Tektronix 070-8030-01 User Manual

Service Manual

1780R-Series
Video Measurement Set
SN B030000 & Up

070-8030-01

This document supports firmware version 1.16
and above.

Warning

The servicing instructions are for use by qualified
personnel only. To avoid personal injury, do not
perform any servicing unless you are qualified to
do so. Refer to all safety summaries prior to
performing service.

Copyright © T ektronix, Inc. All rights reserved.
T ektronix products are covered by U.S. and foreign patents, issued and pending. Information in this publication supercedes

that in all previously published material. Specifications and price change privileges reserved.
Printed in the U.S.A.
T ektronix, Inc., P.O. Box 1000, Wilsonville, OR 97070–1000
TEKTRONIX and TEK are registered trademarks of T ektronix, Inc.

Service Assurance

If you have not already purchased Service Assurance for this product, you may do so at any time during the product’s
warranty period. Service Assurance provides Repair Protection and Calibration Services to meet your needs.

Repair Protection extends priority repair services beyond the product’s warranty period; you may purchase up to three
years of Repair Protection.

Calibration Services provide annual calibration of your product, standards compliance and required audit documentation,
recall assurance, and reminder notification of scheduled calibration. Coverage begins upon registration; you may purchase
up to five years of Calibration Services.

Service Assurance Advantages

H Priced well below the cost of a single repair or calibration
H Avoid delays for service by eliminating the need for separate purchase authorizations from your company
H Eliminates unexpected service expenses

For Information and Ordering

For more information or to order Service Assurance, contact your T ektronix representative and provide the information
below . Service Assurance may not be available in locations outside the United States of America.

Name VISA or Master Card number and expiration
Company date or purchase order number
Address Repair Protection (1,2, or 3 years)
City , State, Postal code Calibration Services (1,2,3,4, or 5 years)
Country Instrument model and serial number
Phone Instrument purchase date

WARRANTY

T ektronix warrants that the products that it manufactures and sells will be free from defects in materials and workmanship
for a period of three (3) years from the date of shipment. If a product proves defective during this warranty period,
T ektronix, at its option, either will repair the defective product without charge for parts and labor, or will provide a
replacement in exchange for the defective product.

In order to obtain service under this warranty, Customer must notify Tektronix of the defect before the expiration of the
warranty period and make suitable arrangements for the performance of service. Customer shall be responsible for
packaging and shipping the defective product to the service center designated by T ektronix, with shipping charges prepaid.
T ektronix shall pay for the return of the product to Customer if the shipment is to a location within the country in which the
T ektronix service center is located. Customer shall be responsible for paying all shipping charges, duties, taxes, and any
other charges for products returned to any other locations.

This warranty shall not apply to any defect, failure or damage caused by improper use or improper or inadequate
maintenance and care. T ektronix shall not be obligated to furnish service under this warranty a) to repair damage resulting
from attempts by personnel other than T ektronix representatives to install, repair or service the product; b) to repair
damage resulting from improper use or connection to incompatible equipment; c) to repair any damage or malfunction
caused by the use of non-T ektronix supplies; or d) to service a product that has been modified or integrated with other
products when the effect of such modification or integration increases the time or difficulty of servicing the product.

THIS WARRANTY IS GIVEN BY TEKTRONIX IN LIEU OF ANY OTHER WARRANTIES, EXPRESS OR
IMPLIED. TEKTRONIX AND ITS VENDORS DISCLAIM ANY IMPLIED WARRANTIES OF
MERCHANTABILITY OR FITNESS FOR A P ARTICULAR PURPOSE. TEKTRONIX’ RESPONSIBILITY T O
REP AIR OR REPLACE DEFECTIVE PRODUCTS IS THE SOLE AND EXCLUSIVE REMEDY PROVIDED TO
THE CUSTOMER FOR BREACH OF THIS WARRANTY . TEKTRONIX AND ITS VENDORS WILL NOT BE
LIABLE FOR ANY INDIRECT , SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES IRRESPECTIVE
OF WHETHER TEKTRONIX OR THE VENDOR HAS ADVANCE NOTICE OF THE POSSIBILITY OF SUCH
DAMAGES.

Table of Contents

Specifications

Operating Information

General Safety Summary xi. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Service Safety Summary xiii. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Preface xv. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Product Description 1–1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

CR T Options 1–2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Power Cord Options 1–2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Specifications 1–3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Performance Qualification 1–3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Heat Dissipation 1–3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Installation 2–1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Packaging 2–1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Accessories 2–1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Rear Panel Connectors 2–2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Installation Requirements 2–4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Electrical Installation 2–4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Power Source 2–4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Mains Frequency and Voltage Ranges 2–4. . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Operating Options 2–5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Floating Video Input Connectors 2–8. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

REMOTE Connector 2–9. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Remote Operation 2–9. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

SERIAL Interface Connector 2–10. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Serial Remote Information 2–10. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

25-Pin to 9-Pin RS232D Adapter 2–10. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Command Set 2–11. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

XY INPUT Connector 2–12. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Mechanical Installation 2–13. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Rack Mounting The 1780R-Series 2–14. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Rack Installation 2–14. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Portable Case Installation 2–17. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Initial Calibration 2–17. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Calibration Menu Information 2–18. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Waveform Calibration Information 2–18. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Waveform Calibration Procedure 2–18. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Vectorscope Calibration Information 2–21. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Vectorscope Calibration Procedure 2–21. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Repackaging 2–24. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Identification T ag 2–24. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Repackaging for Shipment 2–24. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

1780R-Series Service Manual

i

Table of Contents

Theory of Operation

Operating Information 2–27. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Front-panel Controls 2–28. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Functional Measurement Controls 2–31. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Block Diagrams 3–1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Schematic Diagrams 3–2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Diagrams 1 & 2 Input Amplifiers 3–5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Diagram 3 Probe Input and DC Restorer 3–7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Diagram 4 Input & Reference Selection 3–10. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Diagram 5 Difference Amplifier & Video Filters 3–12. . . . . . . . . . . . . . . . . . . . . . . .

Diagram 6 Vertical Deflection 3–15. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Diagram 7 Vertical Control Logic, Calibrator, & Cursors 3–17. . . . . . . . . . . . . . . . . .

Diagram 8 Reference Sync Generation 3–21. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Diagram 9 H & V Sync Generators 3–24. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Diagram 10 Ramp Generator 3–28. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Diagram 11 Horizontal Magnifier & Output Amplifiers 3–32. . . . . . . . . . . . . . . . . . .

Diagram 12 Horizontal Latches & DAC 3–35. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Diagram 13 Slow Sweep & Ext Horiz Input 3–37. . . . . . . . . . . . . . . . . . . . . . . . . . . .

Diagrams 14 & 15 SCH Phase Timing & Sync Locked Oscillator 3–39. . . . . . . . . . .

Diagrams 16 & 17 Master MPU, ROM & NVRAM 3–44. . . . . . . . . . . . . . . . . . . . . .

Diagram 17 Dynamic RAM 3–46. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Diagram 18 Line Rate Controller 3–49. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Diagram 19 UART & A/D 3–54. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Diagram 20 Readout Engine & Read Output 3–57. . . . . . . . . . . . . . . . . . . . . . . . . . . .

Diagram 21 Interconnect 3–60. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Diagrams 22, 23, & 24 MPU Annex, Front Switch Panel, & T ouch Panel 3–62. . . . .

Diagram 25 Vectorscope Input & Gain 3–65. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Diagram 26 Diff Phase/Gain 3–67. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Diagram 27 Vector Timing & Blanking 3–70. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Diagram 28 Demodulators 3–73. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Diagram 29 XY Inputs & PIX Monitor 3–75. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Diagram 30 Vector Deflection Amps 3–77. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Diagram 31 Subcarrier Regenerator 3–80. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Diagram 32 Digital Phase Shifter 3–84. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Diagram 33 Horizontal AFC & Post Regulators 3–87. . . . . . . . . . . . . . . . . . . . . . . . .

Diagram 34 Diff Gain/Phase Alt Mode Switch 3–89. . . . . . . . . . . . . . . . . . . . . . . . . .

Diagram 35 Digital Recursive Filter 3–91. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Diagram 36 Z-Axis 3–95. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Diagrams 37 & 38 Timing Cursors & Counters 3–97. . . . . . . . . . . . . . . . . . . . . . . . .

Diagram 39 CRT Display DAC 3–102. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Diagrams 40 & 45 Scale Illum & Trace Rotation – Graticule Lights 3–104. . . . . . . . .

Diagram 41 Vector High V olts 3–107. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Diagram 42 Waveform High Volts 3–1 10. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Diagram 43 Low Voltage Power Supply 3–113. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Performance Verification

Recommended Equipment List 4–1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Short Form Procedure 4–7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Performance Check Procedure 4–10. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

ii

1780R-Series Service Manual

Adjustment Procedures

Maintenance

Table of Contents

General Information 5–1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Recommended Equipment List 5–4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Adjustment List 5–8. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Procedure 5–12. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Preventive Maintenance 6–1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Cleaning or Changing the Fan Filter 6–1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Performance Checks and Readjustments 6–1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Cleaning 6–1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Visual Inspection 6–2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Static-Sensitive Components 6–3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Corrective Maintenance 6–5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Obtaining Replacement Parts 6–5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Mechanical Disassembly/Assembly 6–6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Inner Bezel Frame Removal 6–6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Graticule Light Removal 6–7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Instrument Removal from Rack Mounting Cabinet or Portable Case 6–8. . . . .

CR T Removal 6–8. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

CR T Replacement 6–9. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Removing the Input & BNC Board 6–11. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Removing the Fuse Board 6–11. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Removing the Waveform HV Supply Board 6–12. . . . . . . . . . . . . . . . . . . . . . . .

Removing the Microprocessor (MPU) Board 6–12. . . . . . . . . . . . . . . . . . . . . . . .

Removing the MPU Annex Board 6–12. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Removing the LV Power Supply Board 6–13. . . . . . . . . . . . . . . . . . . . . . . . . . . .

Removing the Vectorscope Board 6–13. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Removing the Oscillator Board 6–14. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Removing the Z-Axis Board 6–14. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Troubleshooting 6–15. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Troubleshooting Aids 6–15. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Foldout Pages 6–15. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Parts Lists 6–16. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Selected Components 6–16. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

General Troubleshooting Techniques 6–19. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Troubleshooting Procedures 6–21. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Board Accessibility 6–21. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Z Axis and Oscillator Boards 6–21. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

LV Power Supply Board 6–21. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Power Supply 6–22. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Troubleshooting Equipment 6–22. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Current Limit Adjustment (A1R466) 6–27. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

T ouch Panel Sensitivity Adjustment (A9R292) 6–29. . . . . . . . . . . . . . . . . . . . . . . . . .

Equipment Required List 6–29. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

1780R-Series Service Manual

iii

Table of Contents

Options

Electrical Parts List
Diagrams
Mechanical Parts List

CR T Options 7–1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Power Cord Options 7–1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

iv

1780R-Series Service Manual

List of Figures

Table of Contents

Figure 1–1: Simplified representation of the 1780R-Series

Video Measurement Set 1–1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Figure 2–1: Rear panel for the Tektronix 1780R-Series

Measurement Set 2–3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Figure 2–2: Settings for the rear-panel mains selector switch 2–5. . . . . .

Figure 2–3: Upper right portion of the 1780R-Series rear panel,

showing the location of the four loop-through signal inputs 2–8. . . .

Figure 2–4: Remote connector and the function of each pin.

A / before a function indicates a low to activate 2–9. . . . . . . . . . . . . . .

Figure 2–5: Serial interface connector showing the function of

each pin 2–10. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Figure 2–6: RS232D serial interface adapter diagram 2–11. . . . . . . . . . . .

Figure 2–7: Rear-panel XY connector diagram showing the function

of each pin 2–13. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Figure 2–8: Location of the four screws that secure the instrument

to rack mounting cabinet or portable case 2–14. . . . . . . . . . . . . . . . . . .

Figure 2–9: Dimensions used for rack mounting the 1780R-Series

Video Measurement Set 2–15. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Figure 2–10: Dimensions of the adjustable rear rackmounting

bracket 2–15. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Figure 2–11: Installing rear rack-mounting brackets for rack

applications of depths from 18 to 24 inches 2–16. . . . . . . . . . . . . . . . . .

Figure 2–12: Portable case for the 1780R-Series Video Measurement

Set. Case has handle, feet, and an elevating bail along with two

panel covers 2–17. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Figure 2–13: Waveform Calibration menu display 2–20. . . . . . . . . . . . . . .

Figure 2–14: 1780R (NTSC) Vectorscope Calibration menu display

with CAL OSC on 2–23. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Figure 2–15: 1781R (PAL) Vectorscope Calibration menu display 2–23. .

Figure 2–16: 1780R-Series repackaging 2–25. . . . . . . . . . . . . . . . . . . . . . . .

Figure 2–17: Simplified representation of the 1780R Series showing

the location of the control groups 2–27. . . . . . . . . . . . . . . . . . . . . . . . . .

Figure 2–18: Front panel of the 1780R-Series Video Measurement

Set 2–28. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Figure 2–19: The right front panel for the Tektronix 1780R-Series,

showing the Functional Measurement Controls 2–31. . . . . . . . . . . . . .

1780R-Series Service Manual

v

Table of Contents

Figure 4–1: 5% signal Attenuator for checking differential gain 4–4. . . .

Figure 4–2: Rear view of the X Y plug connections. (Pins 2, 4, 6,

10, 12, and 14 can be used to make ground connections.) 4–5. . . . . . .

Figure 4–3: REMOTE connector modified for Remote Sync input 4–5. .

Figure 4–4: RGB Parade Display Test Connector 4–6. . . . . . . . . . . . . . . .

Figure 4–5: Initial equipment hook-up for the Performance Check

Procedure 4–11. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Figure 4–6: Test equipment connections for checking calibrator

amplitude accuracy 4–13. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Figure 4–7: Identification of marks and divisions on the graticule

baseline 4–16. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Figure 4–8: Test equipment connections for checking CH A

frequency response 4–23. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Figure 4–9: Connections for checking AUX OUT frequency response.

(Only Ch 1 of the test oscilloscope dual-trace unit is used.) 4–27. . . . .

Figure 4–10: Vector graticule showing the –3 dB points for checking

frequency response 4–55. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Figure 4–11: Properly adjusted xy input gains 4–61. . . . . . . . . . . . . . . . . . .

Figure 4–12: Connections for checking line strobe pulse timing 4–63. . . .

Figure 4–13: Setting up the Return Loss Bridge: a) setup 500 mV

amplitude; b) Nulling the bridge 4–66. . . . . . . . . . . . . . . . . . . . . . . . . . .

Figure 4–14: Measuring return loss of 1780R-Series CH A INPUT 4–67. .

Figure 5–1: Simplified representation of the 1780R-Series Video

Measurement Set, showing the location of the four control

groups 5–2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Figure 5–2: Calibrate menu as displayed on the Vectorscope CRT 5–2. .

Figure 5–3: 1780R-Series circuit board assembly locations 5–3. . . . . . . .

Figure 5–4: Rear view of the X Y plug connections. (Pins 2, 4, 6,

10, 12, and 14 can be used to make ground connections.) 5–7. . . . . . .

Figure 5–5: RGB Parade Display Test Connector 5–7. . . . . . . . . . . . . . . .

Figure 5–6: Initial signal connections for re-adjustment of the

1780R-Series 5–13. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Figure 5–7: Adjustment and test point locations on the

Waveform HV Supply circuit board (Assembly 16.) 5–15. . . . . . . . . . .

Figure 5–8: Adjustment locations on the Vectorscope HV Supply

circuit board (Assembly A3) 5–17. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Figure 5–9: Adjustment locations on the Microprocessor circuit

board (Assembly A5) 5–18. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Figure 5–10: Waveform circuit board (Assembly A2) adjustment,

test point, and jumper locations. 5–19. . . . . . . . . . . . . . . . . . . . . . . . . . .

vi

1780R-Series Service Manual

Table of Contents

Figure 5–11: Adjustment locations on the Vectorscope circuit board

(Assembly A6) 5–21. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Figure 5–12: Connections for adjusting the calibrator amplitude 5–22. . .
Figure 5–13: Input & BNC circuit board (A8) adjustments, shown as

they would appear with the instrument on its left side 5–25. . . . . . . . .

Figure 5–14: Test equipment connections for matching CH A and

CH B1 input gains. 5–26. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Figure 5–15: Test equipment connections for adjusting CH A

frequency response 5–31. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Figure 5–16: Adjustment and test point (TP) locations for the

Oscillator circuit board (Assembly A7). 5–41. . . . . . . . . . . . . . . . . . . . .

Figure 5–17: Noise Reduction–ON. DAC offset properly adjusted 5–47. .
Figure 5–18: Noise Reduction–OFF. Demod offset properly adjusted 5–48
Figure 5–19: Z-Axis circuit board (A4) adjustment and test

point locations 5–51. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Figure 5–20: Vector graticule x- and y-axis markings for adjusting

xy input gains 5–53. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Figure 5–21: Properly adjusted xy input gains 5–54. . . . . . . . . . . . . . . . . . .

Figure 6–1: Front panel parts 6–6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Figure 6–2: Positions of the waveform CRT deflection leads 6–9. . . . . . .

Figure 6–3: Rear panel for the Tektronix 1780R-Series Video

Measurement Set showing the location of sub-assembly

mounting screws 6–10. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Figure 6–4: Using foldout pages 6–15. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Figure 6–5: 1780R-Series circuit board assembly locations 6–18. . . . . . . .

Figure 6–6: Connections for the external power supply leads 6–23. . . . . .

Figure 6–7: Connecting the AC mains to the 1780-R Series for

troubleshooting 6–24. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Figure 6–8: A. Q250 collector waveform. B. Q250 base waveform.

C. Q350–Q451 emitter waveform. D. U460 pin 3 waveform.

E. U460 pin 4 waveform 6–27. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Figure 6–9: +5 V supply output waveform when over voltage

protection is operating 6–28. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Figure 6–10: Power supply load used when adjusting current limit

(A1R466). Load can be connected between the top end of

A2L638 and ground 6–28. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

1780R-Series Service Manual

vii

Table of Contents

List of Tables

Table 1–1: Input/Output 1–4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Table 1–2: Waveform Monitor Vertical System 1–5. . . . . . . . . . . . . . . . .

Table 1–3: Waveform Monitor Probe Input 1–8. . . . . . . . . . . . . . . . . . . .

Table 1–4: Waveform Monitor Horizontal Deflection System 1–8. . . . . .

Table 1–5: Waveform Monitor dG and dP Display 1–11. . . . . . . . . . . . . . .

Table 1–6: Synchronization 1–12. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Table 1–7: Vectorscope Vector Display 1–13. . . . . . . . . . . . . . . . . . . . . . . . .

Table 1–8: Vectorscope X-Y Display 1–15. . . . . . . . . . . . . . . . . . . . . . . . . . .

Table 1–9: Vectorscope SCH Phase Display 1–15. . . . . . . . . . . . . . . . . . . . .

Table 1–10: CRTs and High Voltage Supplies 1–16. . . . . . . . . . . . . . . . . . .

Table 1–11: Power Requirements 1–16. . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Table 1–12: Environmental Summary 1–17. . . . . . . . . . . . . . . . . . . . . . . . .

Table 1–13: Physical Characteristics 1–17. . . . . . . . . . . . . . . . . . . . . . . . . .

Table 1–14: Certifications and Compliances 1–18. . . . . . . . . . . . . . . . . . . .

Table 2–1: 1780R-Series Standard Accessories 2–1. . . . . . . . . . . . . . . . . .

Table 2–2: Partial List of Optional Accessories Available for the

1780R-Series 2–2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Table 2–3: Plug Jumpers for Waveform Board (Assembly A2)

(Schematic Diagrams 3 through 15) 2–6. . . . . . . . . . . . . . . . . . . . . . . .

Table 2–4: Plug Jumpers and DIP Switch on the Microprocessor

Board (Assembly A5) (Schematic Diagrams 16 through 19) 2–7. . . .

Table 2–5: Plug Jumpers for Vectorscope Board (Assembly A6)

and Oscillator Board (Assembly A7) 2–7. . . . . . . . . . . . . . . . . . . . . . .

Table 2–6: Serial Remote Commands 2–11. . . . . . . . . . . . . . . . . . . . . . . . . .

Table 2–7: Serial Remote Responses 2–12. . . . . . . . . . . . . . . . . . . . . . . . . . .

Table 3–1: Schematics and Circuit Board Assemblies 3–3. . . . . . . . . . . .

Table 3–2: Input Channel Selection Logic 3–18. . . . . . . . . . . . . . . . . . . . . .

Table 3–3: Filter Selection Logic 3–19. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Table 3–4: Memory Switch Outputs 3–93. . . . . . . . . . . . . . . . . . . . . . . . . . .

Table 4–1: Recommended Equipment 4–1. . . . . . . . . . . . . . . . . . . . . . . . .

Table 4–2: 1780R-Series Initial Control Settings 4–10. . . . . . . . . . . . . . . . .

Table 4–3: Common Mode Rejection 4–35. . . . . . . . . . . . . . . . . . . . . . . . . .

Table 4–4: Sweep Timing and Linearity 4–42. . . . . . . . . . . . . . . . . . . . . . . .

viii

1780R-Series Service Manual

Table of Contents

Table 5–1: Recommended Equipment 5–4. . . . . . . . . . . . . . . . . . . . . . . . .

Table 5–2: 1780R-Series Adjustments for Calibration Procedure 5–8. .

Table 5–3: 1780R-Series Initial Control Settings 5–12. . . . . . . . . . . . . . . . .

Table 5–4: Low Voltage Power Supply Tolerance 5–14. . . . . . . . . . . . . . . .

Table 6–1: Static Susceptibility 6–3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Table 6–2: Test Selectable Components 6–16. . . . . . . . . . . . . . . . . . . . . . . .

Table 6–3: Circuit Board Assemblies 6–17. . . . . . . . . . . . . . . . . . . . . . . . . .

Table 6–4: Power Supply External Load Resistances 6–25. . . . . . . . . . . . .

1780R-Series Service Manual

ix

Table of Contents

x

1780R-Series Service Manual

General Safety Summary

Review the following safety precautions to avoid injury and prevent damage to
this product or any products connected to it. To avoid potential hazards, use this
product only as specified.

Only qualified personnel should perform service procedures.

To Avoid Fire or
Personal Injury

Use Proper Power Cord. Use only the power cord specified for this product and

certified for the country of use.
Connect and Disconnect Properly . Do not connect or disconnect probes or test

leads while they are connected to a voltage source.
Ground the Product. This product is grounded through the grounding conductor

of the power cord. To avoid electric shock, the grounding conductor must be
connected to earth ground. Before making connections to the input or output
terminals of the product, ensure that the product is properly grounded.

Observe All Terminal Ratings. To avoid fire or shock hazard, observe all ratings
and markings on the product. Consult the product manual for further ratings
information before making connections to the product.

Do not apply a potential to any terminal, including the common terminal, that
exceeds the maximum rating of that terminal.

Recharge Batteries Properly. Recharge batteries for the recommended charge
cycle only.

Do Not Operate Without Covers. Do not operate this product with covers or panels
removed.

Use Proper Fuse. Use only the fuse type and rating specified for this product.

1780R-Series Service Manual

Avoid Exposed Circuitry. Do not touch exposed connections and components
when power is present.

Wear Eye Protection. Wear eye protection if exposure to high-intensity rays or
laser radiation exists.

Do Not Operate With Suspected Failures. If you suspect there is damage to this
product, have it inspected by qualified service personnel.

Do Not Operate in Wet/Damp Conditions.
Do Not Operate in an Explosive Atmosphere.
Keep Product Surfaces Clean and Dry .
Provide Proper Ventilation. Refer to the manual’s installation instructions for

details on installing the product so it has proper ventilation.

xi

General Safety Summary

Symbols and Terms

T erms in this Manual. These terms may appear in this manual:

WARNING. Warning statements identify conditions or practices that could result
in injury or loss of life.

CAUTION. Caution statements identify conditions or practices that could result in
damage to this product or other property.

T erms on the Product. These terms may appear on the product:
DANGER indicates an injury hazard immediately accessible as you read the

marking.
WARNING indicates an injury hazard not immediately accessible as you read the

marking.
CAUTION indicates a hazard to property including the product.
Symbols on the Product. The following symbols may appear on the product:

CAUTION

Refer to Manual

WARNING

High Voltage

Double

Insulated

Protective Ground

(Earth) Terminal

Not suitable for

connection to

the public telecom-

munications network

xii

1780R-Series Service Manual

Service Safety Summary

Only qualified personnel should perform service procedures. Read this Service
Safety Summary and the General Safety Summary before performing any service

procedures.
Do Not Service Alone. Do not perform internal service or adjustments of this

product unless another person capable of rendering first aid and resuscitation is
present.

Disconnect Power. To avoid electric shock, disconnect the mains power by means
of the power cord or, if provided, the power switch.

Use Caution When Servicing the CRT. To avoid electric shock or injury, use
extreme caution when handling the CRT. Only qualified personnel familiar with
CRT servicing procedures and precautions should remove or install the CRT.

CRTs retain hazardous voltages for long periods of time after power is turned off.
Before attempting any servicing, discharge the CRT by shorting the anode to
chassis ground. When discharging the CRT, connect the discharge path to ground
and then the anode. Rough handling may cause the CRT to implode. Do not nick
or scratch the glass or subject it to undue pressure when removing or installing it.
When handling the CRT, wear safety goggles and heavy gloves for protection.

Use Care When Servicing With Power On. Dangerous voltages or currents may
exist in this product. Disconnect power, remove battery (if applicable), and
disconnect test leads before removing protective panels, soldering, or replacing
components.

To avoid electric shock, do not touch exposed connections.
X-Radiation. To avoid x-radiation exposure, do not modify or otherwise alter the

high-voltage circuitry or the CRT enclosure. X-ray emissions generated within
this product have been sufficiently shielded.

1780R-Series Service Manual

xiii

Service Safety Summary

xiv

1780R-Series Service Manual

Preface

This Service Manual is part of a 2-volume set. Its companion manual is the
Operator’s Manual, which is aimed primarily at operating personnel. Information
in this volume is intended for those who are required to maintain the 1780R-Se­ries Video Measurement Set.

Specific instructional procedures can be found in the Performance Check,
Adjustment Procedures, Maintenance and Installation sections. In addition, the
lists of Replaceable and Mechanical Parts along with circuit board component
locating dollies and schematic diagrams are at the back of this manual.

Operating Information is a very simple explanation of the controls and connec­tors. If there is a question involving one of the specific measurement applica­tions, it may be necessary to consult the Operator’s Manual to determine if there
is an instrument malfunction or simply an operator error.

Special techniques are required to service the 1780R-Series Low Voltage Power
Supply. Consult Troubleshooting before attempting to work on the Low Voltage
Power Supply.

To assist in locating information in this volume there is a complete Table of
Contents, augmented by a List of Illustrations and a List of Tables.

1780R-Series Service Manual

xv

Preface

xvi

1780R-Series Service Manual

Product Description

The Tektronix 1780R-Series Video Measurement Set is a 19-inch wide,
5 1/4-inch high, 18-inch deep dual-CRT Waveform Monitor/Vectorscope. It
weighs approximately 28 pounds and is intended for rack-mount applications,
but can also be configured as a full (rack) width cabinet model for bench and
portable applications. See Figure 1–1. The remainder of the front-panel area
contains controls and switches that manually configure the instrument for
measurements. Both CRTs have alphanumeric readout and touch-screen control
to simplify measurement tasks and operating menus.

Figure 1–1: Simplified representation of the 1780R-Series Video Measurement Set

The left CRT is selectively used for vectorscope, picture monitor, SCH phase,
and XY displays, while the right one is used for the waveform monitor displays.
The picture monitor display has a bright-up strobe; when the instrument is in a
line select mode, that makes its display identical to that of a picture monitor
driven from the rear-panel Pix Mon Out.

1780R-Series Service Manual

The right CRT is used for the normal filtered waveform monitor displays.
Waveform monitor measurements can have voltage and time cursors added to the
display to improve measurement accuracy. The elapsed time or amplitude
difference between cursors is displayed as alphanumeric CRT readout. Besides
the typical waveform monitor displays the right CRT is used for high-resolution,
high-accuracy differential gain and phase measurements.

Signal and reference input is through 75 W bridging loop-through inputs. There
are four composite video inputs, making it possible to use the 1780R-Series to
measure analog component signals, if desired. In addition to the normal 1- or
2-line, and 1- or 2-field displays, both component and composite signals can be
displayed in parade or overlay mode. The external reference can be either
composite sync or black burst. The 1780R-Series can also be operated with an
external subcarrier reference input, similar to the Tektronix 520-Series.

All instruments in the series have a front-panel, high impedance (1 MW) probe
input. Signals input through the probe can be displayed as single or multiple
lines or fields and can also be overlayed or paraded with the rear-panel input

1–1

Product Description

signals. The probe input has gain and input compensation for both X1 and X10
probes.

The instrument control system is based on a National Semiconductor 32CG16
Microprocessor, with an additional line rate processor that makes line-by-line
measurement decisions. Front-panel switching and CRT touch-screen selections
are acted upon by the processors. The front-panel switches are momentary
touch-type, which toggle through a short list of functions and provide additional
selections when held in. Each switch has a back-lighted functional indicator or
built-in indicator to relay switch status to the operator. In addition to sensing and
acting on switch and touch panel changes, the Microprocessor controls the
alphanumeric CRT readout for menu selections and measurement results.

The current front-panel configuration (switch and touch screen) is always stored
in non-volatile memory allowing the instrument to power back up in its previous
measurement configuration. In addition, front-panel configurations can be stored
and recalled (one-button measurement), like the Tektronix 1730-Series.

The use of touch screens and an assignable, multi-function control greatly
simplifies the operator interface. The control is an optical encoder that is used for
line selection, voltage measurements, timing measurements, and subcarrier phase
measurements, along with other menu/touch screen assigned tasks. A pair of
push buttons, adjacent to the control, can be used to duplicate the function of the
control when individual steps are desired.

CRT Options

Power Cord Options

The waveform monitor has reduced spot size and provides a bright display for
showing an individual line. The left CRT provides the vectorscope, picture
monitor, SCH phase and XY displays. Both CRTs have internal measurement
graticules, and can accommodate external graticules that are used for specialized
measurements and some photographic applications. Variable graticule scale
illumination provides uniform lighting over the usable area for both the internal
and external graticules.

Option 74 provides a P4 (white) phosphor tube.

Any of the power cord options described in Maintenance can be ordered for the
1780R-Series. If no power cord option is ordered, instruments are shipped with a
North American 125 V power cord and one replacement fuse.

1–2

1780R-Series Service Manual

Specifications

This section of the manual contains the specifications for the 1780R-Series.
Tabular information is divided into two categories. First there are the Perfor­mance Requirements which is assured by Tektronix Inc. Second are the items in
the Supplemental Information column, which due to a number of reasons may be
only typical numbers or could vary slightly from one instrument to the next.

The Performance Verification is provided to verify listed Performance Require-
ments. If a step for a specific requirement is not included in this procedure, it is
because the performance has been built into the instrument and is therefore
assured by either the fact that the instrument is operational or is proven correct
by other performance check steps. In a few instances, the procedure to verify a
specification can be extremely difficult or require extremely expensive equip­ment to verify, which might also cause them to be omitted from the procedure. In
these cases the factory has a procedure, that can be provided if necessary.

The step numbers, that can be used to verify the Performance Requirements and
some critical Supplemental items, are in a column following the Supplemental
Information.

Performance Qualification

The Performance Requirements listed in the Electrical Specification apply over
an ambient temperature range of 0_ C to +50_ C. The rated accuracies are valid
when the instrument is calibrated at an ambient temperature range of +20_ C to
+30_ C, after a warm-up time of 20 minutes. Test equipment used to verify
Performance Requirements must be calibrated and working within the limits
specified under the Equipment Required list.

Heat Dissipation

Maximum heat dissipation is 120 Watts (410 BTU/ Hour).

1780R-Series Service Manual

1–3

Specifications

T able 1–1: Input/Output

Characteristic Performance Requirement Supplemental Information

Vertical Ranges

Volts Full Scale Accuracy

Performance
Check Step

1.0 1.0 V ±0.007 V. Peak-to-peak Amplitude for Full
Graticule 1.0 volt/140 IRE.

Var ≤0.5:1 to ≥1.5:1 (0.67 V to 2.0 V

input signal can be made full
scale).

Input Gain Ratios

A to B 1 to 1 ±0.002 (0.998 – 1.002). 10
Auxiliary Video Input to A Input 1.5 dB ±0.3 dB. 10
Input A to Auxiliary Video Output 1 to 1 ±0.005 (0.995 – 1.005). 10
Input A to Picture Monitor Output 1 to 1 ±0.02 (0.98 – 1.02). 10

Vertical Magnifier

X5 Accuracy 0.2 V ±0.007 V .
Peak-to-peak Amplitude for Full

Graticule

Maximum Input Signal

AC Coupled All Inputs 2.0 V , peak-to-peak, 10%–90%

APL.

DC Coupled All Inputs ±1.5 V (DC + peak AC).

0.2 V/28 IRE.

Aux Video Out and Pix Mon
(terminated), 1.0 V peak-to-peak,
10%–90% APL.

4

5

Max volts from Loop-Thru common
terminal to chassis

Max DC Output Voltage

Aux Video Out ±0.5 V into 75 W.
Pix Mon Out ±0.5 V into 75 W.

Remote Control

Interface Standard RS422, RS232 (subset of all

Control Enable Ground closures and presets.

2 V

at mains frequency. Rejection ratio of common-to-

RMS

chassis in floating ground mode,
≥34 dB at mains frequency.

Line strobe but no input signal.

controls).

1–4

7

1780R-Series Service Manual

T able 1–2: Waveform Monitor Vertical System

Characteristic Performance Requirement Supplemental Information

Return Loss

CH A, B1, B2, or B3 >40 dB DC to 5 MHz. (Terminated in 75 W.) 58

Specifications

Performance
Check Step

Aux Video In, Aux Video Out, & Pix
Mon Out

Ext. Sync Input >46 dB to 5 MHz. 58

Loop-Through Isolation >80 dB at FSC, between channels

Crosstalk Typically 70 dB isolation between

Frequency Response

Flat (X1)

50 kHz – 5 MHz ±1%. All inputs, 1 V Full Scale, Var.

5 MHz – 10 MHz ±1%. CH A, 1 V Full Scale, Var. Gain

>34 dB DC to 5 MHz. Instrument On only. 58

and each channel and EXT REF.
Measured externally.

channels. Measured at F
between channels and each
channel and EXT REF .

Gain off. Adjusted for min. lum/
chroma gain error. T ypically
<0.5%.

±2%. Aux In, and Aux Out. 15–16

off.

±2%. Ch B1, Ch B2, Ch B3, Aux In, and

Aux Out.

SC

11–15

11

12–16

10 MHz – 15 MHz +2% –5%. All Inputs, 1 V Full Scale, Var.

Gain off.

15 MHz – 20 MHz +2% –15%. All Inputs, 1 V Full Scale, Var.

Gain off. –3 dB at >20 MHz.

Lum/Chroma Gain ±0.5%. X5 Gain with Modulated Sin

Pulse (12.5T NTSC, 10T PAL).

Voltage Cursor

Accuracy ±0.2%. 6
Resolution 1 mV .

Cal Amplitude

Accuracy 1.00 V ±0.2%. NTSC = 0.714 V ±0.5%.

PAL = 0.700 V ±0.5%.

Resolution 1 mV at 1.00 V.

1780R-Series Service Manual

11–15

11–15

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3

1–5

Specifications

Adjusted

e

1

error

1

de

s

.

0

T able 1–2: Waveform Monitor Vertical System (Cont.)

Characteristic

DC Restorer

Performance

Supplemental InformationPerformance Requirement

Check Step

Clamp Point Backporch or Sync Tip.

(All clamps controlled together.)

Mains Hum Atten.

Slow Clamp ≤0.9 dB. Attenuation ≤10%.
Fast Clamp ≥26 dB.

Shift caused by presence or absence
of burst

Lum/Chroma Gain Ratio

NTSC (50 kHz – 3.58 MHz) 1:1 ±1%.
PAL (50 kHz – 4.43 MHz) 1:1 ±1%.

DC Channel Matching Typically within 30 mV. 8
Common Mode Rejection AB1 B1B2 / B1B3

60 Hz ≥46 dB ≥46 dB
15 kHz (Lum) ≥46 dB ≥46 dB
1 MHz ≥40 dB ≥34 dB

3.58 or 4.43 MHz (Chroma) ≥34 dB ≥34 dB A – B1 typically >46 dB to

Filters

NTSC = 1 IRE.
PAL = ≤7 mV.

to minimize luminanc
to chrominance gain
Full Scale, typically ≤0.5%.

V peak-to-peak common mo
ignal

6.0 MHz and >40 dB to 10.0 MHz.

at 1 V

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22

24

9

26

Luminance <3 dB down at 1 MHz. ≥40 dB

down at 3.58 or 4.43 MHz.
Low Pass ≥14 dB down at 500 kHz. Typically –3 dB at 300 kHz.
Chrominance

3.58 MHz ±1% of flat at 3.58 MHz.
3 dB points:

Lower: 2.83 ±0.15 MHz.
Upper: 4.33 ±0.15 MHz.

4.43 MHz ±1% of flat at 4.43 MHz.
3 dB points:

Lower: 3.68 ±0.15 MHz.
Upper: 5.18 ±0.15 MHz.

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2

1780R-Series Service Manual

T able 1–2: Waveform Monitor Vertical System (Cont.)

Re

Characteristic

Diff Steps

Specifications

Performance

Supplemental InformationPerformance Requirement

Check Step

(Differentiated Steps Attenuation) >40 dB at 3.58 MHz

(4.43 MHz PAL).

Noise Measurements

Accuracy To 56 dB within 1 dB; 60 dB

within 2 dB.

Offset Accuracy To 56 dB within 0.5 dB; 60 dB

within 1 dB.

Non-Linear Waveform Distortion

Differential Gain

Aux Video Out ≤0.25%, 10% – 90% APL. W aveform modes.
Pix Mon Out ≤0.25%, 10% – 90% APL.

Differential Phase

Aux Video Out ≤0.25°, 10% – 90% APL.
Pix Mon Out ≤0.25°, 10% – 90% APL.

Linear Waveform Distortion

Pulse Overshoot & Ringing ≤1% of applied pulse amplitude. Typically

Pulse and Bar ≤1% of applied pulse amplitude. Typically

25 ms Bar Tilt ≤1% of applied bar amplitude.

5 step, 20 IRE staircase within
2% of flat display.

Vertical Gain increase approx. 5X
to compare staircase risers.

lative to 700 mV

set to maximum.

<0.5% on T Pulse, and
<1.0% on T/2 Pulse.

<0.5% on T Pulse, and
<1.0% on T/2 Pulse.

RMS

, Var Gain

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Field Square Wave Tilt ≤1% of applied square wave

amplitude.

2T Sin2 Pulse-to-Bar Ratio 1:1 ±1%.

Vertical Overscan

Baseline Distortion <7 mV variation in baseline of

chroma when positioned any­where between sync tip and
100% white.

1780R-Series Service Manual

Typically <0.5%.

1 V p-p PAL or NTSC Modulated

2

composite video signal

Sin
(12.5T NTSC, 10T PAL). X1 or
X5, Variable Gain of f. Typically
<0.5%.

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