NEC D2246 Operating manual

D2246 8-INCH
WINCHESTER DISK DRIVE
MAINTENANCE GUIDE
NEe
NEe Information Systems, Inc.
819-000080-5001 Rev. 00
12-83

LIABILITY DISCLAIMER
NEC InformationSystems, Inc. (NECIS)products are warrantedin accordance with the
terms
of the applicable NEC Information Systems, Inc. product specification. Product
performance
is affected by system configuration, software, the application, customer
data, and operatorcontrol of the system among otherfactors. While NECIS productsare
considered to be compatible with most systems, the
product functional implementation
by customers
of the product may vary.
Therefore, the suitability
of a product for a specific application must be determined by
the customer and
is not warranted by NECIS.
This manual
is as complete and factual as possible at the time of printing; however, the
information in this manual may have been updated since
that time. NEC Information
Systems, Inc. reserves the right
to change the functions, features, or specifications of its
products
at any time, without notice.
NEC Information Systems, Inc. has prepared this document for use by NECIS
employees
and customers. The information contained herein is the property of NECIS
and shall not be reproduced without prior written approval from NEelS.
First Printing -December 1983
Copyright 1983
NEC Information Systems, Inc.
5 Militia Drive
Lexington, MA 02173
Printed in U.S.A.

Contents
Page
Chapter 1 System Overview
1.1 D2246 System Design. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 1-1
1.2 Disk Circuitry ..................................................... 1-4
1.3 Power Requirements. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 1-4
1.4 Features .......................................................... 1-4
1.4.1 Enhanced Seek Time .......................................... 1-4
1.4.2 Rapid
Data Transfer Rate. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 1-4
1.4.3
Compact Mounting ........................................... 1-4
1.4.4 Simplified Maintenance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 1-6
1.4.5 Design Reliability. . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . .. 1-6
1.4.6 Standard Interfaces ........................................... 1-6
1.4.7 Safety....................................................... 1-6
1.4.8 System Configuration Flexibility . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 1-6
1.5 Related Document. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 1-7
1.6 Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 1-7
1.7 Options........................................................... 1-7
Chapter 2 Installation Procedures
2.1 Unpacking/Repacking .............................................. 2-1
2.2 Terminating Resistors. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 2-2
2.3
Jumper Requirements. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 2-4
2.4 Switch
Settings. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 2-4
2.4.1 Installation Switch Assembly
................................... 2-5
2.4.2
Control Mode Switch Assembly. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 2-6
2.4.3 Sector Select Switch
Assembly. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 2-7
2.5
Cabinet/Rack Installation ........................................... 2-16
2.6 Cable Connections. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
.. 2-16
2.6.1 Interface Cables
.............................................. 2-16
2.6.2 System
Ground Cable ......................................... 2-18
2.6.3 Power Cable
................................................. 2-18
2.7 Lock
Control Assembly .... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 2-18
Chapter 3 Preventive Maintenance and Troubleshooting
3.1 General Maintenance Rules. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 3-1
3.2 Maintenance Tools ................................................. 3-1
3.3 Preventive Maintenance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 3-2
3.4
Troubleshooting........... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 3-2
3.5 Servo System Signals
................................................ 3-13
3.6 Seek Operations Testing
............................................. 3-18
3.6.1 Repeat Seek Operation
........................................ 3-18
3.6.2 One-Cylinder Seek Operation
................................... 3-18
III

Contents (cont'd)
Chapter 4 Removal and Replacement Procedures Page
4.1 G9QST (Logic and Servo) PCB Removal .............................. 4-1
4.2 G9QSN (Read/Write) PCB Removal. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 4-3
4.3 Earth Pad Assembly Removal. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 4-3
4.4 G9QSQ (Power Amplifier) PCB
Removal. . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 4-4
4.5
Motor Stator Assembly Removal ..................................... 4-6
Chapter 5 Adjustments
5.1 Required Tools... . ........ .... . .......................... . .. ....... 5-1
5.2 Servo Offset Adjustment. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 5-1
5.3 Seek Speed Adjustment. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 5-3
Chapter 6 Illustrated Parts Breakdown. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 5-1
Chapter 7 DKUOOO-H3PM 3-Input DC Regulator Option
7.1 General Description....... . .... ....... . ..... .. . ... .... .... . ...... .. 7-1
7.2 Interface Requirements. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 7-2
7.2.1
DC Power Connector (P4) ..................................... 7-2
7.2.2 Signal
Ground Terminal. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 7-3
7.2.3 DC Power Input Requirements ................................. 7-3
7.3 Installing the 3-Input DC Power Regulator. . . . . . . . . . . . . . . . . . . . . . . . . . . .. 7-4
Chapter 8 DKU-HDPI Dual-Port Interface Option
8.1 General Description ................................................ 8-1
8.2 Switches and Indicators ............................................. 8-2
8.2.1 Port A (Route 0) Switches and Indicators. . . . . . . . . . . . . . . . . . . . . . .
.. 8-3
8.2.2 Port B (Route
1) Switches and Indicators. . . . . . . . . . . . . . . . . . . . . . . .. 8-3
8.2.3 Release Timer. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 8-3
8.3 Drive Selection. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 8-3
8.4 Interface .......................................................... 8-4
8.5 Status Commands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
.. 8-4
8.5.1 Release
Command ............................................ 8-4
8.5.2 Priority
Select. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 8-4
8.6 Installing the Dual-Port
Interface. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 8-7
Appendix A Schematic Diagrams
A.1 Signal Tracing Scheme .............................................. A-I
A.2 Drawings......................................................... A-I
Appendix B Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. B-1
IV

Contents (cont' d)
Page
Appendix C DKUOOO-HLOG Diagnostic Panel
C.I Control Panel .. 0 0 000 0 000 000 0 0 0 0 0 0 0 0 0 0 0 • 0 0 0 0 000 0 • 0 0 0 0 0 0 • 0 0 0 •• 0 000 0 0 C-I
Col.1 Keypad 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 C-4
C.I.2 LED Status Indicators 0 0 0 0 0 0 0 0 0 • 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 C-6
C.I.3
LCD Display Window 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 C-6
C.1.4 Diagnostic Panel Summary Charts 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 C-6
C.2 Status Mode 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 • 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 C-6
C.2.1 Starting Status Mode0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 C-6
C.2.1.1 Drive Status0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 C-7
C.2.1.2 Cylinder and Head Addresses 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 C-ll
C.2.2 Using Status Mode 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 •••• 0 •••••••••••• C-II
C.2.3 Ending Status Mode 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 C-II
C.3 Test Mode 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 C-II
C.3.1 Starting Test Mode 00000.0000000000000000000000000000000000000 C-II
C.3.1.1 Input Parameters 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 C-II
C.3.1.2 Seek Modes 00000000000000000000000000000000000000000000 C-13
C.3.2 Using Test Mode
000000000000000000000000000000000000000000000 C-14
C.3.3 Ending Test Mode
.. 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 000000000000 C-14
C.4 Log Read Mode
0000000000000000000000000000 o. 0000000000000000000000 C-14
C.4.1
Error/Count Log 000000000000000000000000000000000000000000000 C-14
C.4.2 Sequential Operations Log 0 0 0 0 0
0000 0 0 0 0 0 0 0 0 0 0 0 0 00000 0 0 0 0 0 0 0 0 0 0 0 C-16
C.4.3 Ending Log Read Mode 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 C-17
v

Illustrations
Figure Title Page
1-1 D2246 Major Components. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 1-1
1-2 D2246 Disk and Read/Write Head Arrangement. . . . . . . . . . . . . . . . . . .. 1-2
1-3 D2246 Servo Disk Surface. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 1-3
1-4 D2246 Functional Block Diagram ................................ 1-4
1-5 Daisy-Chain System Configuration ............................... 1-6
1-6
Radial System Configuration. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 1-7
2-1 D2246 Packaging. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 2-1
2-2 G9QST Terminating Resistor and Jumper Locations ................ 2-2
2-3 Terminating Resistors in Radial
System. . . . . . . . . . . . . . . . . . . . . . . . . . .. 2-2
2-4 Individual Drive
Termination/Daisy-Chain System. . . . . . . . . . . . . . . . .. 2-3
2-5 Last Drive
Termination/Daisy-Chain System. . . . . . . . . . . . . . . . . . . . . .. 2-3
2-6
DIP Switch Assembly Locations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 2-4
2-7 Installation
DIP Switch ......................................... 2-5
2-8
Control Mode DIP Switch. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 2-6
2-9 Sector Select Switch
............................................ 2-7
2-10 Sector Allocation. . . .. . . . . . . .. . ... . .. . . . .. . .. ... . . .. . . .. .. ... . .. 2-7
2-11 Mounting Bracket .............................................. 2-16
2-12 Horizontal
and Vertical Installation ............................... 2-16
2-13 Interface Cable Connections
..................................... 2-17
2-14 Cable
A/Daisy-Chain System .................................... 2-17
2-15 Signal
Ground and Power Connections . . . . . . . . . . . . . . . . . . . . . . . . . . .. 2-18
2-16 Lock
Control Assembly ......................................... 2-18
3-1 Troubleshooting Flowcharts ..................................... 3-2
3-2
G9QST Test Point Locations ..................................... 3-13
3-3 Repeat Seek Using
TPI .......................................... 3-18
3-4 One-Cylinder Seek Using
TPI .................................... 3-18
4-1 D2246 Board Cover. . . . . . . . . . .. . .. . . . . . . . .. . . . .. . . . .. .. .. . . .. .. 4-2
4-2
G9QST Cable Connectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 4-2
4-3 D2246 Air
Separators. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 4-3
4-4
G9QSN Cable Connectors. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 4-4
4-5 G9QSQ Cable
Connectors. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 4-5
4-6 D2246
Fan. . . . .. . . . . .. . . . . . . . . . . . . . . . . . . .. . . . .. . . . . . .. . . . . . . .. 4-5
4-7 D2246
Stator Assembly ......................................... 4-6
5-1 Servo Offset and Seek Speed Adjustment Test Points ................ 5-2
5-2 Servo Offset Waveform
......................................... 5-2
5-3 Seek Speed Waveform
.......................................... 5-2
5-4 Transient Response Waveform
................................... 5-3
5-5 Increment Seek (Cylinder 000
to Cylinder 691) Waveform. . . . . . . . . . .. 5-4
6-1 D2246 Standard Assembly. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 6-2
6-2 D2246
Head/Disk Enclosure (External Parts) ...................... 6-4
VI

Illustrations (cont' d)
Figure Title Page
7-1 3-Input DC Regulator Block Diagram. . . . . . . . . . . . . . . . . . . . . . . . . . . .. 7-1
7-2 3-Input DC Regulator Dimensions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 7-2
7-3 P4 Connector. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 7-2
7-4 Installing the 3-Input
DC Regulator. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 7-4
8-1 Dual-Port System Cabling. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 8-2
8-2 Dual-Port Control Switches and Indicators. . . . . . . . . . . . . . . . . . . . . . .
.. 8-2
8-3 Unit Select Timing for Dual-Port Option .......................... 8-5
8-4 Sample Priority Select Timing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 8-6
8-5 Installing the Dual-Port Interface. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 8-7
A-I Schematic
Format .............................................. A-2
B-1 D2246 Basic Assembly Dimensions ............................... B-7
B-2 D2246 Standard Assembly Dimensions. . . . . . . . . . . . . . . . . . . . . . . . . . .. B-7
B-3 Cable A Signals. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. B-8
B-4 Cable B Signals ................................................ B-9
C-l Diagnostic Panel. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. C-2
C-2 Attaching the Diagnostic Panel to the
Drive. . . . . . . . . . . . . . . . . . . . . . .. C-3
C-3 Diagnostic Panel Cable and
Connector. . . . . . . . . . . . . . . . . . . . . . . . . . .. C-3
C-4 Status Mode Display Format. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. C-6
C-5 Status Mode
Error Display Format ............................... C-ll
C-6 Low Cylinder Parameter Display ................................. C-12
C-7 High Cylinder Parameter Display
................................. C-12
C-8 Interval Timing Parameter Display ................................ C-12
C-9 Seek Mode Display
............................................. C-13
C-I0 Error/Count Log Display Format ................................ C-15
C-ll Error/Count Log Power-On Count ............................... C-16
C-12
Error/Count Log Error Display Format ........................... C-16
C-13 Sequential Operations Log Display Format ........................ C-17
C-14 Sequential Operations Log Entries
................................ C-17
Vll

Tables
Table Title Page
1-1 DC Power Requirements. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 1-5
1-2 Available Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 1-7
2-1 Sector Select Switch Settings (Segment 1 = 0) . . . . . . . . . . . . . . . . . . . . . .. 2-8
2-2 Sector Select Switch Settings (Segment 1 = 1) ....................... 2-12
3-1 Test Point Signal Outputs ....................................... 3-14
3-2 G9QST Servo Signals
........................................... 3-15
4-1 D2246 Field Replaceable Components. . . . . . . . . . . . . . . . . . . . . . . . . . . .. 4-1
6-1 D2246 Standard Assembly. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 6-1
6-2 Head/Disk Enclosure External Parts. . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 6-3
7-1 P4 Pin Assignments. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 7-3
7-2 DC Power Requirements ........................................ 7-3
A-I Schematic Drawings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-I
B-1 Operating Specifications. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. B-1
B-2 Design Specifications ........................................... B-3
B-3
Physical Dimensions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. B-3
B-4 Interface Cable Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. B-4
B-5 Power Cable Descriptions ....................................... B-4
B-6 Option Cable Description ....................................... B-4
B-7 Interface Connector Descriptions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. B-5
B-8 DC Power Cable Connector Description. . . . . . . . . . . . . . . . . . . . . . . . . .. B-5
B-9 AC Power Cable Connector Description. . . . . . . . . . . . . . . . . . . . . . . . . .. B-5
B-I0 3-DC Option Cable Connector Descriptions. . . . . . . . . . . . . . . . . . . . . . .. B-6
B-ll Operator Panel Cable Connector Descriptions. . . . . . . . . . . . . . . . . . . . .. B-6
C-l Mode Selection Keys. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. C-4
C-2 Diagnostic Panel
Functions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. C-5
C-3 Disk Drive Operational
States. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. C-7
C-4 Drive Status
Reports. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. C-7
C-5 Seek Modes
................................................... C-13
viii

Abbreviations
A Ampere
ac alternating current
AM Address Mark
AWG American Wire Gauge
CA Cylinder Address
CRC Cyclic Redundancy Check
dc direct current
DE Disk Enclosure
DIP
Dual-inline-packaged
DKC Disk Controller
DKU
Disk Unit
ECC
Error Correction Code
EOR
End of Record
GND
Ground
HA
Head Address
HEX
Hexadecimal
1GB Inner
Guard Band
I/O
Input/Output
LED
Light emitting diode
m meter
MB Megabyte
MFM
Modified Frequency Modulation
MHz Megahertz
mm Millimeter
ms
Millisecond
mV Millivolt
MTBF Mean Time Between Failures
MTTR Mean Time to Repair
NRZ Non-Return-to-Zero
ns Nanosecond
OGB Outer
Guard Band
PCB Printed Circuit Board
PLO Phase Locked Oscillator
RMS Root-Mean-Square
ROM Read only memory
RPM Revolutions per Minute
R/W
Read/Write
SA Sector Address
TTL
Transistor/Transistor Logic
V Volt
f.ls
microsecond

Chapter 1
System Overview
The D2246 is a new addition to the NEe D2200 series of disk drives. It is a compact,
highly reliable, low-cost unit
and is fully compatible with earlierD2200 models. It offers
85 megabytes (MB) of unformatted data storage on four 8-inch platters. Actual storage
capacity depends upon the formatting method used.
1.1 D2246 SYSTEM DESIGN
The D2246 uses fixed-disk, Winchester-type technology, which provides the most
advancedmethod
of storing and retrieving large amounts of data. Each D2246 disk drive
contains four 8-inch platters sealed within a protective, air-tight enclosure. This enclo-
sure protects the recording piatters from atmospheric dust
and dirt to improve opera-
tional reliability. A spindle, a drive motor, a rotary actuator assembly, and movable
read/write heads are also contained within the enclosure. Figure
1-1 shows the major
components
of the D2246.
Figure
1-1 D2246 Major Components
1-1
3-INPUT DC
'I
I,
:1
,I
'I
.... .1.;
R/W PREAMP PCB

Figure 1-2 shows the arrangement of recording platters and read/write heads within the
D2246.
DATADISK
I
DATADISK
I
DATADISK
I
DATA DISK
I
I
I
692 CYLINDERS
SPINDLE
I
I
I
I
I
DATASURFACE
A
HEADS
HEAD4
V
DATASURFACE
DATASURFACE
A
HEAD2
HEAD 1
v
DATA SURFACE
DATA SURFACE
A
HEAD3
HEADO
V
DATA SURFACE
A
SERVO HEAD
Figure 1-2 D2246 Disk and Read/Write Head Arrangement
1-2

The servo disk surface is shown in Figure 1-3.
Figure 1-3 D2246 Servo Disk Surface
The Index signal is a six-bit pattern written along one radius of the servo surface. It
identifies the beginning of a recording track. The index pattern repeats each time the
radius intersects one
of the recording tracks.
The servo
data zone contains 692 concentric recording tracks. Each recording track
containsprerecordedpositioningdata, includingclock andsynchronizationsignals, that
provide information to place and maintain the read/write heads on track.
The inner
and outer guard bands bracket the servo data zone. They contain recurring
six-bit patterns to distinguish them from the servo data zone.
The landing zone
is a silicon-coated surface where the read/write heads rest when the
recording disks are not spinning. During read, write,
and seek operations the heads
"float" approximately 20 microinches above the surface of the disk.
1-3

1.2 DISK CIRCUITRY
A block diagram of a D2246 disk drive is shown in Figure 1-4. The functional compo-
nents are the interface, the read/write circuits, the servo control, and the motor control
circuits.
~
DISK
DRIVE
CONTROLLE
(SMDI
DC
POWE -
-
R:::::
-
r--
-
--
LOGIC & SERVO
READ/WRITE
READ DATA/CLOCK
WRITE DATA/CLOCK
J READPLO&
READ
I _
SEPARATOR
CIRCUIT
I
-a "eA,GA"
CONTROL
I NRZ TO MFM
WRITE
CONVERTER
CIRCUIT
f j
~SO-9~
I "eA","m I
TAG 3
FAUL T SENSE
SMD
I
TAG 2
CONTROL
TAG 1 LSI
!L.
I
HEAD
TAG 4 l
SELECT
-
A
SENSE LINES
SERVO
~
CONTROL
,
l~
LSI
~
I
/I
PHASE
SERVO
UNIT
DETECTOR PLO
t-
SELECT
It
r-
+
~
t I
",m,o,
SIGNAL
AGC-AMP
MAPPED
DEMODULATOR
PROFILE
t
VELOCITY j
GENERATOR
t
__ t5V
rH SERVO
~
SERVO POWER
__ -5V
ANALOG AMP
f-+- t12V
AMOTO" I
r-- -12V
MICRO-PROCESSOR
r-- t24V
CONTROL SYSTEM
(MCSI
/
-, CONTROL l
AMP I
POWER AMP
Figure 1-4 D2246 Functional Block Diagram
r
~
DE
ASSEMBLY
"
r
-H
"eA"WR'"
LSI
I
DATA HEADS
r-
POSITIONER
I
SERVO HEAD
lH
PRE-AMP
r -
DISK
--,-
SPINDLE
I
MOTOR
L
The interface circuits route data, addresses, status information, and control signals
between the disk drive and the controller.
The read/writecircuits control the transfer
of data from the disk(read operation), and to
the disk(write operation). Duringa write operation, the circuits receive serial nonreturn-
to-zero (NRZ) format data from the controller and convert the data to a modified
frequency modulation (MFM) format. The MFM data is then written
on the disk.
During a read operation, the circuits read and amplify the data from the disk, convert it
from MFM to NRZ format, and send the NRZ data serially to the controller.
The servo control reads the data prerecorded on the servo disk. The servo control uses
this data to position and maintain the read/write heads on the correct cylinder. The
motor control circuits drive the spindle motor.
1-4

1.3 POWER REQUIREMENTS
D2246 disk drives operate on externally supplied dc power.
DC power requirements are
listed in Table
1-1.
Table 1-1 DC Power Requirements
REQUIRED
DAMAGE
RIPPLE
VOLTAGE TOLERANCE
THRESHOLD CURRENT
(PEAK TO PEAK)
+5.0V ±0.25 V ±10% 4.0A
100mV
-5.0V
±0.25 V ±10% 0.5 A
100mV
+12.0V ±0.60 V ±10% 0.6 A
100mV
-12.0 V ±0.60 V ±10% 0.5 A
100 mV
+24.0 V ±2.40 V ±10% 2.5
A*
240mV
5.0 A**
*2.5 A - average running current
**5.0 A - peak starting current (25 seconds maximum duration)
All power line voltages must be established within 500 milliseconds (ms)
of power on.
Voltages must be enabled in the following order: +5 V, -5 V, ±12 V, +24 V. When power
is turned off, lines must be disabled in the reverse order: +24 V, ±12 V, -5 V, +5 V.
1.4 FEATURES
Shorter access times, high-speed data transfers, and mechanical reliability are required
for efficient computernetwork operations. To meet these demands the D2246 disk drive
offers the following features.
1.4.1 Enhanced Seek Time
Seek time is the time required to find requested data on the disk. The D2246 has an
average seek time of 25 milliseconds (ms), and a maximum of 50 ms.
1.4.2 Rapid
Data Transfer Rate
The D2246 provides a data transfer rate of approximately 1.2 MB per second.
1.4.3 Compact Mounting
The compact size
of the D2246 allows for either horizontal or vertical mounting in a
limited space. The drive's lock mechanism is easily accessible even after the drive has
been placed within a system cabinet.
The D2246 also features an integrated cooling fan
that reduces space and power
requirements.
1-5

1.4.4 Simplified Maintenance
The air-tight, sealed
disk/head assembly and the D2246's simplified design produce a
disk drive
that requires no periodic maintenance. Neither installation nor field service
requires special tools. Motor electronics are placed outside the head/disk assembly and
do not need "clean room" repair facilities.
An optionaldiagnostic panel is available for test and maintenancepurposes(see Appen-
dix C).
1.4.5 Design Reliability
Lightweight, contact-type
start/stop heads that reduce damage to the heads and disks
are used within the D2246 disk drive. A simplified rotary actuator, a directly coupled,
brushless dc motor,
and a closed-loop air circulation system are the drive's major
mechanical components. The controllogic
is microprocessorcontrolled and designed to
minimize electronic components. This design strategy ensures high reliability and low
cost.
1.4.6 Standard Interfaces
The D2246 uses standardoriginal equipment manufacturer interfacesfor connection toa
disk controller and
to a power supply.
1.4.7 Safety
The D2246 conforms to Underwriter's Laboratories Safety Regulation UL478.
1.4.8 System Configuration Flexibility
A maximum
of four D2246 diskdrives can be connected to a single controllerin eithera
daisy-chain
or radial system (see Figures 1-5 and 1-6).
DISK DRIVE CONTROLLER
SG
AO BO
B1 Bn
r CABLEA
CABLE B
/ -\ / -\
V V -
~
V -
~
si) A
IB~
A
IB-
A
Is~
*TERM *TERM *TERM
DISK DRIVE DISK DRIVE
---
DISK DRIVE
0 1 4 (maximum)
* TERMINATING RESISTORS INSTALLED ON EACH DRIVE
Figure 1-5 Daisy-Chain System Configuration
1-6

DISK DRIVE CONTROLLER
SG
AO
BO
SG
A1
B1
SG
An
Bn
S~
A
1;-
~~
A
1;-
S~
A
IB ....
*TERM *TERM *TERM
DISK DRIVE DISK DRIVE
---
DISK DRIVE
a 1 4
(maximum)
* TERMINATING RESISTORS INSTALLED ON EACH DRIVE
Figure 1-6 Radial System Configuration
1.5 RELATED DOCUMENT
For additional informationon the D2246 disk drive, refer totheD22468-Inch Winchester
Disk Drive Product Description (NEC document 819-000080-4001).
1.6 SPECIFICATIONS
Product specifications are listed in Appendix
B.
1.7 OPTIONS
Table 1-2 lists available options for the D2246 disk drive.
Table 1-2 Available Options
OPTION DESCRIPTION
3-Input DC Regulator Option Supplies internal dc
"power set" (+24 V,
+ 12 V, +5 V, -5 V, -12 V) from external dc
input
of +24 V, +5 V, and -12 V.
Dual-Port Option ! Enables disk drive interface with two con-
I trollers.
!
\.
DC Power Supply ISupplies internal dc
"power set" from ac
input power. Provides power for two disk
drives.
Diagnostic Panel ITests and monitors disk drive operation.
1-7

Chapter 2
Installation Procedures
This chapter provides procedures for installing a D2246 disk drive. When preparing the
installation site, refer to the environmental specifications listed in Appendix B.
2.1 UNPACKINGIREPACKING
Before unpacking the disk drive, examinethe shippingcartonfor damage. If damage has
occurred, notify the carrier immediately.
Do not open the carton until the carrier's
representative
is present.
If there is no damage to the shipping carton, use these procedures to unpack the disk
drive. Failure to follow these procedures can void the product warranty.
1. Open the top of the shipping carton.
2. Remove the top packing brace (see Figure 2-1).
3. Carefully remove the disk drive from the shipping carton.
4. Remove the D2246 from the plastic shipping bag.
5. Save all packing material for reshipping.
6. Check all items against the bill of material to insure that no items are missing.
7. Check all items for shipping damage.
To repack the disk drive, reverse these procedures.
TOP PACKING BRACE
02246 DISK DRIVE
SHIPPING CARTON
Figure 2-1 D2246 Packaging
2-1

2.2 TERMINATING RESISTORS
Terminating resistors are installed on the G9QST logic and servo printed circuit board
(PCB) as shown in Figure
2-2.
TERMINATING RESISTORS JUMPERS
G9QSTLOGIC
AND SERVO PCB
DCJC3 CJ~
c:::::3.c] c::J [] 0 [JJ
CJD
~~ CJ 0000
c:::::3 0 0
CJ c:::J c:::J
o 0
EJ JPl CPU RESET lONE STEP(JUMPER REMOVED)
~ JP6 FIRST RETRY ONIOFF (RETRY ENABLED)
lOB I JP8 FAULT (FAULT ENABLED)
Figure 2-2 G9QST Terminating Resistor and Jumper Locations
If the D2246 drive is connected tothe controllerin a radial configuration, install a set of
four terminating resistors in place as shown in Figure 2-3. Terminating resistors can be
either 150a or 56 n.
DISK DRIVE CONTROLLER
SG
AO
BO
SG
A1
B1
SG
An
Bn
~~
A
r;-
S~
A
r;-
S~
A
,;-
*TERM *TERM *TERM
DISK DRIVE DISK DRIVE
---
DISK DRIVE
0 1 4 (maximum)
* TERMINATING RESISTORS INSTALLED ON EACH DRIVE
Figure 2-3 Terminating Resistors in Radial System
2-2

In a daisy-chain configuration, two types of termination methods can be used. To
terminate individual drives, install a set of four 150nresistors in each drive as shown in
Figure 2-4.
DISK DRIVE CONTROLLER
SG
AO BO B1 Bn
r CABLEA
CABLE B
--
/ -\ / -\
V V
~
V
~
~~
A
IB~
A
I;
A
IB~
*TERM *TERM *TERM
DISK DRIVE DISK DRIVE
---
DISK DRIVE
0 1 4
(maximum)
* TERMINATING RESISTORS INSTALLED ON EACH DRIVE
Figure 2-4 Individual Drive Termination/Daisy-Chain System
To terminate the lastdrive, install a set of four 56n resistors in the final drive of thechain
as shown in Figure 2-5.
DISK DRIVE CONTROLLER
SG
AO BO B1
Bn
r CABLEA
-CABLE B
/ -\ / -\
V V -
~
V -
~
S~ I A I
ls-
I A I
[B-
A
IB~
*TERM
DISK DRIVE DISK DRIVE
---
DISK DRIVE
0 1 4
(maximum)
* TERMINATING RESISTORS INSTALLED ONLY ON LAST DRIVE
Figure 2-5 Last Drive Termination/Daisy-Chain System
2-3