Tektronix 2440 User manual

TEK 070-6603-00
Product Group 37
2440
OSCILLOSCOPE
SERVICE
WARNING I
THE FOLLOWING SERVICING INSTRUCTIONS ARE
FOR USE BY QUALIFIED PERSONNEL ONLY. TO
AVOID PERSONAL INJURY, DO NOT PERFOR ANY
SERVICING OTHER THAN THAT CONTAINED IN
OPERATING INSTRUCTIONS UNLESS YOU ARE
QUALIFIED TO DO SO. REFER TO OPERATORS
SAFETY SU ARY AND SERVICE SAFETY SU 
ARY PRIOR TO PERFOR ING ANY SERVICE.
Please Check for
CHANGE INFORMA TION
at the Rear of This Manual
First Printing JUL 1988
Revised JU 1989 Tfektronix
C O M M I T T E D TO E X C E L L E C E

Copyright © 1988 Tektronix, Inc. Ail 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.
TEKTRO IX, TEK, SCOPE-MOBILE, and are registered
trademarks of Tektronix, Inc.
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 Tektronix, Inc., Beaverton, Oregon, USA
100000 Tektronix Guernsey, Ltd., Channel Islands
200000 Tektronix United Kingdom, Ltd., London
300000 Sony/Tektronix, Japan
700000 Tektronix Holland, V, Heerenveen.The etherlands

TABLE OF CONTENTS
2440 Service
Page
LIST OF ILLUSTRATIONS ........................................ iii
LIST OF TABLES...................................................... v
OPERATORS SAFETY SU ARY . .......................... vi
SERVICING SAFETY SU ARY .............................. vii
Section 1 SPECIFICATIO
I TRODUCTIO ................................. 1-1
PERFORMA CE CO DITIO S ....... .. 1-4
Section 2 PREPARATIO FOR USE
SAFETY ............................................. 2-1
LI E VOLTAGE SELECTIO ............. 2-1
LI E FUSE ........................................ 2-1
POWER CORD................................... 2-3
I STRUME T COOLI G ................... 2-3
START-UP ..... ! ................................... 2-3
POWER-DOW .................................. 2-4
REPACKAGI G FOR SHIPME T ...... 2-4
Section 3 THEORY OF OPERATIO
SECTIO ORGA IZATIO ................ 3-1
I TEGRATED CIRCUIT
DESCRIPTIO S................................. 3-1
SIMPLIFIED BLOCK DIAGRAM
DESCRIPTIO ........................................ 3-2
DETAILED BLOCK DIAGRAM
DESCRIPTIO ....................................... 3-8
I TRODUCTIO ....... . ......................... 3-8
I PUT SIG AL CO DITIO I G
A D A ALOG SAMPLI G............ . 3-8
ACQUISITIO PROCESS
A D CO TROL.................................. 3-10
DATA CLOCKI G TO
ACQUISITIO MEMORY ................... 3-10
A ALOG DATA CO DITIO I G
A D A/D CO VERSIO .................... 3-11
ACQUISITIO PROCESSI G
A D DISPLAY.................................... 3-12
DETAILED CIRCUIT
DESCRIPTIO ....................................... 3-15
SYSTEM PROCESSOR ..................... 3-15
WAVEFORM PROCESSOR
SYSTEM ............................................ 3-22
Page
FRO T PA EL PROCESSOR ............ 3-28
FRO T PA EL CO TROLS ............... 3-30
SYSTEM DAC A D ACQUISITIO
CO TROL REGISTERS....................... 3-31
SYSTEM DAC (cont) A D
AUXILIARY FRO T PA EL................. 3-33
SYSTEM CLOCKS............................... 3-35
TIME BASE CO TROLLER
A D ACQUISITIO MEMORY ......... .. 3-39
ATTE UATORS A D
PREAMPLIFIERS................................. 3-43
PEAK DETECTORS A D
CCD/CLOCK DRIVERS ....................... 3-45
TRIGGERS A D PHASE CLOCKS .... 3-51
JITTER CORRECTIO RAMPS ......... 3-56
TRIGGER HOLDOFF, JITTER
COU TERS, A D CALIBRATOR ...... 3-58
CCD OUTPUT...................................... 3-61
A/D CO VERTER A D
ACQUISITIO LATCHES .............. , .... 3-62
DISPLAY A D ATTRIBUTES
MEMORY.............................................. 3-63
DISPLAY CO TROL ........................ 3-66
DISPLAY OUTPUT .............................. 3-73
HIGH VOLTAGE POWER
SUPPLY A D CRT ............................. 3-75
SYSTEM I/O.......................................... 3-80
VIDEO OPTIO .................................... 3-84
LOW VOLTAGE POWER SUPPLY .... 3-92
LOW VOLTAGE REGULATORS ........ 3-98
Section 4 PERFOR ANCE CHECK AND
FUNCTIONAL VERIFICATION
PROCEDURE
I TRODUCTIO ..................................... 4-1
PREPARATIO .................................. 4-1
I ITIAL SETUP..... .............................. 4-4
VERTICAL SYSTEM ................ 4-6
TRIGGERI G SYSTEMS ......................... 4-18
HORIZO TAL SYSTEM .......................... 4-26
ADDITIO AL VERIFICATIO S
A D CHECKS..................................... 4-29

2440 Service
TABLE OF CONTENTS (cont)
Page
Section 5 ADJUSTME T PROCEDURE
I TRODUCTIO . .......... 5-1
: CALIBRATIO SEQUE CE A D
PARTIAL PROCEDURES ................... 5-1
WARM-UP TIME REQUIREME T ..... 5-1
PRESERVATIO OF
I STRUM E T - *
CALIBRATIO ...... . .............................. 5-2
I TER AL ADJUSTME TS .... . ............... 5-3
SELF CALIBRATIO . ............................... 5-19
EXTER AL CALIBRATIO ..................... 5-20
Section 6 MAI TE A CE
I STRUME T CALIBRATIO ............ 6-1
ATIO AL BUREAU OF
STA DARDS TRACEABILITY .... . ...... 6-2
VOIDI G CALIBRATIO ..... . ............... 6-2
STATIC-SE SITIVE COMPO E TS ...... 6-3
PREVE TIVE MAI TE A CE ................ 6-4
I TRODUCTIO .................. . ................ 6-4
GE ERAL CARE..... ... .................... 6-4
I SPECTIO A D CLEA I G ........... 6-4
LUBRICATIO ...................................... 6-6
SEMICO DUCTOR CHECKS ............. 6-6
PERIODIC READJUSTME T ............. 6-6
TROUBLESHOOTI G ......... . ...... 6-7
I TRODUCTIO .............. 6-7
TROUBLESHOOTI G AIDS .......... . 6-7
TROUBLESHOOTI G
EQUIPME T......................................... 6-9
TROUBLESHOOTI G
TECH IQUES ......... ............................. 6-9
CORRECTIVE MAI TE A CE ............ . 6-11
I TRODUCTIO .... ................ : ............. 6-11
MAI TE A CE PRECAUTIO S ........ 6-11
OBTAI I G REPLACEME T
PARTS.. ........ . .................... 6-11
MAI TE A CE AIDS.... ..................... 6-12
. I TERCO ECTIO S ........................ 6-12
TRA SISTORS A D
I TEGRATED CIRCUITS .................... 6-12
SOLDERI G TECH IQUES ............... 6-14
REMOVAL A D REPLACEME T
PROCEDURE....................................... 6-15
Page
DIAG OSTICS A D
I TER AL CALIBRATIO
ROUTI ES . .......... 6-25
I TRODUCTIO ....... .... . ........ 6-25
OVERVIEW......................................... 6-25
CALIBRATIO ROUTI ES .............. 6-25
DIAG OSTIC ROUTI ES . ......... 6-27
DIAG OSTICS OPERATIO
VIA THE GP1B I TERFACE................ 6-34
DIAG OSTIC PROCEDURES.. .......... 6-35
Section 7 OPTIONS AND ACCESSORIES
OPTIO S DESCRIPTIO ................... 7-1
OPTIO S A1-A5:—I TER ATIO AL
POWER CORDS . .......... 7-1
OPTIO 1R—RACKMOU TED
2440 ....................................................... 7-1
OPTIO 03—WORD
RECOG IZER PROBE ....... . .............. 7-2
OPTIO 05—VIDEO OPTIO ............ 7-2
OPTIO 11 —PROBE POWER ........... 7-2
STA DARD ACCESSORIES.............. 7-2
RACKMOU TI G ACCESSORIES .... 7-2
OPTIO AL ACCESSORIES..... ........... 7-2
Section 8 REPLACEABLE ELECTRICAL PARTS
Section 9 DIAGRA S
Section 10 REPLACEABLE ECHANICAL PARTS
CHANGE INFOR ATION
Diagnostic and Troubleshooting Information:
Diagnostics . ............................... 6-25
Diagnostic Operation .................................... 6-30
Diagnostic Procedures.....^............................. 6-32
2440 Troubleshooting Procedures Table ___ 6-35
Video Option Troubleshooting Table .... . ..... 6-99
Troubleshooting Charts.................................Section 9

2440 Service
LIST OF ILLUSTRATIONS
Figure Page
The 2440 Digital Oscilloscope................................................................................................. viii
1- 1 Dimensional drawing .............. ................................................................................................. 1-24
2- 1 LI E VOLTAGE SELECTOR, line fuse, and power cord receptacle...................: .................... 2-1
3- 1 2440 simplified block diagram.................................................................................................. 3-3
3-2 Simplified Memory Map of the 2440........................................................................................ 3-18
3-3 System Clock waveforms......................................................................................................... 3-37
3-4 Simplified Peak Detector block diagram...................................................................-........... 3-47
3-5 Simplified CCD architecture.................................................................................................. . 3-49
3-6 Trigger Logic Array Control Data Byte ............................. ...................................................... 3-53
3-7 Jitter correction waveforms....................................................................................................... 3-57
3-8 Readout State Machine flow chart................................................ 3-71
3-9 Vertical Vector Generator....................................................................................... ................ 3-73
3-10 DC Restorer............................................................. . ............................................................. 3-78
3-11 GPIB data flow diagram........................ 3-81
3-12 GPIB three-wire handshake state diagram ............................................................................. 3-82
3-13 Video Option waveforms...........................................................................................................3-87
3-14 Video Option field-sync identification...................................................................... 3-88
3-15 ' PWM Regulator and Inverter................................................................................................. 3-94
3-16 PWM switching waveforms ............................................... . ..................................................... 3-96
5-1 Adjustment locations for Displays 4 through 6 ........... 5-4
5-2 Display 5—Vertical and Horizontal Gain, Offset, and Vector
Compensation adjustment pattern......................................................................................... 5-5
5-3 Display 6—Integrator Time adjustment pattern ......................... 5-6
5-4 (S B010250 & Above) CH 1 and CH 2 CCD Clock Adjustments
(shown centered, as after doing part b).................................................................................. 5-7
5-4 (S B010249 & Below) CH 1 and CH 2 CCD Clock Adjustments
(shown centered, as after doing part b ) .............. 5-8
5-5 CCD counts display and CM adjustment menu ...................................................................... 5-8
5-6 CCD sides 1-4 for CH 1 before L-clock adjustment................................................................. 5-12
5-7 Sides 1 and 3 before adjustment of LIS and after.................................................................. 5-13
5-8 CH 1 with L-clocks correctly adjusted, but with stray samples............................. 5-14
5-9 Display for adjusting CCD A and T clocks .................... 5-15
5-10 Typical CH 1 and CH 2 displays after clock adjustment......................................................... 5-16
5-11 Checking sample dispersion ........................................................... 5-17
5- 12 Input and output (after adjustment) waveforms ...................................................................... 5-20
6- 1 Multipin connector.................................................................................................................. 6-8
6-2 Circuit board Location............................................................................................................ 6-16
6-3 Installation sequence for installing the crt frame screws......................................................... 6-23
6-4 Trigger LED binary coding for diagnostic tests....................................................................... 6-29
6-5 Main EXT DIAG Menu............................................................................................................ 6-30
6-6 Initial troubleshooting chart ................................................................ - .................................. 6-36
6-7 Mux Test waveforms.............................................................................................................. 6-41
REV SEP 1988

2440 Service
LIST OF ILLUSTRATIONS (cont)
Page
6-8 Typical Register test waveforms................................. 6-55
6-9 Front Panel tiP diagnostics test................................................................................................ 6-79
6-10 System mP data bit D7 in the Bus Isolate mode .................................................... 6-102
9-1 Color codes for resistors and- capacitors. - ------- - ‘“ "" . ..........
9-2 Semiconductor lead configurations.
9-3 Locating components on schematic diagrams and circuit board illustrations.
9-4a Detailed 2440 Block Diagram.
9-4b Detailed 2440 Block Diagram (cont).
9-5 A12—Processor Board.
9-6 A13—Side Board.
9-7 A14—Front Panel Board.
9^8 A10—Main Board.
9-9 A30, A31, A32 and A33—Gain Cell Boards.
9-10 A ll—Timebase/Display Board.
9-11 A17—High Voltage Board.
9-12 A16—Low Voltage Power Supply Board.
r
IV

2440 Service
Table
1-1
1-2
1-3
1- 4
2- 1
3-1
3-2
3-3
3-4
3-5
3-6
3-7
3- 8
4- 1
4-2
4-3
4-4
6-1
6-2
6-3
6-4.
6-5
6-6
6-7
6-B
LIST OF TABLES
Page
Electrical Characteristics............................................................................... * ..................... 1-5
Environmental Characteristics .......... . ................................................................................... 1-19
Mechanical Characteristics................................................................................................... 1-21
Option 05 (TV Trigger) Electrical Characteristics.................................................................. 1-22
Voltage, Fuse, and Power-Cord Data........................... 2-2
Host Memory-Mapped I/O................................................................................................ 3-20
Processor Control Register Functions ................................................................................. 3-21
Processor Miscellaneous Register (PMREG) Output Functions............................................ 3-22
Waveform fiP Address Decoding.......................................................................................... 3-27
Trigger Logic Array Addresses (6080h-6087h)..................................................................... 3-52
Phase Clock Array Control Lines (CC3 through CCO) .......................................................... 3-55
Holdoff Delay Range for Current Source vs Charging Capacitor
Combinations....................................................................................................................... 3-59
Side Board Address Decoding............................................................................................. 3-60
Test Equipment Required.................................................................................................... 4-2
Accuracy Limits CH 1 and CH 2 CURSOR VOLTS Readout and A and
B TRIGGER LEVEL Readouts ...... . ...................................................................................... 4-10
Minimum Display Level for CH 1 or CH 2 Triggering ..................... 4-19
Minimum Signal Level for EXT1 or EXT2 Triggering............................................................ 4-21
Relative Susceptibility to Static-Discharge Damage............................................................. 6-3
External inspection Check List............................................................................................. 6-5
Internal Inspection Check List................................................................................................. 6-6
Power Supply Voltage and Ripple Limits .................................................. . ......................... 6-10
Maintenance Aids................................................................................................................ 6-13
2440 Troubleshooting Procedures........................................................................................ 6-37
Video Option Troubleshooting.................................................................. 6-104
I IT PA EL States.............................................................................................................. 6-108
V

2440 Service
OPERATORS SAFETY SU ARY
The eneral safety information in this part of the summary is for both operatin and servicin personnel.
Specific warnin s and cautions will be found throu hout the manual where they apply and do not appear in this
summary.
Terms in This anual Grounding the Product
CAUTIO statements identify conditions or practices that
could result in damage to the equipment or other property. This product is grounded through the grounding conductor
of the power cord. To avoid electrical shock, plug the
power cord into a properly wired receptacle before making
WAR I G statements identify conditions or practices that
could result in personal injury or loss of life. any connections to the product input or output terminals.
A protective ground connection by way of the grounding
conductor in the power cord is essential for safe operation.
Terms as arked on Equipment
CAUTIO indicates a personal injury hazard not immedi
ately accessible as one reads the markings, or a hazard to
property, including the equipment itself.
Danger Arising from Loss of Ground
Upon loss of the protective-ground connection, all accessi
ble conductive parts (including knobs and controls that
DA GER indicates a personal injury hazard immediately
accessible as one reads the marking. may appear to be insulated) can render an electric shock.
Symbols in This anual
This symbol indicates where applicable cau-
a tionary or other information is to be found. For
maximum input voltage see Table 1-1.
Use the Proper Power Cord
Use only the power cord and connector specified for the
instrument.
Symbols as arked on Equipment Use the Proper Fuse
DA GER — High voltage. To avoid fire hazard, use only the fuse specified in the
instrument parts list. A replacement fuse must meet the
type, voltage rating, and current rating specifications for
the fuse that it replaces.
Protective gound (earth) terminal.
/ j \ ATTE TIO — Refer to manual. Do Not Operate in Explosive Atmospheres
To avoid explosion, do not Operate this instrument in an
atmosphere of explosive gasses.
Power Source
This product is intended to operate from 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.
Do Not Remove Covers or Panels
To avoid personal injury, the instrument covers or panels
should only be removed by qualified service personnel. Do
not operate the instrument without covers and panels
properly installed.

2440 Service
SERVICING SAFETY SU ARY
FOR QUALIFIED SERVICE PERSONNEL ONLY
Refer also to the precedin Operators Safety Summary.
Do Not Service Alone
Do not perform internal service or adjustment of this pro
duct 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 connec
tions or components while power is on.
Disconnect power before removing protective panels, sol
dering, or replacing components.
Power Source
This product is intended to operate from a power source
that does not apply more than 250 volts rms bwetween
the supply conductors or between either supply conductor
and ground. A protective ground connection by way of the
grounding connector in the power cord is essential for safe
operation.

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