Tektronix 7A16P User manual

Tektronix, Inc.
P.O.
Box 500
Beaverton, Oregon 97077
070-2308-00
Product Group 45
Tektron~
COMMITTED TO EXCELLENCE
PLEASE CHECK FOR CHANGE INFORMATION
AT THE REAR OF THIS MANUAL.
7A16P
PROGRAMMABLE
AMPLIFIER
INSTRUCTION MANUAL
Serial Number ___ ~_~~ ______ _
First Printing MAY 1978
Revised JUL 1983

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Copyright @; 1978 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 i! 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:
BOOOOOO
100000
200000
300000
700000
Tektronix, Inc., Beaverton, Oregon, USA
Tektronix Guernsey, Ltd., Channel Islands
Tektronix United Kingdom, Ltd., London
Sony/Tektronix, Japan
Tektronix Holland, NV, Heerenveen,
The Netherlands

7A16P INSTRUCTION
TABLE OF CONTENTS
SAFETY SUMMARY
PREFACE
SECTION 1 - INTRODUCTION
Specifications
Summary of Programmable Features
Front-Panel Buttons
Front-Panel Controls
Block Diagram
SECTION 2 - MANUAL OPERATION
@
Installation
Controls, Connectors, and Indicators
INPUT Connectors
A-B Switch
1 Megohm -50 Ohm Switch
AC-GND-DC Switches
POSITION Control
VARIABLE (CAL IN) Control
GAIN Adjustment
BANDWIDTH Switch
POLARITY Swi tch
VOLTS/DIV Switches
IDENTIFY Swi tch
Functional Check
Preliminary Setup
Power-up Sequence
Procedure
General Operating Information
Signal Connections
Vertical Gain Check and Adjustment
Input Coupling
VOLTS/DIV and VARIABLE
POLARITY Switch
Trace Identification
i
vii
ix
1-1
1-6
1-7
1-8
1-10
2-1
2-3
2-3
2-3
2-3
2-3
2-4
2-4
2-4
2-4
2-4
2-5
2-5
2-5
2-5
2-6
2-6
2-8
2-8
2-8
2-8
2-9
2-9
2-9

7A16P INSTRUCTION
Applications
General
Peak-to-Peak Voltage Measurements CAC)
Instantaneous Voltage Measurements CDC)
Comparison Measurements
SECTION 3 - PROGRAMMING
Introduction to the IEEE 488 Bus
A
Typical System
Types Of Instruments
Types of Messages
Maximum Number of Devices
Maximum Cable Length
Electrical Specifications
Bus Signal Lines
Data Bus
Transfer Bus
Management Bus
Bus Messages
7A16P Interface Function Subsets
Source Handshake
Acceptor Handshake
Talker
Listener
Service Request
Remote/Local
Parallel Poll
Device Clear
Device Trigger
Controller
Addressing the 7A16P
Addressing Schemes
Primary Addressing
Secondary Addressing
Determining Device Addresses
ii
2-10
2-10
2-10
2-12
2-14
3-2
3-2
3-2
3-3
3-4
3-4
3-4
3-5
3-5
3-5
3-6
3-8
3-10
3-10
3-10
3-10
3-10
3-11
3-11
3-11
3-11
3-11
3-11
3-12
3-12
3-12
3-12
3-14

7A16P INSTRUCTION
High-Level Messages
Explanation of Command Syntax
Set Commands
Query Commands
Messages
Messages
with Multiple
Messages
with
Multiple
The SET? Query
Messages
with Sets
Query Responses
Low-Level Messages
Set Messages
Query Messages
and
Transmitting Messages
Transmitting Set Messages
Transmitting Query Messages
Serial-Poll Responses
Power on
Command error
Execution error
Busy
Sets
Queries
Queries
WARNING
3-15
3-16
3-16
3-17
3-20
3-20
3-21
3-22
3-22
3-23
3-24
3-25
3-29
3-32
3-32
3-36
3-40
3-40
3-40
3-41
3-41
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.
SECTION 4 - MAINTENANCE
Preventive Maintenance
Cleaning
Exterior
Interior
Visual Inspection
Lubrication
Troubleshooting
Troubleshooting Aids
Schematic Diagrams
iii
4-1
4-1
4-2
4-2
4-2
4-2
4-2
4-3
4-3

7A16P INSTRUCTION
Circuit-Board Illustrations
Component-Locator Grids
Component and Wiring Color Code
Semiconductor Lead Configurations
Multi-Pin Connector Identification
Rear Interface Connector Pin Locations
Troubleshooting Equipment
Semiconductor Tester
Multimeter
Test Oscilloscope
Plug-in Extender
Troubleshooting Procedure
Check Control Settings
Check Associated Equipment
Visual Check
Check
Instrument Performance
Check Voltages
Trace the Signal
Check Individual Components
Repair and Readjust the Circuit
Specific Troubleshooting Info.
Microprocessor System
Self Test Addresses
Corrective Maintenance
Obtaining Replacement Parts
Standard Parts
Ordering Parts
Soldering Techniques
Attenuator Circuit Board
Circuit Boards (except Attenuator
Board)
Metal Terminals
Component Replacement
Semiconductor Replacement
Front-Panel LED's
Free-Standing Components
iv
4-3
4-3
4-3
4-3
4-3
4-3
4-5
4-5
4-5
4-6
4-6
4-7
4-7
4-7
4-7
4-7
4-7
4-7
4-8
4-9
4-10
4-10
4-11
4-13
4-13
4-13
4-13
4-14
4-14
4-15
4-15
4-16
4-16
4-16
4-16
REV A JUN 1979

7A16P INSTRUCTION
Circuit Board Removal
Removal
of LED and SWITCH Boards
Removal of ATTENUATOR and
ACTUATOR Boards
Removal of AMPLIFIER, SHIELD, and
PROGRAMMING-LOGIC Boards
Recalibration After Repair
Repackaging for Shipment
SECTION 5 - CIRCUIT DESCRIPTION
Introduction
Block Diagram
Attenuator
Input and Coupling Circuit
X10 Attenuators
Buffer Amplifier
Low Impedance Attenuator
Amplifier
Polarity Amplifier
2X Gain Amplifier
Gain Amplifier
Positioning Circuit
Signal Splitter
Microprocessor System
MPU and Memory
PIA's
Power-up Circuit
Clock Circuit
Front Panel Buttons
Switching Logic
GPIB Interface
IEEE 488 Data Bus
Acceptor Handshake
Source Handshake
Readout
Circuit
Basic Readout Operation
Summing the Time Slots
Selecting Rowand Column Currents
Encoding a Time-Slot
MPU Control Example
REV A JUN 1979 v
4-17
4-18
4-18
4-19
4-20
4-20
5-1
5-1
5-3
5-3
5-3
5-5
5-5
5-6
5-6
5-6
5-7
5-7
5-8
5-9
5-9
5-9
5-10
5-11
5-12
5-12
5-13
5-14
5-14
5-14
5-15
5-15
5-16
5-17
5-18
5-18

7A16P INSTRUCTION
SECTION 6 - CALIBRATION
Introduction
Tektronix Field Service
Performance Check
Cali bration
Test Equipment Required
General
Calibration Equipment Alternatives
Checking Programmable Features
Performance Check Procedure
Checking Front Panel Functions and Readout
Checking Balance
Checking Gain
Checking Rise Time
Checking Bandwidth
Calibration Procedure
Preliminary Procedure for Calibration
Check/Adjust MPU Clock Speed
Check/Adjust DC Balance
Adjust Low Frequency Gain
Check/Adjust Gain
Adjust Positioning
Adjust Input Compensation
Adjust Attenuator Compensation
Adjust Low Frequency Compensation
Adjust High Frequency Compensation
Check Bandwidth
SECTION 7 - ELECTRICAL PARTS LIST
SECTION 8 - DIAGRAMS AND CIRCUIT BOARD ILLUSTRATIONS
SECTION 9 - MECHANICAL PARTS LIST
vi
6-1
6-1
6-1
6-1
6-2
6-2
6-2
6-2
6-5
6-5
6-6
6-6
6-6
6-7
6-8
6-8
6-9
6-10
6-12
6-13
6-15
6-16
6-17
6-18
6-18
6-19
REV A JUN 1979

7A16P INSTRUCTION
SAFETY SUMMARY
This manual contains safety information which the user must follow to ensure safe operation of this instrument. WARNING
information is intended to protect the operator; CAUTION information is intended to protect the instrument. The following
are general safety precautions that must be observed during all phases of operation and maintenance.
[WARNING'
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 Operate in Explosive Atmosphere
Do not operate this instrument in an area where flammable gases or fumes are present. Such operation could cause an
explosion.
Avoid Live Circuits
Electrical-shock hazards are present in this instrument. The protective instrument covers must not be removed by operating
personnel. Component replacement and internal adjustments
must be referred to qualified service personnel.
Do Not Service or Adjust Alone
Do not service or make internal adjustments to this instrument unless anotherperson, capable of giving first aid and resusci-
tation, is present.
[WARNING'
Warning Statements
Warning statements accompany potentially dangerous procedures in this manual. The following warnings appear in this
manual and are listed here for additional emphasis.
To avoid electrical shock, disconnect the instrument from the power source before soldering.
To avoid electrical shock, disconnect the instrument from the power source before replacing components.
@
vii

7A16P INSTRUCTION
PREFACE
This manual contains two main divisions: operation and service.
These divisions are separated by a heavy divider page. Information
following this divider sheet is intended for qualified service personnel
only.
The first division (operator's portion) begins with an introductory
section that briefly describes the 7A16P Programmable Amplifier.
Specifications and programmdble features of the plug-in are also listed.
Section 2 describes each of the front-panel controls and connectors, and
gives complete instructions for manual operation of the plug-in.
Measuring techniques and applications are also discussed in Section 2.
The last section of the operator's portion describes programmable
operation of the 7A16P via the IEEE 488 Interface Bus, also known as the
General Purpose Interface Bus (GPIB).* A complete list of device
mnemonics is provided in this section.
The second division of the manual (service portion) begins with a
section on preventive and corrective maintenance. Included in this
section are some general troubleshooting procedures. Section 5 then
provides a detailed circuit description of both the analog and digital
portions of the 7A16P. Section 6 is a calibration procedure; it lists the
equipment needed, and the steps required for calibrating the instrument
within specified limits. The remaining three sections provide electrical
parts lists, schematic diagrams, and mechanical parts lists.
At the back of the manual is a removable sheet which serves as a
pocket programming aid. It lists all of the high-level mnemonic codes and
low-level hexadecimal codes for exercising programmable control of the
7A16P Programmable Amplifier.
*Detailed information on the IEEE 488 Bus is provided in IEEE Standard
488-1975, published by the Institute of Electrical & Electronics
Engineers -- 345 E. 47 Street, New York, NY 10017.
ix

7A16P INSTRUCTION
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Date: 2008.11.16 18:05:12 -06'00'

7A16P INSTRUCTION
SECTION 1
INTRODUCTION
The TEKTRONIX 7A16P Programmable Amplifier is a wide-bandwidth plug-
in amplifier designed for use in TEKTRONIX 7000-Series programmable
mainframes. The 7A16P may be inserted in any 7000-Series mainframe
without damage, but. :LS recommended for use only in a programmable
mainframe.
The 7A16P has calibrated deflection factors ranging from 10
millivolts/division to 5 volts/division. Variable, but uncalibrated,
deflection factors are also provided by using the VARIABLE control. The
amplifier input can be switched between tHO input connectors to aid in
automatic calibration of the plug-in. Either a 50-ohm or 1-Megohm
amplifier input impedance can be selected. AC or DC coupling of the
input signal can be selected or the amplifier input grounded to establish
a zero-reference level.
The 7A16P has readout encoding and trace identify functions. Thus,
vertical scale factors can be displayed on a programmable mainframe
having readout display capability.
All functions of the 7A16P can be remotely programmed with the
exception of the VARIABLE and GAIN controls and the probe IDENTIFY
switch. The status of each programmable function can be set or read by
commands sent over the IEEE 488 bus. These commands can be sent in either
a high-level or low-level language, both of \.;hich are decoded by a
microprocessor in the 7A16p.
Specifications
The following tables describe the electrical, programming,
environmental, and physical specifications of the 7A16P. Characteristics
whose specifications are checked in the calibration procedure are listed
under a column entitled PERFORMANCE REQUIREMENTS. Specifications for all
other characteristics are listed under SUPPLEMENTAL INFORMATION.
Information in the SUPPLEMENTAL INFORMATION column is of a general nature
and should not be considered as performance requirements. In cases where
a particular plug-in specification is mainframe-dependent, a note has
been included referencing the manual for the mainframe.
1-1

CHARACTERISTICS
Deflection Factor
Cal ibrated Range
Gain-Ratio
Accuracy
7A16P INSTRUCTION
TABLE 1-1
ELECTRICAL SPECIFICATIONS
PERFORMANCE REQUIREMENTS
10 mV/div to 5 V/div, 9
steps in a 1-2-5 sequence.
+ 2% of indicated deflection
factor with GAIN adjusted at
10 mV/div.
SUPPLEMENTAL INFORMATION
~--------------------~---------------------------------+-----------------------------
Uncal ibrated
(VARIABLE)
Frequency Response
Bandwid th 50 ohm input -200 MHz in
7900-Series programmable
mainframe.
1 Megohm input -150 MHz in
7900-Series programmable
main fr arne.
Continuously variable
between calibrated steps;
ex tend s deflection factor
to at least 12.5 V/div.
Expands deflection factor
selected to at least 2.5
times calibrated value.
~~-------------------f-------------------~------~--~------------ ------------- -----------~--------
AC Coupl ed Lower
Band wid th Limit
10 Hz or less.
~-----------------------j--------------~--- ---------~---~---+---------~------ ----- ----------
Limited Bandwid th
Step Response
Risetime
50 ohm input - <1.8 nanoseconds
in 7900-Series programmable
mainframe.
20 MHz, + 3 MHz.
-----------------------+~--------------------- - --------- -------------------------~--
Limited-Bandwidth
Risetime
1-2
21 nanosecond s max imum.
REV B JAN 1981

7A16P INSTRUCTION
TABLE 1-1 (cont.)
CHARACTERISTICS PERFORMANCE REQUIREMENTS
SUPPLEMENTAL INFORMATION
Maxillua Input Voltage
1
Megohm
DC Coupled 250 V
(DC + peak AC);
AC component 500 V P-P
maximum, 1 kHz or less.
AC Coupled 500 V
(DC + peak AC);
AC component 500 V P-P
maximum, 1 kHz or less.
50 ohms
0.5 watts maximum.
Input Rand
C
1
Megohm
Resistance
1 Megohm ±. 2%.
Capacitance Approx.
20 picofarads.
50 ohm
DC Resistance
50 ohms ±. 1 ohm.
VSWR
1.5:1 or less up
to 200 MH z.
Baseline Shift
VARIABLE
0.5 division or less when
turned
through entire
range.
1-3

CHARACTERISTICS
Baseline Shift (cont.)
VOLTS/DIY
POLARITY
BANDWIDTH
IDENTIFY
POSITION
Front Panel Control
Remote Control
Displayed Noise
(measured tangen-
tially)
7A16P INSTRUCTION
TABLE 1-1 (cont.)
PERFORMANCE REQUIREMENTS
1-4
SUPPLEMENTAL INFORMATION
0.5 division or less when
switched between 10 mV/div
and 20 mV /div.
0.5 division or less when
switched between +UP and
INV.
0.5 division or less when
switched between FULL and
20 MHz.
Deflects trace +0.2 to +0.4
divisions.
At least +10 divisions
to at least -10 divisions
from graticu~. e center.
From +10.24 to -10.22
divisions in 0.02 division
steps.
10 mV/div: 0.1 divisions
or less at FULL bandwidth;
0.02 divisions or less
at limited bandwidth.

CHARACTERISTICS
Overdrive Recovery Time
(tested at 25
0
C)
7A16P INSTRUCTION
TABLE 1-1 (cont.)
PERFORMANCE REQUIREMENTS
SUPPLEMENTAL INFORMATION
100 microseconds or less
to recover to within 1
division of baseline after
removal of overdrive signal.
Overdrive occurs when the
following peak amplitudes
are exceeded:
4.0V (on 10-50 mV range)
40V (on 100-500 mV range)
70V (on 1-5 V range)
--------- ------------- ---------------+------------------------
Crosstalk
(unused input to
selected input)
Feedthrough
(ground functions
selected)
CHARACTERISTICS
Set-up Time
(Full
front panel)
High-level
Low-level
TABLE 1-2
PROGRAMMING SPECIFICATIONS
PERFORMANCE REQUIREMENTS
1-5
2% or less up to 200 MHz.
2% or less up to 200 MHz.
SUPPLEMENTAL INFORMATION
Front-panel set-up time is:
(decode time)+(byte count)x
(~ime/byte)+(overhead).
Decode time ~ 11.0
ms
Byte count ~ 60
Overhead
~ 0.4 ms
Decode time ~ 1.0 ms
Byte count =
10
Overhead ~ 0.1 ms

7A16P INSTRUCTION
TABLE 1-3
ENVIRONMENTAL SPECIFICATIONS
For temperature, altitude, vibration, shock, and humidity
specifications, refer to the manual for the associated mainframe.
TABLE 1-11
PHYSICAL SPECIFICATIONS
----------y-----------------
Weight 1.2 Kg. (2.6 lbs.)
Dimensions Fits 7000-Series mainframe plug-in compartment.
Summary of Prograamable Features
The TEKTRONIX 7A16P Programmable Amplifier can be operated in either
Local or Remote mode. In Local mode, it operates like a non-programmable
plug-in, such as the TEKTRONIX 7A16A. That is, its functions are
controllable only from the front panel.
When the 7A16P is set to Remote mode, however, the front panel is
rendered inoperative except for three non-programmable functions:
VARIABLE, GAlN, and IDENTIFY. Under remote control, functions can be
controlled only by commands sent over the IEEE 488 bus. However, as
control settings are effected remotely, the front-panel lights will
indicate accordingly.
The Remote/Local state of the 7A16P is slaved to the Remote/Local
state of the mainframe in which it is installed. Thus the mainframe must
be
set to Remote mode for programmed control of the plug-in, and must be
set to Local mode for front-panel control of the plug-in.
1-6
----------------------------- -- ---

7A16P INSTRUCTION
Front-Pane1 Buttons
Each pushbutton on the 7A16P front panel serves as both a switch and
an
indicator. A Light Emitting Diode (LED) mounted behind each button
indicates the present state of the function controlled by that button,
regardless of whether the corresponding function was set manually or
under program control. The switches themselves are a momentary-contact
type; it is only necessary to tap a particular button to set that
function.
The operation of the front-panel buttons generally falls into one of
two categories. The first category includes the VOLTS/DIV and AC-GND-DC
functions. Since there are more than two switch settings for each of
these functions, pushbuttons in this category are part of a ganged-switch
arrangement. Pressing a particular button cancels the setting of the
previously pressed button and selects the new setting. For example, if
GND has been pressed or remotely set as indicated by the lighting of the
GND button, pressing the AC button will extinguish the GND light and
switch the input coupling to AC; the AC button will then be lit to
indicate the new setting.
The second category of buttons includes the following functions:
BANDWIDTH (Full or 20 MHz)
POLARITY (+Up or Invert)
INPUT Connector (A or B)
INPUT Impedance (1 Megohm or 50 ohms)
Since there are just two settings for each of the above functions,
buttons in this category are essentially toggle switches, and the
lighting of each button indicates the current state of the function
controlled by that button. For example, repeatedly pressing the POLARITY
button alternately illuminates and extinguishes the POLARITY button.
When POLARITY is lit, inverted polarity is selected; when POLARITY is not
lit, normal polarity is selected.
@ 1-7

7A16p INSTRUCTION
Front-Panel Controls
There are three 7A16P front-panel rotary controls: POSITION,
VARIABLE, and GAIN. Only the POSITION control is fully programmable. When
the 7A16P is in Local mode, the POSITION control operates just like that
of a non-programmable plug-in. That is, the vertical position of the
trace is controlled by the current position of the knob. When the 7A16P
is set to Remote mode, the POSITION control is disabled and the trace
position is determined by commands which set a 10-bit Digital-to-Analog
Converter (DAC). Since the POSITION control is disabled during Remote
operation, its current knob setting may not indicate the true trace
position. However, when the 7A16P is again set to Local mode, the
vertical position of the trace reverts back to the position indicated by
the POSITION control. During Remote operation, the trace position can be
read as well as set over the IEEE 488 bus.
The VARIABLE control allows the vertical scale factors to be
increased to about 2.5 times their calibrated value (e.g., on 5 Volts/Div
the scale factor can be increased to about 12.5 Volts/Div). In Local
mode, the VARIABLE control can be continuously varied over its entire
range and is operative only when in the extended (unlatched) position. In
Remote mode, the setting of the VARIABLE control can not be read or set.
However, the VARIABLE control can be enabled or disabled under remote
control, regardless of whether the control is in the extended or
unextended position. When changing from Local to Remote mode, the
VARIABLE control is automatically set to OFF so that the vertical scale
factors are calibrated.
The GAIN adjustment is a front-panel screwdriver adjustment that can
vary the amplifier gain over a narrow range to allow for differences in
gain between mainframes. It is disabled when VARIABLE is selected.
The probe IDENTIFY switch adds an offset to the displayed trace to
help the operator locate the trace in a multi-trace display. This switch
is available only at the probe tip and can not be set under remote
control. The switch setting can, however, be read under remote control.
Table 1-5 provides a list of all the 7A16p functions and indicates
which functions can be set or read (queried) under manual and remote
operation. Setting a function manually refers to pressing a given button
or turning a control; reading a function manually refers to looking at
1-8 REV A
JUN 1979