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COfAMI'rT-D TO EXCELLENCE




CHECK CHANGE INFORMATION
T THE OF THIS MANUAL .




ION MANUAL
Tektronix, Inc.
P.O . Box 500
Beaverton, Oregon 97077 Serial NL mber
070-2309-00 First Printing MAY 1978
Product Group 42
Revised SEP 1984
Copyright (s) 1978 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 a registered trademark of Tektronix U .K . Limited .

Printed in U .S.A . Specification and price change privileges
are reserved .




INSTRUMENT SERIAL NUMBERS

Each instrument has a serial number on a panel 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 :
B000000 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, Heerenveen,
The Netherlands
7B90P INSTRUCTION



TABLE OF CONTENTS

SAFETY Sid ARY viii




SECTION 1 - INTRODUCTION


Specifications 1-1
Summary of Programmable Features 1-8
Front-Panel Buttons 1-8
Front-Panel Controls 1-9
Block Diagram 1-11

SECTION 2 - MANUAL OPERATION


Installation 2-1
Controls, Connector, and Indicators 2-2
LEVEL Control 2-2
SLOPE Switch 2-2
TRIG'D Indicator 2-2
READY Indicator 2-2
TRIGGERING-MODE Pushbuttons 2-2
TRIGGERING-COUPLING Pushbuttons 2-4
TRIGGERING-SOURCE Pushbuttons 2-4
TIME/DIV Pushbuttons 2-5
POSITION Control 2-5
HOLD OFF Control 2-5
SWP CAL Adjustment 2-5
EXT TRIG IN 2-6
Functional Check 2-6
Preliminary Setup 2-6
Power-up Sequence 2-7
Procedure 2-7
General Operating Information 2-10
Triggering Switch Logic 2-10
Triggering Modes 2-11
PP AUTO 2-11
NORMAL 2-11
SINGLE SWEEP 2-11




REV A JULY 1979
7B90P INSTRUCTION



Trigger Coupling 2-12
AC 2-12
AC LF REJ 2-12
AC HF REJ 2-12
DC 2-12
Trigger Source 2-13
INTERNAL 2-13
LINE 2-13
EXTERNAL 2-13
Trigger Slope 2-14
Trigger Level 2-14
Horizontal Sweep Rates 2-14
Sweep Magnification 2-16
Time Measurement 2-16
Variable Hold off 2-17
Applications 2-18
Period and Frequency Measurements 2-19
Rise-Time and Fall-Time Measurements 2-20
Pulse-Width Measurements 2-21


SECTION 3 - PROGRAMMING


Introduction to the IEEE 488 Bus 3-2
A Typical System 3-2
Types of Instruments 3-2
Types of Messages 3-3
Maximum Number of Devices 3-4
Maximum Cable Length 3-4
Electrical Specifications 3-4
Bus Signal Lines 3-5
Data Bus 3-5
Transfer Bus 3-5
Management Bus 3-6
Bus Messages 3-7
7B90P Interface Function Subsets 3-9
Source Handshake 3-9
Acceptor Handshake 3-9
Talker 3-9
Listener 3-9
Service Request 3-10
Remote/Local 3-10
Parallel Poll 3-10




ii REV A JULY 1979
7B90P INSTRUCTION



Device Clear 3-10
Device Trigger 3-10
Controller 3-10
Addressing the 7B90P 3-11
Addressing Schemes 3-11
Primary Addressing 3-11
Secondary Addressing 3-11
Determining Device Addresses 3-12
High-Level Messages 3-14
Explanation of Command Syntax 3-14
Set Commands 3-15
Query Commands 3-16
Messages 3-19
Messages with Multiple Sets 3-19
Messages with Multiple Queries 3-20
The SET? Query 3-21
Messages with Sets and Queries 3-21
Query Responses 3-22
Low-Level Messages 3-23
Set Messages 3-23
Query Messages 3-30
Transmitting Messages 3-33
Transmitting Set Messages 3-33
Transmitting Query Messages 3-37
Serial-Poll Responses 3-41
Power on 3-41
Command error 3-41
Execution error 3-42
End of Sweep 3-42
Busy 3-42




REV A JULY 1979
7B90P INSTRUCTION



WARNING


The remaining portion of this table of contents lists the
Servicing instructions . These Servicing instructions are
for use by qualified personnel only . To avoid electrical
shock, do not perform any servicing other than that called
out in the Operating instructions unless qualified to do so .


SECTION 4 - MAI TENANCE

Preventive Maintenance 4-1
Cleaning 4-1
Exterior 4-1
Interior 4-1
Visual Inspection 4-2
Lubrication 4-2
Troubleshooting 4-3
Troubleshooting Aids 4-3
Schematic Diagrams 4-3
Circuit-Board Illustrations 4-3
Component-Locator Grids 4-3
Component and Wiring Color Code 4-3
Semiconductor Lead Configurations 4-3
Rear Interface Connector Pin Locations 4-3
Troubleshooting Equipment 4-5
Semiconductor Tester 4-5
Multimeter 4-5
Test Oscilloscope 4-5
Plug-in Extender 4-6
Troubleshooting Procedure 4-6
Check Control Settings 4-6
Check Associated Equipment 4-6
Visual Check 4-6
Check Instrument Adjustment 4-6
Isolate Trouble to a Circuit 4-7
Check Individual Components 4-7
Repair and Readjust the Circuit 4-8
Specific Troubleshooting Information 4-9
Analog Circuits 4-9
Trigger Circuits 4-9
Sweep Generator 4-10
Readout Circuits 4-11




iv REV A JULY 1979
7B90P INSTRUCTION



Microprocessor System 4-12
Self Test Addresses 4-13
Control Line State Tables 4-13
Corrective Maintenance 4-17
Obtaining Replacement Parts 4-17
Standard Parts 4-17
Ordering Parts 4-17
Soldering Techniques 4-18
Circuit Boards 4-18
Metal Terminals 4-18
Component Replacement 4-19
Semiconductor Replacement 4-19
Front-Panel LED's 4-19
Free-Standing Components 4-20
Circuit Board Removal 4-20
Removal of LED and SWITCH Boards 4-21
Removal of TRIGGER BOARD 4-21
Removal of HORIZONTAL PROGRAMMING and
SHIELD Boards 4-22
Removal of SWEEP Board 4-22
Recalibration After Repair 4-23
Repackaging for Shipment 4-23

SECTION 5 - CIRCUIT DESCRIPTION


Introduction 5-1
Block Diagram 5-1
Sweep Generator 5-3
Timing Current Source 5-3
Ramp Generator 5-5
Auxiliary Sweep .Preamp 5-6
Power Supplies 5-6
Horizontal Preamplifier 5-7
Input Differential Amplifier 5-7
Current Follower 5-7
Output Amplifier 5-8
Positioning Circuit 5-9
Trigger Generator 5-9
Line Source 5-10
Internal Source 5-10
External Source 5-12
Trigger Level Circuit 5-13




REV A JULY 1979 v
7B90P INSTRUCTION



Trigger Source Selector and Amplifier 5-13
Peak-to-Peak Auto Circuit 5-14
Slope Selector and Trigger Generator 5-16
Gate Generator 5-17
Sweep Logic 5-17
PP AUTO Mode 5-17
Normal Mode 5-19
Single Sweep Mode 5-19
Holdoff Circuit 5-19
Lockout Buffer Amplifier 5-20
Microprocessor System 5-21
MPU and Memory 5-21
PIA's 5-21
Power-up Circuit 5-22
Clock Circuit 5-23
Front Panel Buttons 5-24
Front Panel Lamp Decoders 5-24
GPIB Interface 5-24
IEEE 488 Data Bus 5-25
Acceptor Handshake 5-25
Source Handshake 5-25
Readout Circuit 5-26
Basic Readout Operation 5-26
Summing the Time Slots 5-27
Selecting Row and Column Currents 5-28
MPU Control Example 5-28

SECTION 6 - CALIBRATION

Introduction 6-1
Tektronix Field Service 6-1
Performance Check 6-1
Calibration 6-1
Test Equipment Required 6-2
General 6-2
Calibration Equipment Alternatives 6-2
Checking Programmable Features 6-2
Performance Check Procedure 6-5
Check Triggering Modes 6-6
Check External Level Range 6-7
Check Internal/External Low-Frequency
Triggering Sensitivity 6-8




Vi REV A JULY 1979
7B90P INSTRUCTION



Check Internal/External Mid-Frequency
Triggering Sensitivity 6-11
Check Internal/External High-Frequency
Triggering Sensitivity 6-13
Check Internal Trigger Jitter 6-14
Check Line Triggering 6-15
Check Sweep Length and Positioning 6-15
Check Magnifier Gain 6-16
Check Sweep Timing 6-17
Check Magnified Sweep Timing 6-17
Check Holdoff 6-18
Calibration Procedure 6-19
Preliminary Procedure for Calibration 6-19
Check/Adjust MPU Clock Speed 6-21
Check/Adjust Trigger Offset Null,
Normal Balance, and Slope Balance 6-22
Check/Adjust External X1 and X10 Balance 6-23
Check/Adjust Sweep and Magnifier Calibration 6-24
Check/Adjust Balance 6-25
Check/Adjust Sweep Timing 6-26
Check/Adjust Sweep Position 6-28

SECTION 7 - ELECTRICAL PARTS LIST


SECTION 8 - DIAGRAMS AND CIRCUIT BOARD ILLUSTRATIONS


SECTION 9 - MECHANICAL PARTS LIST




REV A JULY 1979 Vii
7B90P INSTRUCTION




This manual contains safety information which the user must follow to ensure safe operation of this instrument . WARNING
information is intended to protect the operator ; CAUTION information is intended to protec : the instrument . The following
are general safety precautions that must be observed during all phases of operation and maintenance .




WARNING I


Ground the Instrument

To reduce electrical-shock hazard, the mainframe (oscilloscope) chassis must be properly grounded. Refer to the mainframe
manual for grounding information .


Do Not Operate in Explosive Atmosphere

Do not operate this instrument in an area where flammable gases or fumes are present. Such operation could cause an
explosion.


Avoid Live Circuits

Electrical-shock hazards are present in this instrument. The protective instrument covers must not be removed by operating
personnel. Component replacement and internal adjustments must be referred to qualified service personnel.


Do Not Service or Adjust Alone

Do not service or make internal adjustments to this instrument unless another person, capable of giving first aid and resusci-
tation, is present.




Warning Statements

Warning statements accompany potentially dangerous procedures in this manual . The following warnings appear in this
manual and are listed here for additional emphasis .



f