HP 7925M Manuals

Manuals and User Guides for HP 7925M. We have 1 HP 7925M manual available for free PDF download: Service Manual

HP 7925M Service Manual

HP 7925M Service Manual (265 pages)

Brand: HP | Category: Storage | Size: 29.77 MB

Table of Contents

Table of Contents

5
- Theory of Operation
  11
- Addressing Structure of an HP 7925 Disc Drive
  11
- Introduction
  11
- Addressing Structure
  11
- Sector Clock and Index Generation
  12
- Addressing Modes
  12
  - Surface Mode
    12
  - Cylinder Mode
    12
- Logical Vs. Physical Sectors
  13
- Surface Mode Vs. Cylinder Mode
  13
- Sector Format
  13
- HP 7925 Disc Drive, Simplified Block Diagram
  15
  - I/O Control System
    16
    
    Tag Bus Logic
    17
    
    Control Bus Logic
    19
    
    Select Logic
    19
- Functional Description
  15
- Tag Bus Timing
  19
  - Unit Identity Logic
    20
  - Status Logic
    20
- Status Word Bit Assignments
  20
  - Attention Logic
    21
  - Spindle Rotation System
    22
    
    Spindle Logic Initialization
    22
    
    Door Control Logic
    22
    
    Run Spindle Command Logic
    22
    
    Phase Encoding and Decoding
    22
    
    Speed Control
    23
    
    Motor Current Regulation
    23
- Phase Selection Timing
  24
  - Dynamic Braking
    25
  - Speed down Detection
    25
  - Overcurrent Protection
    25
  - Overvoltage Protection
    25
  - Head Positioning System
    25
    
    Initial Head Load Operation
    25
    
    Normal Head Unload Operation
    28
    
    Seek Operation
    29
    
    Offset Operation
    30
    
    Recalibrate Operation
    31
    
    Emergency Retract Operation
    32
  - Sector Sensing System
    32
  - Read/Write System
    33
    
    Head Selection
    33
    
    Read Mode Operation
    34
    
    Write Mode Operation
    34
    
    Read/Write Fault Detection
    35
  - Fault Detection System
    35
    
    Illegal Address Detection
    35
    
    Timeout Fault Detection
    36
- Summary of Timeout Conditions
  36
  - AGC Fault Detection
    37
  - Interlock Fault Detection
    37
  - Read/Write Fault Detection
    37
- Fault Events
  37
  - Air Circulation and Filtration System
    39
- Types of Contaminants and Critical Elements
  40
  - Power Distribution System
    41
    
    Power Panel Assembly
    41
    
    Power Supply Assembly
    41
    
    Voltage Regulator Circuits
    41
    
    Voltage Protection Circuits
    41
    
    Supply Voltage Distribution
    41
- Power Distribution List
  41
- Standard Tools
  42
  - Special Test Equipment
    43
- Maintenance
  42
- Introduction
  42
- Maintenance Precautions
  42
  - Standard Test Equipment
    42
  - Special Tools
    42
- Special Tools
  43
  - DSU Controls and Indicators
    45
  - DSU Operation
    46
  - Head Alignment Meter Calibrations
    46
- Preventive Maintenance Routines
  47
- Preventive Maintenance
  47
  - General Cleaning Information
    47
  - Preliminary Steps
    47
- Pack Lock Lubrication Tool
  50
  - Cleaning the Spindle Assembly and Pack Chamber Assembly
    52
- Alignment and Adjustment
  53
- Introduction
  53
- Service Adjustments Not Requiring the DSU
  53
  - Door Lock Assembly
    53
    
    Door Unlock Solenoid
    53
    
    Door Closed and Door Locked Switches
    53
  - Carriage Latch and Detector Assembly
    54
  - Head Cam Alignment
    54
- Service Adjustments Requiring the DSU
  54
  - Installing the DSU
    55
- Use of Head Cam Alignment Tool
  55
  - Exercising the Disc Drive
    56
  - Head Cam Tool Alignment
    56
  - Velocity Command Gain Adjustment
    57
  - DSU Installed
    57
    
    Warmup
    59
    
    Circumferential Alignment
    59
- Data Head Alignment Locations
  59
  - Use of Circumferential Timing Tolerance Label
    60
    
    Track Follower Alignment
    61
    
    Servo Head Alignment
    61
  - Interpretation of Circumferential Timing Data Graph
    62
- Data Graph Example
  63
  - Data Graph Example
    64
  - Data Graph Example
    65
  - Data Graph Example
    66
  - Data Graph Example
    68
  - Track Follower Alignment
    70
    
    Data Head Alignment Check
    71
    
    Data Head Alignment
    71
- Description of Circumferential Timing
  71
- 3-20. On-Line Checkout
  73
- Troubleshooting
  75
- Diagnostic Test Programs
  75
- Troubleshooting Flowcharts
  75
- Power Sources
  75
- Visual Indication of Drive Status
  76
- Disc Service Unit
  76
- System Functional Diagrams
  76
- Wiring Connections
  76
- Power Distribution
  76
- Disc Service Unit (DSU) Functions
  80
- Spindle Rotation Troubleshooting Flowchart
  105
- Head Positioning Troubleshooting Flowchart
  108
- Motherboard PCA-A7 Signal Distribution List
  120
- Removal and Replacement
  129
- Introduction
  129
- Preparation for Service
  129
- Shroud Removal and Replacement
  129
- Door and Side Cover Removal and Replacement
  129
- Prefilter Removal and Replacement
  130
- Absolute Filter Removal and Replacement
  130
- Front Frame Assembly
  130
- Indicator Assembly PCA-A11 and Incandescent
  131
  - Pack Chamber Assembly Removal and Replacement
    131
- Printed Circuit Card Removal and Replacement
  131
  - Card Cage Pca's
    131
  - Spindle Logic PCA-A8
    132
  - Read/Write Preamplifier PCA-A6
    132
  - Card Cage Chassis and Motherboard PCA-A7
    133
  - Power and Motor Regulator PCA-A9
    133
  - Fault Indicator PCA-A12
    133
- Pack Detector Assembly Removal and Replacement
  134
- Data and Servo Head Removal and Replacement
  134
  - Velocity Transducer and Velocity Transducer Shaft
    138
  - Head Cam
    139
  - Head Cam Support
    139
    
    Use of Head Cam Alignment Tool
    140
- Spindle Assembly Removal and Replacement
  141
  - Head Cam Tool Alignment
    141
- Encoder PCA-A10 Removal and Replacement
  142
- 5-26. Spindle Bottom Cover
  142
- Spindle Ground Contact and Encoder Disc
  143
- Pack Lock
  143
- Blower Motor Starting Capacitor
  145
- Replaceable Parts
  147
- Introduction
  147
- Ordering Information
  147
  - Appendix A
    149
  - Change 1
    149
- HP 7925D Disc Drive, Replaceable Parts
  149
  - Pack Detector Assembly
    153
  - Mainframe Assembly, Replaceable Parts
    153
- Operator Panel and Lower Card Cage
  154
- Mainframe Assembly, Exploded View
  155
  - Front Frame Assembly, Exploded View
    156
- Front Frame Assembly, Replaceable Parts
  156
- Power Panel Assembly, Exploded View
  171
- Termination Assembly, Replaceable Parts
  174
  - Termination Assembly, Exploded View
    175
  - Reference Designations and Abbreviations
    176
- Sector Format
  181
Illustrations

182
- Iillustrations
  
  184
- I Tables
  
  189
  - Controller Mnemonics
    189
  - Conditions
    193
  - Phase Selection Timing
    196
    
    Head Positioning
    197
  - Summary of Timeout Conditions
    208
  - Fault Events
    209
  - HP 7925H Air Circulation and Filtration System
    211
  - Types of Contaminants and Critical Elements
    212
  - For HP 7925H
    214
  - Visual Indication of Drive Status
    218
  - HP 7925H Mainframe Assembly
    219
  - Functional Diagram
    220
  - Wiring Diagram
    220
  - HP 7925H Operation Control System, Functional Diagram
    220
  - HP 7925H Head Positioning System, Functional Diagram
    220
  - Signal Distribution List
    220
  - Self-Test Controls and Indicators
    221
  - Self-Test Control Operation
    222
  - Self-Test Function Test Description
    223
  - Visual Indication of Drive Status
    228
  - HP 7925H Power-Up Troubleshooting Flowchart
    229
  - HP 7925H Integrated Controller
    230
  - HP 7925H Sector Sensing System, Functional Diagram
    235
  - HP 7925H Fault Detection System, Functional Diagram
    237
  - HP 7925D Disc Drive - Part Changes for HP 7925H
    251
  - Mainframe Assembly - Part Changes for HP 7925H
    252
  - Controller Secondaries Coding Summary
    256

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