Tektronix 7A18 User manual

INSTRUCTION
MANUAL
7A18/7A18N .
DUAL .. TRACE
AMPLIFIER
Tekfronix, Inc. p, 0. Box 500 • Beaverton, Oregon 97005 • Phone 644·0161 • Cables: Tektronix
070-1126-01 1271

Scans
By
Artel Media
Artek Media
1042 Plummer Gir. SW
Rochester, MN 55902
www.artekmedia.com
"High resolution scans of obsolete technical manuals"
If your looking for a quality scanned technical manual
in PDF format please visit
our WEB site at www.artekmedia.com or drop us
an email at
[email protected] and
we will be happy to email you a current list ofthe
manuals we have available.
If you don't see the manual you need on the list drop us a line anyway we may
still be able to point you to other sources. If you have an existing manual you
would like scanned please write for details, This can often be done very
reasonably
in consideration for adding your manual to our library.
Typically the scans in our manuals are done as follows;
1) Typed text pages are typically scanned in black and wh ite at 300 dpi.
2) Photo pages are typically scanned
in gray scale mode at 600 dpi
3) Schematic diagram pages are typically scanned in black and white at 600
dpi unless the original manual had colored high lighting (as is the case for
some 70's vintage Tektronix manuals).
If you purchased this manual from us (typically through our Ebay name of
ArtekMedia) thank you very much. If you received this from a well-meaning
"friend" for free we would appreciate your treating this much like you would
"share ware". By that we mean a donation of at least $5-10 per manual is
appreciated in recognition ofthe time (a manual can take as much as 40 hours to
reproduce, book, link etc.), energy and quality of effort that went into preserving
this manual. Donations via PayPal go to: [e-mail] or can be
mailed to us the address above.
Dave &Lynn Henderson
Artek Media

"
All TEKTRONIX ,in$#uments are warranted against
defective materIals !ilfldworkmanship for one year. Any
questions withresp'eC't
to the warranty should be taken up
with
your TE'KTRel'UXField Engineer or representative.
~ 0 x>" , ,"
All requests for"repai';s and replacement parts should be
directed
to tbeTEKrRONJ~FieldOfficeor representati
in your areai~~This wilt'!'~~~~re you tti~';ii~stestPos' •
service. Pleas~:jnchlfle tb~)ilfl~rument Ty~.~~umber or
Number and Serial all
'Cop¥~~:'!®<~~;~,'~~~ material 1974, by Tektronix,
Inc., Beaverton, Oregon. Printed in the United States of
America.
All rights reserved. Contents of this publication
may
not be reproduced in any form without permission of
Tektronix, Inc.
U.S.A. and foreign TEKTRONIX products covered by U.S.
and foreign patents and/or patents pending.
TEKTRONIX is a registered trademark of Tektronix, Inc.

7A18/7A18N
TABL.E OF CONTENTS
SECTION 1 SPECIFICATION
Introduction
Electrical Characteristics
7A18 And Mainframe Frequency
Response
Environmental Characteristics
Physical Characteristics
SECTION 2 OPERATING INSTRUCTIONS
Installation
Front Panel Controls and Connectors
General Operating Information
Basic Applications
SECTION 3 CIRCUIT DESCRIPTION
I ntrod uction
Block Diagram Description
Detailed Circuit Description
SECTION 4 MAINTENANCE
Preventive Maintenance
T rou blesh ooting
Replacement Parts
Component Replacement
SECTION 5 CALIBRATION
©I
Recalibration Interval
Test Equipment Required
Part I - Performance Check
Part II - Adjustment
Page
1·1
1·1
1·3
1·3
1·3
2·1
2·1
2·2
2·4
3·1
3·1
3·1
4·1
4·1
4·3
4·4
5·1
5·1
5·3
5·7
OPTION INFORMATION
SECTION 6 ELECTRICAL PARTS LIST
Abbreviations and Symbols
Parts Ordering Information
SECTION 7 DIAGRAMS AND CIRCUIT BOARD
ILLUSTRATIONS
Symbols and Reference Designators
Voltage and Waveform Conditions
SECTION 8 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 Standard 260 "Standard
Symbols for Units", MIL·STD·12B and other standards of_
the electronics industry. Change information, if any, is
located at the rear of this ma-nual.
REV_ JUNE 1974

• -
1 to
•
=(@) H'
,
•
•
~.~
I::"
•
~
-
CH'
~
,
•
•
_"",!"",o
'A"
-
CH'
=~
:J
... ~.
Fig. 1·1. 7A18 ~nd 7A 1 8N Amplifier.
-
--
@
7A18nAl~8N ____________________________________________________________________ ____ ______ __ __

7A1817A18N
SECTION 1
SPECIFICA TION
Change information, if any, affecting this section will be found at the rear of the manual.
Introduction
The 7A18 and 7A18N Dual Trace Amplifier plug-in
units are designed for use with Tektronix 7000-Series
Oscilloscopes. The 7A18 and 7A18N are electrically iden-
tical except that readout encod ing capab ilities and an
"IDENTIFY" function are provided only in the 7A18. All
references made to the 7A18 apply equally to the 7A18N
unless otherwise noted. The 7A 18 is a dual-channel,
medium-bandwidth amplifier. Internal gain and compensa-
tion circuits are automatically switched to correspond to
the setting of the VOL TS/DIV switch. Channel 2 can be
inverted for differential measurements. The 7A18 can be
operated in any plug-in compartment of the 7000-Series
Oscilloscopes.
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.
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.
~~
f---~--
Deflection Factor Accuracy Within 2% with GAIN adjusted at
10 mV/Div.
-------~~-------
--
Uncalibrated
Continuously variable between calibrated
(VARIABLE)
steps; extends deflection factor to at
least 12.5 V/Div.
-----~--------~~-
~~--------~--- .. -.-~---- .- ---------
1---
GAIN
Permits adjustment of deflection factor
for calibrated operation with all 7000-
series oscilloscopes.
~~----~ .. ---------.------~----- -~--
"._--" ---
... _--------
-.- ------~----~ f------------.-~-----
Frequency Response
System Dependent
(8 div reference signal)
Upper Bandwidth
DC (Direct) Coupled
See Table A
-~--.--- ~--
Lower Bandwidth
10 Hertz or less
AC (Capacitive) Coupled
--------
With lOX Probe
1 Hertz or less
----
©
1-1

Specification-7A 18/7 A18N
TABLE 1-1 (cont)
Characteristic Performance Requirement Supplemental Information
-
Maximum Input Voltage
DC Coupled 250 volts, (DC + Peak AC); AC com-
ponent 500 volts peak-to-peak maxi-
mum, one kilohertz or less.
AC Coupled
500 volts, (DC + Peak AC); AC compo-
nent 500 volts peak-to-peak maxi-
mum, one kilohertz or less.
Channel I solation
50: 1 display ratio up to 50
megahertz.
Input Rand C
Resistance
1 Mn ± 2%
Capacitance
Approximately 20_0 pf
RC Product
Within ±1%
between
all
deflection
factors.
Displayed Noise
(Tangentially Measured)
300 microvolts or less at 5 mV /Div in
7000-Series Oscilloscope_
Overdrive Recovery Time 0.1 ms or less to recover to within one
division after the removal of an over-
drive signal
of up to + 75 divisions or
-75 divisions regardless of overdrive
signal duration.
Common Mode Rejection
At least 10:1 up to 50 megahertz_
Ratio
DC Drift
Drift with Time (ambient 0_02 division or less in anyone minute,
temperature and line voltage
after one hour warmup.
constant)
Drift with Temperature
No more than 0.01 division per degree C.
(line voltage constant)
Time Delay between Channels
700 picoseconds or less_
Display Modes
Channell only_
Dual-trace, alternate between channels.
Added algebraically.
Dual-trace chopped between channels_
Channel 2 only.
1-2 @

Specification-7 A 18/7 A18N
TABLE
1-1 (cont)
----.--.----.-.-.----.-.------.-.-- .. ----.~~-.----.-.----;---.-.- .... ----.--~.---.------.---~-.-~--~-
Characteristic
Trigger source Selection
Performance Requirement
Channell only.
Follows DISPLAY MODE selection.
Channel 2 only
TABLE A
7A18 AND MAINFRAME
FREQUENCY RESPONSE
Supplemental Information
.~ __ W_;th7:7:::::,~~J_~_~~h6:5::::'" -_1 __
With 7400 Series
50 MHz
TABLE 1-2
ENVIRONMENTAL CHARACTERISTIC
Refer to the Specification for the associated oscilloscope.
TABLE 1-3
PHYSICAL
__ :_i:_~_9_h_t ~~~--_- - - t: :'::~~~~~'~:~:::'~:~"" -- -----~-----------
© 1-3

NOTES
-----------.------------~----------------------------------------
.- ... ----~.-------- --------------------------------------
--~-.- ..- ..•. -..... ---- .. ~~~~~~- -------------------------------
--.--------------.--~~~~-

-
7A18 / 7A18N
SECTION 2
OPERA TING INSTRUCTIONS
Change information, if any, affecting this section will be found at the rear of the manual.
General
To effectively use the 7A 18, the operation and capabili·
ties of the instrument must be known. Thi s section des·
cribes front·panel co ntrol functions, ge neral information on
signal input connections, an d other su bjects that pertain to
va rious measurement application s.
Installation
The 7A 18 is calibrated and ready for use as received. It
ca n be installed in any compartment of T ektron ix 7000 ·
Ser ies oscilloscopes, but is intended for principal use in
vertical plug·in compar
tment s. To install, al i gn the upper
and lower rails
of the 7A18 with the oscilloscope tracks and
fully insert it. The front will be flush with the front of the
oscilloscope when the 7A 18 is fully inserted, and the latch
at the bottom ·l eft corner of the 7A 18 will be in place
aga inst the front panel.
To remove the 7A 18, pull on the latch (which is
inscribed with the unit identification "7 A 18" or "7 A1 8N")
and the 7A 18 wi ll un latch. Continue pulling on the latch to
slide the 7A 18
out of the oscilloscope.
FRONT PANEL CONTROLS
AND CONNECTORS
The following descriptions apply to the controls and
connectors
of both Input Amplifier channels when appli·
cable. See Fig. 2· 1.
Input Connector
AC·GND·DC
@
Provides sign al connection to t he
channel.
Selects signal input coupling mode.
AC-The AC component of the si g·
n al is coupled to the amplifier
input whi le the DC component
is blocked.
GND -Grounds the amplifier input
while maintaining the same load
for the input signal. Pr ovides a
charge path for the AC coupli ng
capacitor to precharge t he input
circu i t before switching the
input to AC.
eM2 ...ot..AR11"Y
•• u.
J:! ,.....,
-
........
~H2
~.
DUAl T1lAC£ AMf"UFtEfII
F;9. 2·1. Front ·punel co ntr ols lind co nn &<:lors. 17A 18 snown .)
POSITION
IDENTIFY
(7 A 18 o nly )
DC -80 th AC and DC components
of the signal are coupled to the
amplifier input.
Controls positio n of the trace. Posi-
tioning of the tra ce in the "ADD"
Display Mode is co ntr olled by CH 1
POSITION control only.
Deflects trace about 0 .2 division for
trace id entification. In instruments
wi th readout, also replaces readout
w
it h the word "IDENTIFY".
2·'