Zenith Z-100 PC series Service Manual page 319

TABLE OF CONTENTS (CONT.)
SECTION IV THEORY OF OPERATION ................................................
4-1
4.1
Theory of Operation .................... , ............................
4-1
4.2
Read/Write Operations ..............................................
4-1
4.3
Read/Write Head ., ................................................
4-3
4.4 Write Circuit Operation ............................................... 4-4
4.5
Read Circuit Operation ...............................................
4-5
4.6
Drive Motor Control .................................................
4-5
4.7
Index Detector. . . . . . . . . . . . . . . . . . . . . . . . .. . .........................
4-6
4.8
Track Zero Indication ................................................
4-6
4.9
Track Accessing ....................................................
4-6
4.9.1
Stepper Motor .................. , ............................
4-6
4.9.2
Stepper Control ..............................................
4-6
4.10 Drive Select ...................................................... 4-7
4.
11
Write Protect .....................................................
4-8
4.12
Ready .................. , .......................................
4-6
SECTION V MAINTENANCE .... , ....................................................
5-1
5.1
Maintenance Equipment. , ............................... , ............
5-1
5.1.1
Alignment Diskette ............................................
5-1
5.1.2
Exerciser PCB ...............................................
5-1
5.1.3
Special Tools ................................................
5-2
5.2
Diagnostic Techniques ...............................................
5-2
5.2.1
Introduction .................................................
5-2
5.2.2
"Soft Error" Detection and Correction ..............................
5-2
5.2.3
Write Error ..................................................
5-2
5.2.4
Read Error ..................................................
5-3
5.2.5
Seek Error ..................................................
5-3
5.3
Trouble-Shooting ...................................................
5-3
5.4
Adjustments .......................................................
5-8
5.4.1
Head Radial Alignment ........................................
5-8
5.4.2 Read/Write Head(s) Azimuth Check ... , .......................... 5-9
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5.4.3
Head Amplitude Check ........................................
5-10
5.4.4
Track Zero Detector Assembly Adjustment ..........................
5-11
5.4.5
Index/Sector Timing Adjustment .................................
5-12
5.4.6
Motor Speed Adjustment (Using a Frequency Counter) .................
5-13
5.4.7
Write Protect Detector .........................................
5-13
5.4.8
Test Points On Drive PCB .......................................
5-13
5.5
Removals and Replacements ..........................................
5-15
5.5.1
Faceplate Latch ..............................................
5-15
5.5.2
Direct Drive Motor Assembly ....................................
5-15
5.5.13
Head and Carriage Assembly ...................................
5-15
5.5.4 Stepper Motor and Actuator Assembly ............................. 5-15
5.5.5
Clamp Hub .................................................
5-15
5.5.6 Write Protect Sensor and Index Detector ............................ 5-15
5.5.
7 Track Zero Photo Detector ......................................
5-16
5.6
Recommended Incoming Receiving Inspection .............................
5-16
5.6.1
Necessary Equipment ..........................................
5-16
5.6.2 Procedure .................................................. 5-16
SECTION VI SCHEMATIC DIAGRAMS .................................................
6-1
SECTION VII ILLUSTRATED PARTS CATALOG .........................................
7-1
7 . 1 Description........................................................
7-1
7.2
Quantity Per Assembly ...............................................
7-1
7.3 Recommended Spare Parts Stocking Guide ............................... 7-11
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