Quantum Q250 User Manual

TAB L E o F
CON TEN T S
PREFACE
. .
ii
SECTION 1.
INTRODUCTION .
. . .
1-1
1.1
1.2
Features . . . . . .
Logic Conventions ..
. . . . . . . . 1-1
. . . . . . . . 1-2
SECTION 2.
PRINCIPLES OF OPERATION ..
2-1
2.1 Head Disk Assembly (HDA) . . . . . . .. . ...... 2-1
2.1.1 Base casting Assembly. . . . .. . ...... 2-1
2.1.2 Disk Stack Assembly. . . . . ....... 2-2
2.1.3 Rotary positioner Assembly (Actuator) ....... 2-2
2.1.4 Headstack Assembly. . . . . . . . . . . 2-2
2.1.S Automatic Actuator Lock (AIRLOCK) ......... 2-2
2.1.6 DC Drive Motor. . . . . . ......... 2-2
2.1.7 Air Filtration. ... . . ......... 2-3
2.2 Drive Electronics. . .. . .............. 2-4
2.2. 1 Disk Format . . . . . . . . . .. ....... 2-4
2.2.2 Simplified Explanation--Block Diagram ....... 2-4
2.2.3 SCSI Bus Physical Interface. . ...... 2-8
2.2.4 SCSI Bus Signal Descriptions ............ 2-10
2.2.S SCSI Bus Timing. . .. ...... . . 2-11
2.2.6 Power Requirements. . . . .. ...... . 2-14
2.2.7 Shorting Plug Options. . ........... 2-16
2.2.8 Flex Circuit .................... 2-19
2.3 PCB Functional Elements. . .. . ........... 2-19
2.3.1 Power-On-Reset (POR) and Warm Reset ........ 2-19
2.3.2 Motor Control Circuit ............... 2-20
2.3.3 Electronic Return Spring. . . . .. . ..... 2-21
2.3.4 S080 SCSI Bus Controller. . . . ...... 2-21
2.3.S Servo Control, AMC and Servo AGC. . . . .. .. 2-23
2.3.6 Actuator Positioning circuit. . .. . ..... 2-27
2.3.7 Read/Write Circuit. . . . . . . . . . . . . .. 2-27
2.3.8 FYLO Timing Controller IC, and xtal Oscillators .. 2-29
2.3.9 DICEY Data Controller IC. ........ . 2-30
2.3.10 Microprocessor and EPROM ......... 2-32
2.4 Power-Up Sequence/Recalibration. . .......... 2-32
2.S Read Command Sequence. . . . . . . . . ...... 2-33
2.6 write Command Sequence. . .. . ........... 2-33
SECTION 3.
ENGINEERING DRAWINGS .
.
3-1
iii

Quantum Q250 Specifications

General

Brand	Quantum
Model	Q250
Category	Storage
Language	English