Tektronix 7A42 User manual

COMMITTED
TO
EXCELLENCE
WARNING
THE
FOLLOWING
SERVICING. lt)JSTHUCTIONS
ARE FOR USE BY
QUALIFIED
PERSONNELONLY.
TO
AVOID
PERSONAL
INJURY,
DO
NOT
PERFORM
ANY
SERVICING OTHER
THAN
THAT
CONTAINED
IN OPERATING
INSTRUCTIONS
UNLESS YOU ARE
QUALIFIED
TO
DO SO. REFER
TO
OPERATORS SAFETY SUMMARY PRIOR
TO
PERFORMING
ANY
SERVICE.
PLEASE CHECK
FOR
CHANGE INFORMATION
AT
THE
REAR
OF
THIS MANUAL.
Tektronix
, Inc.
P.O.
Box
500
Beaverton
,
Oregon
Product
Gro
up 42
070-4286-00
97077
7A42
LOGIC
TRIGGERED
VERTICAL AMPLIFIER
SERVICE
(VOLUME
1)
For
Qualified Service Personnel
Only
INS
T
RUC
T
ION
M A
NUA
L
Serial
Number
First Printing MAY 1983

Copyright ® 1983 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.
f
·-
1
r-
~
.

7A42 Service Volume 1
TABLE OF CONTENTS
SECTION 1-GENERAL INFORMATION Page GENERAL INFORMATION {CONT) Page
TECHNICAL MANUALS .......................... 1-1 AND .•................... · ................... 1-29
OPERATORS MANUAL
....................... 1-1
OR ......................................... 1-29
SERVICE MANUAL
........................... 1-1 CLEAR ..................................... 1-30
INSTALLATION
.................................... 1-2 NOT ........................................ 1-30
INITIAL INSPECTION
............................ 1-2 EDGE
...................................... 1-30
OPERATING TEMPERATURE
..........•.......... 1-2
INSTALLING THE 7A42 IN THE MAINFRAME
...... 1-2
MAINFRAME COMPATIBILITY
.................... 1-2 SECTION
2-THEORY OF OPERATION
PACKAGING FOR SHIPMENT .................... 1-3 BLOCK DIAGRAM ........................................ 2-1
SPECIFICATION .......................................... 1-4 DESCRIPTION ..................................... 2-2
STANDARD ACCESSORIES
.............................. 1-15 DETAILED CIRCUIT OPERATION .......................... 2-8
OPTIONAL ACCESSORIES {NOT INCLUDED)
............. 1-15 FRONT PANEL DISPLAY AND CONTROL ............ 2-8
PROBES
............................................. 1-15 KEYBOARD DECODER
.......................... 2-8
OPERATING INSTRUCTIONS
............................ 1-15 CHANNEL STATUS
AND SWITCH LED
CONTROLS, CONNECTORS, AND INDICATORS
........ 1-15 DRIVER ......................................... 2-8
DETAILED OPERATING INFORMATION
................... 1-18 THRESHOLD DISPLAY DRIVER
................... 2-8
SELF-TEST
....................................... 1-18 MATRIX LED DRIVER
........................•... 2-8
FRONT-PANEL INITIALIZATION
.................... 1-18 ATTENUATORS
AND CONTROL .................... 2-8
BATTERY BACKUP
.........................•...... 1-19 ARMATURE RELAY DRIVERS
............. : ...... 2-8
OPERATOR MESSAGES
........................... 1-19 OVERLOAD COMPARATORS
...................• 2-10
SIGNAL CONNECTIONS
........................... 1-21
TRIGGER PICKOFF .......................... 2-10
RECOMMENDED PROBES
...................... 1-23 CHANNEL SWITCHING
AND AMPLIFIERS ........... 2-10
PROBE COMPENSATION
.................... 1-23 CHANNEL AMPLIFIERS
......................... 2-10
COAXIAL CABLES
........................... 1-23 POSITION CONTROL
........................ 2-10
CRT READOUT
........................•.......... 1-23 CHANNEL SWITCHES
.......................... 2-11
POSITION ........................................ 1-24 DISPLAY CONTROL ............................... 2-11
GAIN ............................................. 1-24 ADDRESS DECODER
AND LATCH .............. 2-11
STATUS INDICATORS {CH1, CH2, CH3, CH4) ....... 1-24 DISPLAY CONTROL
•........................... 2-11
DISPLAY ....................................... 1-24 HORN ..................................•...... 2-12
ECLrrTL ....................................... 1-24 TRIGGER COMPARATORS, BOOLEAN LOGIC,
GND
.................................•........ 1-24
AND FILTERS ..................................... 2-12
50n/1MO ...................................... 1-24 THRESHOLD DACS ............................ 2-12
AL T/CHOP ........................................ 1-24 COMPARATORS
•.............................. 2-12
TRIGGER FUNCTION
.............................. 1-25 BOOLEAN LOGIC .............................. 2-12
A TRIGGER FUNCTION AND B TRIGGER TRIGGER FILTERS
............................. 2-12
FUNCTION
.....................•............... 1-25 EDGE DETECTORS
............................... 2-13
A THEN B NESTED TRIGGERING
...•........... 1-25 A THEN B LOGIC AND TRIGGER 1/0 ............... 2-13
TRIG VIEW
....................................... 1-25 A THEN B LOGIC .............................. 2-13
TRIGGER FILTER
................................. 1-25 TRIGGER
OUT AMPLIFIER ...................... 2-14
EXT
CLOCK SYNC ................................ 1-25 RESET BUFFER ................................ 2-14
SLOPE SELECT
................................ 1-25 EXT
CLOCK ................................... 2-14
EXT CLOCK INPUT
..................•.........• 1-26 TRIGGER VIEW SELECT ........................ 2-14
RESET INPUT
..................................... 1-26 TRIGGER CONTROL
.............................. 2-15
TRIGGER
OUT .................................... 1-26 TRIGGER CONTROL LATCH
.................... 2-15
PROG CHAN/TRIG
................................ 1-26 TRIGGER CONTROL SHIFT REGISTERS ......... 2-15
PROGRAM CHANNEL MODE
.................... 1-27 CPU
............................. : ................ 2-15
CH1, CH2, CH3, CH4
........................ 1-27 DIAGNOSTIC CONTROL
........................ 2-15
DISPLAY
.................................... 1-27 MPU
.................................... · ...... 2-15
TTLIECL
.................................... 1-27 ADDRESS LATCH
................•............. 2-15
VOLTS/DIV
................................. 1-27 ROM DECODER
................................ 2-15
GND
....................................... 1-29 ROM
.......................................... 2-15
1Mn/500 ................................... 1-29 RAM
.......................................... 2-15
THRESH
.......... , ......................... 1-29 BATTERY BACKUP
............................. 2-15
PROBE OFFSET
............................. 1-29 EXTERNAL BUS BUFFERS
...................... 2-15
LEVEL
...................................... 1-29 ADDRESS DECODER
........................... 2-16
PROGRAM TRIGGER MODE
.................... 1-29 1/0
............................................ 2-16
CH1, CH2, CH3, AND CH4
................... 1-29 POWER-UP RELAY DRIVE DISABLE
............. 2-16

7A42 Service Volume 1
TABLE OF CONTENTS (CONT)
THEORY OF OPERATION (CONT)
Page
AUTO
RESTART
..................•.....•......
2-16
WAITSTATE GENERATOR
......................
2-16
REAL TIME CLOCK
......•......................
2-16
GENERAL INPUT LATCH
...............•.......
2-16
PROBE OFFSET ACQUISITION
..................
2-16
PROBE CODING AND DIAGNOSTIC HOOKS
MUX
.................•...............•.........
2-19
DIAGNOSTIC HOOKS
...•......................
2-19
READOUT
....••..•......................•........
2-19
POWER SUPPLY
AND
DISTRIBUTION
..•...........
2-19
POWER STAGE
.•..............................
2-19
RECTIFIERS
AND
FILTERS
...................•..
2-21
CURRENT LIMIT
...............................
2-21
INPUT FILTER
...........•.....................
2-21
PULSE
WIDTH
MODULATION (PWM)
CONTROLLER
.....................•...•.•.....
2-21
DRIVERS
........................•.............
2-21
SNUBBER
..•............................•.....
2-22
ATTENUATOR SUPPLIES
.........•............
,2-22
SECTION 3-MAINTENANCE
PREVENTIVE MAINTENANCE
.............•.•.............
3-1
PLUG-IN PANEL REMOVAL
.....•................•..
3-1
CLEANING
............................••..•.•.....
3-1
EXTERIOR
........................•.............
3-1
INTERIOR
...................•.............•....
3-1
LUBRICATION
.....................................
3-4
VISUAL INSPECTION
...............................
3-4
SEMICONDUCTOR CHECKS
....................•...
3-4
ELECTRICAL ADJUSTMENT
............•...........
3-4
ADJUSTMENT AFTER REPAIR
......................
3-4
TROUBLESHOOTING
...........................•.........
3-4
ii
TROUBLESHOOTING AIDS
.........................
3-4
DIAGRAMS
..................•..................
3-4
CIRCUIT BOARD ILLUSTRATIONS
...............
3-4
COMPONENT COLOR CODING
.....•............
3-5
WIRING COLOR CODE
......................•...
3-5
SEMICONDUCTOR LEAD CONFIGURATIONS
.....
3-5
STATIC-SENSITIVE DEVICE
CLASSIFICATION
.........................•.....
3-5
MULTI-PIN CONNECTOR IDENTIFICATION
.......
3-8 .
TROUBLESHOOTING EQUIPMENT
..................
3-8
TROUBLESHOOTING TECHNIQUES
.................
3-9
1.
CHECK CONTROL SETTINGS
..............••.
3-9
2.
CHECK ASSOCIATED EQUIPMENT
.......•.•...
3-9
3.
VISUAL CHECK
...............................
3-9
4.
ISOLATE TROUBLE TO A CIRCUIT
..........•..
3-9
5.
CHECK INSTRUMENT ADJUSTMENT
...........
3-9
6.
CHECK VOLTAGES
...........................
3-9
7.
CHECK INDIVIDUAL COMPONENTS
.....•.....
3-9
TRANSISTORS
...............................
3-9
INTEGRATED CIRCUITS
................•.....
3-9
DIODES
...................................•
3-10
RESISTORS
........•........................
3-10
CAPACITORS
.........•.....................
3-10
8.
REPAIR
AND
ADJUST THE CIRCUIT
•.........
3-10
MAINTENANCE (CONT)
Page
DIAGNOSTICS
AND
TROUBLESHOOTING
................
3-12
SELF TEST
.......................................
3-12
EXTENDED DIAGNOSTICS
.........................
3-12
BACKGROUND INFORMATION ON
SIGNATURE ANALYSIS
.........................
3-15
EXTENDING CIRCUIT BOARDS
FOR
TROUBLESHOOTING
...........................
3-15
HOW
TO
EXTEND THE
A6
TRIGGER BOARD
..
3-15
HOW
TO
EXTEND THE A7 DIGITAL BOARD
...
3-18
WHAT
TO
DO IF
THE
7A42 DOES NOT
RESPOND
TO
FRONT-PANEL CONTROLS
..........
3-18
FORCED INSTRUCTION FREERUN
.•...........•
3-18
EXTERNAL BUS EXERCISE (XBUSX)
.............
3-21
INTERVAL 1 (SEE FIG. 3-9)
...................
3-21
INTERVAL 2
..................•.............
3-21
INTERVAL 3
................................
3-21
INTERVAL 4
.................................
3-21
EXTERNAL BUS OPERATION
................
3-22
FRONT-PANEL LED OPERATION
.............
3-22
FRONT PANEL KEYS
AND
DVM DISPLAY
.....
3-22
PROBE OFFSET DAC AND COMPARATOR
....
3-22
AUTO
RESTART CIRCUIT
...................
3-22
DIAGNOSTIC TEST DESCRIPTIONS
..........•.....
3-23
ROMS
..........•...............................
3-25
1-ROM
A8U145
.............................
3-25
2-ROM
A8U245
.............................
3-25
3-ROM
A8U340
.............................
3-25
4-ROM
A8U345
.............................
3-25
RAMS
.........................................
3-25
5--RAM
A8U615
.............................
3-25
6-RAM
A8U615
....•................•.......
3-25
MPU BOARD MISCELLANEOUS
.................
3-25
7-REAL
TIME INTERRUPT CIRCUIT (RST5.5)
A8U815, A8U900B
...........................
3-25
8-EXTERNAL
BUS CLEAR
.....•............
3-26
9-WAIT
STATE GENERATOR A8U835
........
3-26
10-PROBE
OFFSET
ADC
A8U600,
A8U505A
....................................
3-26
DIGITAL BOARD MISCELLANEOUS
.............
3-27
11-DISPLAY
CONTROL A7U700, A7U800,
A7U820, A7U900
..........•..................
3-27
12-READOUT;
RST7.5 A8U830A,
B,
D,
AND
A8Q720A
......•............................
3-27
13-READOUT;
SID A7Q720C
.....•..........
3-28
A6
TRIGGER BOARD DIAGNOSTICS
...........•...
3-28
LEGEND
......................................
:3-30
EXAMPLE
#1
...................................
3-30
EXAMPLE #2
...................................
3-31
INSTRUCTIONS
................................
3-31
TROUBLESHOOTING TIPS FOR THE
TRIGGER BOARD
...•.............................
3-36
TRIGGER CONTROL LOGIC
...................•
3-36
A1.
TRIGGER CONTROL (WRMD) LATCH,
A6U1010
..............•.....................
3-36
A2. TRIGGER CONTROL LEVEL SHIFTING
TRANSISTORS, RESET BUFFER
........•.....
3-36
I
I
(
(
\

(
7A42 Service Volume 1
TABLE OF CONTENTS (CONT)
MAINTENANCE (CONT) Page
A3. TRIGGER CONTROL SHIFT
REGISTERS
................................. 3-36
TRIGGER INTERCONNECT
.................. 3-36
B1. TRIGGER TEST BIT INTERCONNECT ..... 3-36
B2. TRIGGER FILTER INTERCONNECT ....... 3-37
B3. A THEN B GATE OUTPUT CABLE ........ 3-37
THRESHOLD DACS AND COMPARATORS
....... 3-37
C1. THRESHOLD DACS ...................... 3-37
C2. THRESHOLD COMPARATORS ............ 3-38
BOOLEAN LOGIC AND TRIGGER FILTEAS
....... 3-38
01. BOOLEAN LOGIC
....................... 3-38
02. TRIGGER FILTERS
...................... 3-38
03. TRIGGER FILTER CURRENT SOURCES
... 3-39
A THEN B LOGIC
.............................. 3-39
E1. A THEN B LOGIC ........................ 3-39
EDGE DETECTORS
............................ 3-39
F1. SYNC CONTROL LINES .................. 3-39
F2. EDGE-DETECTOR CIRCUITS ............. 3-41
F3. MULTIPLEXERS .......................... 3-41
EXTERNAL CLOCK ............................. 3-41
G1. CLOCK CONTROL LINES ................ 3-41
G2. EXTERNAL CLOCK LOGIC ............... 3-41
TRIGGER BOARD TEST DESCRIPTIONS ............ 3-41
TRIGGER CONTROL ........................... 3-41
14- TRIGGER CONTROL REGISTER .......... 3-41
15-- TRIGGER PICKOFF A/D-1 ................ 3-41
16-TRIGGER PICKOFF A/D-1 ................ 3-41
17-TRIGGER PICKOFF A/D-1 ................ 3-41
18-TRIGGER PICKOFF A/D-1 ................ 3-41
19---TRIGGER PICKOFF A/D-2 ................ 3-41
20-- TRIGGER PICKOFF A/D-2 ................ 3-42
21- TRIGGER PICKOFF A/D-2 ................ 3-42
22- TRIGGER PICKOFF A/D-2 ................ 3-42
23--BOOLEAN LOGIC-FUNCTION A
.......... 3-42
24-BOOLEAN LOGIC-FUNCTION B .......... 3-42
25--BOOLEAN LOGIC-TCR
.................. 3-42
26-A THEN B LOGIC ....................... 3-42
27-A THEN B LOGIC ....................... 3-42
28-A THEN B LOGIC ....................... 3-42
29---A THEN B LOGIC
....................... 3-42
30--A THEN B LOGIC ....................... 3-42
31-A THEN B LOGIC ....................... 3-42
32-A THEN B LOGIC ....................... 3-42
33--A THEN B LOGIC ....................... 3-42
34-65-EDGE DETECTORS ................... 3-42
66-BUFFERED EXTERNAL CLOCK
........... 3-42
67-BUFFERED EXTERNAL CLOCK
........... 3-42
68-BUFFERED EXTERNAL CLOCK
........... 3-42
69---BUFFERED EXTERNAL CLOCK
........... 3-43
70--EXTERNAL CLOCK
...................... 3-43
71-EXTERNAL CLOCK ...................... 3-44
72-EXTERNAL CLOCK
...................... 3-44
TROUBLESHOOTING CIRCUITS NOT COVERED
BY DIAGNOSTICS
................................. 3-44
MAINFRAME SUPPLY CURRENT LIMITED
........ 3-44
7A42
+S Vo, -2 Vo, -S Vo FAILURES .......... 3-44
MAINTENANCE (CONT)
Page
AMPLIFIER BOARD ........................... 3-44
TRIGGER
BOARD ............................ 3-4S
TRIGGER
OUT TO MAINFRAME ........... 3-4S
TRIGGER VIEW
OUTPUT .................. 3-45
FRONT PANEL TRIGGER
OUT ............. 3-4S
ATTENUATORS
.............................. 3-4S
DIGITAL BOARD ............................. 3-4S
ARMATURE RELAY DRIVE CIRCUITRY
.... 3-4S
READOUT
................................. 3-47
CALIBRATION AND TROUBLESHOOTING
AIDS
............................................ 3-47
ROM PART NUMBER
(LEVEL..o- KEY) .......... 3-47
FRONT-PANEL INTERACTIVE (LEVEL-fr
KEY)
......................................... 3-47
SPEAKER
CONTROL (PROBE OFFSET KEY) .. 3-47
THRESHOLD
DAC RAMP (A KEY) ............. 3-48
ATTENUATOR OFFSET CALIBRATOR
(B KEY) . . . . . . .. . . . . .. . . .. . .. . . .. . .. . .. . . .. . . . 3-48
DISPLAY READOUT CHARACTERS
(A THEN B KEY)
.............................. 3-48
TRIGGER THRESHOLD CALIBRATION
(NOT KEY)
................................... 3-48
CORRECTIVE
MAINTENANCE ......................... 3-49
OBTAINING REPLACEMENT PARTS
............. 3-49
SPECIAL PARTS
............................. 3-49
ORDERING PARTS
........................... 3-49
SOLDERING TECHNIQUES
...................... 3-49
REMOVING
AND REPLACING PARTS ............ 3-SO
SEMICONDUCTORS .......................... 3-SO
CHASSIS PARTS ............................. 3-S1
HOW TO REMOVE THE FRONT-PANEL
ASSEMBLY
................................ 3-S1
HOW TO REPLACE THE FRONT PANEL ... 3-S1
HOW TO REPLACE FRONT-PANEL
COMPONENTS
............................ 3-S2
LEOS
.................................. 3-S2
POTENTIOMETERS
.................... 3-S2
SWITCHES
............................. 3-S3
HOW TO REMOVE AND REPLACE THE FRONT-
PANEL OVERLAY
AND/OR THE A10 DVM
BOARD
................................... 3-S3
HOW TO REMOVE AND REPLACE THE REAR
PANEL
.................................... 3-S3
CIRCUIT BOARDS ............................ 3-S4
HOW
TO REMOVE THE A1 SWITCH BOARD-
A2 LED BOARD ASSEMBLY ............... 3-S4
HOW TO INSTALL THE A1 SWITCH BOARD-
A2 LED BOARD ASSEMBLY . . .. . .. . . .. . .. . 3-S4
HOW
TO REMOVE THE A4 ATTENUATOR
CONTROL BOARD . . .. . . .. .. . .. . . . .. . . .. . . 3-SS
H_OW TO REPLACE THE A4 ATTENUATOR
CONTROL BOARD . . .. . .. . .. . .. . . . .. . .. . . . 3-SS
HOW TO REMOVE THE AS AMPLIFIER
BOARD
................................... 3-SS
HOW TO REPLACE THE AS AMPLIFIER
BOARD
................................... 3-S6
iii

7A42 Service Volume 1
TABLE OF CONTENTS (CONT)
MAINTENANCE (CONT) Page
HOW TO REMOVE AND REPLACE THE A6
TRIGGER BOARD ASSEMBLY ................ 3-56
HOW TO REMOVE AND REPLACE THE A7
DIGITAL BOARD .............•.............. 3-57
HOW TO REMOVE AND REPLACE THE AS
MPU BOARD ................................ 3-57
HOW TO REMOVE THE A9 POWER SUPPLY
BOARD
..................................... 3-57
HOW TO REMOVE AND REPLACE
ATTENUATOR MODULES
.................... 3-58
HOW TO REMOVE AND REPLACE
ARMATURE RELAYS
•....................... 3-59
HOW TO REPLACE THE DELAY LINES ....... 3-59
HOW TO REPLACE VERTICAL CHANNEL
SWITCH MICROCIRCUITS
................... 3-60
PLUG-IN LATCH
............................ 3-60
INTERCONNECTING PINS ...................... 3-60
COAXIAL-TYPE END-LEAD CONNECTORS
.... 3-61
CIRCUIT-BOARD PINS ...................... 3-61
CIRCUIT-BOARD PIN SOCKETS ............•. 3-61
MULTI-PIN CONNECTORS ................... 3-62
ADJUSTMENT AFTER REPAIR
.................. 3-62
SECTION
4-CHECKS AND ADJUSTMENT
USING THESE PROCEDURES
....................... 4-1
PERFORMANCE CHECK AND ADJUSTMENT
SUMMARY
...................................... 4-1
TEST EQUIPMENT .............................. 4-6
TEST EQUIPMENT ALTERNATIVES
........•...... 4-6
PART
I-FUNCTIONAL CHECK PROCEDURE .............. 4-9
7A42 FUNCTIONAL CHECK ......................... 4-9
1. SELF TEST .......•........................... 4-9
2. INITIALIZING THE 7A42 ....................... 4-9
3. DISPLAY AND TRIGGER FUNCTIONS .......... 4-9
4. A THEN B NESTED TRIGGERING ............. 4-11
5. EXT CLOCK OPERATION ..................... 4-11
PART II-PERFORMANCE CHECK PROCEDURE ........... 4-12
INDEX
TO PART II-PERFORMANCE CHECK
PROCEDURE ..................................... 4-12
PERFORMANCE CHECK INITIAL SETUP
PROCEDURE
..................................... 4-13
A. CHANNEL AMPLIFIERS ............................ 4-14
B. TRIGGER VIEW TRACE ............................ 4-21
C. THRESHOLD AND PROBE OFFSET ................. 4-25
D. EXTERNAL CLOCK ................................ 4-31
E. TRIGGER-LEVEL SENSITIVITY ...................... 4-41
F. TRIGGER-EDGE SENSITIVITY .•..................... 4-46
G. TRIGGER-A THEN B ............................... 4-54
H. TRIGGER-RESET
...................•.............. 4-61
iv
CHECKS AND ADJUSTMENT (CONT) Page
PART
Ill-ADJUSTMENT PROCEDURE ................... 4-67
INDEX
TO PART Ill-ADJUSTMENT
PROCEDURE ..................................... 4-67
ADJUSTMENT
INITIAL SETUP PROCEDURE ........ 4-67
A. POWER SUPPLY ................................... 4-69
B. ATTENUATOR OFFSET ............................ 4-71
C. AMPLIFIER ........................................ 4-73
D. TRIGGER THRESHOLD AND PROBE
OFFSET
............................................. 4-78
SECTION
5-INSTRUMENT OPTIONS
SECTION
&-REPLACEABLE ELECTRICAL PARTS
SECTION
7-DIAGRAMS AND CIRCUIT BOARD
ILLUSTRATIONS DIAGRAM
FRONT PANEL DISPLAY & CONTROL
....................... 1
ATTENUATORS & CONTROL ............................... 2
CHANNEL SWITCHING & AMPLIFIERS
....................... 3
DISPLAY CONTROL
........................................ 4
TRIGGER COMPARATORS, BOOLEAN LOGIC & FILTERS ..... 5
EDGE DETECTORS
....•................................... 6 (
A THEN B LOGIC & TRIGGER 1/0
........................... 7
TRIGGER CONTROL ....................................... 8
CPU.- ...................................................... 9
READOUT
................................................ 10
POWER SUPPLIES & DISTRIBUTION ....................... 11
INTERCONNECT .......................................... 12
CONNECTORS
TO MAINFRAME ........................... 13
CABLING ................................................. 14
SECTION
&-REPLACEABLE MECHANICAL PARTS
CHANGE INFORMATION
RELATED DOCUMENTATION
For information on related 7A42 documentation refer to General
Information, Section 1 of this manual under Technical Manuals and
Standard Accessories.

Figure
No.
1-1
1-2
1-3
1-4
1-5
1-6
1-7
1-S
1-9
1-10
1-11
1-12
1-13
1-14
1-15
2-1
2-2
2-3
2-4
2-5
3-1
3-2
3-3
3-4
3-5
3-6
3-7
3-S
3-9
3-10
3-11
3-12
3-13
7A42 Service Volume 1
LIST OF ILLUSTRATIONS
Page
7A42 Features
.....................................
x
7A42 release latch
.............................•.
1-2
7A42 dimensional drawing
.......................
1-14
7A42 controls, connectors, and indicators
..........
1-16
Self-test in progress
...................•.........
1-1S
Self-test finished
................................
1-1S
Typical self-test failure display
....................
1-19
Initialization
of
the
7A42 front-panel
controls
........................................
1-21
Location
of
J747 Battery Enable link plug
..........
1-21
Channel readout display
.........................
1-24
Channel readout display with 10X probe attached
to
inputs
of
CH1, CH2, CH3, and
CH4
............
1-24
Location
of
J634, External Clock Jumper,
on
A6
Trigger Board
............................
1-26
Timing diagram showing the relationship
of
the
TRIGGER
OUT
waveform
to
the
input signal
.......
1-27
Timing diagram depicting the TRIGGER FUNCTION
reacting
to
the input signals
......................
1-27
Example
of
A THEN
B,
level and EDGE sensitive
TRIGGER FUNCTION, showing
th~
Normal and
A THEN B Gate waveform alternatives
............
1-2S
Location
of
J701, on A6 Trigger Board
............
1-2S
Simplified Block Diagram
.........................
2-1
Armature Relay Matrix (Actuating the
CH1
2.5X attenuator)
.............................
2-9
Partial
AS;
Auto
Restart Circuit
...................
2-17
Successive Approximation Example
...............
2-1S
7A42 Readout Timing
...........................
2-20
Color
code
for
resistors and capacitors
.............
3-6
Semiconductor lead configuration
.................
3-7
Orientation
of
multi-pin connectors
................
3-S
Functions
of
front-panel keys with 7A42 in
extended diagnostic test mode
...................
3-13
Right and left views
of
extended
A6
Trigger Board and its connections
................
3-16
Extended view
of
A7 Digital Board
and its connections
.............................
3-17
Location
of
jumpers on
AS
MPU Board
............
3-19
Location
of
jumpers on the A7 Digital
Board
.........................................
3-19
Timing
of
XBUSX operation
......................
3-21
A typical ''walking-zeros" waveform ,
..............
3-22
(A) Partial
AS
CPU diagram: probe-offset
DAC
and (B) waveforms when operating
...............
3-23
(A) Partial
AS
CPU diagram: auto-restart
circuit, (B) waveforms when operating normally,
and (C) waveforms when kernel has failed
.........
3-24
Waveforms in real-time interrupt circuit
............
3-26
Figure
No.
3-14
3-15
3-16
3-17
3-1S
3-19
3-20
3-21
3-22
3-23
3-24
3-25
3-26
3-27
3-2S
3-29
3-30
4-1
4-2
4-3
4-4
4-5
4-6
4-7
4-8
4-9
4-10
4-11
4-12
Page
Waveforms in wait-state generator
................
3-27
(A) Probe offset
AID
converter and
(B) its waveforms
...............................
3-2S
(A) Readout circuitry and (B) waveforms
at 50
JJS/div.,
(C) 500
JJS/div
.......•..............
3-29
How
to
connect a signature analyzer
or
the
7A42 Signature Analyzer TTL-to-ECL Converter
to
the
AS
MPU Board
...........................
3-37
Timing
of
waveforms in A Then B Logic test
.......
3-40
Voltages at 10 pins on attenuator module
..........
3-46
(A) Row and column currents and (B) readout
during Display Readout Characters test
...........
3-48
Recommended desoldering sequence
.............
3-50
How
to
remove
the
latch-release knob
.............
3-51
Interconnections between front panel and
A6 Trigger Board
...............................
3-52
Pins
of
single-color and two-color LEOs
.......•...
3-52
Trigger Board ground screws
....................
3-57
The 10 pins that must be unsoldered
to
remove an attenuator module
....................
3-58
Placement
of
delay lines
..........•..............
3-60
Latch assembly
.................................
3-61
Coaxial-end lead connector assembly
.............
3-62
Exploded view
of
circuit-board pin and
ferrule
.....................................•...
3-62
Location
of
the
J747 Battery Enable link
plug
.....••.•..................................
4-13
· Trigger view waveform amplitude with ECL
input signal
....................................
4-22
Trigger view and channel transition time
coincidence
....................................
4-24
100kHz
sine-wave signal triggered at the
zero-volt level
..................................
4-26
Typical waveform display
for
measuring the
hysteresis level
...............•.................
4-29
Location
of
J634 External Clock Jumper
(link-plug) on the
A6
Trigger Board
...............
4-32
External clock view and channel transition
time coincidence
................................
4-33
Typical external
clock
transition display
in
the
ECL mode
...............................
4-35
Typical external
clock
transition display
in
the
TTL
mode
................................
4-36
Threshold voltage range
of
the external
clock input, in
the
ECL mode
....................
4-38
Threshold voltage range
of
the external
clock input, in
the
TTL
mode
.....................
4-38
Typical trigger view and channel pulse display
for
checking the trigger filter range
...............
4-42
v

7A42 Service Volume 1
LIST OF ILLUSTRATIONS (CONT)
vi
Figure
No.
4-13
4-14
4-15
4-16
4-17
4-18
Typical waveform display
of the 50 kHz
reference signal and the resultant trigger output
Page
signal .......................................... 4-44
Location
of J701 (Link-Plug} on the A6
Trigger Board
.................................. 4-56
Trigger view transitions referenced to the
CH1 waveform voltage levels ..................... 4-62
Relationship between the CH1, CH2, and
Trigger View waveforms when checking the reset
input pulse width
............................... 4-64
Relationship between the CH1, CH2, and CH3
waveforms when checking the Reset Input Pulse
Width
.......................................... 4-64
Location
of the J747 BE (Battery Enable}
link plug
....................................... 4-68
The illustrations in section 7 are located near their associated
diagrams on the foldout page.
7-1
7-2
7-3
7-4
7-5
7-6
7-7
7-8
7-9
7-10
7-11
Semiconductor lead configurations.
7A42 board locator illustration.
A1-5witch circuit board assembly.
A2-LED circuit board assembly.
A4-Attenuator Control circuit board assembly.
A5-Amplifier circuit board assembly.
A7-Digital circuit board assembly.
A6-Trigger circuit board assembly. ·
A8-MPU circuit board assembly.
A9-Power Supply circuit board assembly.
A3-lnterconnect circuit board assembly.
(
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7A42 Service Volume 1
LIST OF TABLES
Table
No.
Page
1-1
Shipping Carton Test Strength
....................
1-3
1-2
Electrical Characteristics
..........................
1-4
1-3 Environmental Characteristics
....................
1-13
1-4 Physical Characteristics
..........................
1-13
1-5
7A42
Self-Test Failure
Messages
..................
1-20
1-6
7A42
Front-Panel Control Settings
When
Initialized
......................................
1-22
1-7
7A42
Operator
Message
Summary
................
1-22
1-8 Channel Volts/Division
Ranges
...................
1-29
2-1
Signal Name Dictionary
...........................
2-2
3-1
Part
Number Reference For Support Items
..........
3-2
3-2 Color Codes of Coaxial
Cables
....................
3-5
3-3
Relative Susceptibility To
Damage
From
Static Discharge
.................................
3-5
3-4 What To Check After Replacing Components
on
The A6 Trigger Board
...........................
3-11
3-5 CRT And SWITCHING THRESHOLD VOLTS
Displays
.......................................
3-12
3-6 Extended Test Failure
Messages
..................
3-14
3-7 Alphabetical List of Link-Plug Jumpers
on
Digital and
MPU
Boards
.........................
3-20
3-8
Purposes of Link-Plug Jumpers
on
Digital
and
MPU
Boards
...............................
3-20
3-9 Front-Panel Interactive
Keys,
Codes,
and
LEOs
......................
e
••••••••••••••••
3-22
3-
to
Names
and
Codes of Trigger Diagnostic
Tests
..........................................
3-31
3-11
Failure
Codes,
Sets,
And
Resets
For
Edge Detectors
.................................
3-43
3-12
Front-Panel Interactive
Keys,
Codes,
and
LEOs
..........................................
3-47
4-1
Performance Check
and
Adjustment Summary
......
4-2
4-2 Test Equipment
..................................
4-6
4-3
7A42
Front-Panel Power-Up Control Settings
......
4-10
4-4 Calibrated
Range
At Input Connectors
............
4-15
4-5 High-
and
Low-Frequency Compensation
Adjustments
..........
;
.........................
4-77
vii

7A42 Service Volume 1
OPERATORS SAFETY SUMMARY
The general safety information
in
this part
of
the summary
is
for
both operating and servicing personnel. Specific
warnings and cautions will
be
found
throughout
the manual where they apply, but may not appear in this summary.
TERMS
IN THIS MANUAL
CAUTION statements identify conditions
or
practices
that could result in damage to the equipment or other
property.
WARNING statements identify conditions
or
practices
that could result in personal injury
or
loss
of
life.
AS
MARKED ON EQUIPMENT
CAUTION indicates a personal injury hazard not
immediately accessible
as
one reads the marking,
or
a
hazard
to
property including the equipment itself.
DANGER indicates a personal injury hazard immediately
accessible
as
one reads the marking.
SYMBOLS
IN THIS MANUAL
@
Static-Sensitive Devices
A
This
symbol
indicates
where
applicable
~
cautionary
or
other information
is
to
be
found.
AS
MARKING ON EQUIPMENT
f
DANGER-High
voltage
@
Protective ground (earth) terminal.
A
ATTENTION-refer
to manual.
viii
WARNINGS
POWER SOURCE
This product is intended
to
operate in a mainframe
connected to a power source that will not apply more
than
250
volts rms between the supply conductors
or
between either supply conductor and ground. A
protective ground connection by way of the grounding
conductor
in
the power cord
is
essential
for
safe
operation.
GROUNDING THE PRODUCT
This product
is
grounded through the grounding
conductor
of
the mainframe power cord. To avoid
electric shock, plug the mainframe power cord into a
properly wired receptacle before connecting to the
product input
or
output
terminals. A protective-ground
connection by way
of
the grounding conductor in the
mainframe power cord is essential for safe operation.
DANGER ARISING FROM LOSS OF GROUND
Upon loss
of
the protective-ground connection, all
accessible conductive parts (including knobs and
controls that may appear to be insulating), can render
an
electric shock.
DO
NOT
OPERATE IN EXPLOSIVE
ATMOSPHERES
To avoid explosion, do not operate this product
in
an
atmosphere of explosive gasses.
DO
NOT
REMOVE COVERS
OR
PANELS
To avoid personal injury, do not remove the product
covers
or
panels. Do not operate the product
without
the
covers and panels properly installed.
DO
NOT
OPERATE WITHOUT COVERS
To avoid personal injury, do not operate this product
without covers or panels installed. Do not apply power
to
the plug-in via a plug-in extender.

7A42 Service Volume 1
SERVICING SAFETY SUMMARY
FOR QUALIFIED SERVICE PERSONNEL ONLY
Refer also to the preceding Operators Safety Summary
DO
NOT
SERVICE ALONE
Do
not
perform internal service
or
adjustment
of
this
product unless another person capable
of
rendering first
aid and resuscitation
is
present.
USE CARE WHEN SERVICING WITH
POWER ON
Dangerous voltages exist at several points in this
product. To avoid personal injury, do not touch exposed
connections and components while power is on.
Disconnect power before removing protective panels,
soldering,
or
replacing components.
ix

7A42 Service Volume 1
4286-1
7A42 FEATURES
The 7A42 Logic Triggered Vertical Amplifier
is
a
four
channel, wide bandwidth, plug-in unit, compatible with Tektronix 7000-series
Oscilloscopes. It was specifically designed to display and make measurements on digital
logic
signals in the
TTL,
ECL and CMOS
logic families. While the display output from the 7A42 is analog, the trigger output
is
digital and is comprised
of
a user selectable
Boolean function
of
the four input channels. A fifth TRIGGER VIEW trace depicts either the trigger function output
or
the external
clock input.
X
(
I
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f
I

Section 1-7A42 Volume 1
GENERAL INFORMATION
This section contains a basic content description of both the Operators and Service manuals, information on
instrument installation, power requirements, packaging for shipment, Standard Accessories, Optional Accessories,
Specifications and a dimensional drawing
of the 7A42. The specification portion consists of three tables: Electrical,
Environmental, and Physical Characteristics.
TECHNICAL MANUALS
An operators and two service manuals are supplied with
your 7A42 as standard accessories. The following
information outlines the content
of these manuals.
Operators Manual
The Operators Manual is divided into the following four
sections:
Section
1-GENERAL INFORMATION contains
content descriptions of the Operators and Service
manuals, instrument description, mainframe and
plug-in compatibility, packaging instructions and
instrument specifications.
Section
2-0PERATING INSTRUCTIONS contains a
block diagram description, a front-panel drawing and
brief description of controls, connectors and
indicators. Get-Acquainted Exercises provide a basic
operating procedure for the first-time user followed
by a systematic demonstration of all front-panel
controls. A detailed description
of all front-panel
controls
is also given in this section.
Section
3-APPLICATIONS gives examples of how to
use the 7A42 to make some difficult measurements.
Section 4-INSTRUMENT OPTIONS contains a
description
of available options.
Service Manual
WARNING I
The following service instructions are for use
by qualified personnel only. To avoid
personal injury, do not perform any service
other than that contained in the operating
instructions unless
you are qualified to do
so. Refer to Operators Safety Summary and
Service Safety Summary prior to performing
any service.
The service manual is divided into 2 volumes. Volume 1
contains the following:
Section
1-GENERAL INFORMATION contains
content descriptions of the Operators and Service
manuals,
mainframe and plug-in compatibility,
packaging instructions, instrument specifications,
and operating instructions.
Section
2- THEORY OF OPERATION contains basic
and general
circuit analysis that is useful for servicing
the instrument.
Section
3-MAINTENANCE describes preventive
maintenance procedures, conventional troubleshoot-
ing and diagnostic troubleshooting procedures with
detailed
instructions for replacing assemblies,
subassemblies, and individual components.
Section
4-CHECKS AND ADJUSTMENT contains
procedures to check the operational performance
and electrical characteristics
of the instrument.
Procedures also include methods for adjustment
of
the instrument to meet specifications.
Section
5-INSTRUMENT OPTIONS contains a
description of available options.
Section
6-REPLACEABLE ELECTRICAL PARTS
contains information necessary to order replaceable
parts and assemblies related
to the electrical
functions of the instrument.
Section
?-DIAGRAMS AND CIRCUIT BOARD
ILLUSTRATIONS includes detailed circuit
schematics, locations of assembled boards within the
instrument, voltage and waveform information and
circuit board component locators.
Section
a-REPLACEABLE MECHANICAL PARTS
includes information necessary to order replaceable
mechanical parts and shows exploded drawings
which identify assemblies.
Volume 2
of the service manual contains signature
analysis tables
to be used with the diagnostic
information provided in the Maintenance section of the
Volume 1 service manual.
1-1

General lnformation-7A42 Volume 1
INSTALLATION
INITIAL INSPECTION
This instrument was inspected both mechanically and
electrically before shipment. It should
be free of mars or
scratches and should meet or exceed all electrical
specifications.
To confirm this, inspect the instrument for
physical damage incurred in transit and check the basic
instrument functions by performing the Performance
Check Procedure in the Checks and Adjustment section
of this manual. If there is damage
or deficiency, contact
your local Tektronix Field Office or representative.
OPERATING TEMPERATURE
The 7A42 can be operated where the ambient air
temperature is from 0° to +50° C and can be stored in
ambient temperatures from
-55° to +75° C. After storage
at temperatures outside the operating limits, allow the
chassis temperature to reach operating limits before
applying power.
INSTALLING THE 7A42 IN THE MAINFRAME
The 7A42 is designed to operate in the two center or the
two left plug-in compartments of a Tektronix 7000-series
oscilloscope mainframe.
NOTE
Switch
off the mainframe power before
installing
or removing the 7A42.
CH1
f@2=~~a
GNOQ 0
~IM015pf Q
CH2
DISPLAY Q
ALT
~
1611
DISPLAY
1611
1611
tOLTS/
OIV
lbll
To install the 7A42 in the mainframe, align the grooves
in the top and bottom
of the instrument with the guides
at the top and bottom
of the plug-in compartment. Then
push the 7A42 in until its front panel
is flush with the
front panel
of the mainframe.
To remove the 7A42 from its host mainframe, pull the
release latch (see Fig. 1-1)
to disengage the unit from
the mainframe, then pull the 7A42 straight out from the
plug-in compartment leaving the mainframe on the
bench.
MAINFRAME COMPATIBILITY
The 7A42 is compatible with all Tektronix 7000 series
mainframes. In four-wide plug-in compartment
mainframes, it can be installed in either the two left or
two center plug-in compartments. When used in the two
left compartments, select the Left Vertical Mode to
display the analog signals. The associated time base
plug-in Trigger Source should
be Left Vertical with the
time-base trigger controls set to Auto
or Norm, De,
Internal, Slope to +, with the Level control centered. The
A Then B Gate Output can be picked
off from the
RIGHT VERTICAL TRIGGER SOURCE by a 7011
or
7015 from either horizontal compartment. In three-wide
plug-in compartment mainframes, the 7A42 must be
used in the
two left compartments in a similar way.
When the 7A42 is installed in the center two plug-in
compartments
of a four compartment mainframe; set the
.(}LEVEL fr
TRIG J
SWITCHING THRESHOLD
1611 IEil
VIEW
1611
!'///~~~ Vpk PROBE OFFSIT
TTL/ECL
"' CD TIP IEil
lbll
VOLTS
THRESH
~TRIGGERFU~N~ ~
llJ
PROG
~
~ ~00 ~
~ ~:~:: 0
,.,g () 1611
GND t=~
ANO
ATHENS
l!rui]tM015pt Q
.~too
1611~
lbll
T
RESIT
CH3
DISPLAY Ql
IM0/500 CLEAR
s
Vpk::S5V
~~~.T:::o
1611 [jJ
···()()
5DD
fCill'
ANO
~.'?
@
1611 llJ
'---
~IM015pf 0 GAIN
EXT CLOCK
.r~
TRIGGER FILTER
0
CH2 OR
SYNC
, .. Gt ..
CH4
DISPLAY Q
1611 1611
1611
1611
~ ~rnQ 0
CH3
NOT
EXT CLOCK INPUT
TRIGGER OUT
GNO() 0
1611
1611
M~Al~~~
&~i:~
CH4 EDGE
[lli!JIM015pl Q
1611 1611
~ '----
~
c==> ronix
7A42 ~~~Wcl~'l'Z,1.~7~.ER
w
~ ...
LATCH 4286-101
Figure 1-1. 7A42 release latch.
1-2
[-

mainframe Vertical Mode and Trigger Source to Right
Vertical. The mainframe A Then 8 Gate Output can
not
be
used in this configuration, however, the A Then 8
Gate is still available at the front-panel TRIGGER
OUT
bnc connector.
Since all analog channels are sent out the 7A42's left
interface connector, it cannot use the full capabilities
of
a dual beam oscilloscope such
as
the 7844,
R7844,
and
the 76120. However, it has full compatibility with these
mainframes in a single beam configuration.
Since the 7A42 uses the mainframe crt readout to
display the channel volts per division and error warning
messages, the 7A42 is not recommended
for
use in
mainframes without readout.
If the 7A42 is used with two time-base units in a
four
compartment mainframe where Chop has been selected
as
the Horizontal Mode, and if exactly four traces are to
be
displayed by the 7A42, two
of
the traces may
synchronize
to
one time base while the other
two
traces
synchronize to the other time
base.
To prevent this from
happening, one trace should be removed,
or
a fifth trace
should be added to the mainframe crt display (even if it
is
positioned
off
screen so it cannot be seen). With one,
two, three,
or
five traces, the channel display will
not
synchronize
to
the horizontal chop frequency.
The 7A42 is compatible with the 7854 Oscilloscope
mainframe when the 7854
is
operated in real-time.
However, when the 7854
is
operated in digital storage,
and waveform and readout acquisition is desired, the
7A42-7854 mode should be selected by moving jumper
P540
to the 7854 mode. To locate
P540
refer to Figure 3-
7 in the Maintenance section
of
this manual. Once the
7A42-7854 mode has been selected, proper readout and
waveform acquisition can
be
guaranteed with the
following 7A42 display conditions:
1.
Any single channel displayed alone (CH1, CH2,
CH3, CH4,
or
TRIG VIEW).
2.
Channels 1 and 2 only displayed together, ALT
display mode selected.
3.
Channels 3 and 4
only
displayed together, ALT
display mode selected.
Refer to the Applications section in the Operators
manual
for
further information.
General
lnformation-7A42
Volume 1
PACKAGING FOR SHIPMENT
If this instrument is to be shipped by commercial
transportation, we recommend that the instrument be
packaged in the original manner. The carton and
packaging material in which your instrument was
shipped should be saved and used for this purpose.
NOTE
Package
and
ship
Plug-Ins and Mainframes
separately.
If this instrument is to be shipped to a Tektronix Service
Center for service
or
repair, attach a tag to the
instrument showing the following: Owner
of
the
instrument (with address), the name
of
a person at
your
firm who can
be
contacted, complete instrument type
and serial number, and a description
of
the service
required.
If the original package is unfit
for
use
or
not available,
package the instrument
as
follows:
1.
Obtain a corrugated cardboard shipping carton
having inside dimensions at least six inches greater
than the instrument dimensions; refer to Table
1-1
for
carton test strength requirements.
2.
Enclose the instrument with polyethylene sheeting
or
equivalent to protect the finish
of
the instrument.
3.
Cushion the instrument on all sides by tightly
packaging dunnage
or
urethane foam between the
carton and the instrument, allowing three inches
of
packaging on each side.
4.
Seal the carton with shipping tape
or
with
an
industrial stapler.
5.
Mark the address
of
the Tektronix Service Center
and your return address on the carton in one
or
more prominent locations.
TABLE
1-1
Shipping Carton Test Strength
Gross Weight Carton Test strength
(I
b)
(lb)
0 200
10-30 275
30-120 375
120-140 500
1-3

General lnformation-7A42 Volume 1
SPECIFICATION
The electrical characteristics listed in Table 1-2 apply when the following conditions are met:
(1)
Adjustment of the
instrument must have taken place at
an
ambient temperature between +20° and +30°
C,
(2)
the instrument is allowed a
20-minute warm-up period,
(3)
specifications are valid at
an
ambient temperature
of
0°
to
+50°
C,
unless otherwise
stated,
(4)
the instrument must be in an environment that meets the limits described in Table 1-3,
(5)
the instrument
must be operated in a calibrated 7000-series mainframe.
Any
applicable conditions not listed above may be stated
as
part
of
the characteristic. Environmental characteristics
are listed in Table 1-3 and Physical characteristics are listed in Table 1-4.
Characteristic
Deflection Factor
Calibrated Range at Input
BNC Connector
TTL (CMOS) Family
ECL Family
Calibrated Range through a
10X Probe
TTL
(CMOS) Family
ECL Family
Channel
to
Channel Gain Match
Gain Ratio Accuracy
within the same Channel
GAIN Range
Frequency Response
Bandwidth
1-4
TABLE
1-2
Electrical Characteristics
Performance
Requirement
DISPLAY
0.1,
0.2,
0.5 V/div.
20,
50,
100 mV/div.
Within
2%
in ECL Logic Family,
20 mV/div, 1 Megohm input
impedance.
Within
2%
of
indicated deflection
factor relative
to
ECL Logic
Family,
20
mV/div, 1 Megohm
input impedance.
Refer to Tektronix Product
Catalog 7000-Series Oscilloscope
System Specification
for
system
bandwidths.
1,
2,
5 V/div.
Supplemental
Information
0.2, 0.5, 1 V/div.
P~rmits
adjustment
of
deflection
factor
for
calibrated operation
with any calibrated 7000-series
mainframe. Adjustable at least
+4%
to -4% from calibrated
setting.
(
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Characteristic
Input Signal Dynamic Range
Maximum Signal Voltage at
tip
of
10X Probe
TTL (CMOS) Family
ECL Family
Output Dynamic Range
Maximum Input Voltage
1 Megohm
50
Ohm
50-0hm
Input
Protection
Reaction Time
Maximum time to open input
with applied overvoltage of:
10V
DC
15
V DC
20
V DC
Input Characteristics
Input Coupling
DC
GND
High Impedance
Low Impedance
VSWR
TABLE 1-2 (CONT)
Electrical Characteristics
Performance
Requirement
DISPLAY
(CONT)
10 seconds.
1 second.
0.5 second.
1 Megohm
±1%,
in parallel with
approximately
15
pF.
50 ohms
±1
ohm at de.
General lnformation-7A42 Volume 1
±30
v.
±6
v.
Supplemental
Information
Limited
to
the CRT display
area. Mainframe Vertical Trace
Separation should not be used
to bring
an
off-screen signal
onto screen.
25
V
(de+
peak ac)
36 MHz
or
less, derated linearly
to 3 V (peak ac) at
300
Mhz.
5 V RMS during any 1 ms time
interval. Active internal protection
opens all inputs
if
overvoltage
is applied to any channel.
Incoming signal
is
de-coupled
to the amplifier.
A grounded input is actually
open at the input BNC, (i.e.,
1 Megohm
or
50
Ohm termination
is disconnected). Internally,
the amplifier input is grounded
to provide a zero-volt input
reference.
~1.15:1,
de to 300 MHz.
1-5

General lnformation-7A42 Volume 1
Characteristic
VOLTS/DIV Shift
POSITION Range
Displayed Noise
DC Drift
Drift with Time
Drift with Temperature
Differential Delay Between Any
Two Channels, set to Same
Logic Family and VOLTS/DIV
Plug-in Delay Time -
Channel to Channel Crosstalk
Chop Frequency
TRIG VIEW
or External
Clock View
Amplitude
Position
Risetime
1-6
TABLE 1-2 (CONT)
Electrical Characteristics
Performance
Requirement
DISPLAY (CONT)
0.2 divisions or less shift when
VOLTS/DIV is changed in either
TTL or ECL Families or between
Families.
200
ps maximum.
0.35 divs
±0.1 div.
Supplemental
Information
At least +7 divisions to -7
divisions but less than +9
divisions to -9 divisions from
graticule center with gain
calibrated.
Grounded input at maximum
sensitivity, 7A42 triggered on
another channel, tested
at
1 ms/div and 10 ns/div,
not more than 0.02 divisions
RMS, as measured in a 7854.
Not more than 0.2 divisions in
any
10 minutes after twenty
minute warm-up (ambient temp-
erature and line voltage constant).
Not more than 0.2 divisions
for 10° C ambient change (line
voltage constant).
Typically
25 ns from channel
input
to A11 and B11 of
mainframe interface connector.
Typically less than 0.05 divisions
with logic signal inputs applied
through a 10X probe.
See mainframe manual
for
specifications.
Baseline
to be set 3 divisions
(±0.5 divisions) below graticule
center. Internally adjustable
approximately
±4 divisions from
graticule center.
See Section 4
for adjustment procedure.
2
ns or less.

Characteristic
TRIG VIEW
or
External
Clock View (cont)
Time Coincidence with
Channel Display
TRIG VIEW
External Clock View
Readout
SWITCHING THRESHOl-D
Voltage Range
At
Input
BNC
TTL
(CMOS) Family
ECL Family
At
tip
of
10X probe with
readout compensation
TTL
(CMOS) Family
ECL Family
Resolution
At
tip
of
10X probe with
readout compensation
TTL
(CMOS) Family
ECL Family
Accuracy, at Center Value of
Hysteresis Window
At
Input
BNC
TTL
(CMOS) Family
ECL Family
At
tip
of
10X probe with
readout compensation
TTL
(CMOS) Family
ECL Family
Hysteresis, Centered at
Threshold
At
Input BNC
TTL
(CMOS) Family
TABLE 1-2 {CONT)
Electrical Characteristics
Performance
Requirement
DISPLAY
(CONT)
Within 3
ns.
Within 5
ns.
TRIGGER
+1.28 V
to
-1.27
V.
+256 mV
to
-254
mV.
±5
mV
±2%
of
setting.
±1
mV
±2%
of
setting.
40 mV
±20%.
General lnformation-7A42 Volume 1
Supplemental
Information
Displayed on crt,
see
detailed
operating information.
+12.8 V to -12.7
V.
+2.56 V to -2.54
V.
100
mV.
20
mV.
±50
mV
±2%
of
setting.
±10
mV
±2%
of
setting.
1-7

General lnformatlon-7A42 Volume 1
Characteristic
SWITCHING THRESHOLD (cont)
Hysteresis, Centered
at Threshold (cont)
ECL Family
At
tip
of
10X probe with
readout compensation
TTL (CMOS) Family
· ECL Family
Presets
At tip
of
10X probe with
readout compensation
TTL
(CMOS) Family
ECL Family
PROBE OFFSET Activated
TIP (PROBE OFFSET) Input
Maximum Voltage Range
Input Resistance
DVM Resolution
DVM Accuracy
TRIGGER FILTER
Range
Match, Function A
to
Function B
.&.
EXT CLOCK Input
Maximum Voltage Range
Threshold
TTL
Level
Logic Zero
Logic One
1-8
TABLE 1-2 (CONT)
Electrical Characteristics
Performance
Requirement
TRIGGER (CONT)
8 mV
±20%.
+5.10 V to -5.10
V,
de only.
±20
mV
±2%
of
reading.
Off,
or
adjustable from
<15
ns
to
>300
ns.
Within
20%,
at maximum setting.
50.8
v.
:2:2
v.
400 mV
±20%.
80
mV
±20%.
+1.4 v.
-1.30
v.
ov.
:e:1oo
Kn.
20
mV.
Supplemental
Information
The trigger filter cannot
be
activated
if
the EXT CLOCK is
turned on,
nor
will it operate
with any trigger function that
contains an edge sensitive channel.
+5V
to
-5V (DC + peak AC).
Two EXT CLOCK INPUT modes are
available,
TTL
or
ECL;
for
selection
of
either mode
see
Figure 1-11.
(
[