Tektronix 7A29 User manual

Tektronix, Inc.
P.O. Box 500
Beaverton, Oregon 97077
070-2320-00
Product Group 42
COMMITTED TO EXCELLENCE
PLEASE CHECK FOR CHANGE INFORMATION
AT THE REAR OF THIS MANUAL.
7A29
AMPLIFIER
WITH OPTIONS
INSTRUCTION MANUAL
------
Serial Number ______ _
First Printing APR 1979
Revised APR 1987

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Copyright @) 1979 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 pa"'el 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
100000
200000
300000
700000
Tektronix, Inc., Beaverton, Oregon, USA
Tektronix Guernsey, Ltd., Channel Islands
Tektronix United Kingdom, Ltd., London
SonylTektronix, Japan
Tektronix Holland,
NV, Heerenveen,
The Netherlands

7A29 Instruction
TABLE OF CONTENTS
PAGE
LIST OF ILLUSTRATIONS .................................. iii
LIST OF TABLES .......................................... iii
OPERATORS SAFETY SUMMARy .......................... iv
SERVICE SAFETY SUMMARY ............................... v
SECTION 1 GENERAL 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 2 OPERATING 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
VARIABLE DELAY (OPTION 4) ................... 2-5
MATCHING DELAY TIMES USING TWO
7A29 UNITS, ONE HAVING VARIABLE
DELAY (OPTION 4) ............................. 2-5
WARNING I
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.
@
PAGE
SECTION 3 THEORY 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 ................................. 3-4
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 4 MAINTENANCE
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 ................. 4-6
1. CHECK CONTROL SETTINGS ................. 4-6
2. CHECK ASSOCIATED EQUiPMENT ............ 4-6
3. VISUAL CHECK .............................. 4-6
4. CHECK INSTRUMENT ADJUSTMENT .......... 4-6
5. ISOLATE TROUBLE TO A CIRCUIT ............ 4-6
6. CHECK VOLTAGES AND WAVEFORMS ....... 4-7
7. CHECK INDIVIDUAL COMPONENTS ........... 4-7
8. REPAIR AND ADJUST THE CIRCUIT ........... 4-7

7A29 Instruction
TABLE OF CONTENTS (CONT.)
PAGE
CORRECTIVE MAINTENANCE. .. .. . . . . . . . . . .. .. .. 4-8
OBTAINING REPLACEMENT PARTS.. . . . . . . . . .. 4-8
SOLDERING TECHNIQUES ................... 4-8
COMPONENT REMOVAL AND REPLACEMENT... 4-9
OPTION 4 VARIABLE DELAY LINE. . . .. .. . . .. 4-9
CIRCUIT BOARDS. . . . . . . . . . . . . . . . . . . . . . .. 4-9
AC-OFF-DC SWITCH . . . . . . . . . . . . . . . . . . . . .. 4-10
INPUT ATTENUATORS . . . . . . . . . . . . . . . . . .
.. 4-11
SEMiCONDUCTORS...................... 4-14
INTEGRATED CiRCUiTS................... 4-14
INTERCONNECTING METHODS............. 4-15
COAXIAL END-LEAD 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
SELECTED COMPONENT
CRITERIA. . . . . . . .. 4-17
REPACKAGING FOR SHIPMENT. . . . .. . . .. .. 4-17
SECTION 5 CALIBRATION
ii
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 1- PERFORMANCE CHECK . . . . . . . . . .. 5-8
INDEX TO PART I-PERFORMANCE CHECK 5-8
PERFORMANCE CHECK POWER-UP
SEQUENCE. . . . . . . . . . . . . . . . . . . . . . . . . .. 5-8
A. LOW FREQUENCY .................. 5-9
B. HIGH FREQUENCY. . . . .. . . . .. .. . . . .. 5-14
C. INPUT PROTECTION................ 5-18
PART II-ADJUSTMENT AND PERFORMANCE
CHECK................................. 5-21
INDEX TO PART II-ADJUSTMENT
AND PERFORMANCE CHECK. . . . . . . . . . .. 5-21
ADJUSTMENT AND PERFORMANCE CHECK
POWER-UP SEQUENCE. . . . . . . . . . . . . . . .. 5-21
A. LOW FREQUENCY . . . . . . . . . . . . . . . . .. 5-22
B. HIGH FREQUENCY. . . . . . . . . . . . . . . . .. 5-29
C. INPUT PROTECTION ................ 5-36
SECTION 6 INSTRUMENT OPTIONS
SECTION 7 REPLACEABLE ELECTRICAL PARTS
SECTION 8 DIAGRAMS AND CIRCUIT BOARD
ILLUSTRATlONS
SECTION 9 REPLACEABLE MECHANICAL PARTS
CHANGE INFORMATION
REV JUN 1983

FIGURE
NO.
1-1
1-2
1-3
2-1
3-1
4-1
4-2
4-3
4-4
4-5
4-6
4-7
7 A29 Instruction
LIST OF ILLUSTRATIONS
PAGE
FIGURE
NO.
4-8 Exploded view of circuit-board pin and
PAGE
7A29 Features .................................. vi
ferrule ....................................... 4-16
VARIABLE (Volts/Div) control effects on 4-9 Front-panel light socket assembly ............. 4-17
bandwidth. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. .. 1-4
Maximum rms input voltage .................... 1-5
7A29 dimensional drawing ..................... 1-7
Front-panel controls. connectors and
The illustrations in section 8 are located near their associated
diagrams on the foldout page.
indicators
..................................... 2-2 8-1 Semiconductor Lead Configurations.
Basic block
diagram of the 7A29 Amplifier ..... 3-2 8-2 Circuit Board Locations.
Color code for resistors ........................ 4-3
8-3 A 1-Main circuit board assembly.
Semiconductor lead configurations .............. 4-4
8-4 A3-Readout Switching circuit board assembly.
Inter-board mUlti-pin connector assembly ....... 4-5 8-5 A 1-Main circuit board assembly.
Orientation of multi-connector holders .......... 4-5 8-6 A2-High Frequency circuit board assembly.
Location of pin numbers on interface 8-7 A 1-Main circuit board assembly.
connector
..................................... 4-6
8-8 A2-High Frequency circuit board assembly.
HYPCON connector assembly .................. 4-12 8-9 7A29 Troubleshooting Chart.
Coaxial end-lead connector assembly
.......... 4-15 8-10 Test Point & Adjustment Locations.
LIST OF TABLES
TABLE
NO.
1-1
1-2
1-3
4-1
4-2
5-1
5-2
5-3
5-4
5-5
5-6
5-7
5-8
5-9
6-1
Electrical Characteristics ................... .
Environmental Characteristics
............... .
Physical Characteristics
................... .
Attenuator Fault Location
.................. .
Selected Component Criteria ............... .
Calibration Procedure Electives ............. .
Preformance Check Summary
.............. .
Test Equipment
.......................... .
Vertical Deflection Accuracy ................ .
Control Settings for Low-Frequency
Step Response .......................... .
1 GHz Gain
............................. .
Vertical Deflection Accuracy ............... : .
Control Settings for Low-Frequency
Step Response .......................... .
Vertical Amplifier Frequency Gain ............ .
Option Information Locator
................. .
PAGE
1-2
1-5
1-6
4-11
4-17
5-1
5-2
5-5
5-11
5-12
5-15
5-26
5-27
5-33
6-1
REV JUN 1983 iii

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 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 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.
PREVENT INSTRUMENT DAMAGE
iv
To prevent instrument damage, plug-in units should not be installed or removed without first turning off the
mainframe power.
@

7 A29 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 I
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 from the power source before removing
protective panels, soldering, or replacing components.
AVOID EXCESSIVE MOISTURE
Circuit boards and components must be dry before applying power to prevent damage from electrical arcing.
Pins 2 and 3 of 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 a multilayer 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
A void 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 a fluorinated
solvent (i.e. trifluorotrichloroethane), such as Freon TF cleaner or Spray-On #2002. 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 pin sockets ensures a good connection between the circuit board and the pin. This
spring tension can be destroyed by using the pin sockets as a connecting point for spring-loadedprobe tips,
alligator clips, etc.
v

7A 29 I nstruct i on
-
-
~- ,
.. ... - ....
7A29
AMPlIFI(1I
O PTION 4 INSTRUMENT
7A29 FEATURES
7A29
STANDARD IN STRUMENT
2320·2
T he 7A29 is a wide-bandwidth Amplifier Plug-In U ni t designed primarilv for use in ve rti cal compartments of the 7000-
Se ries Oscilloscopes. The input is 50-ohm impedance with selectable DC or AC co upling and automat ic overload
disconnect. Seven calibrated deflection factors, VARIABLE deflecti
on factor and polarity INVERT selections are pro vided.
Readout encoding provides for
defl ect ion factor readout including coded probes. uncalibrated indication. polarity INVERT
and IDENTIFY functions . A Variab le Signal Delay of +0.5 ns is available with the Option 4 instrument .
vi @

Section 1-7A29
GENERAL INFORMATION
INTRODUCTION
The Instruction Manual is divided into the following main
sections:
@
Section l-General Information contains instrument
description, electrical specifications, environmental
characteristics, standard and recommended
accessories, installation, and packaging for shipment
instructions.
Section 2-0perating Instructions contains
information relative to operating and checking the
instrument operation.
WARNING I
THE REMAINING PORTIONS OF THIS
INSTRUCTION
MANUAL CONTAIN SERVIC-
ING INSTRUCTIONS. THESE SERVICING
INSTRUCTIONS ARE
FOR USE BY QUALIFIED
SERVICE PERSONNEL ONLY. TO A VOID
ELECTRIC SHOCK OR OTHER PERSONAL
INJURY, DO NOT PERFORM ANY SERVICING
OTHER THAN THA T DESCRIBED IN THE
OPERA TlNG 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 4-Maintenance 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-lnstrument Options contains a description
of available options and locations of incorporated
information for those options.
Section
7-Replaceable 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 9-Replaceable Mechanical Parts includes
information necessary to order replaceable
mechanical parts and shows exploded drawings which
identify assemblies.
INSTALLATION
INITIAL INSPECTION
[ WARNING I
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 2 and 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
~
To 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 tan be operated where the ambient air
temperature is between 00 and +500 C and can be stored
in
ambient temperatures from -55
0
to +750 C. After
storage at temperatures outside the operating limits,
allow the chassis temperature to reach a safe 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 a Tektronix Service
Center for service or repair, attach a tag 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 a description of the service
required.
If the original packaging is unfit for use or not available,
package
the instrument as follows:
1. Obtain a corrugated cardboard carton with at least a
200-pound test strength and dimensions at least six
inches larger
than the instrument's dimensions.
2. Surround the instrument with polyethylene sheeting,
or equivalent, to protect
the instrument.
3. Allow a 3-inch cushion on all sides by tightly packing
dunnage or urethane foam between the carton and the
instrument.
4. Seal the carton with shipping tape or with an
industrial stapler.
5. Mark 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
0 C and +300
C, (2) the instrument must be
allowed a 30-minute warm-up period, and (3) all specifications are valid at an ambient temperature of 00 to +50
0
C,
unless otherwise stated.
Characteristics
Deflection Factor
Calibrated Range
Attenuator Accuracy
VARIABLE (VOLTS/DIV) Range
GAIN Range
1-2
TABLE 1-1
Electrical Characteristics
Performance Requirement
From 10 mV/div to 1 V/div in 7 switch positions using a
1-2-5 switching sequence.
All deflection factors within 2% with gain adjusted at
0.1 VOL TS/DIV when driven from a 50 n source.
At least 2.5:1. See Figure 1-1 for effect on bandwidth.
Adjustable to at least 3% from nominal at 0.1 V /div.
@

Characteristic
Frequency Response (10 mV/DIV to 1 V/DIV)
High Frequency, AC or DC Coupled
Low Frequency, AC Coupled
Maximum Input
DC Coupled
AC Coupled
Input Protection Disconnect Threshold
Input Protection Disconnect Time
Input Impedance
Resistance
Reflection Coefficient
VSWR (Except Option 4)
DC Coupled
AC Coupled
VSWR (Option 4)
DC Coupled
AC Coupled
Input Offset Current
VARIABLE (VOLTS/DIV) Balance
@
TABLE 1-1 (CONT.)
Electrical Characteristics
General Information-7 A29
Performance Requirement
When operated in the vertical compartment of the following
oscilloscope series: 7100, 1 GHz (00 to 35
0
C); 7900, 500 MHz
(00 to 30
0
C); 7800, 400 MHz (00 to 35
0 C);
7700, 175 MHz;
7600, 100 MHz; 7300, 25 MHz.
NOTE
Use of the VARIABLE (Volts/Oivj control affects
frequency response. See Figure 1-1.
1 kHz or less from a 50 0 source; 200 Hz or less with a
10X 50 0 probe.
10 V rms or 1-watt-second pulses not exceeding 50 V peak.
See Figure 1-2, and Detailed Operating Information, section
2.
100 V additional dc component. Derate linearly to 0 V
additional at 60 Hz.
~
Signals of more than 50 V peak amplitude must be
connected
with input switch in OFF position so that
input coupling capacitor is precharged.
+10 V dc within 2 V dc, -10 V dc within 2 V dc, or approximately
10 V rms up to 100 MHz.
Less than
30 ms for 50 V dc of either polarity; 40 ms to 150 ms
for
25 V dc of either polarity.
Dc coupled:
50 0 within 1 O. Ac coupled: 50 0 within 1 0
in series with at least 1.6 IlF.
0.05 or less in a 1 GHz ±20% time domain reflectometer system.
1.4:1 at
10 mVOLTS/OIV. 1.20:1 from 20 mVOLTS/OIVto
1 VOL TS/DIV; dc to 1 GHz.
1.4:1 at
10 mVOLTS/OIV. 1.20:1 from 20 mVOLTS/DIV to
1 VOLTS/DIV; 1 MHz to 1 GHz.
1.5:1 dc to
800 MHz.
1.5:1, 1 MHz
to 800 MHz.
50 IlA or less.
0.2 div maximum trace shift.
1-3

General Information-7 A29
Characteristic
POLARITY Balance
IDENTIFY
POSITION Range
DC Drift
Drift
With Ambient Temperature
(Line Voltage Constant)
Delay Range (Option 4 only)
1.2 GHz
1.1 GHz
1.0 GHz
I
900 MHz
-11-
«9
5:?5
0..0
~~
800 MHz
co
700 MHz
600 MHz
500 MHz
0.4
TABLE 1-1 (CONT.)
Electrical Characteristics
Performance Requirement
0.5 div maximum trace shift.
Deflects trace upward 0.2 to 0.4 div.
9 div each direction from graticule center
within 1.0 div.
0.04 diy/DC or less.
At least 1 ns.
0.5
0.6
0.7 0.8 0.9 1.0
CALIBRATED .J'
RELATIVE LOW-FREQUENCY SENSITIVITY
MAXIMUM
GAIN
2320·"
Figure 1-1. VARIABLE (Volts/Div) control effect on bandwidth.
1-4
@

100V
10 V
1.0 V
Temperature
Calibration
Operating
Storage
Altitude
Operating
Storage
Transportation
@
General Information-7 A29
.01 SEC
"""'-
.........
~
"""
~
-..~
""',,-
RATED MAXIMUM
J"
~
RMS INPUT VOLTAGE
I-'"
~
"""'"
.1 SEC
DURATION
Figure 1-2. Maximum rms input voltage.
TABLE 1-2
Environmental Characteristics
Note: The peak input
voltage must not exceed
50 V when dc coupled.
1 SEC
Characteristic
Performance Requirement
+20° to +30°C (+68° to +86° Fl.
0° to 50° C (+32° to +122° Fl.
-55° to +175° C (-67° to +167° Fl.
To 15,000 feet.
To
50,000 feet.
r-
f-
Qualified under National Safe Transit Committee Test
Procedure 1
A, Category II.
2320-7
1-5
ArtekMedia
Digitally signed by ArtekMedia
DN: cn=ArtekMedia, o=ArtekMedia.com, ou,
[email protected], c=US
Date: 2008.11.16 20:41:25 -06'00'

General Information-7 A29
TABLE 1-3
Physical Characteristics
Characteristic
Overall Dimensions
Net
Weight
Standard Instrument
Option 4 Instrument
Performance Requirement
Compatible with all 7000-series plug-in compartments;
see Figure 1-3, for dimensional drawing.
Approximately 2 Ibs. 8
oz. (1.14 kg).
Approximately 3 Ibs. 4 oz. (1.48 kg).
STANDARD ACCESSORIES
1 ea ............................................................................. Instruction Manual
RECOMMENDED ACCESSORIES
The following accessories have been selected from our
catalog specifically for your instrument. They are listed as
a convenience to help you meet
your measurement
needs. For detailed
information and prices, refer to a
Tektronix Products Catalog
or contact your local Tektronix
Field Representative.
PROBES
P6056
The P6056 is a passive lOX attenuating probe with a
bandwidth of dc to 3.5 gigahertz, and a 500 ohm input
resistance for use with 50 ohm inputs.
1-6
P6057
The P6057 is a passive l00X attenuating probe with a
bandwidth of dc to 1.4 gigahertz and a 5 kilohm input
resistance for use with 50 ohm inputs.
P6201
The P6201 is an active (FET) nonattenuating probe
with a bandwidth from dc to 900 megahertz, an input
impedance of 100 kilohms and 3 picofarads (1
megohm and 1.5 picofarads with lOX and 100X
attenuating heads).
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General Information-7 A29
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Figure 1-3. 7A29 dimensional drawing.
1-7

Section 2-7A29
OPERATING INSTRUCTIONS
To use the 7A29 effectively, the operation and capabilities of the instrument must be known. This section describes
front-panel control functions, general information on signal input connections, and other subjects that pertain to various
measurement applications.
CONTROLS AND CONNECTORS
~
Before applying any signal in excess of 10
volts to the 7 A29, refer to Detailed Operating
Information given later in this section of the
manual.
The 7A29 front panel is shown in Figure 2-1. A brief,
functional description of each control and connector is
included in
the illustration. Refer to Detailed Operating
Information for additional information.
CHECKOUT PROCEDURE
The following procedure can be used for incoming
inspection to verify proper operation, and may also be
used by
the operator for instrument familiarization. Only
instrument functions (not measurement quantities or
specifications) are checked in the procedure; therefore, a
minimum amount of test equipment is required. If
performing the Checkout Procedure reveals improper
performance or instrument malfunction, first check the
operation of associated equipment; then refer to qualified
service personnel for repair or adjustment of the
instrument.
NOTE
Refer qualified service personnel to the
Calibration section of this manual for the
procedure to check the Option 4 VARIABLE
DELAY contro/.
BEFORE YOU BEGIN:
Refer to the Change Information at the rear of this
manual for any modifications which may affect this
procedure.
TEST EQUIPMENT REQUIRED
The following test equipment was used in preparing the
Operators Checkout Procedure. Other test equipment
which meets these requirements may be substituted.
When other equipment is substituted, the control
settings or setup may need to be altered.
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1. 7000-series oscilloscope mainframe (e.g. 7104, 7904,
or 7704A).
2.
7B-series time-base unit (e.g. 7B10, 7B15, 7B80, or
7B85).
3. One bnc cable: 50-ohm coaxial, Tektronix Part 012-
0057-01.
SETUP PROCEDURE
1. With the 7000-series oscilloscope power switch in the
off position, connect the oscilloscope to a suitable power
source.
2. Install the 7A29 in the left vertical compartment.
3. Install the 7B-series time-base unit in the B horizontal
compartment.
4. Set the front-panel controls as follows:
7A29 AMPLIFIER:
VOLTS/DIV ................................. 0.1 V
VARIABLE (Volts/Div) ..................... CAL IN
POSITION ................................ Midrange
POLARITY ..................................... +UP
AC-OFF-DC
................................... OFF
Time-Base Unit:
Time/Div ................................... 1 ms
Position .................................. Midrange
Magnifier ...................................... X1
Triggering
Mode ..................................... Auto
External Trigger In ........................... In
Coupling
.................................... AC
Source ................................ , Internal
Oscilloscope:
Vertical Mode ................................. Left
Horizontal Mode ................................. B
B
Trigger Source ....................... Vert Mode
Calibrator ..................................... 4 V
A and B Intensity ................ Counterclockwise
2-1

Operating Instructions-7A29
n[fi)I::,I~IVOr;:w
POSITION
VARIABLE DELAY
(RANGE ±O.Sns)
o
-0.1 I +0.1
)- __ ++--_0_.2 .. ___ +0.2
-0.3 ...... _-+0.3
/ \
-0.4 I +0.4
±O.S
INPUT
son
MAXIMUM INPUT
lOY RMS 50Y PEAK
lektronix
AC-OFF-DC (Switchl-Selects signal input coupling mode.
v
(
VARIABLE I CAL IN )
VOL TS/ DIV.~_-+l- __ ----j
POLARITY
rIl + UP
lDJ INVERT
AMPLIFIER
CD
AC: The ac component of the signal is coupled to the amplifier input while the dc component is blocked.
1 OFF: Disconnects input signal. precharges input coupling capacitor, and resets input protection system when OVERLOAD light is on.
DC: Both ac and de components of the signal are coupled to the amplifier input.
CD OVERLOAD (lndicatorl-When on, indicates that input signal exceeded the safe input level.
f';;'\ POLARITY (Switchl-Provides a means of inverting the display.
\.!) +UP: A positive-going signal at the INPUT connector deflects the crt display upward.
INVERT: A positive-going signal at the INPUT connector deflects the crt display downward.
CD VARIABLE (Controll-Provides continuously variable deflection factors between settings of the VOLTS/DIV switch.
eD VOLTS/DIV (Switchl-Selects calibrated deflection factors from 10 mV/Div to 1 V/Div; 7 steps in a 1-2-5 sequence.
(;\6 IDENTIFY (Switchl-Deflects the trace about 0.2 division for trace identification. In instruments with readout. also replaces readout with
\V the word "IDENTIFY".
o POSITION (Controll-Controls the vertical position of the trace.
CD GAIN (Controll-Screwdriver adjustment permits calibration of deflection factor.
fn'\9 Option 4 VARIABLE DELAY (Controll-Delays the signal up to + and -
\.V standard 7A291.
500 picoseconds by using a calibrated 10 turn dial (deleted on the
@ INPUT (Connectorl-Provides a means for connecting a signal.
2320·3
Figure 2-1. Front-panel controls. connectors and indicators.
2-2
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5. Set the oscilloscope's power switch on and allow at
least 20 minutes warmup.
AMPLIFIER FUNCTIONS
1. Connect a bnc cable from the oscilloscope's calibrator
output connector to the 7A29 INPUT connector.
2. Rotate the B intensity control clockwise until the trace
is
just visible.
3. Set the 7A29 AC-OFF-DC switch to DC.
4. With the POSITION control, align the display with the
center 4 divisions of the graticule area. Adjust the GAIN
(screwdriver adjustment) for 4 divisions of display.
5. With the POSITION control, align the bottom of the
displayed signal with the center horizontal graticule line.
6.
Set the AC-OFF-DC switch to AC. Notice that the
displayed signal shifts downward approximately 2
divisions, and
that the tops of the waveforms are tilted.
7. Set the AC-OFF-DC switch to DC. With the POSITION
control,
align the trace with the center and top-most
graticule lines.
8. Set the POLARITY switch to the INVERT position.
No1ice that the displayed signal is now inverted, being
roughly aligned with the center and bottom graticule
lines.
9. Set the POLARITY switch to the +UP position.
10. Rotate the POSITION control fully counterclockwise
and notice
that the displayed signal can be positioned off
the graticule area at the bottom of the crt.
11.
Set the POLARITY switch to INVERT.
12. Rotate the POSITION control fully clockwise, and
notice
that the displayed signal can be positioned off the
graticule area at the top of the crt.
13. Return
the POLARITY switch to the +UP position.
Position
the display to the center 4 divisions of the
graticule area.
14. Press to release
the VARIABLE (Volts/Div) control.
Rotate the VARIABLE (Volts/Div) control fully
counterclockwise and notice approximately 1.6 divisions
of displayed signal. Rotate the VARIABLE (Volts/Div)
control fully clockwise and notice at least 4 divisions of
displayed signal.
15. Press the VARIABLE (Volts/Div) control in.
16. Set
the AC-OFF-DC switch to the OFF position and
notice
that no signal is displayed on the crt.
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Operating Instructions- 7 A29
17. Press the IDENTIFY button. Notice that the displayed
trace is deflected
upward approximately 0.25 division
and, in oscilloscope mainframes equipped with readout,
notice
that the 7 A29 readout display is replaced with the
word "IDENTIFY".
18. Rotate the VOLTS/DIV control through each position
and
note that the 7 A29 readout display corresponds with
the front-panel nomenclature. Change the POLARITY
switch to INVERT. Rotate the VOLTS/DIV control through
each position. Again note that the 7 A29 readout display
corresponds with the front-panel nomenclature. Note
additionally that a downward-pointing arrow appears
within the readout display.
19. Press and release the VARIABLE (Volts/Div) control.
Note that a ">" symbol appears in the readout display
between the downward pointing arrow and the deflection
factor
information.
20. Change the POLARITY switch to +UP. Note the
disappearance of the "j" symbol. Press and latch the
VARIABLE (Volts/Div) control. Note the disappearance of
the ">" symbol.
21. Disconnect the bnc cable from the INPUT connector
of
the 7A29.
22. Connect a 10X readout-encoded probe to the INPUT
connector and note the corresponding change in the
deflection factor of the displayed readout. Repeat with
100X probe.
NOTE
Readout encoding is accomplished by
connecting a resistanc.e from the outer ring of
the 7A29 INPUT connector to ground. The
following gives the resistance value
necessary to simulate a probe, and may be
used in place of an actual probe.
Function
Resistance
X1 ................................. Open circuit
X10 .......................... 11 KO, within 5%
X1 00 ........................ 6.2 kO, within 5%
IDENTIFY ............................... 0 ohms
23. This completes the Operators Checkout Procedure.
2-3

Operating Instructions- 7 A29
DETAILED OPERATING
INFORMATION
PROBES
Probes recommended for use with the 7A29 are the
P6056 (10X) or P6057 (100X). Both probes are
compatible with 50-ohm systems, and will allow good
frequency response. These probes also contain trace
IDENTIFY and readout encoding functions.
If the P6201 Probe is used, a one-megohm input
impedance may be achieved (with some loss in
bandwidth).
Consult your local Tektronix Field Engineer
or Representative for further information.
VERTICAL GAIN CHECK AND ADJUSTMENT
To check the gain of the 7A29, set the VOL TS/DIV
switch to 0.1 V and connect a 0.4 V, 1 kHz signal from
the oscilloscope mainframe calibrator to the 7A29 INPUT
connector.
NOTE
Oscilloscope calibrators typically have an
output impedance of either 50 0 or 450 O.
The 50-ohm input impedance of the 7 A29
forms a voltage divider with the calibrator
output impedance, reducing the voltage to the
7A29 by a precise factor of 2 (for 50-ohm
calibrators) or 10 (for 450-ohm Calibrators).
Thus
the 4 V calibrator output of the 7104
and 7904 must be selected for an output
voltage of 0.4 volts.
The vertical
deflection should be exactly four divisions. If
not,
adjust the front-panel GAIN adjustment for exactly
four vertical divisions.
INPUT COUPLING
The AC-OFF-DC switch allows a choice of input coupling
methods. The type of display desired and the applied
signal
will determine the coupling to use.
The
DC coupling position can be used for most
applications. For signals with frequencies below about 1
kHz
the DC coupling position is necessary to avoid signal
attenuation.
In the AC coupling position the dc component of the
Signal is blocked by a 2 microfarad capacitor in the input
circuit. The AC coupling position provides the best display
of signals with a dc component much .Iarger than the ac
component.
2-4
In the OFF position of the input coupling switch, the
signal path of the amplifier is interrupted so that there is
no displayed signal. However, a Signal connected to the
INPUT connector will be loaded by approximately 390
kilohms dc, or by 195 kilohms ac. At extremely high
frequencies a small portion of the input signal will still be
displayed. For example, the signal attenuation in the OFF
position is about 32 dB at 1 gigahertz.
The OVERLOAD
protection feature of the 7 A29 activates
when a Signal capable of causing damage (to 7A29
internal circuitry) is applied to the INPUT connector. To
reset
the 7A29, turn the AC-OFF-DC switch to the OFF
position and remove the cause of overloading. The 7A29
is then ready for normal operation.
The 7A29 is capable of withstanding short term
overloads in excess of its continuous rating of 10 V rms.
Thus, it is possible to apply 50 V peak (the same as 50 V
rms
for a single pulse) for 20 ms, or a 20 V rms signal for
125 ms. The 7A29 integrates the rms input power and
disconnects
the signal before damage can occur.
Generally speaking, the 7A29 will protect itself from
excessive (damaging) signals; however, there are
exceptions.
Continuous wave or pulsed radio frequency
signals above 100 MHz are not sensed by the input
protection circuitry and may cause damage to the input
attenuator if in excess of the 10 V rms, 50 V peak, rating.
The relay contacts which disconnect the 7A29 from
excessive voltages may themselves be damaged by
arcing.
If the contacts open with a signal greater than 50
V applied to the INPUT, the contacts may be permanently
damaged.
The ac
coupling capacitor used in the AC position of the
AC-OFF-DC switch is rated at 100 V dc. Since the input
protection circuitry is located after the ac coupling
capacitor, application of up to 100 V dc to the INPUT is
possible in the AC coupled mode. However, in order to
avoid a fast-rise pulse being sent to the 7A29 from a
signal in excess of 50 V dc, turn the AC-OFF-DC switch
to OFF before connecting such a signal to the 7A29
INPUT. In the OFF position, the ac coupling capacitor is
safely precharged to the average dc Voltage.
Figure 1-2 in section 1 shows the maximum rms
amplitude which may safely be applied to the 7A29
INPUT. Figure 1-2 also corresponds approximately to the
rms voltage the 7A29 will accept without automatically
disconnecting itself. A complex pulse, whose rms value is
equal to the amount shown in Figure 1-2, is safe if it is
also less than 50 V peak.
For example, a
30 V rms sinusoid may be applied for up
to 55 ms, but a 36 V rms sinusoid may not be applied
because the peak voltage exceeds 50 V. The 7A29 INPUT
may be connected to a 50 V power supply for up to 20 ms
because
the rms and peak values of the resulting pulse
are both 50 V.
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