Tektronix 7B87 User manual

HaktfDnix-
CXDMMITTED TO EXCELLENCE
PLEASE CHECK FOR CHANGE INFORMATION
AT THE REAR OF THIS MANUAL.
7B87
TIME BASE
WITH
PRETRIGGER
ACQUIRE CLOCK
INSTRUCTION MANUAL
Tektronix. Inc.
P.O. Box 500
Beaverton. Oregon 97077 Serial Number
070-2788-00
Product Group 42
First Printing APR 1980
Revised JAN 1986

Copyright -i' 1980 Tektronix. Inc. All rights reserved.
Contents of this publication may not be reproduced in any
form without the written permission of Tektronix. Inc.
Products of Tektronix. Inc. and its subsidiaries are covered
by U.S. and foreign patents and/or pending patents.
TEKTRONIX. TEK. SCOPE-MOBILE, and are
registered trademarks of Tektronix. Inc. TELEQUIPMENT
is aregistered trademark of Tektronix U.K. Limited.
Printed in U.S.A. Specification and price change privileges
are reserved.
INSTRUMENT SERIAL NUMBERS
Each instrument has aserial number on apahel insert, tag,
or stamped on the chassis. The first number or letter
designates the country of manufacture. The last five digits
of the serial number are assigned sequentially and are
unique to each instrument. Those manufactured in the
United States have six unique digits. The country of
manufacture is identified as follows:
BOOOOOO Tektronix. Inc.. Beaverton. Oregon, USA
100000 Tektronix Guernsey. Ltd., Channel Islands
200000 Tektronix United Kingdom. Ltd., London
300000 Sony/Tektronix. Japan
700000 Tektronix Holland. NV. Meerenveen,
The Netherlands

7B87 Instruction
TABLE OF CONTENTS
PAGE PAGE
LIST OF ILLUSTRATIONS
LIST OF TABLES iv
OPERATOfiS SAFETY SUMMARY w
SERVICING SAFETY SUMMARY, wit
SECTION 1OPERATING INSTRUCTIONS
INSTALLATION t-1
CONTROLS. CONNECTORS. AND INDICATORS 1-1
FUNCTIONAL CHECK 1-1
SETUP PROCEDURE 1-1
SWEEP FUNCTIONS 1-4
TRIGGERING FUNCTIONS 1-4
PRETRIGGER ACQUIRE CLOCK FUNCTIONS 1-S
GENERAL OPERATING INFORMATION 1-6
TRIGGERING SWITCH LOGIC 1-6
TRIGGERING MOOES 1-6
TRIGGER COUPLING 1-9
TRIGGER SOURCE 1-9
TRIGGER SLOPE 1-11
TRIGGER LEVEL 1-11
HORIZONTAL SWEEP RATES 1-11
TIME MEASUREMENT 1-11
SWEEP MAGNIFICATION 1-11
VARIABLE HOLD OFF 1-12
MAINFRAME OPERATING MOOES 1-12
APPLICATIONS 1-12
TIME INTERVAL MEASUREMENTS 1-12
PERIOD AND FREQUENCY MEASUREMENTS ...1-12
RISE TIME AND FALL-TIME MEASUREMENTS ..1-13
PULSE WIDTH MEASUREMENTS 1-14
SECTION 2SPECIFICATION
STANDARD ACCESSORIES 2-4
LmmIhmmJI
THE REMAINING PORTION OF THIS TABLE OF CONTENTS
LISTS SERVICING INSTRUCTIONS. THESE SERVICING
INSTRUCTIONS ARE FOR USE BY QUALIFIED PERSONNEL
ONLY. TO AVOID ELECTRICAL SHOCK. OO NOT PERFORM
ANY SERVICING OTHER THAN THAT CALLED OUT IN THE
OPERATING INSTRUCTIONS UNLESS QUALIFIED TO DO
SO.
SECTIONS THEORY OF OPERATION
BLOCK DIAGRAM DESCRIPTION 3-1
TRIGGER GENERATOR 3-1
SWFFP GENERATOR 3-1
PICKOFF AMPLIFIER AND DELAY GATE
GENERATOR 3-1
LOGIC 3-1
DIGITAL VOLTMETER 3-1
CLOCK GENERATOR 3-1
DETAILED CIRCUIT DESCRIPTION 3-1
FRONT-PANEL DISTRIBUTION .3-3
TRIGGER GENERATOR 3-3
EXTERNAL SOURCE 3-3
INTERNAL AND LINE SOURCE 3-3
TRIGGER SOURCE SELECTOR AND
AMPLIFIER 3-3
PEAK TO-PEAK AUTO 3-3
SLOPE SELECTOR AND TRIGGER
GENERATOR 3-5
GATE GENERATOR 3-5
LOGIC 3-5
SWEEP MOOES 3-5
HOLD OFF TIMING 3-6
LOCKOUT BUFFER AMPLIFIER 3-7
HOLD OFF OUTPUT AMPLIFIER 3-7
SWEEP GENERATOR 3-7
TIMING CURRENT SOURCE 3-7
RAMP GENERATOR 3-10
HORIZONTAL PREAMPLIFIER 3-10
SWEEP GATE GENERATOR 3-10
DVM 3-10
DELAY TIME COMPARATOR AND DELAY
GATE GENERATOR 3-10
OIGHAL VOLTMETER 3-11
DELAY COMPARISON VOLTAGE-TO RAMP
CONVERTER 3-12
COMPARATOR 3-12
REFERENCE CURRENT SOURCE 3-12
REFERENCE CURRENT INVERTER 312
COUNTER AND ENCODER 3-12
CLOCK GENERATOR 3-12
CONTROL LOGIC 3-13
OSCILLATOR 3-13
FIRST DIVIDER 3-15
XI X10MULTIPIEXER 3-15
DECADE DIVIDER 3-15
INTERNAL CLOCK MULTIPLEXER 3-15
OUTPUT CLOCK MULTIPLEXER 3-15
INTENSIFY CIRCUIT 3-15
7B87 IN AHORIZ PLUG-IN COMPARTMENT 316
IN1FRNAL BUTTON PRESSED 3-16
7B87 IN BHORIZ PLUG IN COMPARTMENT 3-16
INTERNAL BUnON PRESSED 316
TIME DIVISION AND READOUT SWITCHING 3-17
BASIC READOUT SYSTEM 3-17
TIME DIVISION READOUT 3-17
ACOUIRE-STOP DELAY TIME READOUT 3-17
INTERFACE CONNECTIONS AND POWER
SUPPLY 3-17
SECTION 4MAINTENANCE
PREVENTIVE MAINTENANCE 4-1
CLEANING 41
EXTERIOR 4-1
INTERIOR 41
SWITCH CONTACTS 4-1
REV JUN 1981

7B87 Instruction
TABLE OF CONTENTS (CONT)
PAGE
VISUAL INSPECTION 4-1
LUBRICATION 4-1
CAM SWITCH LUBRICATION 4-2
SEMICONDUCTOR CHECKS 4-2
ADJUSTMENT AUER REPAIR 4-2
TROUBLESHOOlING 4-2
TROUBLESHOOTING AIDS 4-2
DIAGRAMS 4-2
VOLTAGES AND WAVEFORMS 4-2
CIRCUIT-BOARD ILLUSTRATIONS 4-2
SWITCH CAM IDENTIFICATION 4-4
DIODE COLOR CODE 4-4
WIRING COLOR CODE 4-4
SEMICONDUCTOR LEAD CONFIGURATIONS 4-4
IN TER BOARD PIN CONNECTOR
IDENTIFICATION 44
MULTI-PIN CONNECTOR IDENTIFICATION 4-4
INTERFACE CONNECTOR PIN LOCATIONS 45
PERFORMANCE CHECK AND ADJUSTMENT 4-5
STATIC SENSITIVE DEVICES 45
TROUBLESHOOTING EQUIPMENT 4-6
TROUBLESHOOTING TECHNIQUES 4-6
TROUBLESHOOTING PROCEDURE 4-6
CORRECTIVE MAINTENANCE 4-8
OBTAINING REPLACEABLE PARTS 4-8
SOLDERING TECHNIQUES 4-9
COMPONENT REMOVAL AND REPLACEMENT 4-10
CIRCUIT BOARDS 410
SWITCHES 4-12
SEMICONDUCTORS 415
INTERCONNECTING PINS 4-15
CIRCUIT-BOARD PINS 415
FRONT-PANEL LIGHTS 4-16
ADJUSTMENT AFTER REPAIR 4 16
INSTRUMENT REPACKAGING 416
PAGE
SECTION 5PERFORMANCE CHECK AND
ADJUSTMENT
PRELIMINARY INFORMATION 5-1
ADJUSTMENT INTERVAL 5-1
TEKTRONIX FIELD SERVICE 51
USING THIS PROCEDURE 5-1
TEST EQUIPMENT REQUIRED 5-1
SPECIAL FIXTURES 51
TEST EQUIPMENT ALTERNATIVES 51
INDEX TO PERFORMANCE CHECK AND
ADJUSTMENT PROCEDURE 5 4
PRELIMINARY PROCEDURE 5-4
ATRIGGERING SYSTEM 5-5
BHORIZONTAL 'AQS SYSTEM 5-10
SECTION 6-INSTRUMENT OPTIONS
SECTION 7REPLACEABLE ELECTRICAL PARTS
SECTION 8DIAGRAMS AND CIRCUIT BOARD
ILLUSTRATIONS
SECTION 9REPLACEABLE MECHANICAL PARTS
CHANGE INFORMATION
ii REV JUN 1981

7B87 Instruction
LIST OF ILLUSTRATIONS
FIG PAGE
NO
Frontis
piece 7B87 Features vni
1-
1Location of release latch 1-1
I2Front panel controls, connectors, and
indicators 1-2
13Single Sweep Accguisilion 15
14Effect of LEVEL control and SLOPE switch
on cri display 1-10
15Area of graticule used for most accurate
time measurements 1-11
1-6 Operation of sweep magnifier 1-12
17Measuring the period and determining the
frequency of adisplayed waveform 1-13
18Measuring the rise time and fall time of
a displayed waveform 1-14
19Measuring the poise width of adisplayed
waveform 1-14
2-
17887 dimensional drawing 2-5
3-
1Basic block diagram of the 7687 Delaying
Time Base Unit 3-2
3-2 Detailed block diagram of Trigger Generator 3-4
33Timing diagram for Gate Generator stage
(092, Q96, Q98) 3-6
3-4 Detailed block diagram of Logic circuit 3-7
3-5 Detailed block diagram of Sweep Generator 3-8
3-
6Timing of events that form the Delay
Gate signal 3-11
4-
1Lubrication procedure for atypical
cam switch 4-2
42Semiconductor lead configuration 43
4-3 Inter-board mulli-pin connector assembly 44
FIG. PAGE
NO
4-4 End-lead mulli-pm connector assembly 4 4
4-5 Location of pin numbers on Interface
connector 4-5
4-6 7B87 troubleshooting chart 47
4-7 fteadoiii board removal procedure 4-10
4-8 Coaxial end lead connector assembly 4-11
49Location of securing screws and inier-board
multi-pin connectors on clock circuit hoard 4-12
4-10 Cam switch removal procedure 4-13
41 1 Removal procedure lor typical pushbutton
switch 4-14
4-12 Exploded view ol circuit-board pin and
ferrule 4-16
4-13 Front-panel light socket assembly 4-16
The illusiralions in Section 8are located near their associated
diagrams on the foldoul pages.
8-1 Semiconductor Lead Configurations
8-2 Locations of circuit boards in the 7B87.
8-3 A2 Trigger circuit board assembly
6-4 A1 -Interface circuit board assembly
8-5 A1 -Interface circuit board assembly.
8-6 A1 -Interface circuit board assembly
8-7 A4 Clock circuit board assembly
8-8 A4-Clock circuit board assembly
89A3 Readout circuit board assembly.
8-10 A1 -Interface circuit board assembly
8-1 1Test Point and Adjustment Locations.
REV JUN1981 Ml

7687 Instruction
LIST OF TABLES
TABLE PAGE
NO.
1-1 TIME/OIV Setting Relationship To 7B87
Internal Acquire Clock Rep Rate 1-7
2-1 Elecirical Characteristics 2-1
2-2 Mainframe Horizontal Compatibililv 2-3
2-3 Environmental Characteristics 2-4
2-
4Physical Characteristics 2-4
3-
tTruth Table. TIME/OIV Setting vs Strobes
lor U637 andU638 3-13
3-2 Selected Inputs or XI and X10 Mulliploxers 3-14
3-3 Operation of Output Multiplexer U6S5 3-15
3-4 Current in CHI Readout Line vs Acquire
Clock Mode. During TS10 3-16
3-
5Readout Character Selection 3-18
4-
1Relative Susceptibility 4-5
5-
1Test Equipment 5-2
5-2 Acquire Clock Repetition Rale Output 5-11
5-3 Delay Time Linearity 5-12
5-4 Acquire-Stop Delay Accuracy 5-13
5-5 Sweep Timing 5-14
5-6 Magnified Sweep Timing 5-15
IV

7B67 instruction
OPERATORS SAFETY SUMMARY
The general safety information in this part of the summary is for both operating and servicing personnel. Specific
warnings and cautions will be found throughout the manual where they apply, but may not appear in this summary.
TERMS
IN THIS MANUAL
CAUTION statements identify conditions or practices that could result in damage to the equipment or other property.
WARNING statements identify conditions or practices that could result in personal injury or loss of life.
AS MARKED ON EQUIPMENT
CAUTION indicates apersonal injury hazard not immediately accessible as one reads the marking, or ahazard to
property including the equipment itself
DANGER indicates apersonal injury hazard immediately accessible as one reads the marking.
SYMBOLS
IN THIS MANUAL
Static-Sensitive Devces.
AThis symbol indicates where applicable cautionary or other information is to be found.
AS MARKED ON EQUIPMENT
DANGER High voltage.
Protective ground (earth) terminal
ATTENTION -refer to manual
WARNINGS
POWER SOURCE
This product is intended to operate in amainframe connected to apower source that will not apply more than 250 volts
rms between the supply conductors or between either supply conductor and grourtd. Aprotective ground connection by
way of the grounding conductor in the mainframe power cord is essential for safe operation
GROUNDING THE PRODUCT
This product is grounded through the grounding conductor of the mainframe power cord To avoid electrical shock, plug
the mainframe power cord into aproperly wired receptacle before connecting to the product input or output terminals A
protective ground connection by way of the grounding conductor in the mainframe power cord is essential for safe
operation.
V

7B87 Instruction
DANGER ARISING FROM LOSS OP GROUND
Upon loss of the protective-ground connection, all accessible conductive parts (including knobs and controls that may
appear to be insulating), can render an electric shock
DO NOT OPERATE IN EXPLOSIVE ATMOSPHERES
To avoid explosion, do not operate this product in an atmosphere of explosive gases unless it has been specifically
certified for such operation.
DO NOT OPERATE PLUG-IN UNIT WITHOUT COVERS
To avoid personal injury, do not operate this product without covers or panels installed Do not apply power to the plug-in
unit via aplug-in extender
VI

7B87 Instruction
SERVICING SAFETY SUMMARY
FOR QUALIFIED SERVICE PERSONNEL ONLY
Refer also to the preceding Operators Safety Summary
DO NOT SERVICE ALONE
Do not perform internal service or adjustment of this product unless another person capable of rendering first aid and
resuscitation is present.
USE CARE WHEN SERVICING WITH POWER ON
Dangerous voltages exist at several points mthis product. To avoid personal injury, do not touch exposed connections
and components while power is on.
Disconnect power before removing protective panels, soldering, or replacing components.
POWER SOURCE
This product is intended to operate in amainframe connected to a power source that will not apply more than 250 volts
rms between the supply conductors or between either supply conductor and ground. Aprotective ground connection by
way of the grounding conductor in the mainframe power cord is essential for safe operation.
VII

7B87 Instruction
}TM )
7B87 FEATURES
The 7B87 Time-Base unit Preuigger Acquire Clock provides calibrated sweep rales from Sseconds to 10 nanoseconds andiriggering to 400
megahertz for 7000-Series Oscilloscopes AX10 Magnifier increases each sweep rate by afactor of 10 anda VAflIABLE TIME/DIV control
provides continuously-variable sweep rates between calibrated steps Variable holdoff and alphanumeric readout are provided Also, when
operating in the AUTO TRIGGERING MODE, abright baseliite trace is displayed in the absence of atrigger signal The 7B67 can be operated
as an independent time base or as a delayed-sweep unit with acompanion delaying time-base unit Sweep mode is determined by the
companion delaying time base
The7B87 also feat uresaninternally-gerteraied clock andan external clock input lor sequential single sweep acquisition when operating in a
7000-series digitizing oscilloscope The frequency range of the internally gerteraied clock is 20 46 mHz {millihertzl to 20 48 MHz as
determined by the TIME OlV, X10 MAG, aitd INT -1000 switches Also, an ACQUIRE-STOP DECAY function varies delay pickoff, ornl
therefore pretrigger time, in compatible digitizing plug-m oscilloscopes The portion of the oscilloscope real-time display between tbe
triggering event and the end of delay lime is intensified The exact delay lime is displayed on the cri readout
viii