Tektronix 7A18A User manual

Tektronix, Inc.
P.O. Box 500
Beaverton, Oregon 97077
070-4329-00
Product Group 42
Tektrone<
COMMITTED TO EXCELLENCE
PLEASE CHECK FOR CHANGE INFORMATION
AT THE REAR OF THIS MANUAL.
7A18A
DUAL
TRACE
AMPLIFIER
INSTRUCTION
MANUAL
Serial Number
First Printing OCT 1982
Revised NOV 1983

Copyright © 1971, 1982 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:
BO000000 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

7A18A
TABLE OF CONTENTS
Page
Section 1 SPECIFICATION
Introduction ....... 6... eee eee ee 1-1
Electrical Characteristics .......... 1-1
7A18A and Mainframe Frequency
Response ........ 0. eee eee eee 1-1
Environmental Characteristics ...... 1-2
Physical Characteristics .......... 1-2
Section 2 OPERATING INSTRUCTIONS
Installation cixciesemieeiweswrses 2-1
Front Panel Controls and Connectors 2-1
General Operating Information
Basic Applications
THE FOLLOWING SERVICING
INSTRUC-
TIONS ARE FOR USE BY QUALIFIED PER-
SONNEL
ONLY. TO AVOID PERSONAL INJU-
RY, DO NOT PERFORM ANY SERVICING
OTHER THAN THAT CONTAINED
ATING
QUALIFIED TO DO SO.
Section 3 CIRCUIT DESCRIPTION
Introduction .............
Block Diagram Description .
Detailed Circuit Description .
Section 4 PERFORMANCE CHECK &
ADJUSTMENT
Recalibration Interval ......
Test Equipment Required ..
Part I—Performance Check
Part li—Adjustment
IN OPER-
INSTRUCTIONS UNLESS YOU ARE
Section 5
Section 6
Section 7
Section 8
Section 9
Page
MAINTENANCE
Preventive Maintenance .......... 5-1
Troubleshooting .............0055 5-1
Replacement Parts .............. 5-3
Component Replacement ......... 5-4
OPTION INFORMATION
ELECTRICAL PARTS LIST
Abbreviations and Symbols
Parts Ordering Information
DIAGRAMS AND CIRCUIT BOARD
ILLUSTRATIONS
Symbols
Symbols
and Reference Designators
Voltage and Waveform Conditions
MECHANICAL PARTS LIST
Mechanical Parts List Information
Index of Mechanical Parts Illustrations
Mechanical Parts List
Accessories
CHANGE INFORMATION
Abbreviations and symbols used in this manual are based
on or taken directly from IEEE Standards 260 “Standard
Symbols for Units”, MIL-STD-12B and other standards of
the electronics industry. Change information, if any, is locat-
ed at the rear of this manual.

7A18A
LIST OF ILLUSTRATIONS
Fig.
No.
2-1
2.2
2-3
2-4
2-5
2-6
3-1
5-1
6-1
6-2
6-3
Front-panel controls and connectors .....
Measuring the peak-to-peak voltage of a
WaVETOIM ©... ee eee eee nee
Measuring instantaneous voltage with
respect to some reference .............
Measuring phase difference betwen two
SIQNalS. 2... eee eee eee
High resolution phase measurment using
time-base magnifier ...................
Using the ADD mode for common-mode
rejection 2... eee eee
Channel 1 Input Amplifier detailed block
GIGS os cscevemismiewimseaimmimean
Channel 2 Input Amplifier detailed block
GaGa vices cmiees wa sms wea eee wow wane
U270 input combinations for DISPLAY
MODE selection ................0000.
Input/Output combinations for DISPLAY
MODE and TRIGGER SOURCE switch
SOIGCHONS sacccienimrasswacwadmem meme
Locations of adjustments used in this
procedure ........ eee eee eee eee
Electrode configuration for semiconductors
used in this instrument ................
7A18A Option 06 ............... 00 eee
Side view of 7A18A—Option 06 .........
Rear view of A2-Amplifier board for either
Option 06 or standard 7A18A ...........
8-1 and 8-2 are of circuit board assemblies and are in the
diagrams section

7A18A
OPERATORS SAFETY SUMMARY
The general safety information in this part of the summa-
ry 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 the 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.
Terms as Marked on Equipment
CAUTION indicates a personal injury hazard not immedi-
ately accessible as one reads the marking, or a hazard to
property including the equipment itself.
DANGER indicates a personal injury hazard immediately
accessible as one reads the marking.
Symbols In This Manual
/ This symbol indicates where applicable
cautionary or other information is to be found.
Symbols As Marked On Equipment
4 DANGER - High voltage.
ss Protective ground (earth) terminal.
A ATTENTION - refer to manual.
Power Source
This product is intended to operate from a power source
that will not apply more than 250 volts rms between the
supply conductors or between either supply conductor and
ground. A protective ground connection by way of the
grounding conductor in the power cord is essential for safe
operation.
Grounding the Product
This product is grounded through the grounding conduc-
tor of the power cord. To avoid electrical shock, plug the
power cord into a properly wired receptacle before connect-
ing to the product input or output terminals. A protective
ground connection by way of the grounding conductor in the
power cord is essential for safe operation.
Danger Arising From Loss Of Ground
Upon loss of the protective-ground connection, all acces-
sible conductive parts (including knobs and controls that
may appear to be insulating) can render an electric shock.
Use The Proper Power Cord
Use only the power cord and connector specified for your
product.
Use only a power cord that is in good condition.
Refer cord and connector changes to qualified service
personnel.
“Use The Proper Fuse
To avoid fire hazard, use only the fuse of correct type,
voltage rating and current rating as specified in the parts list
for your product.
Refer fuse replacement to qualified service personnel.
Do Not Operate In Explosive Atmospheres
To avoid explosion, do not operate this product in an
explosive atmosphere unless it has been specifically certi-
fied for such operation.

7A18A
SERVICE SAFETY SUMMARY
FOR QUALIFIED SERVICE PERSONNEL ONLY
Refer also to the preceding Operators Safety Summary
Do Not Service Alone
Do not perform intenal service or adjustment of this prod-
uct 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 in this prod-
uct. To avoid personal injury, do not touch exposed connec-
tions and components while power is on.
Disconnect power before removing protective panels,
soldering, or replacing components.
Power Source
This product is intended to operate from a power source
that will not apply more than 250 volts rms between the
supply conductors or between either supply conductor and
ground. A protective ground connection by way of the
grounding coductor in the power cord is essential for safe
operation.

7TA18A
7A18A Dual Trace Amplifier
4329-01
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Section 1—7A18A
SPECIFICATION
Introduction
switch.
Channel
2
can
be
inverted
for
differential
measure-
The
7A18A
Dual
Trace
Amplifier
plug-in
unit
is
designed
mens
ne
lal
a
ais
i
alee
all
for
use
with
TEKTRONIX
7000-Series
Oscilloscopes.
.
ae.
The following electrical characteristics are valid over the
stated environmental range for instruments calibrated at an
ambient temperature of +20°C to +30°C, and after a five
minute warmup unless otherwise noted.
The 7A18A is a dual-channel, medium-bandwidth amplifi-
er. Internal gain and compensation circuits are automatically
switched to correspond to the setting of the VOLTS/DIV
Table 1-1
ELECTRICAL
Characteristic Performance Requirement Supplemental Information
Deflection Factor
Calibrated Range 5 mV/Div to 5 V/Div; ten steps in a
1,2,5 sequence.
Deflection Factor Accuracy Within 2% with GAIN adjusted at
10 mV/Div.
Uncalibrated (VARIABLE) Continuously variable between
calibrated steps; extends deflection
factor to at least 12.5 V/Div.
GAIN Permits adjustment of deflection factor for
calibrated operation with all 7000-series
oscilloscopes.
Frequency Response System
Dependent (8 div reference signal)
Upper Bandwidth DC (Direct) 75 MHz
Coupled
Lower Bandwidth AC (Capacitive) 10 Hertz or less
Coupled
With 10X Probe 1 Hertz or less
Maximum Input Voltage
DC Coupled 250 volts, (DC + Peak AC); AC
component 500 volts peak-to-peak
maximum, one kilohertz or less.
AC Coupled 500 volts, (DC + Peak AC); AC
component 500 volts peak-to-peak
maximum, one kilohertz or less.
Channel Isolation 50:1 display ratio up to 50 megahertz.
1-1

Specification—7A18A
Table 1-1 (cont)
Characteristics
Performance Requirements
Supplemental Information
Input R and C
Resistance 1 MQ +2%.
Capacitance Approximately 20.0 pF
RC Product Within + 1% between all deflection
factors.
Displayed Noise
(Tangentially Measured)
0.06 div or less at all deflection factors
Overdrive Recovery Time
0.1 ms or less to recover to within one
division after the removal of an
overdrive signal of up to +75 divisions
or —75 divisions regardless of
overdrive signal duration.
Common Mode Rejection Ratio
At least 10:1 up to 50 megahertz.
DC Drift
Drift with Time (Ambient
temperature and line voltage
constant)
0.02 division or less in any one minute,
after one hour warmup.
Drift with Temperature (line voltage
constant)
Nor more than 0.01 division per degree
C.
Time Delay between Channels
700 picoseconds or less.
Display Modes
Channel 1 only.
Dual-trace, alternate between
channels.
Added algebraically.
Dual-trace chopped between channels.
Channel 2 only.
Trigger source Selection
Channel 1 only.
Follows DISPLAY MODE selection.
Channel 2 only.
Table 1-2
ENVIRONMENTAL CHARACTERISTIC
Refer to the Specification for the associated oscilloscope.
Table 1-3
PHYSICAL
Size
Fits all 7000-series plug-in compartments.
Weight
-~2 Pounds 10 Ounces (1.4 kilograms)
1-2