Tektronix 442 User manual

tron
COMMITTED TO EXCELLENCE
WARNING
THE
FOLLOWING
SERVICING
INSTRUCTIONS
ARE
FOR
USE
BY
QUALIFIED
PERSONNEL
ONLY.
TO
AVOID PERSONAL INJURY, DO NOT PERFORM ANY
SERVICING OTHER THAN THAT CONTAINED IN
OPERATING INSTRUCTIONS UNLESS YOU ARE
QUALIFIED
TO
DO
SO.
INSTRUCTION
MANUAL
Tektronix, inc.
P.O.
Box
500
|
|
Beaverton,
Oregon
97077
Serial
Number
070-237
4-01
First
Printing
AUG
1977

Copyright ©. 4977, 1980 Tektronix, Inc. Allrightsteserved. |
Contents ofthis publication may not be reproducedin any
form: without the written permission of Tektronix, rnc.
Products: of “Fektronix, Ine. and: ‘its subsidiaries are
coveted. by U.S. and foreign patents. and/or pending =
patents... =
TEKTRONIX
Ly aes trade

442 Service
TABLE
OF
CONTENTS
Page
LIST OF ILLUSTRATIONS ................ ii
LIST OF TABLES ....................... iv
SAFETY SUMMARY ...............-...., Vv
Section 1 SPECIFICATION ............... 1-1
ELECTRICAL CHARACTERISTICS .. 1-1
ENVIRONMENTAL
CHARACTERISTICS ............ 1-4
PHYSICAL
CHARACTERISTICS
....
1-5
ACCESSORIES
................
1-5
Section 2 OPERATING INSTRUCTIONS ...... 2-1
INTRODUCTION ............... 2-1
INSTALLATION ................ 2-1
CONTROLS, CONNECTORS, AND
INDICATORS..........000.000. 2-3
BASIC OSCILLOSCOPE OPERATION 2-8
Section 3 THEORY OF OPERATION ........ 3-1
GENERAL ....... eee eee eee 3-1
BLOCK DIAGRAM DESCRIPTION... 3-1
DETAILED
CIRCUIT
DESCRIPTION
.
3-2
VERTICAL
INPUT
............,
3-2
VERTICAL
SWITCHING
........
3-3
VERT
OUTPUT
AMPL,
CRT,
&
PROBE
ADJ
..........-2005.
3-5
TRIGGER
«1.2...
ee
eee
eee
3-6
SWEEP
AND
HORIZONTAL
AMPLIFIER
............00005
3-8
HORIZONTAL OUTPUT
AMPLIFIER
3-9
POWER
SUPPLY
.............
3-9
REV A MAY 1980
Page
Section
4
CALIBRATION
PROCEDURE
......
4-1
GENERAL
............
0.000005
4-1
Introduction.
..........00000,
4-1
Test
Equipment
Required
......,
4-1
PERFORMANCE
CHECK
.........
4-3
Introduction..............0,,
4-3
Preliminary
Procedure
.........,
4-4
Procedure
........0-
2.0
eee
4-5
ADJUSTMENT
PROCEDURE
......
4-12
Introduction.................
4-12
Preliminary
Procedure
.........
4-14
A.
DISPLAY
AND
POWER
SUPPLY
4-17
B. VERTICAL AMPLIFIER ....... 4-19
C. HORIZONTAL ............. 4-23
D. TRIGGERING ............. 4-25
Section 5 MAINTENANCE ................ 5-1
INTRODUCTION ............... 5-1
PREVENTIVE MAINTENANCE...... 5-2
TROUBLESHOOTING ........... 5-4
CORRECTIVE MAINTENANCE ..... 5-12
Section 6 REPLACEABLE ELECTRICAL PARTS
Section 7 DIAGRAMS & CIRCUIT BOARD
ILLUSTRATIONS
Section
8
REPLACEABLE
MECHANICAL
PARTS

442
Service
Fig.
No.
1-1
2-1
2-3
2-4
2-5
2-6
2-7
2-8
2-10
2-11
2-12
2-13
2-14
2-15
2-16
2-17
2-18
3-14
LIST
OF
ILLUSTRATIONS
Page
442 Oscilloscope ..............08. viil
442 Oscilloscope dimensions......... 1-6
Commonly used power plugs ........ 2-2
Power switch locations on bottom of the
442 Le es 2-2
Power input fuse location on the 442 back
panel... ce ee ee ees 2-3
Crt Display and Power front panel controls
and connectors ..............-+-- 2-3
External Z AXIS INPUT connector on the
back panel of the 442 .............. 2-4
Controls and switches accessible through
the bottom of the 442 cabinet ........ 2-5
Vertical system controls ............ 2-5
Horizontal system controls .......... 2-6
Triggering system controls .......... 2-7
Probe Compensation ...........05. 2-9
Display of 0.5 V PROBE ADJ output signal 2-10
Measuring peak-to-peak voltage of a
wavefOrm . occ ee ee ene 2-11
Measuring instantaneous dc voltage with
respect to a reference voltage ........ 2-11
Measuring the time duration between
points on a waveform ......... 0006, 2-14
Measuring rise time ............08, 2-15
Measuring time difference between two
PUISES Po ee es 2-15
Measuring phase difference.......... 2-16
Phase difference measurement with an X-Y
display ... ee ee ee es 2-17
Sweep generator and sweep gate timing
diagram... . es 3-9
Foldback circuit action ..........004 3-10
Vertical deflection accuracy test setup .. 4-5
Bandwidth check test setup.......... 4-7
Triggering and Z-Axis input.check test
SQCtUD. 2 eee 4-9
Timing accuracy check test setup ..... 4-114
442 cabinet removal ............0-. 4-13
Moving Interface board to adjustment
access position .........0 0 eee nee 4-15
Low-voltage power supply adjustment
location. oe ee ees 4-17
Fig.
No.
4-8
4-9
4-10
4-11
4-12
4-13
5-9
Page
Interface board adjustment locations
(board shown in access position)...... 4-18
Vertical attenuator, preamplifier, delay line
driver, and CH 2 dc trigger level adjustment
locations .. 2.2... ee ees 4-21
Display of correct (idealized) attenuator
compensation
........-.-.0.0008-
4-21
Horizontal adjustment locations on A14
Horizontal
Output
board
............
4-23
Horizontal adjustment locations on A12
Horizontal
board
and
A114
Trigger
Switch
board
..
2...
eee
ee
eee
4-24
Triggering
and
X-Axis
adjustment
locations
on the A1i Trigger Switch board ...... 4-26
Cabinet
removal...............0485.
5-1
Moving
Interface
board
to
access
position
5-3
Color codes ...................-. 5-5
Semiconductor
lead
configuration
.....
5-6
Multi-pin connector holder indexing. ... 5-7
Pin connector re-installation in multi-pin
Holders . 6. ce eee 5-15
Shaft-knob
assembly
removal
........
5-17
Attenuators, Attenuator Shift, Horizontal
Output, and Power Supply assembly
rEMOVAl 2. ee ee es 5-17
Interface, Trigger Switch, Horizontal, and
Timing (SEC/DIV switch) assemblies
rEMOVAl ww ee ee 5-19
The following illustrations are located on foldout
pages in Section 7 Diagrams and Circuit Board
Hlustrations.
A6—CH 1 Attenuator circuit board
component locations
A7—CH 2 Attenuator circuit board
component locations
Attenuator circuit board locations
442 Oscilloscope block diagram
A8—Vertical circuit board component
locations
Vertical circuit board location
REV
A
MAY
1980

442 Service
LIST
OF
ILLUSTRATIONS
(cont)
Fig.
Fig.
No. No.
7-7
Ai—Interface
circuit
board
component
7-11
A1l2—Horizontal
circuit
board
locations
locations
7-12
Horizonta!
circuit
board
location
7-8
Interface
circuit
board
location
7-13
A14—Horizontal
Output
circuit
board
7-9A
_
All-Trigger
Switch
circuit
board
component
locations
component
locations
for
SN
B021532
and
7-14
Horizontal
Output
board
location
up
7-15
A2—Power
Supply
circuit
board
7-9B
All—Trigger
Switch
circuit
board
component
locations
component
locations
for
SN
below
7-16
Power
Supply
board
location
BO21532
7-17
442
Oscilloscope
troubleshooting
chart
7-10
Trigger
Switch
circuit
board
location
REV A MAY 1980 iii

442 Service
iv
LIST OF TABLES
Table
No. Page
1-1 Electrical Characteristics............ 1-1
1-2 Environmental Characteristics ........ 1-4
1-3 Physical Characteristics ............ 1-5
2-1 Power Cord Conductor identification ... 2-1
2-2 Ac Regulating Ranges ...........-. 2-2
2-3
Power
Input
Fuse
Values............
2-2
3-1 Attenuator and Gain Switching Sequence 3-3
4-1 Test Equipment Required ........... 4-1
4-2 Vertical Deflection Accuracy ......... 4-5
4-3 Sweep Rate Timing Accuracy ........ 4-10
5-1 Power Supply Tolerance ............ 5-8
5-2 Relative Susceptibility to Static Discharge
Damage............ 0... eee es 5-13
5-3 Maintenance Aids..............-4. 5-23
REV A MAY 1980

442
Service
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 damageto the equipment or other property.
WARNING statements identify conditions or practices
that could result in personal injury or loss of life.
Terms As Marked on Equipment
CAUTION indicates a personal injury hazard not im-
mediately 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
This symbol indicates where applicable
cautionary or other information is to be
found.
Symbols As Marked on Equipment
4 DANGER — High voltage.
Protective ground (earth) terminal.
A ATTENTION — refer to manual,
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.
REV A MAY 1980
Grounding the Product
This product is grounded through the grounding conduc-
tor of the power cord. To avoid electrical shock, plug the
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 power cord is essential for safe opera-
tion.
Danger Arising From Loss of Ground
Upon loss of the protective-ground connection, all
accessible conductive parts (including knobs and con-
trols that may appear to be insulating) can render an
electric shock.
Use the Proper Power Cord
Use only the power cord and connector specified for your
product.
Use only a power cord that is in good condition.
For detailed information on power cords and connectors,
see Operating Instructions section.
Refer cord and connector changes to qualified service
personnel.
Use the Proper Fuse
To avoid fire hazard, use only the fuse of correct type,
voltage rating and current rating as specified in the parts
list for your product.
Refer fuse replacement to qualified service personnel.
Do Not Operate in Explosive Atmospheres
To avoid explosion, do not operate this product in an
explosive atmosphere unless it has been specifically
certified for such operation.
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.

442 Service
SERVICE 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 connec-
tions and components while power is on.
REV A MAY 1980
Disconnect power before removing protective panels,
soldering, or replacing components.
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.
vii

442 Service
442 Oscilloscope.
viii
REV
A
MAY
1980

Fi
f
‘Z
T
iz
he
5

Section 1—442 Service
SPECIFICATION
This
manual
contains
a
specification,
operating
in-
structions,
and
service
information
pertaining
to
the
TEKTRONIX
442
Oscilloscope.
The
442
is
a
portable,
35
MHz,
dual
trace
instrument
with
a
choice
of
alternate
or
chop
sweep
presentation
on
a
single
time
base.
The
Vertical
Amplifier
provides
calibrated
deflection
factors
from
2
mV
to
10
V/div.
The
Time
Base
provides
stable
triggering
over
the
full
bandwidth
of
the
Vertical
Amplifier
and
provides
calibrated
sweep
rates
from
0.5
s/div
to
0.1
us/div.
A
X10
magnifier
switch
extends
the
fastest
sweep
rate
to
10
ns/div.
The following instrument specification applies over an
ambient temperature range of —15° to +55°C for in-
struments that have been calibrated at an ambient
temperature between +20° C and +30° C unless otherwise
indicated
when
the
instrument
has
had
a
warmup
period
of
about
20
minutes.
The
adjustment
procedure
in
Section
4,
when
performed
completely,
allows
the
442
to
meet
the
electrical
specification
listed
in
Table
1-1.
Table 1-1
ELECTRICAL CHARACTERISTICS
Performance Requirements
VERTICAL SYSTEM
Characteristics
Supplemental
Information
Deflection Factor
Calibrated Range 2 mV to 10 V/div; 12 steps,
in a 1-2-5 sequence.
oll
Gain
adjusted
with
VOLTS/DIV
Within
3%.
switch
set
to
2
m.
Accuracy
+20°C
to
+30°C
—15°C to +55°C
Uncalibrated (VAR)
Range
Within 4%.
Extends
maximum
deflection
factor
to
at
least
25
V/div.
Continuously
variable
between
settings.
Increases
deflection
factor
by
approximately
2.5:1.
5-division
reference
signal
centered
vertically
from
a
25
Q
sourse
with
VOLTS/DIV
VAR
control
in
calibrated
detent.
Frequency Response
Bandwidth
2mtoiV Dc to at least 35 MHz.
Dc to at least 25 MHz.
2V,5V,& 10 V
Chopped Mode Repetition Rate
Input Resistance
Input Capacitance Approximately 30 pF.
Maximum Input Voltage 400 V (dc + peak ac).
800
V
p-p
ac
at
1
KHz
or
less.
REV
A
MAY
1980
1-1

Specification—442 Service
Characteristics
Table 1-1 (cont)
Performance Requirements
Supplemental Information
VERTICAL SYSTEM (cont)
CMRR (DIFF Mode)
At least 10:1 at 1 MHz in
10
mV/div
(1X
window)
position
for common mode signals of
8 divisions or less with gain
adjusted for best CMRR at
50 kHz.
Sweep Rate
Calibrated Range
HORIZONTAL DEFLECTION SYSTEM
0.5 s to 0.1 us/div; 21 steps
in a 1-2-5 sequence.
Uncalibrated (VAR)
Range
Continuously variable between
calibrated settings. Decreases
sweep rate by at least 2.5.1.
Accuracy
+20°C to +30°C
Unmagnified
Extends slowest sweep rate to
at least 1.25 sec/div.
Within 3%.
Sweep accuracy applies over the
center 8 divisions. Exclude the first
50 ns of sweep for both magnified
and unmagnified sweep rates as well
as anything beyond the 100th
magnified division.
Magnified
Within 5%.
—15°C to +56°C
Unmagnified
Magnified
X10 Magnifier
Tt
Within 4%.
Within 6%.
Extends fastest sweep rate
to 10 ns/div.
10:1 (in X10 position—
with button pressed in— the sweep
rate is one tenth of that indicated
for the SEC/DIV switch setting).
X-Y Operation
X-Axis Deflection
Accuracy
+20°C to +30°C
+5% (MAGNIFIER in X1 only).
—15°C to +65°C
5-division reference signal.
.
—_
+6% (MAGNIFIER in X71 only).
Sensitivity
1-2
Same as for Channel 1 and
Channel 2 Calibrated Deflection
Factor Range (MAGNIFIER in X1
only).
+
REV A MAY 1980

Characteristics
Table
1-1
(cont)
Performance
Requirements
Specification—442
Service
Supplemental Information
VERTICAL
SYSTEM
(cont)
X-Axis Bandwidth
Dc to at least 2 MHz.
5-division reference signal.
Input Resistance
Approximately 1 MQ.
Input Capacitance
Approximately 30 pF.
Maximum Input Voltage
400 V (dc + peak ac).
800 V p-p ac at 1 kHz or less.
TRIGGERING SYSTEM
Sensitivity
AC CPLG
(AUTO & NORM)
0.5 div internal or 100 mV
external from 60 Hz to 2 MHz,
increasing to 1.5 div internal
or 150 mV external at 35 MHz.
EXT/10 requirements are approxi-
mately ten times the values
listed for EXT.
DC CPLG
(AUTO & NORM)
TV Sync
-
0.5 div internal or 100 mV
external from dc to 2 MHz,
increasing to 1.5 div internal
or 150 mV external at 35 MHz.
Composite sync 1 div internal
or 100 mV external. Composite
video approximately 2.3 div
internal or 230 mV external.
External Trigger Input
(EXT & EXT/10)
Maximum Input Voltage
400 V (dc + peak ac).
800 V p-p ac (1 kHz or less).
Input Resistance
Approximately 1 MQ.
Input Capacitance
LEVEL Range
EXT
Approximately 30 pF.
—0.5 V to +0.5 V.
EXT/10
—5 Vto +5 V.
PROBE ADJUST SIGNAL
Output Voltage
Repetition Rate
Approximately 0.5 V.
Approximately 1 kHz.
Z-AXIS INPUT
Sensitivity
REV A MAY 1980
5 volts causes noticeable
modulation.
1-3

Specification—442 Service
Characteristics
Table 1-1 (cont)
Performance Requirements
————————
Supplemental Information
Z-AXIS INPUT (cont)
Usable Frequency Range
—————————_——_
Dc to 5 MHz.
Maximum Input Voltage
Input Impedance
DISPLAY
Display Area
Trace Rotation Range
Standard crt Phosphor
Nominal Anode Voltage
Line Voltage Ranges, ac
ee
TTNTNTTFT——
lll
30 V (dc + peak ac). 30 V p-p
ac at 1 kHz or less.
Approximately 10 kQ.
8X 10cm.
Adequate to align trace with
center horizontal graticule line.
P31.
Approximately +10 kV.
POWER SOURCE
120 V Range
240 V Range
HI—110 to 132 V rms.
LO—92 to 110 V rms.
HI—220 to 250 V rms.
LO—202 to 242 Vrms.
Line Frequency
120 V/240 V & HI/LO switches
are accessible externally.
48 to 62 Hz.
Power Consumption
Characteristics
Table 1-2
36 watts (max); 0.35 amps (max)
at 120 V, 60 Hz.
ENVIRONMENTAL CHARACTERISTICS
Description
Temperature
Operating
—15°C to +55°C.
Non-operating
—55°C to +75°C.
Aititude
Operating
To 15,000 feet. Maximum operating temperature decreased 1°C/1000 feet
above 5000 feet.
— 2
Non-operating
1-4
To 50,000 feet.
REV
A
MAY
1980

Specification—442 Service
Table 1-2 (cont)
Characteristics Description
Humidity
Operating and Non-operating 5 cycles (120 hours) referenced to MIL-E-16400F.
Vibration (Operating) 15 min along each of 3 major axes at a total displacement of 0.025” p-p
(4 g’s at 55 Hz) with frequency varied from 10 Hz to 55 Hz to 10 Hz in
one minute sweeps. Hold for three minutes at 55 Hz. All major resonances
must be above 55 Hz.
Shock
Operating and Non-operating 30 g’s, 1/2 sine, 11 ms duration, 2 shocks per axis each direction for
a total of 12 shocks.
Table 1-3
PHYSICAL CHARACTERISTICS
Characteristics
Description
Weight
With Panel Cover, Accessories, and
Accessories Pouch 22.5 pounds (10.1 kilograms).
Without Panel Cover, Accessories,
and Accessory Pouch
18.0 pounds (8.1 kilograms).
———
Domestic Shipping Weight 28.5 pounds (12.95 kilograms).
Dimensions Refer to Figure 1-1.
ACCESSORIES
NOTE
Refer to the Accessories tab page inthe Replaceable
Mechanical Parts list for further information about
accessories listed here.
Standard Accessories Optional Accessories
1
Operators
Manual
Protective
Waterproof
Cover
1
Service
Manual
Clear
Light
Filter
2 10X Probes
1 Front Cover
1 Accessory Pouch
REV
A
MAY
1980
15

Specification—442 Service
5.60 INCHES ‘ ee
(14.22 em)
11.25 INCHES
(28.57 cm)
12.95 INCHES
(32.89 cm)
2374-2A
Figure
1-1.
442
Oscilloscope
dimensions.
1-6
REV
A
MAY
1980

6.85 INCHES
(17.39 cm)

TeEKTAONT
992 ssciLLOscoRE