HP 7475a Service Manual

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SERVICE MANUAL
HP 7475A
GRAPHICS PLOTTER
SERIAL NUMBERS
This manual applies directly to plotters
with serial numbers prefixed 2541 V.
For additional important information about
serial numbers, see PLOTTERS COVERED
BY MANUAL in Section I.
©1983, 1987 by HEWLETT-PACKARD1COMPANY
16399 W. BERNARDO DRIVE, SAN DIEGO, CA~IFORNIA 92127-1899
MANUAL PART NO. 07475-90000
Printed: AUGUST 1987

HP 7475a Specifications

General

Brand	HP
Model	7475a
Category	Plotter
Language	English

Summary

SECTION I GENERAL INFORMATION

1-5. SPECIFICATIONS

Lists performance and supplemental characteristics of the plotter.

1-8. SAFETY CONSIDERATIONS

General safety advice for operating and servicing the plotter.

1-19. LINE VOLTAGE AND FUSE SELECTION

Explains how to select line voltage and the importance of correct fuse values.

1-23. GROUNDING REQUIREMENTS

Emphasizes the need for proper grounding for operator safety.

SECTION II OPERATING AND PERFORMANCE TEST

2-13. BASIC OPERATING TEST

Describes front panel controls for testing basic plotter operation.

2-19. TEST PROGRAM

Explains a BASIC test program for checking I/O and logic circuits.

2-21. REPEATABILITY

Instructions for verifying the plotter's repeatability specification.

SECTION III ADJUSTMENTS

3-7. PEN HEIGHT ADJUSTMENT

Details the procedure for adjusting pen height if the carriage is disassembled.

SECTION VI SERVICE

6-7. RS-232-C/CCITT V.24 INTERFACE CIRCUIT (Option 001)

6-14. HP-IB INTERFACE (Option 002)

6-48. POWER SUPPLIES

6-52. TROUBLESHOOTING

Initial steps for troubleshooting plotter operation issues.

6-54. EXCHANGE PRINTED CIRCUIT ASSEMBLY

6-56. DRIVE MOTORS AND PEN SOLENOID

6-58. TROUBLESHOOTING TABLE

Lists common symptoms, possible causes, and procedures for troubleshooting.

6-60. TEST A

Describes a test procedure to exercise motor drive circuits and logic.

6-62. TEST B

Describes a test procedure to isolate motor/encoder or logic circuit problems.

6-64. PART REMOVAL AND REPLACEMENT

General note on removing and replacing parts, mentioning metric screws.

6-65. TOP CASE REMOVAL

6-66. PEN CAROUSEL HOUSING REMOVAL

6-67. PAPER DRIVE MOTOR ASSEMBLY REMOVAL

Instructions for removing the paper drive motor assembly.

6-68. PEN SOLENOID

Procedure for removing the pen solenoid.

6-69. PEN DRIVE MOTOR AND BELT

Instructions for removing the pen drive motor and its belt.

6-72. PEN CARRIAGE, PENHOLDER, AND DAMPER REMOVAL

Steps to remove the pen carriage, penholder, and damper assembly.

6-75. PINCH ROLLERS REMOVAL AND REPLACEMENT

How to remove and replace the pinch rollers.

6-76. PRINTED CIRCUIT ASSEMBLY REMOVAL

Procedure for removing the main printed circuit assembly.

6-77. PINCH ROLLER MECHANISM REMOVAL

How to remove the pinch roller lever and arm.

6-79. PAPER DRIVE SHAFT AND COUPLER REMOVAL

Instructions for removing the paper drive shaft and coupler.

6-80. POWER MODULE AND TRANSFORMER

Steps for removing the power module and transformer.

6-81. POWER MODULE WIRING

6-83. CLEANING