Tektronix 432 Service manual

OPERATORS
HANDBOOK
This
Operators
Handbook
supplements the
complete Instruction Manual provided for this
instrument . For
more
detailed
information
,
refer to the Instruction Manual .
TEXTHINK
TEKTRONIX®
070-1104-00
P.O. Box 500
432
OSCILLOSCOPE
Beaverton
, Oregon
97005
671

Introduction
General
Operating Voltage
Operating
Position
Controls and Connectors
Basic
Operation
User's
Calibration
Trace Rotation
STEP ATTENuator BALance
Probe
Compensation
Vertical GAIN
ASTIGmatism
i
TABLE
OF
CONTENTS
Page
1
1
2
2
9
10
10
10
10
11
Basic
Timing
432
Applications
DC
Voltage
Level
Measurement
Peak - To - Peak Voltage Measurement - AC
Comparison
Measurements
Time - Duration Measurements
Frequency
Measurement
Risetime Measurements
Time - Difference Measurements
Multi - Trace Phase Difference Measurements
X - Y Phase Measurement
Common -
Mode
Rejection
Page
11
12
13
14
17
19
19
20
21
24
Copyright
© 1971
by Tektronix
, Inc. ,
Beaverton ,
Oregon .
Printed in the
United
States of
America . All
rights reserved . Con
tents
of this
publication may not
be reproduced
without
permission of the
copyright owner .
25

INTRODUCTION
432
OSCILLOSCOPE
General
The Tektronix 432 Oscilloscope is a solid - state portable
instrument that combines small size and light weight with
the
ability
to
make
precision
waveform measurements
. The
instrument contains two vertical signal inputs , both of
which
are
capable of 25 -
megahertz
bandwidth ; trigger
cir
cuitry to
permit
obtaining
stable CRT
displays ; and a
hori
zontal deflection system that provides calibrated sweep
rates from 5 seconds to 0.2 microsecond / division ( 20
nanoseconds / division magnified ) .
To effectively use the 432 Oscilloscope , the operation
and
capabilities
of the
instrument
must be
known .
This
Operator's Handbook is intended to give the necessary
information
to allow
a user to
become
familiar with
the
instrument's
power
requirements ,
functions of
controls and
connectors ,
and methods
of
making
several
different
measurements
of
electrical
phenomena .
Also
included is
a
rudimentary
procedure
for
checking
basic
instrument
cali
bration .
Operating
Voltage
The
432
can be
operated on
all
nominal line
voltages
from
100 volts
to 240 volts
AC , 50 to
400 Hertz . It
can
432
also
be
operated
from a 100
volts to 250
volts DC
power
source . No
range
switching or
selection is
necessary
.
CAUTION
This
instrument is
designed for
operation from
a
power
source
with its
neutral
at
or
near
earth
(
ground )
potential ( for both
AC and DC
power
sources
)
with a separate
safety -
earth conductor
. It
is
not
intended
for
operation from two
phases
of
a
multi -
phase AC
system , or
across
the
legs of a
single
phase , three - wire AC system .
The
432 is
designed
to be
used
with
a
three
-
wire
AC
power
system
. If
a
three-
to
two -
wire
adapter is
used to
connect this
instrument to a
two - wire AC
power system ,
be
sure to
connect
the
ground
lead of the
adapter
to
earth
(
ground
) .
Failure to
complete the
ground
system may allow
the
chassis
of
this
instrument to be
elevated above
ground
potential
and
pose
a
shock
hazard
.
When
operating
the
instrument
from
an
external
DC
power
source ,
polarity
of the
external
voltage is
unimpor
1

tant . Again , it
is
imperative
to
complete
the
ground system
to prevent accidental elevation of the instrument chassis
and posing a shock hazard .
Operating
Position
The handle of the 432 can be positioned for carrying or
as a tilt - stand for the instrument . To position the handle ,
press in at both pivot points and turn the handle to the
desired position . Fourteen positions are provided for con
venient carrying or viewing . The instrument can also be set
on the
rear
feet
for
operation or
storage .
2
432
CONTROLS AND CONNECTORS
General
The major controls and connectors for operation of the
432 are located on the front panel of the instrument . Sev
eral auxiliary functions are provided on the rear panel . To
make full use
of the
capabilitites of this
instrument
, the
operator should be familiar with the function and use of
each of these controls and connectors . A brief description
of each control and connector is given here . Some of the
more important instrument specifications are included here
also .
(

A
TYPE 432 OSCILLOSCOPE
TEKTRONIX , INC . , BEAVERTON , OREGON , U.S.A.
SERIAL
8
5
6
1. POSITION - positions the display vertically .
2. STEP ATTEN BAL - balances the input amplifier in the 1 mV ,
2
mV , 5 mV , and
10 mV
positions of the
VOLTS
/ DIV switch
.
3. GAIN - sets the gain of the input amplifier .
4.
VOLTS / DIV -
selects vertical
deflection factor
in a 1-2-5
sequence (
variable
control must be
in the CAL
position for
indicated deflection ) . Calibrated position accuracy within 3 % .
5. Variable - provides continuously variable uncalibrated deflec
tion factors between the calibrated settings of the VOLTS /
DIV switch .
6. AC / DC - in the AC
ition ( button in ) of this push - push
switch
, signals
are capacitively
coupled
to
the vertical ampli
OUT : 1 MHz BW
POSITION
432
AC
STEP ATTEN
BAL
BOTH
IN :
PRECHARGE
OUT OC
GAIN
GND
2
3
5
CH
1
8
all
my
CH 1
IMD 24 of
ALT
VOLTS
/ DIV
CH
1
CH
2
PROBE CAL
08V 1kHz
ADD
N >
5
AA
09
07
AW
OL
CHOP
CH
2
CH 2
1MD
24pf
4EP
ATTEN
BAL
3
GAIN
BOTH IN PRECHARGE
AC
OUT
INVERT
POSITION
OUT
GND
fier
. The DC
component of the
input signal is
blocked . Low
frequency -3 dB point is about 10 hertz . In the DC position
( button out ) , all components of the input signal are passed to
the input
amplifier
.
7. GND - in the GND position ( button in ) of this push - push
switch , the input of the vertical amplifier is disconnected
from the input connector and grounded . Allows precharging
of
the input
coupling
capacitor . When the button
is out
coupling is
determined by
the AC - DC button
.
8. CH 1 and CH 2 - input connectors for application of external
signals to the inputs of the vertical amplifier . Input impedance
is
1 megohm
paralleled by
approximately 24
picofarads . Mini
mum bandwidth : 5 mV and up - 25 megahertz ; 2 mV - 22
megahertz ; 1 mV - 20 megahertz .
3

4
TYPE 432
OSCILLOSCOPE
TEKTRONIX , INC . , BEAVERTON , OREGON , U.S.A.
SERIAL
8000005
9. 5 MHz
BW - in
the out
position
of
this push -
push
switch , the
bandwidth of the
complete vertical
amplifier
system
is
limited
to approximately 5 megahertz .
10. PROBE
CAL 0.6 V 1
kHz -
provides
a
0.6 volt
calibrator
signal to permit probe compensation , adjustment of amplifier
gain , and checking basic horizontal timing .
Vertical Mode
Switch
11. CH
1 -
Channel 1
only
is
displayed
.
12. ALTernate - dual - trace display of signals of both channels .
Display
switched between
channels at the end
of each
sweep .
OUT
: 1 MHz BW
POSITION
AC
STEP
ATTEN
BAL
BOTH IN PRECHARGE
OUT DC
GAIN
432
GND
20
50
CH
1
11
CAL
12
CH 1
1MD 24 of
ALT
VOLTS / DIV
CH 1
CH
2
10
PRO CAL
0.8 KM₂
ADD
13
10
A
*
Og
oz
CAL
Au
OL
CHOP
15. CH 2 -
Channel 2 only is
displayed
.
CH 2
14
CH 2
1Mp
24pF
15
STEP
ATTEN
BAL
GAIN
BOTH IN PRECHARGE
AC
OUT
: INVERT
POSITION
OUT DC
GND
13. ADD - Signals applied to the CH 1 and CH 2 input connectors
are algebraically added , and the algebraic sum is displayed on
the CRT . The INVERT switch in Channel 2 allows the display
to
be CH 1 plus CH
2 or CH 1 minus
CH 2 .
16
14. CHOP - dual - trace display of signals on both channels . Display
is switched at a repetition rate of approximately 100 kilo
hertz
.
16. INVERT - Channel 2 display is inverted in the INVERT
( button out )
position
.
(
A
)

17
BEAM
FINDER
17. BEAM FINDER - compresses an overscanned display to with
in the graticule area , independently of display position or
applied signals .
18. POWER / INTENSITY - a combination control that turns on
instrument power when pulled , and controls brightness of the
display
when rotated
.
19. POSITION - positions the display horizontally .
20. TIME /
DIVision
-
selects
the
sweep
rate of
the sweep
genera
tor ( variable control must be in the CAL position for indi
cated sweep rate ) . Calibrated position accuracy within 3 % .
POWER PULL OUT
INTENSITY
18
OUT : 1 MHz BW
POSITION
19
432
STEP ATTEN
BAL
GAIN
21
20
POSITION
CAL
RESET
READY
TIME / DIV
CAL
152
EXT
HORIZ
VOLTS
/
DIV
CH
1 CH 2
PROBE
CAL
0.6V
1kHz
MAG
PUSH
TURN
20
$
MAG
ONLY
MODE
BOTH
IN SINGLE
AUTO
NORM
22
CAL
TRIGGER
SOURCE
BOTH
IN LINE
CM 1
COMP
BOTH OUT EXT
LF
REJ
LEVEL
L
STEP ATTEN
BAL
IN 1.10
HF
REJ
COUPLING
OUT
OC
GAIN
EXT
ATTEN
OUT
11
AC
OUT
:
INVERT
POSITION
The extreme counterclockwise position of the switch selects
External
Horizontal
mode of
operation
.
21. MAGnifier - a six - position , push - to - turn switch ( concentric
with the TIME /
DIV switch ) that
provides sweep
magnifica
tion up to a maximum of 50 times . Extends fastest sweep rate
to 0.02 microsecond / division .
22. Variable - provides uncalibrated sweep rates between the cali
brated settings selected by the TIME / DIV switch . The sweep
rate in each TIME / DIV switch position can be reduced to at
least the sweep rate of the next adjacent position to provide
continuously variable sweep rates .
LO
5

6
23. COUPLING - determines method of coupling trigger signal to
trigger
circuit .
AC - in the in position of this push - push switch , DC is
rejected and signals below about 20 hertz are attenuated .
Accepts signals between about 20 hertz and 25 megahertz .
DC - when both the AC and the LF REJ push - push
switches are in the out position , signals are directly
coupled
to the trigger
circuit . Accepts
all signals
from DC
to 25
megahertz .
BEAM
FINDER
LF REJ - rejects DC and attenuates signals below approxi
mately 30 kilohertz . Accepts signals between about 30
kilohertz and 25 megahertz .
HF REJ - attenuates signal above approximately 50 kilo
hertz . Accepts signals between DC and approximately 50
kilohertz .
POWER PULL OUT
INTENSITY
OUT
: 1 MHz BW
POSITION
STEP
ATTEN
BAL
GAIN
432
POSITION
CAL
RESET
READY
TIME / DIV
CAL
MAG
PUSH
TURN
EXT
HORIZ
150
VOLTS /
DIV
CH
1 CH
2
PROBE CAL
0.6V
1kHz
us
MAG
ONLY
MODE
BOTH
IN SINGLE
AUTO
CAL
24. SOURCE - selects source of trigger signal .
NORM
24
CH
1
R
SCOJACE
BO
IN
COMP
BOTH OUT EXT
LF HF
BE
REJ
REJ
LEVEL
LOPE
EFAT
23
IN
1.10
EXT
ATTEN
OUT : 11
AC
COPLINGUJT
DC
25
OUT
: INVERT
POSITION
DYS
CH
1 - A
push - push
switch
that in
the CH
1 position
( button in ) selects Channel 1 as an internal trigger source .
COMPosite - a push - push switch that in the COMP position
( button in ) allows the internal trigger source to be deter
mined by the vertical mode of operation .
LINE
- when both the
CH 1 and COMP
switches are pushed
in
, a portion of
the line
frequency is used
as a trigger
signal .
EXTernal - when the
CH 1 and COMP
switches are
both
out
,
signals applied to
the EXT TRIG
input
connector
are
used for
triggering
.
25. EXT ATTENuator - in the 1:10 position ( button in ) of this
push - push switch , external : trigger signals are attenuated by a
factor of ten . In the 1 : 1 position ( button out ) of this switch ,
external trigger
signals are not
attenuated .

BEAM
FINDER
26. SLOPE - selects slope of trigger signal which starts the sweep .
+
-sweep can
be
triggered from
positive - going
portion of
trigger signal .
OUT : 1 MHx BW
POSITION
-sweep can
be
triggered from
negative
-
going portion of
trigger
signal .
generator .
27. LEVEL - selects the amplitude point on the trigger signal at
which the sweep is triggered .
28. MODE - determines the operating mode for the sweep
POWER PULL OUT
INTENSITY
AUTOmatic - in the AUTO position ( button in ) of this
pushbutton switch
, the sweep is initiated
by the applied
trigger signal . In the absence of an adequate trigger signal ,
the sweep free runs and provides a bright reference trace .
432
STEP ATTEN
BAL
GAIN
29
POSITION
CAL
RESET
READY
TIME / DIV
CAL
MAG
PUSH
TURN
1.52
25
EXT
HORIZ
1
PROBE CAL
0.6V 1kMz
02-05
VOLTS
/ DIV
CH 1
CH
2
MAG
ONLY
MODE
BOTH IN SINGLE
AUTO
NORM
CAL
28
TRIGGER
SOURCE
BOTH IN LINE
CH 1
27
COMP
BOTH
OUT
EXT
LF
REJ
LEVEL SLOKE
HF
REJ
COUPLING
OUT
DC
STEP ATTEN
BAL
IN
10
EXT
ATTEN
OUT
11
GAIN
AC
+
26
OUT
: INVERT
POSITION
NORMal - in the NORM position ( button in ) of this push
button switch , the sweep is initiated by the applied trigger
signal . In the absence of an adequate trigger signal , there is
no trace .
BOTH IN : SINGLE sweep - when both the AUTO and
NORM switches are pushed in , the sweep operates in the
Single Sweep Mode . After a sweep is displayed , further
sweeps
cannot be
presented
until the
RESET
button is
pressed .
29. RESET - when the RESET button is pressed ( in the SINGLE
SWEEP mode ) , a single display will be presented ( with correct
triggering ) . After the sweep is completed , the RESET button
must be pressed again before another sweep can be displayed .
If there is not an adequate trigger signal present when the
RESET button is pressed , the sweep generator circuit will
remain armed as indicated by the READY light .
7

8
ASTIG
definition
.
30
)
POSITIVE GOING
INPUT
DECREASES
INTENSITY
32
31
Z AXIS
50
k
30. ASTIGmatism - adjusts CRT beam for optimum display
5 V P - P CAUSES
NOTICEABLE
MODULATION AT
NORMAL INTENSITY
31. Ground Post - connects to oscilloscope chassis . Provides a
common ground return for signal source to insure measure
ment
reliability .
32. Z AXIS - input connector for external blanking signals . A five
volt peak to peak signal will cause noticeable modulation at
normal intensity . A positive - going signal decreases intensity .
33. EXTernal TRIGger - input connector for external trigger
TRACE ROTATION
35
432
EXT
TRIG
( 33 )
1
MS
34
EXT HORIZ
50 k
≈.5 V /
DIV
signals .
Nominal input
signal
level
required for
correct
trigger
operation
is
between 35 and
40
millivolts at
frequencies
below
about five
megahertz
, increasing to
125
millivolts at
megahertz
.
34.
EXTernal
HORIZontal
- input
connector for
external
horizon
tal
signal
when
TIME / DIV
switch is set
to EXT
HORIZ .
Input
impedance
is
approximately 50
kilohms with
a
sensitivity of
approximately
0.5 volt /
division .
35.
TRACE ROTATION
-
adjusts trace to
align with
horizontal
graticule
lines
.
(
A
)