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COMMITTED TO EXCELLENCE
CHECK FOR CHANGE INFORMATION
REAR O THIS MANUAL.
N MANUAL
Tektronix, Inc .
P .O . Box 500
Beaverton, Oregon 97077 Serial Number
070-0931-00 First Printing JUL 1969
Product Group 42 Revised SEP 1986
Copyright C 1969 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 T4 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
7A22
Page Page
Section 1 SPECIFICATION Section 2 OPERATING INSTRUCTIONS
Introduction . . . . . . . . . . . . . . . . . . . . . . . 1-1 (cont)
Electrical Characteristics . . . . . . . . . . . . 1-1 Voltage Measurement . . . . . . . . . . . . . . 2-4
Deflection Factor . . . . . . . . . . . . . . . . 1-1 Signal Input Connectors . . . . . . . . . . . . 2-4
Gain . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1 High Input Impedance . . . . . . . . . . . . . . 2-5
Differential Dynamic Range . . . . . . . 1-1 Display Polarity . . . . . . . . . . . . . . . . . . . . 2-5
DC Offset . . . . . . . . . . . . . . . . . . . . . . 1-1 Deflection Factor . . . . . . . . . . . . . . . . . . 2-5
Frequency Response . . . . . . . . . . . . 1-1 Bandwidth Selection . . . . . . . . . . . . . . . 2-5
Bandwidth Limit . . . . . . . . . . . . . . . . . 1-1 Voltage Comparison Measurements . . . 2-10
Recovery Time . . . . . . . . . . . . . . . . . . 1-1 Differential Operation . . . . . . . . . . . . . . . 2-10
Common-Mode Signal Range . . . . . 1-1 DC Offset Operation . . . . . . . . . . . . . . . 2-11
Common-Mode Rejection Ratio . . . . 1-1 Input Overdrive Indicator . . . . . . . . . . . . 2-12
Maximum Input Voltage . . . . . . . . . . 1-3 Readout . . . . . . . . . . . . . . . . . . . . . . . . . 2-12
Input R and C . . . . . . . . . . . . . . . . . . 1-3 Trace Identify . . . . . . . . . . . . . . . . . . . 2-13
Maximum Input Gate Current . . . . . . 1-3
Variable Balance . . . . . . . . . . . . . . . . 1-3
Step Attenuator DC Balance . . . . . . 1-3
Displayed Noise (Tangentially The remaining portion of this Table of Contents lists the
Measured) . . . . . . . . . . . . . . . . . . . . . 1-3 servicing instructions . These servicing instructions are for
use by qualified personnel only. To avoid electrical shock,
DC Drift . . . . . . . . . . . . . . . . . . . . . . . 1-3 do not perform any servicing other than that called out in the
Isolation Between + and --- operating instructions unless qualified to do so.
Inputs . . . . . . . . . . . . . . . . . . . . . . . . . 1-3
Environmental Characteristics . . . . . . . . 1-3 Section 3 CIRCUIT DESCRIPTION
Altitude . . . . . . . . . . . . . . . . . . . . . . . . 1-3 Introduction . . . . . . . . . . . . . . . . . . . . . . . 3-1
Transportation . . . . . . . . . . . . . . . . . . 1-3 Block Diagram Description . . . . . . . . . . 3-1
Physical Characteristics . . . . . . . . . . . . . 1-3 Input Coupling . . . . . . . . . . . . . . . . . . 3-1
Finish . . . . . . . . . . . . . . . . . . . . . . . . . 1-3 Input Attenuators . . . . . . . . . . . . . . . 3-1
Dimensions . . . . . . . . . . . . . . . . . . . . 1-3 Preamp . . . . . . . . . . . . . . . . . . . . . . . . 3-1
Weight . . . . . . . . . . . . . . . . . . . . . . . . 1-3 L F ---3 dB Point . . . . . . . . . . . . . . . . 3-1
Section 2 OPERATING INSTRUCTIONS Output Amplifier . . . . . . . . . . . . . . . . 3-2
Introduction . . . . . . . . . . . . . . . . . . . . . . . 2-1 H F --3 dB Point . . . . . . . . . . . . . .. . 3-2
Front Panel Controls and Connectors . 2-1 General Information . . . . . . . . . . . . . .. . 3-2
Operating Instructions . . . . . . . . . . . . . . 2-2 Feedback Amplifiers . . . . . . . . . . . . . 3-2
First Time Operation . . . . . . . . . . . . . 2-2 Differential Configuration . . . . . . .. . 3-3
General Operating Information . . . . . . . 2-4 Detailed Circuit Description . . . . . . . . . . 3-3
Trace Drift . . . . . . . . . . . . . . . . . . . . . 2-4 Input Coupling . . . . . . . . . . . . . . . . . . 3-3
Input Gate Current . . . . . . . . . . . . . . . . . 2-4 Input Attenuators . . . . . . . . . . . . . . . 3-4
REV SEP 1981
7A22
SECTION 3 CIRCUIT DESCRIPTION (cont) Page SECTION 4 MAINTENANCE (cont) Page
Gate Current Compensation . 3-4 Special Parts . . . . . . . . . . . . 4-2
Input Amplifier . . . . . . . . . . . 3-4 Soldering Techniques . . . . . . 4-2
X15 Preamp . . . . . . . . . . . 3-4 Component Replacement
Information . . . . . . . . . . . . . 4-3
DC Balance . . . . . . . . . . . 3-4
Troubleshooting . . . . . . . . . . . . 4-5
Floating Power Supply . . . 3-5
Introduction . . . . . . . . . . . . . 4-5
Common-Mode Rejection . 3-5
Indicator Oscilloscope . . . . . 4-5
Cross Neutralization . . . . . 3-6
Operating Procedure and
Input Overdrive Protection 3-7 Control Settings . . . . . . . . . . 4-5
DC Offset . . . . . . . . . . . . 3-7 Trouble Symptoms . . . . . . . . 4-5
Offset Generator . . . . . . . 3-7 Visual Inspection . . . . . . . . . 4-5
Input Overdrive Indicator . 3-8 Calibration Check . . . . . . . . 4-5
L F --3 dB Point Selector . 3-9 Detailed Troubleshooting . . . . . 4-5
Output Amplifier . . . . . . . . . 3-9 Test Equipment Recommended 4-6
Gain Switching Amplifier . 3-9 DC Balance Check . . . . . . . . 4-6
Variable Output stage . . . . 3-11 Troubleshooting by Direct
Signal Output Amplifier . . 3-11 Replacement . . . . . . . . . . . . 4-6
Components Checks . . . . . . 4-6
Trigger Output Amplifier . . 3-11
Transistors . . . . . . . . . . . 4-6
Indicator Oscilloscope Readout 3-11
Diodes . . . . . . . . . . . . . . 4-8
Probe Sensing . . . . . . . . . 3-11
Resistors . . . . . . . . . . . . . 4-8
Trace Identify . . . . . . . . . 3-11
Capacitors . . . . . . . . . . . . 4-9
SECTION 4 MAINTENANCE Repackaging for Shipment . . . . 4-9
Introduction . . . . . . . . . . . . . . . 4-1
Preventive Maintenance . . . . . . 4-1
SECTION 5 PERFORMANCE CHECK/
General . . . . . . . . . . . . . . . . 4-1
CALIBRATION PROCEDURE
Cleaning Front Panel . . . . . . 4-1
Introduction . . . . . . . . . . . . . . . 5-1
Cleaning Interior . . . . . . . . . 4-1
Test Equipment Required . . . . . 5-1
Visual Inspection . . . . . . . . . 4-1
General . . . . . . . . . . . . . . . . 5-1
Transistor Checks . . . . . . . . 4-1 Short Form Procedure . . . . . . . 5-2
Calibration . . . . . . . . . . . . . . 4-1
Performance Check/Calibration
Corrective Maintenance . . . . . . 4-1 Procedure . . . . . . . . . . . . . . . . 5-3
General . . . . . . . . . . . . . . . . 4-1 General . . . . . . . . . . . . . . . . 5-3
Obtaining Replacement Parts 4-2 Preliminary Procedure . . . . . 5-3
REV C, MAR 1979
7A22
SECTION 5 PERFORMANCE CHECK/ SECTION 5 PERFORMANCE CHECK/
CALIBRATION PROCEDURE CALIBRATION PROCEDURE
(cont) Page (cont) Page
Check or Adjust . . . . . . . . . . 5-4 L F ---3 dB Point . . . . . . . . 5-11
AC Step Atten Balance . . . 5-4 CMRR . . . . . . . . . . . . . . . 5-12
Variable Balance . . . . . . . 5-4 Input Overdrive Indicator . 5-12
Coarse DC Balance . . . . . 5-4 Differential Dynamic Range 5-13
+ Gate Current Zero . . . . . 5-5 Overall Noise Level
(Measured Tangentially) . . 5-13
---- Gate Current Zero . . . . . 5-5
Overdrive Recovery Time . 5-14
GAIN . . . . . . . . . . . . . . . 5-5
VARIABLE Control Ratio . . 5-5
VOLTS/DIV Gain Switching 5-5
SECTION 6 ELECTRICAL PARTS LIST
Isolation between 4- and --
Abbreviations and Symbols
Inputs . . . . . . . . . . . . . . . 5-6
Parts Ordering Information
Total DC Offset Range . . . 5-6
Index of Electrical Parts List
C241 +Cross Neutralization 5-7
Electrical Parts List
C141 --Cross Neutralization 5-7
C115 X1 -I-Input Atten Time
Constant . . . . . . . . . . . . . 5-7 SECTION 7 DIAGRAMS AND MECHANICAL
PARTS ILLUSTRATIONS
C215 X1 -Input Atten Time
Constant . . . . . . . . . . . . . 5-7 Diagrams
Input Atten Accuracy . . . . 5-8 Mechanical Parts Illustrations
Input Atten Differential
Balance . . . . . . . . . . . . . . 5-8
SECTION 8 MECHANICAL PARTS LIST
--l-Input Atteh Series
Conpensation . . . . . . . . . 5-9 Mechanical Parts List Information
-Input Atten Compensation 5-9 Index of Mechanical Parts
Illustrations
---Input Atten Shunt
Compensation . . . . . . . . . 5-10 Mechanical Parts List
H F -3 dB Point . . . . . . . . 5-11 Accessories
Abbreviations and symbols used in this manual are based on or
taken directly from IEEE Standard 260 "Standard Symbols for
Units", MIL STD-12B and other standards of the electronics
industry . Change information, if any, is located atthe rear of this
manual .
REV B, MAR 1979
Fig. 1-1 . Type 7A22 Differential Amplifier.
Type 7A22
Type 7A22
Change information, if any, affecting this section will be found at the
rear of the manual .
Introduction DC OFFSET
The Type 7A22 Vertical Plug-in is a DC coupled differ- COARSE Range from
ential amplifier with excellent common-mode rejection char- Electrical Zero
acteristics and high gain for low level applications . 10 [tV/Div to
10 mV/Div
The DC Offset capability of the Type 7A22 allows the
display of the very small low-frequency signals containing 20 mV to 0 .1
a large DC component, at deflection factors not possible with V/Div
AC coupling . The vertical deflection factor range of the At least +100V to -100V
Type 7A22 is from 10/W to 10 V . The high and low fre
2 V to 10 V/Div At least +1000V to --1000 V
quency --3 dB points can be selected at the front panel, ---------- ------------- - ------
to set the bandwidth of the instrument . Thus, for low fre- Frequency Response (8
quency applications the signal-to-noise ratio can be improved div Reference)
by restricting the bandwidth of the Type 7A22 . The band- Overall Frequency
width selection and excellent drift-with-time characteristics Response DC (Direct)
provide measurement capabilities in the biomedical, trans- Coupled Input
ducer, and other areas which require stable, low deflection AC (Capacitive) Cou-
factor, low noise measurements. pled Input Lower
The Type 7A22 is designed for use in Tektronix 7000 Series Bandwidth Frequency
oscilloscopes . Bandwidth Limit
Accuracy
The electrical characteristics described in this section are
HF ---3 dB POINT
valid over the stated environmental range for instruments
100 Hz to 1 MHz
calibrated at an ambient temperature of +20'C to +30