Tektronix 7a15a User manual

•
I.
I
I
I
I
I
•
I
••
I
I
I
I
I
I
I
I·
I
INSTRUCTION
MANUAL
Seriol Number · __
7A15A/AN
AMPLIFIER
Tektronix, Inc . • P. O . 80K 500 • B eo ver lon, Oregon 97005 • Phone 6<14 -0 161 • Cobles : Tektr onix
070-1210-00 871

Scans
By
Artel Media
Artek Media
1042 P lummer 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 W
EB si te at www.artekmedia.com or drop us an email at
[e-mail] and we will be happy to ema
il you a current li st 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 white at 300 dpi.
2) Photo pages are typica ll y 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 ma nu al 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: [email protected] or c
an be
mailed to us the address above.
Dave &Lynn Henderson
Artek Media

I
..-----------~~~ el
WARRANTY
All Tektronilt inltfUments are warranted against
defective material, and workmanship for
one year.
Any questiom with respect to the warranty.
mentioned above, should be taken up with your
Tektroni)( Field En l ;" '!:.t.llf..!' , p,· e.e'll'J ~~ e. ____ _
All requests rep.irs and parts
should to-th e Tektr onix Office
representitii"e in your -. This pr~rt"l1 ~
you the fatest pos$ible service. P JMee include the
Number) .iKI Serial or
Specifications ar price change pri\/i' ~es reserved.
Copyright ® 1971 by Tektronix, Inc., Beaverton,
Oregon. Printed in the United
Sta tes of America. All
rights reserved. Co nt ents of thi s publication may not
be reproduced in arl V form without permission of th e
co pyright owner .
U.S.A. and foreign Tektronix products covered
by U.S. and foreign patent s and/or pat ents pending.
I
I
I
I
I
I
I
e,
I
I
I
,
,
I
I
e,
I

I
I.
I
I
I
I
I
I
I
I.
I
I
I
I
I
I
I.
I
I
7A15A/7A15AN
TABLE OF CONTENTS
SECTION 1 SPECIFICATION
Introduction
Electrical Characteristics
Environmental Characteristics
Physical Characteristics
SECTION 2 OPERATING INSTRUCTIONS
SECTION 3
SECTION 4
Installation
Controls and Connectors
Basic Operation
General Operating Information
Applications
CIRCUIT DESCRIPTION
I
ntrod uction
Block Diagram Description
Detailed Circuit Description
MAINTENANCE
Preventive Maintenance
Troubleshooting
Corrective Maintenance
REV. B, OCT. 1974
Page
1-1
1-1
1-2
1-2
2-1
2-1
2-2
2-2
2-3
3-1
3-1
3-1
4-1
4-1
4-3
SECTION 5 CALIBRATION
Introduction
Test Equipment Required
Performance Check Procedure
Calibration Procedure
SECTION 6 ELECTRICAL
PARTS LIST
Abbreviations and Symbols
Parts Ordering Information
SECTION 7 DIAGRAMS AND CIRCUIT BOARD
I llUSTRA TlONS
Symbols and Reference Designators
SECTION 8 MECHAN
ICAl PARTS LIST
Mechanical Parts List
Information
Index of Mechanical Parts
Illustrations
Mechanical Parts List
Page
5-1
5-1
5-2
5-2

-
.-
--
--
•
~-
I· ~ . " -•
0
"""'fiT __
•
•
•
••
-
-"-
•
•
-
~ ~.
I ·~ . "
..
•
1fIVt'" _ e
--
-•
-•
Fig. 1-1. 7A1 5A . nd 7 A1 5AN Am pl if..... •
••
7A15 A/AN
® •
ArtekMedia
Digitally signed by ArtekMedia
DN: cn=ArtekMedia, o=ArtekMedia.com, ou, [email protected],
c=US
Date: 2008.11.16 17:36:11 -06'00'

I
I.
I
I
I
I
I
I
I
I
I
I
I
I
I
I.
I
I
Introduction
SECTION 1
SPECIFICA TION
7A15A/7A15AN
7A 15A/7 A15AN can be operated in any plug-in compart-
ment of 7000-Series oscilloscopes.
The 7A 15A/7 A15AN Amplifier plug-in unit is a wide
band amplifier designed
for use with Tektronix 7000-Series
oscilloscopes.
The 7A 15A and 7A15AN ,are electrically
identical
except that encoding capabilities and an
"IDENTIFY" function are provided in the 7A15A. The
The
following electrical characteristics are val id 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.
-Characteristic
Deflection Factor
Calibrated Range
Deflection Factor Accuracy
Uncalibrated (VAR IABLE)
X10 GAIN
Frequency Response
Upper
Bandwidth Frequency
(at -3 dB)
X1 (System
Dependent)
X10
Low-Frequency Response
(Lower
-3 dB point)
AC (Capacitive)
coupled
®
TABLE 1-1
ELECTRICAL
Performance Requirement
5 mV/Div to 10 V/Div, 11 steps in a 1-2-5
sequence
Within
2% of indicated deflection factor
with GAIN adjusted at 10 mV/Div
Continuously variable between calibrated
steps; extends deflection factor to at least
25 V/Div
Increases amplifier gain by a factor of 10
within 10%, decreasing deflection factor
to 500 JlV /D iv
With 7900-series With nOO-series
80 MHz
75 MHz
With 7500-series With 7400-series
60 MHz 50 MHz
10 MHz
10Hz or less without probe
1 Hz or less with probe
Supplemental Information
,-,

I
Specification-7 A 15An A 15AN
TABLE 1-1
-Characteristic Performance
Req Supplementalln/o,m.';on .-
(cont)
uirement
-
Maximum Input Voltage
===F=========== I
DC Coupled
AC Coupled
II nput Rand C
Resistance 1 Mn ± 2%
Capacitance Approximately 20.0
pf
RC Tolerance
Overdrive Recovery Time
-
TABLE 1-2
ENVIRONMENTAL CHARACTERISTICS
IRefer to the specifications for the associated oscilloscope I
1-2
250 V (DC + Peak AC); AC component
500 V P-P maximum, 1 kHz or less
500 V (DC + Peak AC); AC component
500 V P-P maximum, 1 kHz or less
Within ± 1% between all deflection
factors.
0.1 ms or less to recover to within one
division after removal
of overdrive signal
of up to +75 divisions to -75 divisions
regardless of overdrive signal duration
TABLE 1-3
I
I
I
I
I
I
PHYSICAL .1
---r----_
Size
Fits all 7000-series plug·in compartments
Weight 1 pound 13 ounces (0.82 kilogram)
®
I
I
I
I
I
I
.-I
I

I
I.
I
I
I
I
I
I
I
I
I
I
I
I
I
7A15A/7A15AN
SECTION 2
OPERA TING INSTRUCTIONS
General
To effectively use the 7A 15A/7 A 15AN, the operation
and capabilities of the instrument must be known. This
section dE!scribes front-panel control functions, general
information on signal input connections, and other subjects
that pertain to various measurement applications.
Installation
The 7A15A/7A15AN is calibrated and ready for use as
received. It can be installed
in any compartment of Tek-
tronix 7000-Series Oscilloscopes, but is intended for use
primarily in vertical plug-in compartments. To install, align
the upper and lower rails of the 7A15A/7A15AN with the
oscilloscope tracks and insert thE! plug-in. The front panel
will be flush with
the front of the oscilloscope when the
7A15A/7A15AN is fully inserted, and the latch at the
bottom-left corner will be in place against the front panel.
To remove the 7A15A/7Al!5AN, pull on the latch
(which is inscribed with the unit identification "7 A 15A" or
"7A15AN") and the 7A15A/7A15AN will unlatch.
Continue pulling on the latch to slide the 7A15A/7A15AN
out of the oscilloscope.
VOLTS/DIV
VARIABl.E
FRONT PANEL CONTROLS
AND CONNECTORS
Selects calibrated deflection factors
from 5 mV/Div to 10 V/Div; 11
steps in a 1-2-!i sequence.
Provides continuously variable un-
calibrated settings between
calibrated steps. Extends the deflec-
t ion factor range to 25 volts/
division or more.
GAIN Adjustment
Screwdriiver adjustment permits
calibration of deflection factor.
MAG
I nput Connector
AC-GND-DC
INVERT: A positive-going signal at
the Input connector deflects the
CRT display downward.
Provides means of decreasing the
deflection factor.
Xl: Deflection factor is that
selected by VOL TS/DIV and
VARIABLE controls.
Xl0 REDUCED BANDWIDTH:
Deflection factor is one-tenth of
the value selected by the VO L TS/
DIV and VARIABLE controls.
Provides signal connection to the
amplifier.
Selects signal
input coupling mode.
AC: The AC component of the
signal is coupled to the amplifier
input, while the DC component is
blocked.
DC: Both AC and DC components
of the signal are coupled to the
amplifier input.
GND: Grounds the amplifier input
while maintaining the same load for
the input signal. Provides a charge
path for the AC coupling capacitor
to pre-charge the input circuit
before switching the input to AC.
I POLARITY
I·
Provides means of inverting the
display.
POSITION
IDENTIFY
(7A15A Only)
Controls position of the trace.
Deflects trace about 0.3 division for
trace identification. In instruments
with readout, also replaces readout
with the word "IDENTIFY".
I ®
+UP: A positive-going signal at the
Input connector deflects the CRT
display upward.
2-1

Operating I nstructions-7 A 15A/J A15AN
BASIC OPERATION
General. This procedure demonstrates the use of the
connectors and controls of the 7A15A/7A15AN, while at
the same time providing a means of checking the basic
operation of the instrument.
Preliminary Setup. Install the 7A 15A/7 A15AN into any
·1000-series oscilloscope vertical compartment and set the
oscilloscope VERTICAL MODE and TRIGGER SOURCE
to the proper settings.
Install a 7-series time-base unit into a horizontal
compartment and set the oscilloscope HORIZONTAL
MODE to ~he proper setting. Set the time-base unit to a
sweep rate
of one-millisecond per division and set the
triggering mode to AUTO.
Procedure
1. Set the 7A15A/7A15AN AC-GND-DC switch to
GND and position the trace to the center of the graticule.
2.
Set the VOL TS/DIV switch to 10 mV and apply a 40
mV 1 kHz square-wave signal from the oscilloscope CALI-
BRATOR
to the 7A15A/7A15AN INPUT connector. Set
the AC-GND·DC switch to DC and check for a four-division
display.
3. Set POLARITY switch to INVERT and check that
the displayed signal is inverted as compared to its appear-
ance
in step 2.
4.
Set the AC-GND-DC switch to AC and check that the
trace is centered on the CRT graticule.
5. Set the oscilloscope CALIBRATOR to 4 mV and the
7A15A/7A15AN MAG switch to X10. Check for a four-
division display.
6. (7A15A Only) Press the 7A15A IDENTIFY button,
check that the display moves upward approximately 0.3
division and the readout (if so equipped) reads
"IDENTIFY".
GENERAL OPERATING INFORMATION
Signal Connections
In general, probes offer the most convenient means of
connecting a signal to the input of the 7A15A/7A15AN. A
10X attenuator probe offers a high impedance and allows
2-2
I
the circuit under test to perform very close to normal I
operating conditions. •
The Tektronix P6053 probe is equipped with a readout I
coding ring which connects to a circuit in the amplifier
unit. This automatically corrects the readout displayed on
the CRT to the actual deflection factor at the tip of the
probe. This probe is recommended for use with the 7A 15A
and an oscilloscope equipped with readout. The Tektronix
P6054 probe is electrically identical to the P6053 but is
intended for use with systems not equipped with readout.
For more information refer to the Tektronix I nco catalog.
Vertical Gain Check and Adjustment
To check the gain of the 7A15A/7A15AN, set the
VOLTS/DIV switch to 10 mV and connect a 40 mV, 1 kHz
signal from the oscilloscope calibrator to the Input connec-
tor. The vertical deflection should be exactly four divisions.
If not, adjust the front panel GAIN for exactly four divi-
sions.
Input Coupling
The AC-GND-DC switch allows a choice of input coup-
ling 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 applica-
tions. For AC signals with frequencies below about 30 Hz
(10Hz with a 10X probe), and square waves whose low-
frequency components are important to the display, it is
necessary to use DC coupling to obtain a satisfactory
presentation.
In the AC coupling position the DC component of the
signal is blocked by a capacitor in the input circuit. The AC
coupling position provides the best display of signals with a
DC component much larger than the AC component. The
pre-charge feature should be used when there is a possibility
of having a residual charge on the input capacitor of the
opposite polarity to the intended input, and when the
algebraic sum of the combination of charges may be greater
than the maximum input limitations of the amplifier. To
use this feature, first set the coupling switch to GND, then
connect the probe to the circuit and wait about two
seconds for the coupl ing capacitor to charge, set the
coupling switch to AC.
I
I
I
I
I
I
I
I
I
I
I
I
The GND position provides a ground reference at the I
input of the amplifier without externally grounding the
Input connectors. However, the signal connected to the.
input is not grounded, and the same DC load is presented I
to the signal source.
REV. S, OCT. 1974 I

I
I.
I
VOLTS/DIV, VARIABLE and MAG Controls
The amount of deflection produced by a signal is deter-
mined by the signal amplitude, the attenuation factor of
the probe, the setting of the VOL TS/DIV switch, the
setting of the VARIABLE Control, and the setting of the
MAG switch. Calibrated deflection factors represented by
the setting of the VO L TS/D IV switch apply only when the
VARIABLE control is in the CAL position (fully clock-
wise) and when the MAG switch is set to Xl.
I
I
I
I
I
I
The VARIABLE control provides variable uncalibrated
settings between the calibrated s,teps of the VOL TS/D IV
switch. With the VARIABLE control set fully counter-
clockwise and the VOL TS/DIV switch set to 5 volts/div,
the uncalibrated deflection factor is extended to at least 2.5
times the attenuator setting. By applying a calibrated
voltage source to the Input connector, any specific deflec-
tion factor can be set within the range of the VARIABLE
control.
The MAG switch increases the VOLTS/DIV switch
sensitivity by a factor of 10 when in the Xl0 position.
Thus, with the MAG switch set to Xl 0 and the VO L TS/
[) IV switch set to 5 mV /d iv, the deflection factor is
extended to 500}J..V/div. The MAG switch also effects a
circuit in the 7A 15A which corrects the readout. With the
MAG switch set to X10, the bandwidth of the amplifier is
reduced. Refer to specifications in Section 1.
Polarity Switch
I.
The POLAR ITY switch provides a means of inve~ting
the displayed signal. With the POLAR ITY set to +ui' a
positive-going signal
at the INPUT produces an up ard
I
I
I
I
I
I
deflection of the CRT display. With the POLAR ITY s t to
INVERT, a positive-going signal will produce a downvVard
deflection of the CRT display. !
Trace Identification (7A15A only)
I
When the IDENTIFY button is pressed, the tract' is
deflected .upward about 0.3 division to identify the 7A 5A
trace. ThiS feature IS particularly useful when mul iple
traces are displayed on the CRT. In mainframes with rfad-
out, It also replaces the deflection factor readout with i the
lIVord "IDENTIFY". i
I
When using a 100X readout coded probe such as a P~09
(Tektronix Part No. 010-0264-01), the 7A 15A encodin of
CRT readout is incorrect for a number of VOL TS/ IV
settings. These incorrect readings occur with the AG
switch
in the 1X gain position as follows: Actual: 50 V,
10V,
20V and lS, should read: 500mV, 100V, 200V land
lkV. If a 100X probe is to be used with the 7A154. at
these sensitivities, in a CRT readout mainframe, it migh be
preferable to defeat the probe coding and multiply the
plug-in VOL TS/DIV by a factor of 100 as in non-c ded
operation. Possible means for achieving this is; use a P6 09
I
Tektronix Part No. 010-0170-00 (no readout connect r),
defeat the probe coding connection in the 7A 15A by dis-
•
connecting R48, defeat the CRT readout entirely for the
7A 15A by unsoldering the A37 and 837 cable connections
I
between the readout EC board and the mainframe EC
board.
I
REV. B, OCT. 1974
Operati ng I nstructions-7 A 15A/7 A 15AN
APPLICATIONS
General
The following information describes the procedures and
techniques for making measurements with a 7A 15A/
7A 15AN and the associated Tektronix oscilloscope and
time-base. These applications are not described in detail,
since each application must be adapted to the requirements
of the individual measurements. This instrument can also be
used
for many applications which are not described in this
manual. Contact your local Tektronix Field Office or
representative for assistance in making specific measure-
ments with this instrument.
Peak-to-Peak Voltage Measurements (AC)
To make peak-to-peak voltage measurements, use the
following procedure:
1. Apply the signal to the I nput connector.
2. Set the Coupling switch to AC.
NOTE
For low-frequency signals below about 30 hertz, use
the
DC position to prevent attenuation of the signal.
3. Set the VOLTS/DIV switch to display about five
vertical divisions of the waveform.
4. Set the time-base Triggering controls for a stable
display. Set the Time Base to a sweep rate wh ich displays
several cycles
of the waveform.
5. Turn the 7A15A/7A15AN POSITION control so the
lower portion of the waveform coincides with one of the
graticule lines below the center horizontal line, and the top
of thl~ waveform is within the viewing area. With the time
base Position control, move the display so one of the upper
peaks lies near the center vertical line (see Fig. 2-1).
6. Measure the divisions of vertical deflection peak to
peak. Check that the VARIABLE control is in the CAL
position.
NOTE
This technique can also be used to make measure-
ments between two points on the waveform, rather
them peak to peak.
7. Multiply the distance measured in step 7 by the
VO L TS/D IV switch setting. I nclude the attenuation factor
of the probe if used.
EXAMPLE: Assume that the peak to peak vertical
deflection is 4.5 divisions using a lOX attenuator probe,
and the VOL TS/DIV switch is set to 1 V.
2-3