Tektronix 7B92A User manual

Tektronix, Inc.
P.O.
Box 500
Beaverton, Oregon
070-1751-02
Product Group 42
97077
COMMITTED TO EXCELLENCE
PLEASE CHECK FOR CHANGE INFORMATION
AT THE REAR OF THIS MANUAL.
7B92A
DUAL TIME BASE
INSTRUCTION
Serial Number
M~~~~§9'
13
0
99170
First Printing JUN 1978
Revised JUN 1987

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Copyright ~. 1974, 1975, 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 8 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

@
SECTION 1
SECTION 2
TABLE OF CONTENTS
LIST OF ILLUSTRATIONS ................................ .
SAFETY SUMMARY
..................................... .
OPERATING INSTRUCTIONS
Page
iii
v
INTRODUCTION ........................................ 1-1
INSTALLATION ........................................ 1-1
FRONT-PANEL CONTROLS, CONNECTORS, AND INDICATORS. . . .. 1-2
Main
Triggering Controls ................................ 1-2
Sweep
Controls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 1-4
Delayed Triggering Controls . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 1-5
Front-Panel
Inputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 1-5
FUNCTIONAL CHECK .................................... 1-5
Setup Procedure
...................................... 1-6
Sweep Functions
...................................... 1-6
Triggering Functions ................................... 1-7
GENERAL OPERATING
INFORMATION ....................... 1-8
Main
Triggering. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 1-8
Main
Trigger Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 1-8
Main
Trigger Coupling .................................. 1-9
Main
Trigger Source ................................... 1-10
Input Impedance ...................................... 1-10
Trigger Slope ........................................ 1-10
Trigger Level. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 1-10
Selecting Sweep Rates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
.. 1-12
Time Measurement .................................... 1-12
Display Modes ....................................... 1-12
Delay Time Multiplier. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 1-13
Delayed Sweep Triggering ............................... 1-13
SPECIFICATION ........................................ 2-1
I WARNING I
THE FOLLOWING SERVICING INSTRUCTIONS ARE FOR USE BY QUALIFIED PER-
SONNEL ONL Y. TO AVOID PERSONAL INJURY, DO NOT PERFORM ANY SERVICING
OTHER THAN
THAT CONTAINED IN OPERATlNG INSTRUCTIONS UNLESS YOU ARE
QUALIFIED TO DO SO.
SECTION 3 THEORY
OF OPERATION
Block Diagram Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 3-1
Detailed Circuit Description ................................ 3-1
Main Trigger Generator ................................. 3-1
Delaying Sweep Generator ............................... 3-3
Delayed Trigger Generator ............................... 3-4
Delayed Sweep Generator ............................... 3-6
Horizontal
Logic ...................................... 3-6
Output Amplifier ...................................... 3-7
Readout
............................................ 3-7
7892A

7B92A
TABLE OF CONTENTS (cont)
SECTION 4 MAINTENANCE Page
Preventive Maintenance
................................... 4-1
Cleaning ............................................ 4-1
Visual Inspection ...................................... 4-1
Lubrication .......................................... 4-1
Semiconductor Checks ................................. 4-2
Adjustment After Repair ................................. 4-2
Troubleshooting ........................................ 4-3
Troubleshooting Aids . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 4-3
Troubleshooting Equipment .............................. 4-6
Troubleshooting Techniques ............................. 4-6
Corrective Maintenance
................................... 4-8
Obtaining Replacement Parts ............................. 4-8
Soldering Techniques .................................. 4-8
Component Removal and Replacement ...................... 4-9
Adjustment After Repair . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 4-11
Repackaging For Shipment
.............................. 4-11
SECTION 5 PERFORMANCE CHECK/CALIBRATION
Preliminary
Information ................................. 5-1
Test Equipment Required ................................ 5-1
Part I Performance Check ................................. 5-4
Outline for Part I Performance Check ....................... 5-6
A. Trigger Sensitivity ................................. 5-4
B. Horizontal System ................................. 5-4
Preliminary Procedure .................................. 5-4
A. Trigger Sensitivity ................................... 5-5
B. Horizontal System ................................... 5-10
Part II Calibration ....................................... 5-16
Outline for Part II Calibration ............................. 5-16
A. Trigger Sensitivity (SN B070000-above) .................. 5-16
B. Trigger Sensitivity (SN B069999-below) .................. 5-16
C. Horizontal System ................................. 5-17
Preliminary Procedure ................................ 5-17
A. Trigger Sensitivity (SN B070000-above) .................... 5-18
B. Trigger Sensitivity (SN B069999-below) .................... 5-25
C. Horizontal System ................................... 5-33
SECTION 6
OPTIONS
SECTION 7 REPLACEABLE ELECTRICAL PARTS
SECTION 8 DIAGRAMS AND
CIRCUIT BOARD ILLUSTRATIONS
SECTION 9 REPLACEABLE MECHANICAL PARTS
Change Information
ii
@

Figure No.
Frontispiece
1-1
1-2
1-3
1-4
1-5
1-6
LIST OF ILLUSTRATIONS
Page
7B92A Dual Time Base
Location
of Variable and Mainframe Selector multi-pin connectors. ...... 1-1
Location of release latch. .................................... 1-2
Front-panel controls and connectors. ........................... 1-3
Effect
of MAIN TRIGGERING LEVEL and SLOPE controls on crt display. .. 1-11
Area of graticule used for most accurate time measurements. .......... 1-12
Typical alternate sweep display. ............................... 1-13
2-1 Dimensional drawing. ...................................... 2-5
REV APR 1984
4-1 Lubrication procedure for a typical cam switch. .................... 4-2
4-2
Semiconductor lead configurations. ............................ 4-4
4-3
4-4
4-5
5-1
5-2
5-3
5-4
5-4A
5-5
5-6
5-7
5-8
5-9
5-10
5-11
5-12
5-13
5-14
5-15
Inter-board multi-pin connector assembly. ........................ 4-5
End-lead multi-pi n connector assembly. ......................... 4-5
Location
of pin numbers of Interface connector. ................... 4-5
Main
Triggering level range. .................................. 5-6
Delayed Triggering level range. ............................... 5-6
Variable Time/Division range. ................................. 5-13
Fast delay
time accuracy. .................................... 5-14
AC HF
REJ Balance ................................................ 5-19
DC balance. (Circle denotes
correct trigger point.) .................. 5-19
Trigger Sensitivity. (Circle denotes correct trigger pOint.) ............. 5-19
Main
Triggering level range. (Circle denotes triggering limits.) ......... 5-19
Delayed Triggering level range. (Circle denotes triggering limits.) ....... 5-21
DC balance.
(Circle denotes correct trigger point.) .................. 5-26
Trigger sensitivity. (Circle denotes correct trigger point.) ............. 5-26
Main
Triggering level range. (Circle denotes triggering limits.) ......... 5-27
Delayed Triggering level range. (Circle denotes triggering limits.) ....... 5-29
Correct DTM Scale and Delay Start adjustment (circle). .............. 5-34
Variable Time/Division range. ................................. 5-38
Fast delay
time accuracy. .................................... 5-39
7B92A
iii

7B92A
iv
LIST OF ILLUSTRATIONS (cont)
The illustrations in Section 8 are located near their associated diagrams on the foldout pages.
Figure No.
8-1
8-2
8-3
8-4
8-5
8-6
8-7
8-8
8-9
8-10
8-11
8-12
8-13
8-14
8-15
8-16
8-17
8-18
8-19
8-20
8-21
8-22
Circuit board locations
810ck diagram
A3 Coupling Switch circuit board
A5 Delayed Triggering Switch circuit board
A2 Source Switch circuit board
A4 Mode Switch circuit board
A1 External Input circuit board
A8 Main Trigger circuit board
(SN 8070000-above)
A8 Main Trigger circuit board
(SN 8069999-below)
A9 Delayed Trigger circuit board
(SN 8096951-above)
A9 Delayed Trigger circuit board
(SN 870000-8096950)
A9 Delayed Trigger circuit board
(SN 8069999-below)
A6 Interface circuit board
(SN 8095741-above)
A6 Interface circuit board
(SN 8095740-below)
A7 Logic circuit board (SN 8059999-below)
A7 Logic circuit board (SN 8060000-above)
A12 Readout circuit board
Location of Sweep Timing adjustments
Location of Main Trigger adjustments (SN 8069999-below)
Location of Delayed Trigger adjustments
(SN 8069999-below)
Location of Main Trigger adjustments
(SN 8070000-above)
Location of Delayed Trigger adjustments (SN 8070000-above)
REV JAN 1985

@
SAFETY SUMMARY
This manual contains safety information that 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 I
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 another person,
capable
of giving first aid and resuscitation, is present.
WARNING I
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 avoidelectricalshock, disconnect the instrument from the power source beforesoldering.
To avoid electricalshock,
disconnect the instrument from the power source before replacing
components.
Handle
silicone grease with care. Avoid getting silicone grease in eyes. Wash hands
thoroughly after use.
7B92A
v
._-_._--_._----

7B 92A
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REV B, JUN 1978

-
-
Section 1- 7B 92 A
OPERATING INSTRUCTIONS
INTRODUCTION
The 7B92A Dual Time Base unit provides normal,
delayed,
inte~sified , and alternate sweep operation for
TEKTRONIX 7DOO-Series Oscilloscopes. Calibrated
sweep rates from 0.2 second to 0.5 nanosecond and
triggering to
500 megahertz are provided. The 7B92A Is
inlended for use with high·frequency 7DOO-Series
Oscilloscope systems; however, most 7B92A functions
are compatible with all 7000·Series Oscilloscopes.
Other features Include lighted pushbutton switches,
compatibility with indicator oscilloscopes having an
alphanumeric readout system, and 0 to 9.8
times con·
tinuous sweep delay. A VARIABLE control allows con·
tlnuously variable sweep rates between calibrated steps.
Also, when operating
in the AUTO MAIN TRIGGERING
Mode, a bright base line is displayed in the absence 01 a
trigger signal.
This section describes the operation of the front·panel
controls and connectors, and provides a functional check
and general operating
information for this instrument.
NOTE
The AL T OFFposition, which al/ows the Intensified
mode
of operation. Is applicable to instruments SN
B06OOOO-above .
M... INFII ...... f_.,,;:=;;. 8 ~~,~~;
SELlC'OIl OlHlll li:i) ,..JS
--
---
INSTALLATION
The 7892A is designed to operate in the horizontal
plug·in compartment 01 the oscilloscope. Thisinstrument
can also be installed
in a vertical plug·in compartment to
provide avertical sweep on the crt.However,when used in
this manner, there Bre no internal triggering or retrace
blanking provisions, and the
unit may not meet the
specllications given In the Specification section of this
manual.
Before proceeding with installation, check the settings
01 the Time / Div Variable Selec tormulti·pln connector and
the Mainframe Selector
mulli·pin connector (see Fig. '·1) .
The Time/Div Variable Selector determines whether the
front·panel
Time /Div VARIABLE cont rol operates in con·
junction with the delaying or delayed sweeps. The Main·
frame Selector adapts the 7B92A to the oscillsocope
mainframebeing used. Thetwo mainframeselectionsare :
1. 7800 and 7900-Serles Oscilloscopes.
2. All other 7DOO-Series Oscilloscopes.
NOTE
The 7871 w ill not delay the 7892A for displaying
alternating Delaying
and Delayedsweep s. Instead, if
causes a sweep lock·up to occur underthefollowing
conditions: with the 7871 in the A horizontal com-
17 5 2·02
Fig . ,-,. L ocation 01 Variable and Malnlrame Selec tor mull1- pln co nneclors.
RE V e, JUN 1978 1·1