •. .. . .. . . . . . . •. •. •••. . . .. 6-59
6-28 Circumferential Alignment, Front Load Drives . . . . . . . . . . . . .. •. . . . . . . . . •
.. 6-61
6-29 Compromise Circumferential Alignment, Front Load Drives ............... 6-61
6-30 Radial Alignment, Head Aligned. . . .. . . . . . . . . . . . .. . . . . . . . . . . . . •. . . .. . .. 6-63
6-31 Radial Alignment .................................................... 6-65
6-32
Solenoid Location and Clearance .............................•••.•••.. 6-70
6-33 Retracted Solenoid Plunger and Lock-Arm Clearance . . . . . . . . . . . . . . . . . . • .. 6-73
6-34 AdapterCasting and Lock-Arm Clearance. . . . . . . . . . . . . . . . . . . . . . . . . . . •. .. 6-73
6-35 Upper Magnetic TransducerGap .................................••••.. 6-74
6-36 GO/NO GO Adjustment Tool, End View ................................ 6-74
6-37 Switch Bracket and Air Filter Retaining Screw Locations ......•........... 6-75
6-38 UpperTransducer Alignment, Top Load Only. . . . . . . . . . . . . . . . . . . . . . . . . . .. 6-77
6-39 Lower Transducer Alignment, Front and Top Load ........................ 6-78
6-40 Belt Treading Pattern ......................................•.•....... 6-79
6-41 Examples of Proper Care and Handling of Heads. . . . •. . . . . . . •••. ••••. . . .. 6-81
6-42 Examples of ImproperCare and Handling of Heads. . . . . . . . . . . ••. . . . . . . . .. 6-82
6-43 Load Pin Seating . .. . . . . . . . . . . . . . .. . . •. .. . . •. . . . . •. . . . •••. ••.. . . . . .
.. 6-83
6-44 Heads Installed on Positioner Carriage (200 tpi) .......................... 6-84
6-45 Head-to-Carrlage Adjustment ......................................... 6-86
6-46 Drive MotorCable Routing
............................................ 6-93
6-47 Drive Motor Replacement ............................................. 6-93
7-1 03000 Disk Drive Photo Parts Index, FrontView. .. .. . . . . . . . . .. • .. .. • .. ... 7-2
7-2 03000 Disk Drive, Photo Parts Index
...........•.•..........••..•••••... 7-4
7-3 03000 Disk Drive Photo Parts Index (Top Load Models)
•.......•.••...•••.. 7-6
7-4 03000 DiskDrive Photo Parts Index, PCBAs in Extended Position
••.•...... 7-8
7-5 03000 Disk Drive Photo Parts Index, Bottom View. . . . . . . . . . . . . . . . . . . . . . .. 7-10
7-6 03000 Disk Drive Photo Parts Index, Power Supply Assembly .............. 7-12
7-7 03000 Disk Drive Photo Parts Index (200 tpi Models Only) ................. 7-14
7-8 PCBA Interconnections, Block Diagram ................................ 7-25
A-1 MnemonicConstruction .................................•.•.••..••... A-1
xii

LIST OF TABLES
Table Page
1·1 Mechanical and Electrical Specifications ........•..•.........•...•..... 1-8
2·1 Power Cord ColorCode ................•...........•.....•.•.•.....•. 2-7
2·2 Interface Input/Output Lines ............................•............. 2-9
3-1 Platter and Head Selection.. . . . . . . .. .... .. .. .. . . . . . . . . . . . .......... ... 3-14
3·2 TRACK OFFSET Operation ............•..........•................... 3-17
5-1 Clock Countdown ................. .. .. . . . . . .. . . . . .. . . . . . . . . . . . . . . . .. 5-21
6-1 Fuse Requirements. •. •. . . . .• .. . . .. . . •. .. . . •. . . . . •. . . . . •. •. . . . . . . •. .. 6-1
6-2 Preventive MaintenanceSchedule ...................................... 6-2
6-3 Part Replacement AdJustments. . . . . . . . .. . . . . . .. . . . . . . . . . . . . . . .. . . . . . .. 6-9
6-4 Repetitive Track Seek Settings forOvershoot and Settling Response Tests. .. 6-39
6-5 RPN Pulsewldth Values ............................ '" ................ 6-45
6-6 VoltageTolerance at TP4 ..... '. . . . . . . . .. . . . . . .. . . . •. . . . . . . . .. . . . . . . . .. 6-67
6-7 Cylinder Address Voltage Limitsat TP4 . . •. . . . . .•. . . •. . . . . . . . . . •. . . . •. .. 6-50
6-8 UpperTransducer Calibration Data. .. . . . . . . . .•. . . •. •. . . . .•. •. •. . . . . •. .. 6-76
6-9 Pulley and Belt Identification. . . . . . . . .. . . . . .. . . . . .. •.. . . .. . •••. . . •. . . .. 6-79
7·1 03000 Disk Drive Photo Parts Index .............. " ........ " .......... 7-3
7-2 03000 Disk Drive Photo Parts Index ........................•........... 7-5
7·3 03000 Disk Drive Photo Parts Index (Top Load Models). . . . . .. . . .. . . . . . . . .. 7-7
7-4
03000 Disk Drive Photo Parts Index .................................... 7-9
7-5 03000 Disk Drive Photo Parts Index ..............•.........•.........•. 7-11
7-6 03000 Disk Drive Photo Parts Index .................................... 7-13
7-7 03000 Disk Drive Photo Parts Index ........................•........... 7-15
7-8 Recommended Spare Parts List .........................•............. 7-16
7-9 Part NumberCross Reference. .. . . . . . . . . . . . . . . .. . . . .. . . . . . . . . .•.. . . . .. 7-17
7-10 IC Power and Ground Pin Summary .................................... 7-20
7-11 Function Control Summary ..•.•................................•..... 7-20
7-12 PCBA Interconnections ....................•......................... 7-21
A-1 Functional Group Classification .....................................•. A-1
A-2 Signal Type Classification . •. . . . .. . . . . . . . . . .. . .. . . . . . . . .. . . . . . . . . . . . .. A-2
A-3 03000 Mnemonics
.................................................•. A-3
xiii

SEcnON I
GENERAL DESCRIPTION AND SPECIFICAnONS
1.1 INTRODUCnON
This section provides a physical description, functional description, and specifications for
the 03000 Series Disk Drive, Models 03300 and 03400, manufactured by the
PERTEC
Division of PERTEC ComputerCorporation, Chatsworth, california.
1.1.1 MODEL IDENTIFICATION
To simplify identification of 03000 Series Disk Drives, Figure 1-1 Illustrates the breakdown
of code combinations employed by PERTEC.
03XXX-XXXX-XXX
'L- Optional Designator
WX =Write Protect Switches
XU =UnitNumber SelectorSwitch
SC = Special Configuration-
OptionallnputiOutput Interface
N =Normal
C =Compatible--
S =Special-
Number of Sectors
SectorConfiguration
I = Electronic on Index Only Cartridge
E = Electronic on Multi-Notched Cartridge
M = Mechanical
Speed Classification (Spindlerpm)
1 =1500
2 =2400
RemovableCartridgeIFixed DiskConfiguration
1 =5440-type Cartridge Only (100 tpi)
2 = 5440-type Plus Fixed Disk (100
or 200 tpi)
3 =2315-typeCartridge Only (100tpi)
4 =2315-type Plus f'lxed Disk (100 or 200 tpi)
Density
3 =
2200 bpi, 100 tpi
4 =
2200 bpi, 200 tpi
Basic Designator
•As specifically ordered; not described in this manual.
--Electricallycompatible with controllers designed to interlace to another manufacturer's
diskdrive.
Figure1-1. Model Identification
1-1

Referring to Figure 1-1, the following illustrates the ease of Identification, using Model
D3322-1064-NWU as an example.
(1) 03 is the basic prefix used on all 03000 Series.
(2) 3 in thethird position indicates a1 00 tpi device.
(3) 2 in the fourth position indicates a5440-type cartridge plus fixed disk.
(4) 2 in the fifth position indicates aspindle speed of 2400 rpm.
(5) I in the sixth position indicates that the 5440-type cartridge to be utilizea has a
normal index notch only.
(6) 064 in theseventh, eighth, and ninth positions indicate a64-sectordevice.
(7) N in the tenth position indicates a Normal (standard) interface configuration
option.
(8) W in the eleventh position indicates the unit is provided with Write Protect
switches.
(9) U in the twelfth position indicates the unit is provided with Unit Number Selector
switch.
1.2
PURPOSE OF EQUIPMENT
The disk drive has the capability of recording digital data on IBM 2315- or 5440-type
cartridges utilizing the double-frequency method of recording. Spindle speeds up to 2400
rpm and data storage of up to101.5 megabits are provided by the 03000 Series Disk Drive.
Data recorded on the removable media
can be recovered when played back on any 03000
Series having the same cartridge type, density, format,
and speed.
The 03000 is a rotating magnetic memory capable of storing and retrieving data in digital
form.
The storage media is an aluminum disk coated on both surfaces with a layer of ferro-
magnetic material suspended in a binder. Data
are stored serially in concentric tracks on
both surfaces of the disk.
The basic disk drive is available
as a single-disk or dual-disk device. All models are
capable
of accepting removable media with the removable disk enclosed in a cartridge
assembly. Depending
on the model, the disk drive will accept either the top loading
5440-type or the front loading 2315-type cartridge.
Single-disk models
have provisions for the removable cartridge only; dual-disk models
have provisions for the removable cartridge and a fixed disk enclosed within the drive
housing.
The disk drive is intended for use in conjunction with a formatter
or controller to provide
rapid access mass memory for small and medium size computers.
An integral power supply is included in the disk drive
and operates directly from Single
phase power.
1.3
PHYSICAL DESCRIPTION OF EQUIPMENT
The top loading configuration of the 03000 Disk Drive utilizes a 5440-type cartridge and is
shown in Figure 1-2; the front loading configuration utilizes a 2315-type cartridge and is
shown in Figure1-3.
1-2

Figure1-2. 03000 Disk Drive,
Top Load Model Figure1-3. 03000 Disk Drive,
Front Load Model
All electrical and mechanical components necessary to operate the disk drive are mounted
Internally within the housing of the drive. The housing is designed to be mounted in a
standard 1g..inch EIA rack, orutilized
as a table top unit.
All models are equipped with the necessary electronics to provide recording and retrieval
of stored data.
Access
to the interior of the disk drive Is gained by removing the dust cover. This cover is
mounted
to the base assembly and protects the interior of the drive from dust and other
environmental contam;nants.
The operational controls, which include indicators that are illuminated when the relevant
functions are being performed, aremounted on the front control panel. These controls are
acces~ible t('l the operator at all times. Power is supplied through a strain·relieved cord
having a standard 3--prong plug. Interface signals are routed through the interface cables
to input/output connectors located within the disk drive housing.
The major electronic assemblies are located near the rear
of the drive. These assemblies
are mounted to
allow ready access without the use of extender cards or other special
tools.
1.4 FUNCTIONAL DESCRIPTION
Data storage is accomplished by utilizing the non-contact method of magnetic recording.
The disk recording media is rotated at a constant speed and the recording heads, capable
of either reading orwriting, are flown over the surface of the disk on a gas-film bearing and
positioned
to the appropriate track by the use of a voice-coil type of linear motor
positioner. This type of disk drive, which utilizes a single head per surface, is referred to
as a moving-head
disk drive.
Addressing
of the stored data isaccomplished by specifying thedesired head position and
the applicable segment
of the disk surface. The read/write electroniCS are capable of
non·simultaneous reading or writing of data on a single surface at a given time.
Figure1-4 is a functional block diagram
of the disk drive, which consists of the disk drive
control logic, start and stop control plus auxiliary controls, and the necessary select and
enable gating.
1-3

SECTOR
INDEX
CClINT
SECIOR
HE CIRONICS
I· 0 CONIRlJL
SIGNALS
DISI:: DRIVE
FUNCIION CONIlCL
tLECTIONICS
L-----------J.;ONTROL SIGN ... LS
REMOVABLE DISK--_
CAIIRIOGE
HEAD
Sf LEO
WRIlE ELEORONKS
IIfAD ELECTRONICS
CLOCK
0 ... 1 ...
POSITIONER
SPINDLE SPUD
CONTROL ElECTRONICS
MOTOR
TRANSDUCER ______ ../
POWEl SUPPL Y
-------------------------~--POWf. LINE
Figure 1-4. Functional Block Diagram
DC powER TO
ElECTRONICS
POSITIONER
SUVO
ElECTRONIC>
1648

The positioner servo electronics comprise a major functional block. As the disk rotates at
a fixed speed, and the recording heads are flown over the disk surface, the positioner is
controlled
In both the velocity and position modes. The positioner moves to the correct
address undercontrol
of the pOSitioner servo control electronics. Data are then written on
the desired surface by selecting thecorresponding
head through the head select network.
The read /write electronics are subdivided into three functional blocks consisting of the
head select network, the write electronics, and the read channel. Write data causes write
current to
be switched according to the pulse train on the WRITE DATA SIGNAL line. The
storage surfac~ will then be magnetized accordingly.
During retrieval
of the stored data, the corresponding head is again selected by the head
select network and the signal obtained from the read/write head Is processed by the read
channel Into separate READ DATA and READ CLOCK Signals for transmission via the
interface. The particularsegment
of the diskwhich Is pasSing under the read/write head is
specified by the sectorpulseand sector count lines from the sectorelectronics.
Control of the rotational speed
of the disk is accomplished by the speed control
electronics group which establishes a known, fixed speed
for the disk rotation within ±1
percent
speed tolerance. The sector electronics block provides pulses at the Interface
which electrically subdivides the disk Into a number
of sectors for the purpose of
addressing datastored on the disk. Figure1·5 Illustratesthe subdiviSion of a platter Into 8
sectors by means
of mechanical sectoring.
The air system consists
of an absolute filter preceded by a pre.fllter, and a blower driven
by the same motor which provides drive
to the disk spindle. This air system provides a
well-filtered flow
of clean air in thedisk area to remove contaminants.
Power to the various electronic circuits Is provided by
an integral power supply. This
power provides dc voltages at suitable levels derived from the linevoltage.
All major components are mounted to the base assembly. An aluminum alloy casting
Is
the basic component of the base assembly. Mounted onto the casting is the drive
mechanism'which consists
of a precision spindle, an ac Induction drive motor, a squirrel
cage blower, and
an idler system. Power to rotate the blower and spindle is transmitted
from thedrive motorby means
of a flat belt. The Idler system provides constant tension of
the beltand compensates forstretch of the belt.
SECTOR SLOT
INDEX SLOT
TOP VIEW
Figure1-5. Mechanical Sectoring
1-~

Mounted to the spindle assembly isa ring with equally spaced notches and one additional
notch spaced midway between two of the other notches; this is referred to as the Phase
Lock Ring and is used for sectoring
and speed control.
In dual disk models, a fixed disk is mounted to the spindle assembly; it is referred to as
the lower disk but is not removable in the same manner as the cartridge. The second
disk is contained within the removable cartridge and is driven by a magnetic clutch which
is located
on top of the spindle assembly. A precision ground cone on the end of the
spindle suitably locates the hub
of the disk which is mounted in the cartridge. Rotary
motion is imparted to both disks simultaneously.
The blower is rotated while the drive motor is running and the disk is spinning. Air flow
from the blower travels through the disk area and purges the air of any contaminants in
this
area. Air is drawn in at the lower front part of the front bezel and passes through a high
efficiency absolute filter located in the lower front portion of the baseassembly.
Air is ducted to the squirrel cage blower and thence to the area below the fixed disk.
Suitable vanes
on the spindle provide additional pumping action to cause air to flow into
the
area of the upper disk. Air is exhausted at the rear of the disk drive. As a function of
exhausting the air, the electronics package Is provided with Suitable cooling.
Additional cooling is provided through convection cooling of the heatsink assemblies
mounted at the rear of the base assembly. Power transistors mounted on these heatsink
assemblies are used in the power supply regulators
and the positionerpower amplifiers.
The base assembly provides mounting attachment pOints for the rack mounting slides,
switch brackets, front bezel,
and the supporting structure for the printed circuit boards
and dust cover.
The pOSitioner, in conjunction with the positionerservo and control electroniCS, is used to
position the read/write heads
to one of a possible 203 or 406 cylinders. Figure 1-6 defines
the relationship between disk, cylinder, and track
as used throughout this document.
The positioner assembly consists
of a large permanent magnet, a carriage which utilizes
ball bearings, a magnetic velocity transducer, and a photo-electric position transducer.
Attached tothe carriage
are the read/write heads, and the pOSitioner coil (voice coli).
Figure1-6. Disk, Cylinder, Track Relationship
1-6