HP 7475a Service Manual

Model 7475A
Table of Contents
TABLE OF CONTENTS
Section
I GENERAL INFORMATION . . . . . . . . . . . . . 1-1
1-1. Introduction . . . . . . . . . . . . . . . . . . . . . . . 1-1
1-6. Specifications . . . . . . . . . . . . . . . . . . . . . 1-1
1-8. Safety ConsidE!rations . . . . . . . . . . . . . 1-1
1-10. Plotters Covered by Manual . . . . . . . . 1-1
1-15. Description . . . . . . . . . . . . . . . . . . . . . . . . 1-2
1-19. Line Voltage and Fuse Selection.... 1-2
1-23. Grounding Requirements . . . . . . . . . . 1-3
1-25. Options . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3
1-29. Accessories Supplied . . . . . . . . . . . . . . . 1-6
1-31. Recommended Test Equipment . . . . . 1-6
1-33. Packaging for Shipment . . . . . . . . . . . 1-6
II OPERATING AND PERFORMANCE
TEST . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1
2-1. Introduction . . . . . . . . . . . . . . . . . . . . . . . 2-1
2-3. Rear Panel Switches
(Option 001) . . . . . . . . . . . . . . . . . . . . . 2-1
2-9. Rear Panel Switches
(Option 002) . . . . . . . . . . . . . . . . . . . . . 2-1
2-13. Basic Operating Test . . . . . . . . . . . . . . 2-1
2-15. Hewlett-Packard Graphics
Language . . . . . . . . . . . . . . . . . . . . . . . 2-2
2-17. Demonstration Plot . . . . . . . . . . . . . . . . 2-2
2-19. Test Program . . . . . . . . . . . . . . . . . . . . . . 2-2
2-21. Repeatability . .. .. . . . . . . . . . . . . . . .. . 2-2
III ADJUSTMENTS......................... 3-1
3-1. Introduction . . . . . . . . . . . . . . . . . . . . . . . 3-1
IV REPLACEABLE PARTS . . . .. . . . . . . . .. . . . 4-1
4-1. Introduction . . . . . . . . . . . . . . . . . . . . . . . 4-1
4-3. Exchange Assemblies . . . . . . . . . . . . . . 4-1
4-5. Replaceable Parts Lists . . . . . . . . . . . . 4-1
4-7. Ordering Information . . . . . . . . . . . . . . 4-1
4-9. Code List of Manufacturers . . . . . . . . 4-1
4-11. Designations and Abbreviations . . . 4-1
V PRODUCT HISTORY .. . . . . . . . . . .. . . .. .. . 5-1
5-1. Introduction . ~..................... 5-1
5-3. History of Assemblies by
Serial Prefix Number . . . . . . . . . . . . 5-1
5- 7. History of Printed Circuit
Assemblies . . . . . . . . . . . . . . . . . . . . . . 5-1
Section
VI SERVICE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-1
6-1. Introduction . . . . . . . . . . . . . . . . . . . . . . . 6-1
6-3. Simplified Theory of Operation . . . . . 6-1
6-7. RS-232-C/CCITT V.24 Interface
Circuit (Option 001) . . . . . . . . . . . . . . 6-1
6-14. HP-IB Interface (Option 002) . . . . . . . 6-2
6-25. Microprocessor Circuit . . . . . . . . . . . . . 6-5
6-29. Read Only Memory Circuit . . . . . . . . . 6-5
6-31. Random Access Memory Circuit . . . . 6-5
6-33. Gate Arrays A and B . . . . .. . .. . . . . . 6-5
6-35. Pen Carousel . . . . . . . . . . . . . . . . . . . . . . 6-5
6-37. Motor Servo Systems . . . . . . . . . . . . . . 6-5
6-41. Motor Supply Sensor Circuit . . . . . . . 6-6
6-44. Motor Current Sensor Circuit . . . . . . . 6- 7
6-46. Pen Down Circuit . . . . . . . . . . . . . . . . . . 6- 7
6-48. Power Supplies .. . . . . . . . . . . .. . . . . . . 6-7
6-50. Recommended Test Equipment . . . . . 6- 7
6-52. Troubleshooting . . . . . . . . . . . . . . . . . . . 6- 7
6-54. Exchange Printed Circuit
Assembly . . . . . . . . . . . . . . . . . . . . . . . . 6-7
6-56. Drive Motors and Pen Solenoid .. .. . 6- 7
6-58. Troubleshooting Table . . . . . . . . . . . . . 6-8
6-60. Test A . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-8
6-62. Test B . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-8
6-64. Part Removal and Replacement . . . . 6-9
6-65. Top Case Removal . . . . . . . . . . . . . . . . . 6-9
6-66. Pen Carousel Housing Removal . . . . 6-9
6-67. Paper Drive Motor Assembly
Removal ......................... 6-10
6-68. Pen Solenoid . . . . . . . . . . . . . . . . . . . . . . 6-11
6-69. Pen Drive Motor and Belt . . . . . . . . . . 6-11
6-72. Pen Carriage, Penholder, and
Damper Removal . . . . . . . . . . . . . . . . 6-13
6- 75. Pinch Rollers Removal and
Replacement . . . . . . . . . . . . . . . . . . . . . 6-14
6-76. Printed Circuit Assembly
Removal . . . . . . . . . . . . . . . . . . . . . . . . . 6-14
6-77. Pinch Roller Mechanism Removal . . 6-15
6-79. Paper Drive Shaft and Coupler
Removal . . . . . . . . . . . . . . . . . . . . . . . . . 6-15
6-80. Power Module and Transformer . . . . 6-16
6-81. Power Module Wiring . . . . .. .. .. .. . . 6-16
6-83. Cleaning . . .. . . . . . . . . . . . . .. .. . . . . . . 6-16
6-85. Pen Stall Cleaning . . . . . . . .. . . . . . . . . 6-17
6-87. Diagrams . . . . . . . . . . . . . . . . . . . . . . . . . 6-17
TABLES
Table
1-1. Specifications ........................ .
1-2. Line Voltage Selection ................ .
1-3. Line Fuses ............................ .
1-4. Accessories Supplied .................. .
1-5. Recommended Test Equipment ........ .
2-1. Baud Rate Selection .................. .
2-2. 7475A HP-GL Instruction Set ......... .
1-1
1-3
1-3
1-6
1-6
2-1
2-3
Table
4-1. Parts List, Main PCA, RS-232-C,
Option 001 . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-2
4-2. Parts List, Main PCA, HP-IB
Option 002 . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-5
4-3. Parts List, Mechanical Parts . . . . . . . . . . . 4-8
4-4. Parts List, Pen Carousel Parts . . . . . . . . . 4-10
4-5. Code List of Manufacturers . . . . . . . . . . . . 4-11
i

HP 7475a Specifications

General

Brand	HP
Model	7475a
Category	Plotter
Language	English