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