Tektronix 7B80 User manual

l^ronix
COMMITTED TO EXCELLENCE
PLEASE CHECK FOR CHANGE INFORMATION
AT THE REAR OF THIS MANUAL.
7B80
TIME BASE
WITH OPTIONS
Tektronix, Inc.
P.O. Box 500
Beaverton, Oregon
INSTRUCTION MANUAL
97077 Serial Number 'Td nil 9
070-1959-00 First Printing DEC 1975
Revised MAR 1981

Copyright ®1975 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. TELEQUIP-
MENT is aregistered trademark of Tektronix U.K
Limited.
Printed in U.S.A. Specification and price change
privileges are reserved.

7B80 Instruction
TABLE OF CONTENTS
PAGE
LIST OF ILLUSTRATIONS iii
LIST OF TABLES iv
SAFETY SUMMARY v
SECTION 1OPERATING INSTRUCTIONS
INSTALLATION 1-1
CONTROLS, CONNECTORS,
AND INDICATORS 1-1
FUNCTIONAL CHECK 1-1
Setup Procedure 1-1
Sweep Functions 1-4
Triggering Functions 1-4
GENERAL OPERATING INFORMATION ..1-5
Triggering Switch Logic 1-5
Triggering Modes 1-5
Trigger Coupling 1-6
Trigger Source 1-6
PAGE
Trigger Slope 1-7
Trigger Level 1-7
Horizontal Sweep Rates 1-7
Time Measurement 1-7
Sweep Magnification 1-7
Variable Hold Off 1-7
Mainframe Operating Modes T9
APPLICATIONS 1-10
TIME-INTERVAL MEASUREMENTS 1-10
Period and Frequency Measurements 1-10
Rise-Time and Fall-Time Measurements. ..1-11
Pulse Width Measurements 1-12
DELAYED-SWEEP MEASUREMENTS 1-12
X-Y PHASE MEASUREMENTS 1-12
SECTION 2SPECIFICATION
STANDARD ACCESSORIES 2-3
WARNING
THE REMAINING SECTIONS OF THIS MANUAL CONTAIN SER-
VICING 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 IN-
STRUCTIONS UNLESS QUALIFIED TO DO SO.

7B80 Instruction
TABLE OF CONTENTS (CONT.)
PAGE
SECTIONS THEORY OF OPERATION
BLOCK DIAGRAM DESCRIPTION 3-1
DETAILED CIRCUIT DESCRIPTION 3-1
LOGIC FUNDAMENTALS 3-1
NON-DIGITAL DEVICES 3-2
FRONT-PANEL DISTRIBUTION .... 3-7
TRIGGER GENERATOR
LOGIC 3-9
SWEEP GENERATOR <s>
TIME/DIVISION READOUT <^. 3-14
INTERFACE CONNECTORS AND
POWER SUPPLY ^3-14
SECTION 4MAINTENANCE
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 4-5
TROUBLESHOOTING TECHNIQUES 4-6
CORRECTIVE MAINTENANCE 4-9
OBTAINING REPLACEMENT PARTS 4-9
PAGE
SOLDERING TECHNIQUES 4-9
COMPONENT REMOVAL AND
REPLACEMENT 4-10
Circuit Boards 4-10
Switches 4-12
Semiconductors 4-12
Interconnecting Pins 4-13
Front-Panel Lights 4-16
ADJUSTMENT AFTER REPAIR 4-16
INSTRUMENT REPACKAGING 4-16
SECTIONS PERFORMANCE CHECK AND
ADJUSTMENT
PRELIMINARY INFORMATION 5-1
TEST EQUIPMENT REQUIRED 5-1
INDEX TO PERFORMANCE CHECK
AND ADJUSTMENT PROCEDURE 5-3
PRELIMINARY PROCEDURE 5-3
SECTION 6REPLACEABLE ELECTRICAL PARTS
SECTION 7INSTRUMENT OPTIONS
SECTIONS DIAGRAMS AND CIRCUIT BOARD
ILLUSTRATIONS
SECTION 9REPLACEABLE MECHANICAL PARTS
CHANGE INFORMATION

7B80 Instruction
LIST OF ILLUSTRATIONS
FIGURE
NO. PAGE
Frontispiece vi
1-1 Location of release latch 1-1
1-2 Front-panel controls, connectors,
and indicators 1-2
1-3 Effect of LEVEL control and SLOPE
switch on crt display 1-8
1-4 Area of graticule used for most accurate
time measurements 1-9
1-5 Operation of sweep magnifier 1-9
1-6 Measuring the period and determining
the frequency of adisplayed waveform ...1-10
1-7 Measuring the rise time and fall time of
adisplayed waveform 1-11
1-
8Measuring the pulse width of adisplayed
waveform 1-12
2-
17B80 dimensional drawing 2-3
3-
1Basic block diagram of the 7B80
Time-Base Unit 3-2
3-2 Detailed block diagram of Trigger
Generator 3-6
3-3 Functional diagram of Trigger Source
Selector 3-8
3-4 Timing diagram for Gate Generator
(Q92, Q96, Q98) 3-9
3-5 Detailed block diagram of Logic circuit ...3-10
3-
6Detailed block diagram of Sweep
Generator 3-12
4-
1Lubrication procedure for atypical
cam switch 4-2
4-2 Semiconductor lead configuration 4-4
4-3 Inter-board multi-pin connector
assembly 4-5
4-4 End-lead multi-pin connector
assembly 4-5
FIGURE
NO. PAGE
4-5 Location of pin numbers on Interface
connector 4-5
4-6 7B80 troubleshooting chart 4-8
4-7 Readout board removal procedure 4-11
4-8 Coaxial end-lead connector assembly 4-12
4-9 Cam switch removal procedure 4-14
4-10 Removal procedure for typical
push-button switch 4-15
4-1 1Exploded view of circuit-board pin
and ferrule 4-16
4-12 Front-panel light socket assembly 4-16
The illustrations in Section 8are located near their associat-
ed Diagrams on the foldout pages.
8-1 Semiconductor lead configurations.
8-2 Location of circuit boards in the 7B80.
8-3 A1—Interface circuit board assembly.
8-4 A2—Trigger circuit board assembly.
8-5 A3—Readout circuit board assembly.
8-6 A1 —Interface circuit board assembly.
8-7 A2—Trigger circuit board assembly.
8-8 A1 —Interface circuit board assembly.
8-9 A1 —Interface circuit board assembly.
8-10 A3—Readout circuit board assembly.
8-1 1A1—Interface circuit board assembly.
8-12 A3—Readout circuit board assembly.
8-13 A1 —Interface circuit board assembly.
8-14 A5—X-Y Switch circuit board assembly.
8-15 Location of Sweep Timing adjustments.
8-16 Location of Triggering adjustments.

7B80 Instruction
LIST OF TABLES
TABLE
NO. page
2-1 Electrical Characteristics 2-1
2-2 Environmental Characteristics 2-3
2-
3Physical Characteristics 2-3
3-
1Basic Logic Reference 3-3
TABLE
NO. page
3-2 Readout Character Selection 3-15
5-1 Test Equipment 5-2
5-2 Sweep Timing .5-10
5-3 Magnified Sweep Timing 5-1
1
@
IV

7B80 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 interna! adjustments to this instrument unless another person, capable of giving first aid and resusci-
tation, 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 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.
Handle silicone grease with care. Avoid getting silicone grease in eyes. Wash hands thoroughly after use.

7B80 Instruction
TRIGGERING
LEVEL
HOLD
OFF
RESIT
MAG
X10 VABtABtE fCAt W|
TIME/OIV
OUTi-tO
£XT TRIG IN
TEKTflOKIX^ IMS
TIME BASE
7B80
7B80 Features
The 7B80 Time-Base unit provides calibrated sweep rates from 5seconds to 10 nanoseconds and triggering to 400 megahertz
for 7700-, 7800-, and 7900-series oscilloscopes. AX10 Magnifier increases each sweep rate by afactor of 10 and aVARI-
ABLE TIME/DIV control provides continuously variable sweep rates between calibrated steps. Variable hold off and alpha-
numeric readout are provided. Also, when operating in the AUTO TRIGGERING MODE, abright baseline trace is displayed
in the absence of atrigger signal. The 7B80 can be operated as an independent time base or asadelayed-sweep unit with acom-
panion delaying time-base unit.
1958-1
@
VI

Section 1—7B80
OPERATING INSTRUCTIONS
The 7B80 Time-Base unit operates with aTektronix 7700-, 7800-, and 7900-series oscilloscope mainframes and a7A-series
amplifier unit to form acomplete oscilloscope system. This section describes the operation of the front-panel controls and
connectors, provides general operating information, afunctional check procedure, and basic applications for this instrument.
INSTALLATION
The time-base unit is designed to operate in the horizontal
plug-in compartment of the mainframe. This instrument
can also be installed in avertical plug-in compartment to
provide avertical sweep on the crt. However, when used in
this manner, there are no internal triggering or retrace
blanking provisions, and the unit may not meet the specifi-
cations given in Section 2.
To install the unit in aplug-in compartment, push it in until
it fits firmly into the compartment. The front panel of the
unit should be flush with the front panel of the mainframe.
Even though the gain of the mainframe is standardized, the
sweep calibration of the unit should be checked when in-
stalled. The procedure for checking the unit is given under
Sweep Functions in the Functional Check procedure in this
section.
To remove the unit, pull the release latch (see Figure 1-1
)
to disengage the unit from the mainframe, and pull it out of
the plug-in compartment.
CONTROLS, CONNECTORS, AND INDICATORS
All controls, connectors, and indicators required for the
operation of the time-base unit are located on the front
panel. Figure 1-2 shows and provides abrief description of
all front-panel controls, connectors, and indicators. More
detailed information is given in the General Operating
Instructions.
FUNCTIONAL CHECK
The following procedures are provided for checking basic
instrument functions. Refer to the description of the con-
trols, connectors, and indicators while performing this pro-
cedure. If performing the functional check procedure
reveals amalfunction or possible improper adjustment, first
check the operation of the associated plug-in units, then re-
fer to the instruction manual for maintenance and adjust-
ment procedures.
Setup Procedure
1
.
Install the time-base unit being checked in the Ahori-
zontal compartment of the mainframe.
2.
Install an amplifier plug-in unit in avertical compart-
ment.
3.
Set the time-base unit controls as follows:
SLOPE (+)
MODE P-P AUTO
COUPLING AC
SOURCE INT
POSITION Midrange
TIME/DIV 1ms
VARIABLE Calibrated (Pushed in
(CAL IN)
HOLD OFF MIN (fully counter-
MAG clockwise)
XI (pushed in)
4.
Turn on the mainframe and allow at least 20 minutes
warmup.
Fig. 1-1. Location of release latch.

Operating instructions—7B80
OC2X3Y4)mC7
«a.®(sa \TRIG DTRIGGERING
LEVEL \III
MODE COUPUmC SOURCE
PPAUTO AC INT
\rCl i<p»..
AUTO ACLFREJ LINE
NORM ACHfREJ EXT
ySINGLE SWP V-
/'-N. IFINE \ff'^ fnl
(Q1LPOSITION \“li=!l OFF •j
^—RESET
I
/Vui mag ll /if)
in X
1
MIN 1vy
OUT xio VARIABLEICAL IN} I
7B80
—nl-
OUT^IO 1I1I
EXT TRIG IN
IIMn
TIME BASE
TRIGGERING
EXTERNAL
TRIGGER
INPUT
Fig. 1-2. Front-panel controls, connectors, and indicators.