Tektronix 7A29 User manual

Tektronix
COMMITTED TO EXCELLENCE
Tektronix. Inc.
P.O. Box 500
Beaverton. Oregon 97077
7A29
AMPLIFIER
WITH OPTIONS
INSTRUCTION MANUAL
070-2320 00 Firsi Printing APRIL 1979

Copyright i9'/9 Tektronix, inc. All rights reserved.
Contents of this purification may not be reproduced in any
form without tne written permission of Tektronix, Inc.
«/jL7fav*w Sr *wf jy Ip /* •/ 9
Products o! Tektronix me. and its subsidiaries -are
covered by U.S. anc foreign patents and/or pending
patents.
TEKTRONIX, TEK, SCOPE-MOBILE, and WsS are reg-
istered trademarks of Tektronix, Inc. TF.LEQU1PMENT is
aregistered trademark of Tektronix U.K. Limited.
Printed in U.S.A. Specification and price change
privileges are reserved.

7A29 Instruction
TABLE OF CONTENTS
PAGE
LIST OF ILLUSTRATIONS iii
LIST OF TABLES in
OPERATORS SAFETY SUMMARY iv
SERVICE SAFETY SUMMARY v
SECTION 1GENERAL INFORMATION
INTRODUCTION 1-1
INSTALLATION 1-1
INITIAL INSPECTION 1-1
OPERATING INFORMATION 1-1
OPERATING TEMPERATURE 1-2
PACKAGING FOR SHIPMENT 1-2
SPECIFICATIONS 1-2
STANDARD ACCESSORIES 1-6
RECOMMENDED ACCESSORIES 1-6
PROBES 1-6
SECTION 2OPERATING INSTRUCTIONS
CONTROLS AND CONNECTORS 2-1
CHECKOUT PROCEDURE 2-1
BEFORE YOU BEGIN 2-1
TEST EQUIPMENT REQUIRED 2-1
SETUP PROCEDURE 2-1
AMPLIFIER FUNCTIONS 2-3
DETAILED OPERATING INFORMATION 2-4
PROBES 2-4
VERTICAL GAIN CHECK AND
ADJUSTMENT 2-4
INPUT COUPLING 2-4
VOLTS/DIV SWITCH 2-5
POLARITY SWITCH 2-5
TRACE IDENTIFICATION AND
READOUT FUNCTIONS 2-5
VARIABLF DELAY (OPTION 4) 2-5
MATCHING DELAY TIMES USING TWO
7A29 UNITS. ONE HAVING VARIABLE
DELAY (OPTION 4) 2-5
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 CAl LEO OUT IN THE
OPERATING INSTRUCTIONS UNLESS QUALIFIED
TO DO SO.
PAGE
SECTION 3THEORY OF OPERATION
BLOCK DIAGRAM 3-1
DETAILED CIRCUIT OPERATION 3-1
INPUT SWITCHING AND READOUT 3-3
DELAY LINE 3-3
AC-OFF DC 3-3
INPUT ATTENUATORS 3-3
INPUT PROTECTION 3-3
POWER SUPPLIES 3-3
READOUT SWITCHING 3-3
INPUT AMPLIFIER 34
FAST OVERLOAD PROTECTION 3-4
FEEDBESIDE 3-4
INPUT AMPLIFIER 3-4
POSITION 3-5
TRIGGER AND OUTPUT AMPLIFIER 3-6
OUTPUT AMPLIFIER 3-6
TRIGGER AMPLIFIER 3-6
SECTION 4MAINTENANCE
PREVENTIVE MAINTENANCE 4-1
CLEANING 4-1
EXTERIOR 4-1
INTERIOR 4-1
VISUAL INSPECTION 4-1
PERIODIC ELECTRICAL ADJUSTMENT 4-2
SEMICONDUCTOR CHECKS 4-2
TROUBLESHOOTING 4-2
TROUBLESHOOTING AIDS 4-2
DIAGRAMS 4-2
CIRCUIT BOARD ILLUSTRATIONS 4-2
TROUBLESHOOTING CHART 4-2
TEST POINT AND ADJUSTMENT
LOCATIONS 4-2
COMPONENT COLOR CODING 4-2
SEMICONDUCTOR LEAD CONFIGURATIONS 4-5
WIRING COLOR CODE 4-5
INTER BOARD PIN CONNECTOR
IDENTIFICATION 4-5
MULTI-PIN CONNECTOR IDENTIFICATION 4-5
INTERFACE CONNECTOR PIN LOCATIONS 4-5
TROUBLESHOOTING EQUIPMENT 4-6
TROUBLESHOOTING TECHNIQUES 46
1CHECK CONTROL SETTINGS 4-6
2CHECK ASSOCIATED EQUIPMENT 4-6
3. VISUAL CHECK 4-6
4CHECK INSTRUMENT ADJUSTMENT 4-6
5ISOLATE TROUBLE TO ACIRCUIT 4-6
6CHECK VOLTAGES AND WAVEFORMS 4-7
7CHECK INDIVIDUAL COMPONENTS 4-7
8REPAIR AND ADJUST THE CIRCUIT 4-7
I

7A29 Instruction
TABLE OF CONTENTS (CONT.)
PAGE
CORRECTIVE MAINTENANCE 4-8
OBTAINING REPLACEMEN1 PARTS 48
SOLDERING TECHNIQUES 4-8
COMPONENT REMOVAL AND REPLACEMENT 4-9
OPTION 4VARIABLE DELAY LINE 4-9
CIRCUIT BOARDS 4-9
AC-OFF-DC SWITCH 410
INPUT ATTENUATORS 4-11
SEMICONDUCTORS 4-14
INTEGRATED CIRCUITS 414
INTERCONNECTING METHODS 4-15
COAXIAL END-LEAD CONNECTOR
(PELTOLA CONNECTOR) 4-16
END-LEAD PIN CONNECTOR (P220) 4-16
MULTIPLE END LEAD PIN CONNECTOR
(HARMONICA CONNECTOR) 4-16
INTERBOARD MULTI-PIN CONNECTOR
(COMB CONNECTOR. J70) 4-16
CIRCUIT BOARD PINS 4-16
FRONT PANEL RESET LIGHT 4-17
ADJUSTMENT AFTER REPAIR 4-17
SECTION 5CALIBRATION
USING THESE PROCEDURES 5-2
PERFORMANCE CHECK SUMMARY 5-2
ADJUSTMENT INTERVAL 5-5
TEKTRONIX FIELD SERVICE 5-5
TEST EQUIPMENT REQUIRED 5-5
SPECIAL FIXTURES 5-5
TEST EQUIPMENT ALTERNATIVES 5-5
PAGE
PART I- PERFORMANCE CHECK 58
INDEX TO PART I—PERFORMANCE CHECK 5-8
PERFORMANCE CHECK POWER-UP SEQUENCE ... 5 8
ALOW FREQUENCY 5-9
BHIGH FREQUENCY 5-14
CINPUT PROTECTION 5-18
PART II ADJUSTMENT AND PERFORMANCE
CHECK 521
INDEX TO PART II—ADJUSTMENT
AND PERFORMANCE CHECK 5-21
ADJUSTMENT AND PERFORMANCE CHECK
POWER-UP SEQUENCE 5-21
ALOW FREQUENCY 5-22
BHIGH FREQUENCY 5-29
C. INPUT PROTECTION 5-36
SECTION 6INSTRUMENT OPTIONS
SECTION 7REPLACEABLE ELECTRICAL PARTS
SECTION 8DIAGRAMS AND CIRCUIT BOARD
ILLUSTRATIONS
SECTION 9REPLACEABLE MECHANICAL PARTS
CHANGE INFORMATION
ii

7A29 Instruction
LIST OF ILLUSTRATIONS
FIGURE
NO. PAGE
7A29 Features vi
1-1 VARIABLE (Volts/Div) control effects on
bandwidth 1-4
1-2 Maximum rms input voltage 1-5
1-
37A29 dimensional drawing 1-7
2-
1Front-panel controls, connectors and
indicators 2-2
3-
1Basic block diagram of the 7A29 Amplifier 3-2
4-
1Color code for resistors 4-3
4-2 Semiconductor lead configurations 4-4
4-3 Inter board multi-pin connector assembly 4-5
4-4 Orientation of multi-connector holders 4-5
4-5 Location of pin numbers on interface
connector 4-6
4-6 HYPCON connector assembly 4-12
4-7 Coaxial end-lead connector assembly 4-15
FIGURE
NO. PAGE
4 8 Exploded view of circuit-board pin and
ferrule 4-16
4-9 Front-panel light socket assembly 4 17
The illustrations in section 8are located near their associated
diagrams on the foldout page.
8-1 Semiconductor Lead Configurations
8-2 Circuit Board Locations.
8-3 Al-Mam circuit board assembly
8-4 A3-Readout Switching circuit board assembly
8-5 Al-Mam circuit board assembly.
8-6 A2-High Frequency circuit board assembly
8-7 Al -Mam circuit board assembly
8-8 A2-High Frequency circuit board assembly
8-9 7A29 Troubleshooting Chart
8-10 Test Point &Adjustment Locations
LIST OF TABLES
TABLE
NO. PAGE
1-1 Electrical Characteristics 1-2
1-2 Environmental Characteristics 1-5
1-3 Physical Characteristics 1-6
4-
1Attenuator Fault Location 4-11
5-
1Calibration Procedure Electives 5-1
5-2 Performance Check Summary 5-2
5-3 Test Equipment 5-5
5-4 Vertical Deflection Accuracy 5-11
5-5 Control Settings for Low-Frequency
Step Response 5-12
5-6 1GHz Gain 5-15
5-7 Vertical Deflection Accuracy 5-26
5-8 Control Settings for Low-Frequency
Step Response 5-27
5-
9Vertical Amplifier Frequency Gain 5-33
6-
1Option Information Locator 6-1

7A29 Instruction
OPERATORS SAFETY INFORMATION
The following general safety information applies to all operators and service personnel Specific warnings and cautions
will be found throughout the manual where they apply and should be followed in each instance
WARNING statements identify conditions or practices which could result in personal injury or loss of life
CAUTION statements identify conditions or practices which could result in damage to the equipment or other property.
WARNING
GROUND THE INSTRUMENT
To reduce electrical-shock hazard, the mainframe Ioscilloscope)chassis must be properly grounded. Refer to
the mainframe manual for grounding information.
DO NOT REMOVE INSTRUMENT COVERS
To avoid electric-shock hazard, operating personnel must not remove the protective instrument covers.
Component replacement and internal adjustments must be made by qualified service personnel only.
DO NOT OPERATE IN EXPLOSIVE ATMOSPHERE
To avoid explosion, do not operate this instrument in an explosive atmosphere unless it has been certified for
such operation.
;CAUTION <
PREVENT INSTRUMENT DAMAGE
To prevent instrument damage, plug in units should not be installed or removed without first turning off the
mainframe power
IV

7A29 Instruction
SERVICE SAFETY INFORMATION
FOR QUALIFIED SERVICE PERSONNEL ONLY
The following are safety precautions which appear in the service information sections of this manual This Service Safety
Information is in addition to the Operators Safety Information given previously.
WARNING
DO NOT SERVICE ALONE
Do not attempt internal service or adjustment unless another person, capable of rendering first aid and
resuscitation, is present.
DISCONNECT INSTRUMENT POWER
To avoid electrical shock hazard, disconnect the instrument horn the power source before removing
protective panels, soldering, or replacing components
'CAUTION \
N^
AVOID EXCESSIVE MOISTURE
Circuit boards and components must be dry before applying power to prevent damage from electrical arcing.
Pins 2and 3of U246 and U266 are especially sensitive to moisture. Excessive moisture in this area of the
circuit board will cause the trace to wander irregularly and possibly leave the screen area
EXERCISE CARE WHEN SOLDERING
The Main Amplifier circuit board is amultilayer type with two identical conductive paths laminated between
the top and bottom board layers. All soldering on this board should be done with care to prevent breaking the
connections to the center conductors. Only experienced maintenance personnel should attempt repair of any
circuit board
USE PROPER CLEANING AGENTS
Avoid the use of chemical cleaning agents which might damage the plastics used in this instrument. Use a
nonresidue type of cleaner, preferably isopropyl alcohol, totally denatured ethyl alcohol, or afluorinated
solvent fie trifluorotrichloroethane). such as Freon TF cleaner or Spray-On U2002 Before using any other
type of cleaner, consult your Tektronix Service Center or representative.
DO NOT USE PIN SOCKETS FOR CONNECTION POINTS
The spring tension of the pm sockets ensures agood connection between the circuit board and the pin. This
spring tension can be destroyed by using the pin sockets as aconnecting point for spring loaded probe tips,
alligator clips, etc.
v

7A29 Instruction
7A29 7A29
OPTION 4INSTRUMENT STANDARD INSTRUMENT
2320 2
7A29 FEATURES
The 7A29 is awide-bandwidth Amplifier Plug-In Unit designed primarily for use in vertical compartments of the 7000-
Series Oscilloscopes The input is 50-ohm impedance with selectable DC or AC coupling and automatic overload
disconnect. Seven calibrated deflection factors. VARIABLE deflection factor and polarity INVERT selections are provided
Readout encoding provides for deflection factor readout including coded probes, uncalibrated indication, polarity INVERT
and IDENTIFY functions. AVariable Signal Delay of +0.5 ns is available with the Option 4instrument

Section 1—7A29
GENERAL INFORMATION
INTRODUCTION
The Instruction Manual is divided into the following main
sections:
Section 1—General Information contains instrument
description, electrical specifications, environmental
characteristics, standard and recommended
accessories, installation, and packaging for shipment
instructions
Section 2Operating Instructions contains
information relative to operating and checking the
instrument operation.
WARNING
THE REMAINING PORTIONS OF THIS
INSTRUCTION MANUAL CONTAIN SERVIC-
ING INSTRUCTIONS THESE SERVICING
INSTRUCTIONS ARE FOR USE BY QUALIFIED
SERVICE PERSONNEL ONLY. TO AVOID
ELECTRIC SHOCK OR OTHER PERSONAL
INJURY. DO NOT PERFORM ANY SERVICING
OTHER THAN THAT DESCRIBED IN THE
OPERATING INSTRUCTIONS UNLESS YOU
ARE QUALIFIED TO DO SO.
Section 3—Theory of Operation contains basic and
general circuit analysis that may be useful for
servicing or operating the instrument.
Section 4Maintenance describes routine and
corrective maintenance procedures with detailed
instructions for replacing assemblies, subassemblies,
and individual components
Section 5~Calibration contains procedures to check
the operational performance and electrical
characteristics of the instrument Procedures also
include methods for adjustment of the instrument to
meet specifications.
Section 6- Instrument Options contains adescription
of available options and locations of incorporated
information for those options.
Section 7Replaceable Electrical Parts contains
information necessary to order replaceable parts and
assemblies related to the electrical functions of the
instrument.
Section 8— Diagrams and Circuit Board Illustrations
includes detailed circuit schematics, locations of
assembled boards within the instrument, voltage and
waveform information, circuit board component
locators, and locations of adjustments to aid in
performing the Adjustment and Performance Check
portions of the Calibration procedure.
Section 9Replaceable Mechanical Parts includes
information necessary to order replaceable
mechanical parts and shows exploded drawings which
identify assemblies.
INSTALLATION
INITIAL INSPECTION
Dangerous voltages exist inside the
instrument To avoid electrical-shock hazards,
operating personnel must not remove
protective instrument covers. Component
replacement and internal adjustments must
be made by qualified service personnel only.
This instrument was inspected both mechanically and
electrically before shipment from the factory and it
should be free of mars or scratches and should meet or
exceed all electrical specifications To confirm this,
inspect the instrument for physical damage incurred in
transit. Test the electrical performance by following the
Operators Checkout Procedure in section 2and then
refer qualified service personnel to the Performance
Check Procedure in this Instruction Manual If there is
damage or deficiency, contact your local Tektronix Field
Office or representative.
OPERATING INFORMATION
'CAUTION '
lo prevent instrument damage, plug in units
should not be installed or removed without
first turning off the mainframe power
The 7A29 is calibrated and ready for use as received It
can be installed in any compartment of Tektronix 7000-
series oscilloscopes, but is intended principally for use in
vertical plug-in compartments. To install, align the upper
and lower rails of the 7A29 with the oscilloscope tracks
and insert. The 7A29 front panel will be flush with the
1-1

General Information—7A29
front of the oscilloscope and the latch at the bottom left
corner of the 7A29 will be in place against the front
panel when the 7A29 is fully installed
To remove the 7A29. pull on the release latch (inscribed
with the unit identification "7A29") and the 7A29 will
unlatch Continue pulling to slide the 7A29 out of the
oscilloscope.
OPERATING TEMPERATURE
The 7A29 can be operated where the ambient air
temperature is between 0° and *50° Cand can be stored
in ambient temperatures from -55° to *75° C. After
storage at temperatures outside the operating limits,
allow the chassis temperature to reach asafe operating
temperature before applying power
PACKAGING FOR SHIPMENT
If this instrument is to be shipped for long distances by
commercial transportation, we recommend that the
instrument be packaged in the original manner The
carton and packaging material in which your instrument
was shipped should be saved for this purpose
If this instrument is to be shipped to aTektronix Service
Center for service or repair, attach atag to the
instrument showing the following: Owner of the
instrument (with address), the name of the person at
your firm who can be contacted, complete instrument
type and serial number, and adescription of the service
required
If the original packaging is unfit for use or not available,
package the instrument as follows
1Obtain acorrugated cardboard carton with at least a
200-pound test strength and dimensions at least six
inches larger than the instrument's dimensions
2Surround the instrument with polyethylene sheeting,
or equivalent, to protect the instrument
3Allow a3inch cushion on all sides by tightly packing
dunnage or urethane foam between the carton and the
instrument
4Seal the carton with shipping tape or with an
industrial stapler.
5Mark the address of the Tektronix Service Center and
your return address in one or more prominent locations
on the exterior of the shipping carton.
SPECIFICATIONS
The electrical characteristics listed in Table 1-1 apply when the following conditions are met (1) Adjustment of the
instrument must have taken place at an ambient temperature between +20° Cand +30° C. (2) the instrument must be
allowed a30-minute warm-up period, and (3) all specifications are valid at an ambient temperature of 0° to +50° C.
unless otherwise stated
TABLE 1-1
Electrical Characteristics
Characteristics Performance Requirement
Deflection Factor
Calibrated Range From 10 mV/div to 1V/div in 7switch positions using a
1-2-5 switching sequence.
Attenuator Accuracy All deflection factors within 2% with gain adjusted at
0.1 VOLTS/DIV when driven from a50 0source.
VARIABLE (VOLTS/DIV) Range At least 2.5:1 .See Figure 1-1 for effect on bandwidth
GAIN Range Adjustable to at least 3% from nominal at 01V/div.
1-2