BK Precision 1472C Service manual

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15 MHz, TRIGGERED

Dual:Trace

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Oscilloscope

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DYNASCAN

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CORPORATION

1801 West Belle

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Chicago,

lllinois

60613

PR|CE

$3.00

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INSTRUCTION

FOR

B

K.PRECISION

&

MODEL T472C
15
DUAL.TRACE

MHz, TRIGGERED

OSCILLOSCOPE

MANUAL

SWEEP

DYNASCAN

6460

Chicogo, lllinois

-

CORPORATION

Wesl

Corflond Street

60635

INTRODUCTION

TABLE

CONTENTS

OF

Page

4
FEATURES
SPECIFICATIONS
OPERATOR'S CONTROLS. INDICATORS AND FACILITIES
OPERATING

Initial Starting
Single{race
Calibrated
Differential Voltage Measurement . .
Calibrated Time
External Horizontal lnput
Z-Axis Input
DualrTrace

DUAL-TRACE APPLICATIONS

Introduction
Frequency
Divide-by-8 Circuit
Propagation Time Measurement . .
Digital Circuit Time
Distortion
Gated Ringing
Delay Line Tests
Stereo
Improving
Amplifier
Television

...

INSTRUCTIONS

Procedure

Waveform

Voltage Measurement

Waveform

Divider Waveforms

Measurement

Circuit

Amplifi

er Servicing

the Ratio of Desired-to-Undesired Signals

Phase

Servicing

Observation

Measurement

Observation

Waveforms

Relationships . . .

Measurements

Shift

. .

(X-Y

. . . .

. .

Operation) .

. . .

. . .

. . . . . . .

7

8

8
l0
11
T2
13
T4
l4

15
15
15
16
16
l8
t9
19
20
20
20
2l

v

SINGLE.TRACE

lntroduction

Television Servicing

Tracing and

Signal

Composite

fulse

Sync

(Vertical

VITS

Vectorscope

TELEVISION ALIGNMENT

Introduction
Importance of

Alignment

Sweep

Alignment

Tuner
IF Alignment
Chroma

APPLICATIONS

Peak-to-Peak Voltage

Waveform Analysis

Video
Analysis

Interval Test Signal)

Operation

Sweep Alignment

Methods

. .

Alignment

Readings

23
23
23
23
25
25
27

30
30
3l
32
32
33

Y

FM

RECEIVER

TABLE

ALIGNMENT

. .

OF

CONTENTS

Page

......35

PHASE
FREQUENCY
SQUARE

CIRCTIIT DESCRIPTION

CALIBRATION

-

MEASUREMENT

MEASUREMENT

WAVE
Introduction
Testing Procedure
Analyzing

General
Vertical Preamplifiers
Mode

Logic
Vertical
Trigger
Sync Amplifier

Housing
230 VAC
Graticule

and

CH A

l12ar;rd
Vertical
Horizontal

TESTING

the Waveforms

Amplifier

Circuit

and Inverter

ADJUSTMENTS

Removal

OPERATION
Removal

CH

B DC Balance

1/5

Attenuator

Gain

Adjustment

Position

Adiustment

. . .

OF AMPLIFIERS

Balance

......35

......37

37
...38
...38

..42

42
.. 42
..42
..42
..42

44

44

44

44

M

44

44

a

WARRANTY

WARRANTY

SERVICE INSTRUCTIONS

...47
...48

8
9

11
10

12

25

24

Fig.

Front panel

l.

controls and

13
14

indicators.

v

OPERATOR'S

CONTROLS.

INDICATORS

AND FACILITIES

a

l.

Cathode Ray
the waveforms

Scale.

2.

3.

4.

J.

6.

7.

8.

9.

10. EXT

11.
following

The 8 x 10
marks
measurements.
able.

POWER
tion
scope.
Further
iilumination

Pilot
SWEEP TIME/CM

time
pSEC/cm

in
CAL
this
permits

Sweep
adjustment.
the sweep

CAL
peak-to-peak

calibration
check the
probes

<>POSITION
position
dual trace mode). Push-pull
fication
when

TRJGGERING
determines
starts;
(+)
switch
(PULL
generated

signal.
SYNC switch. Four-position

(+)
waveform.

(-)
waveform.

(+)
(-)

for

voltage

ILLUM

of

this control
Clockwise rotation

clockwise rotation

lamp.

Lights when oscilloscope

selector.

(microsecond

i

9 steps

switch

equals

SLOPE.
waveforms except

TV.
television
the
automatically selected
to 0.1 mSEC/cm,
automatically
to

.5
Sweep

Sweep

when VARIABLE

position

disables

the

CH B

speed

time is

P-P

lV

of

frequency

used

with the oscilloscope.

of traces

when

pushed

points

(-)

equals

most

selects

AUTO). When

even

jack.

TRIG

positions:

The SLOPE

Sweep

Sweep is

In

the TV

composite

sweep;

pSEC/cm.

is

is triggered

(CRT).

Tube

are viewed.

cm
(vertical)

Illumination

control.

(OFF

level of

[n

is

triggered on

the

switch.

Selects calibrated

(fully

clockwise).
the

input

VARIABLE

extreme

the

calibrated.

jack.

Provides

square wave input

vertical

the

control.

(both

pulled

in.

LEVEL control.

on waveform slope

most

positive point

automatic

without

Input terminals for external trigger

television composite video

triggered

triggered

positions,

the vertical sync

and

selected for

This is the

graticule

of the

Fully

position)

turns

of the

scale.

Horizontal

per

centimeter) to

internal

provide

to

control.

clockwise

calibrated I kHz,

amplifier

compensation adjustment of the

Rotation
traces when operated in the

switch

(PULL

out

negative

triggering

automatic

an input signal.

positions

positive-going

on

on negative-going

video signal

for

sweep times of

horizontal

sweep times of

positive-going

on negative-going

screen

provides

and time

scale is

counterclockwise

turns
on

control increases

is turned

coarse

sweep

times of

control

In the

signal. This

Sync

point

of triggering. Push-pull

lever

are

the

6 is set to the

CH

generator

sweep

horizontal

Fine

(CAL)

attenuators and to

adjusts

selects 5X magni-

5X MAG), normal

level

where sweep

of

triggering and

when

triggering,

switch with

used for

sync

are used

pulses (frame)

pulses (line)

sync

sync

which

on

calibration
(horizontal)
fully

adjust-

rota-

off oscillo-

oscilloscope.

the

on.

sweep

0.5

SEC/cm

0.5

B position,

and

sweep.

sweep

time

position

1 volt

used for

is

horizontal

adjustment

pulled

out

a sweep

the

viewing

pulses

0.5 SEC/cm

50

pulse.

sync

all

signals.

slope

of

slope

of

of

to

trigger

are

are

pSEC/cm

pulse.

SOURCE switch.

12.

triggering source
triggered

CH A
CH B
EXT

13.

Channel B
ment
adjustment when

CH

14.

Channel B DC BAL
adjustment

15.

Channel B INPUT
B. Jack
SWEEP TIME/CM switch

l6

Channel B DC-GND-AC

DC Direct input of AC

GND

AC Blocks DC

t7.

Channel B VOLTS/CM
Channel B
sensitivity. Vertical
from

18

horizontal

switch

Channel

18.
adjustment
In the extreme

is

a

attenuator is
horizontal gain
switch 5 is

MODE

19.

basic operating

CH A Only

CH B Only

A

A + B The

A - B

Channel

20.

Channel A

sensitivity.

by

Sweep

Sweep

Sweep is

at the

POSITION

for

Channel B trace. Becomes horizontal

position.

B

for

becomes

signal.
Opens signal

amplifier.

position

the
when

which

.01

to

is set to

sensitivity

5 is in the

B VARIABLE

provides

in the CH

switch. Five-position

displayed

displayed

& B Dual

and
two

B inputs

as a single trace.
The

from

difference is
only
display is inverted.

A

VOLTS/CM

which

Vertical

Three-position lever switch

for

the

the same

is triggered

is triggered

triggered by an

EXT

SYNC

SWEEP TIME/CM switch

Channel B trace.

Jack.

external

path

This

of

performing

component

provides

sensitivity

volts

20

CAL

CH B

fine

clockwise

calibrated.

control

B

modes of the oscilloscope.

the input signal

as a single

the

as a

trace
Channel B inpu.t signals are
separate

waveforms

are added and the sum is

waveform from

the

a

Channel B input

provides

sensitivity

sweep.

source in

by

Channel A

by Channel

jack

control.

adjustment. Vertical

Vertical input

in

5 is

switch.

and DC component

and

provides a zero-signal

which can

DC

measurements.

switch. Vertical

step

per

cm

when VARIABLE

position.

when

position.

control. Vertical

control of vertical

(CAL) position,

This control

when the SWEEP

position.

input signal to

single

operation;

traces.

from

Channel A

displayed

switch.

coarse

Both

dual trace

external

10.
Vertical

horizontal

the CH B

grounds

used

be

of input

adjustment

is

calibrated in
This

the SWEEP

lever switch; selects the

to Channel A is

trace.

trace.

both the

Channel

Channel B is subtracted

waveform
as a

Vertical

adjustment

is

calibrated in

selects

sweeps

operation.

signal.

B signal.

signal

applied

position

jack

input to vertical

signal.

attenuator for

control

becomes

Channel B is

A and

single

is

attenuator for

adjust-

position

in

5 is

the

DC

balance

of

Channel

input

position.

as a reference

displayed on

present,

when

of input

base line,

of vertical

I I

steps

control

adjusts

TIME/CM

attenuator
sensivitity.

the vertical

fine

the

TIME/CM

Channel A

Channel

displayed

and the

trace. If

the

vertical

of

11

steps

are

from .01
21 is set

Channel

21.
adjustment

In- the
attenuator

Channel

22.

DC

GND Opens

AC

Channel

23.
A.

Channel
adjustment

Channel

25.

ment

to 20'volts

to the

VARIABLE

A

provides

extreme

calibrated.

is
DC-GNDAC

A

Direct
input signal.

vertical

base

a

as
ments.

Blocks DC

INPUT

A

A DC

for

POSITION control.

A

for Channel A trace.

per

CAL

Position.

fine control

clockwise

switch.

of AC

input

signal

amplifier.

position

the

line,

reference

BAL adjustment.

Channel

when

component

jack.

Vertical

A trace.

when

cm

control.

(CAL)

and

path

and

This

performing DC

Vertical

VARIABLE

Vertical

vertical

of

position, the

DC component

ground input

provides

which

of

input

of

jack

input

Vertical DC balance

control

attenuator
sensitivity'

zero-signal

a

can be

measure-

signal.

of Channel

position

vertical

used

adjust-

of

to

ASTIG

26.
optimum
with

28.
after

FOCUS

27.

INTENSITY

28.
Fuse

29.
AC

30.
INT

31.

Combination

32.

Probe

33.
combination
use
signed
in-put
capable

Vector

34.

for

adjustment.

the

Very

initial

control.

holder.

line cord.

MOD

(see

with

for use

impedance

of
Overlay

vectorscope

roundness

spot

FOCUS

readjustment

little

adjustment.

control.

CSA-approved

jack.

Intensity

carrying

Fig. 3).

10:l./Direct

oscilloscope.

this

with an

operation

Astigmatism

control

Adjusts

modulation

handle

B &

The

oscilloscope

megohm

of I

up to

(not

shown).

operation.

adjustment

us9!-11--c9-njunction

when

27 and

probe has

INTENSITY

this control

of

brightness

for

oscilloscopes.

tilt

and

K-Precision

However,

shunted

MHz, can

l5

Interchanges

is

trace'

of

(Z-axis)

stand.

Model

designed

been

any

having

27

by

used.

be

provides

control

required

input.

PR-35

for

probe

de-

a-nominal

pF

and

scale

with

I

J

INITIAL

l. Set

2. Connect

3. SEt

4. Pull TRIGGERING

5.

6.

7.

8.

9.

10.

11.

12.

STARTING

POWER

counterclockwise).

CH

control

.ranges.

position.

Set CH
DC-GND-AC

the

Set
single
dual-trace

Turn
control

light.

will

illumination.

Wait a

warm
mode)

I f no
INTENSITY
observed.

Adjust
for the

Readjust

center

Check
DC
MAINTENANCE
manual.
periodically.

ILLUM

power

cord

POSITION

A

<

13 and

DC'GND-AC

A

switch

MODE

-trace

on

BAL

operation

operation.

oscilloscope

3 clockwise.

few seconds

up. A

should

FOCUS
thinnest,

the
for

control

Turn

trace

appear

trace

control

position

traces.

proper adjustment

-controls

These

PROCEDURE

control

30 to a

>

POSITION

LEVEL

16 to

switch

It will

for the

(two

on the

appears,

28 setting

control

sharPest

controls

14

AND CALIBRATION

adjustments

3 to OFF

12O-volt,

CONITO1

control

switch

the GND

19 to
or the

rotating

by

"click"

clockwise

cathode

if operating

traces

face of the

increase

and

27

trace'

8, 25

of

24

and

25,

to the

8

the CH

A

the

to the

until

INTENSITY

and

ASTIG

as described

require

OPERATING

position

FIz outlet'

50/60

POSITION

CH

JT'

centers

9 to

22

positions.

& B

POWER

on

and

ray

(clockwise) the

the

l3 if

of

AUTO

the

CH

and

position

B

position for

ILLUM

pilot

lamp

desired

(CRT)

tube

the A

in

CRT.

is

trace

control

necessary,

control

26, and

portion

checking

(fully

their

for

scale

to

& B

easily

28

in the

of this

only

INSTRUCTIONS

oscilloscope

The

measurements.

Never
remain

seconds.

few
burned.

motion

B

SINGLE.TRACE

Either Channel

to

4
2

single-trace
that
by
ii no
used

polahty

the

placing the

input to

the

in

Perform

1.
with

connect

The

B & K-Precision
For all

2.

3.

set

arc
waveforms
for DIRect.

10:l
megohm
capacitance

pf

tiO
hightir

used when

be

Set CH

only the AC

now

is

CAUTION

small spot

a

allow

stationary

Reduce

causing

by

operation.

MODE switch

following instructions.

the

MODE-switch

the

the

following

except

for l0:l

to DIRect,

input

shunt

input

DC-GNDAC

B

on the screen

screen

The

intensity

it to sweeP.

WAVEF ORM

or Channel

A

The

the observed

of

Channel

(below

in the

A.

of

steps

probe

cable

instructions
Model

low-amplitude

attentuation.

0.5

Fig.

See

or

impedance

10:l

capacitance

imp-edance

possible,

component

may become

advantage

19

For convenience,

the

19

PR-35 combination

volt

for changing

3

vice

(low'capacity

to

switch

(this

for

ready

of

or keep

OBSERVATION

in

"Initial Starting

in

the

to

peak-to-peak),

versa.

position

in

decrease

making

high brilliance

more

for

permanently

the

B can

using

of

B

CH

For

The

only

and

DIRect

circuit

normal

can

position if

B

INPUT

the

the

probe has

I megohm

position)

AC

waveform

the A-B

the CH

assume

waveforms,

with

the

16 to

is the

waveform

to

than a

in

spot

for

used

be

Channel

be

Channel

Procedute"

position.

use of

probes.

low-amplitude

set

probes from
l8pl

position. The

loading.

for

position for

B is

reversed

there

B is

Then

jack

15.

the

probes

the

probe

the

a 10

shunt

with

should

measuring

Y

8

COMBINATION

AND

CORD WRAP

2.

Fig.

FEET

Rear and side

panel

facilities.

U

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3.

Fig.3.

CLP.18

rocErHER

Probe details.

ffi=

/ffi-

PRoBE

coMPENSATIoN

ADJUSTMENT

TIP

f>

/-

-

a

most mdasurements and must be
being measured
the DC
and the DC
frequency waveform
The GND
ground
readings.

4.

Connect
equipment under
the
measured.

a. If

b. The

5. Set CH B VOLTS/CM
control
six
display on the
The
synchronization and sweep
stable display
forms. Any
deflection
chronize

6. Set SOURCE switch 12 to
provides

being

single trace operation on
switch should

internal sync. Most
internal sync. When

the

position

EXT

Set SYNC switch 1l

7.
for
to the SLOPE(+)
all other types of waveforms.
the
the
negative-going
unknown,

Readjust

8.
synchronized
the control
that
in
disappear if there
sweep, such
amplitude
pull
triggering.

Set

9.
control 6 for
controls may
waveform,

position

reference is required, such as

gound

point

the equipment under test is a
formerless
transformer to
shock.

measurement should not
when using

18

large

squares

lemaining

the sweep.

internal

observed is also used

SOURCE switch should

and a cable should

TRIG

observing television

sweep

(-)

position

TRIGGERING LEVEL control 9 to

produce

will

the

center

the

SWEEP TIME/CM

includes

for

measuring

reference,

position

in the circuit where the

peak-to-peak

to a

signal that

develops

jack

is to

the SLOPE(+)

may be

waveforms. If

control

but

is

clip

test. Connect

WARNING

powered

AC

the DIRect

position

on the scale) vertical

screen will

steps are concerned

showing the desired number

sync so that the

placed

be

waveforms
an

l0 to the external

or

triggered

be

if the

wave.

display

pushed

a

sweep, which

portion

is inadequate

as when

out

the

desired number

set

be

the

trace

large

a

and any

(below

required only when a

probe

of

prevent

voltage at the

switch

that

probably

produces

sufficient tigger

to trigger the sweep.

Channel A,

in the CH A

external

to the TV(+)

composite video

SLOPE(-)

by a

sweep

If

the type of

position

without

in

of its range. The trace

measuring DC or extremely low

no sweep

(PULL

switch 5 and VARIABLE

for

viewing

becomes

used

DC component). Use

both

5 Hz)

to

chassis

the tip of the

use

item,

dangerous

exceed

position

17

and the VARIABLE

gives

speed,

at least I

the

CH

Channel B waveform

should be

sync source

placed

be

connected

be

sync source.

positions

Use

positive-going

is

to
may

jitter.

rotated

and

is usually somewhere

signal

AUTO)

of

only

progressively

if the

the AC component

time a very low

is

to be observed.

for

ground

waveform is

isolation

an

electrical

point

600

of

the

2to 6 cm

deflection. The

unsynchronized.

be

with adjusting

which

signal to syn-

position.

B

the SOURCE

position

viewed

in

or TV(-)

waveforms

for

(+)

the

be triggered

waveform is

used.

be

As a

starting

to any

to

can be

for

whveforms. These

portion

a

point

zero-signal

voltage

DC

of the

probe

to

to be

trans-

of

volts

probe.

(two

to

presents

of wave-

vertical

cm

This

During

for

using

required,

is

the EXT

from

the

positions

observing

position

trigger the

obtained,

automatic

or

if

wave, or

by a

obtain

point,

point

will

of

dimmer

a

a

a

a

smaller

as
sweep
does not

When
rates,
intensity control toward maximum. Under these
conditions,
extreme left
affect
disregarded.

After obtaining the

10.
step

adjustrnent of the TRIGGERING LEVEL control 9.

(-)

The

waveform

the

(+.1

the
waveform
control

desired

i l. For

CALIBRATED

voltages
easily and
oscillosc ope.

4.

5.

a close-up
outward on the
the sweep
displays only the

portion

a
control clockwise. and to view
c€nter. turn
on the control to return the
non- magnifi ed

voltages.

Peak

of a specific

1. Adjust controls
waveform to

Be sure the

2.
fully

clockwise

3.

CH B

Set
vertical

limits of the vertical

Read the

the scale. The CH B POSITION
readjusted
reading if
the CH B POSITION
reference with
GND
deflected
The trace
and

downward

For an accurate
forms
probe
circuit loading;
so

that

cm;and
Calculate the voltage reading

vertical

l7

setting

voltage

l/10th the actual voltage

portion

speed

increases

change.

using very
the

the oscilloscope operation

f.

direction selects the most

may

portion

accurately

deflection

position,

above l0

be

the height

(3)

deflection
reading

fast

operator may wish to operate with

a retrace

the trace.

of

it

is sometimes

direction selects the

at which sweep

at which sweep triiggering will occur. The

be adjusted to start the sweep on any

of the

view

<

factor

by a

ro the left

the

control counterclockwise.

condition.

VOLTAGE

peak-to-peak

as

be measured.

CH B

to

VOLTSiCM

amount of vertical

to

shift the reference

desired.

the

then note the amount the trace

when

the switch is

deflects

for a negative

MHz,

used

in

(2)

the

trace be centered vertically.

(see

example

displayed on the

displayed.

is

but the sweep

NOTE

sweep speed

"pip"

This does

desired

>

POSITION

center portion

portion

measured

previously

vertical
the

When

CH B DC-GND-AC switch

upward

display

the 10:1

the oscilloscope

of the

(in

number

desirable

waveform.

portion

of a

five

of

of center, turn

MEASUREMENT

of a complex

VARIABLE

position.

CAL

switch 17

possible

scale.

measuring a DC

control 13 to a convenient

for

NOTE

of high-frequency

it

important

is

pattern

cm) by the VOLTS/CM

in Fig.

being measured when the

This

is

repetition rate

at low repe.tition

appear

may

not in any

and may

of

waveforms, as

to

make

most negative
triggering

of the waveform,

control 8. This expands

(5X

of the

portions

sweep to the normal,

voltages, DC voltages

on the

instructed

without exceeding

deflection

placed

positive

a

voltage

position

does

follows:

as
a).

will

positive point

magnification) and

sweep. To

<

the

to the right

(See

waveform are

Model

to display the

control 18 is set

for

the maximum

(in

control 13 may

point

for easier

voltage,

in the DC

voltage

input.

that

to

controls be set

not exceed

forget that

Don't

oscilloscope

because the

>

Push

Multiply

(1)

the

at the

way

be

in

final

a

point

on

occur

and

on the

pull

view

POSITION

of

inward

Fig.

a)

and

1472C

the

from

cm)

be

scale

adjust

l6

in the

is

position.

input

wave-

the

reduce

4

the

control

the

is

only

b

10

probe

is set
displayed
ment.

6. Calibration
occasionally
peak

jack

volt

dicated,
TION"

DIFFERENTIAL

This oscilloscope
measure
which
a

differential
push-pull
single
others,

Adjust controls

1.
Starting

Connect a

2.
INPUT

when the

square

7. This calibrated
peak-to-peak. If a need

see

section

voltages

is circuit

section

require this technique.

ground.

amplifier,

amplifier,

of

Procedure."

probe

jacks

for

accuracy

checked

wave signai

the

between

23

ittenuation.

10: I

probe

of

by

"MAINTENANCE

of the manual

VOLTAGE

may be

two

Such

the

amount

the

voltage

divider

previously

as

cable

15.

and

The

actual

for

is set

this oscilloscope
observing
available at

source should

for

MEASUREMENT

used to observe

points

measurements

output of a

of signal developed

or attenuator,

to

both

DlRect

the I

the CAL

read

for recalibration

AND CALIBRA-

complete

in a circuit, neither

as the

phase

described

the CH A and CH

voltage is

measure'

may be

peak-to-

volt

P-P

1V

exactly

is in-

procedures.

(See

Fig. 5)

waveforms

inputs to

splitter

across

many

and

"Initial

under

I

and

of
or

B

probes

Connect

3.

of equipment
probes

are
CH A
point
potential or lower amplitude

A

+.

Set
SOURCE
the controls
Trace
synchronized
height

If only

5.

interest,

a.

a

b.

c.

ground

to

to be

probe

the circuit

in

MODE

the

Waveform Observation"
with the

the AC

use the

Set CH
16

both

CH B

Set
CH B

the

as
If the Channel

phase,
position.
peak

clips of

under

points

the

made.

to the

switch

A and CH

to the

VOLTS/CM
CH

set

difference

in the circuit

It is

higher

and the

switch

12 to

previously instructed

as

waveform

single

VARIABLE

cH A

component

following

AC

VARIABLE

VOLTS/CM switch

A

A and Channel

the

The

displayed

between

two

the

test, and

usually

potential

to the CH

19

the CH A

DC-GND-AC switches

B

position.

switch

MODE switch

connect

where

desirable

or higher

probe

B

CH

point

in the circuit.

A

position

procedure
of 2 to 6 cm

control2l

of the waveform

procedure:

control

18

17

the same

to

20.

waveform

the two

position

in the

to CAL and the

B

l9 to

points

to

is the

chassis

to the

of the

tips

measurements

connect the

amplitude

to the lower

and the

adjust

and

"Single-

vertical

cAL.

is of

22

and

position

are

A-B

peak'to-

of

meas-

a

in

to obtain

set to

inputs

the

POSITION
SO THAT BOTTOM
FORM ALIGNS
A HORIZONTAL

CONTROL

EXACTLY

REFERENCE

EXAMPLE:

VERTICAL DEF

PROBE

PEAK.TO.PEAK

a>

POSITION

OF WAVEFORM CROSSES CENTER

TOP
VERTICAL SCALE

EASE

AND

ADJUSTE D

WAVE-

OF

WITH

LINE

LECTION

VOLTAGE/CM

ATTENUATION

WAVEFORM

CONTROL

MARKER

READING

OF

=

4.2cm

=

.o2

-084V

=

10

=

0.84V

ADJUSTED SO THAT

FOR

OF

ACCURACY

pc?@fl

VOLTS/cm CAL

SET

.o2v

PROBE

@-

o

@).,t

o
o

@

TO

10:1

ATTENUATION

['l@

L"--Jn

CHB

-

Fig. 4. Typical voltage measurement.

1l

urement.
sensitivity
B VOLTS/CM
position.

If

d.

the
out
amplifier,
position
form.
to measure any
of
switches

waveform as
of the
CH B switches set to the

e.

Position
positioning

voltage as

Measurement"

If

the waveform is

may be

Channel A and Channel

phase,

of

set the MODE

to measure the

Set the MODE

measurement. Readjust

l7 and

possible

vertical

the waveform

controls

described

increased

switches

such as the output of

imbalance between the

20

scale,

procedure.

must both

switch to the

as required

without

always

but

and

in

small, the

the

but

B inputs

switch 19 to

peak-to-peak

full

the VOLTS/CM

to obtain

exceeding

keep

same

sensitivity.

as desired with

calculate the

"Calibrated

the

@'

0

@)..t

a
o

@

vertical

CH

A and CH

in

be

the

same

are 180"

push-pull

a

the A-B

wave-

position

A+B

points

two

as large

the limits

the CH A

peak-to-peak

a

and

the

Voltage

t

['-l

L--=lg

6. If a

DC

of

is

interest, use

a. Set CH

position.
Position

b.

the

Use
trace
reference.

Position

c.

position

d. Set CH B

position
introduced

follows:

as
the
POSITION
not

e.

Return
position.

f.

Momentarily
CH A
reference. You

vertical

control. Place
position.

from
voltage
measurement.

voltage,

trace

A+B and
shift as

or the DC

the

A DC-GND-AC

the CH

within the limits of the vertical

the

A POSITION

CH

with one

CH B

as

the

CH

DC-GNDAC

and adjust out

by the

Alternately

A-B
control
the MODE

CH B DC-GNDAC

return

position

positioning

The

the

amount of

Channel A

differential

component of the

following

A VOLTS/CM

of the lines

VOLTS/CM

A VOLTS/CM

and note

may readjust

the

procedure:

switch 22 to the

switch 16 to

any

Channel B

set

the

positions,

until

l3

switch

MODE

the

control,

MODE

displacement of the

reference

between the two

control 25 to

switch

adjusting

the trace

position

switch

the

it

but

switch

waveform

switch 20 to keep

on the

17

switch.

error

that may

positioning

MODE

position

16

switch 19

trace

the

with

not

the

represents

scale.

align the

scale

to the same

the GND

control

switch l9

CH B

the

does

changes.

to

the DC

to

position

Channel A

Channel

in

the A-B

trace

points

DC

for

be

to

the

for

the

of

{

1

B

il

il

PUSH-PULL
AMPLI FI

ER

VERTICAL

PEAK.TO-PEAK WAVEFORM

Typical

5.

Fig.

EXAMPLE:

DEFLECTION

VOLTAGE/cm

differential

=

6cm

=

.O2

1.2V

10PROBE ATTENUATION

12V

measurement.

CALIBRATED

Pulse
other waveform
measured on
ments from
possible.

visible at one
moving
the
to

from

beginning

spot.

1. Adjust
display of the

2. Be sure the
clockwise

3.

Set the

possible

measured,

4. If necessary, readjust

trol

5. Read the

tween

be

POSITION

the measurement
easier

6.

Calculate the

horizontal

switch 5

when

be divided by 5 to obtain

7. Time measdrements

especially
started

TIME MEASUREMENT (See

width,

9

waveform

time

this

.5

low

At

time.

left

and

controls as

to the CAL

SWEEP TIME/CM

display of the

usually

for

the

amount

the

reading.

deflection

setting

the 5X magnification

true when measuring

by a

durations

oscilloscope.
second
sweep

However,

to right

ending

desired wavefbrm.

sweep

one

most

stable display.

points

control

points

time

(see

sync

periods,

down

speeds, the entire

across the

points

previously

VARIABLE

time

position.

cycle.
the TRIGGERING

of horizontal

8 may

with a

duration

(in

example

often

signal from

circuit

easily

are
Calibrated
to

0.1

the

bright

screen,

of

the measurement

described

control 5 for

waveform segment

of measurement.

be

cm) by

the actual time

require external

deflection

readjusted

vertical

follows:

as

the SWEEP

in Fig. 5). Remember,

is

used, the result

delays. The

one

Fig.

6)

delays and

and accurately

time measure-

microsecond

waveform

spot can

control 6 is

to

scale marker for

duration.

circuit and the

is not

be seen

which makes

for

LEVEL

align one

Multiply

sync.

easy

a stable

fully

the

largest

to

con-

(in

The < >

TIME/CM

must

This is

sweep

all

are

be

cm)

of

the

3

is

I2

a>

POSITION
THAT LEADING EDGE
FORM
REFERENCE LINE. EDGE
MAY NOT BE VISIBLE
FAST PULSES;
ALIGN WHEREVER WAVEFORM
BEG I NS.

CONTROL ADJUSTED

ALIGNS WITH A VERTICAL

IN

THIS CASE

OF

ON

WAVE.

VERY

SO

HOR I ZONTA

DE F

LECTI

ON

6.35
cm

L

VARIABLE

CAL

@

o

@

SCt tO
SWEEP TIME/CM
set to 1 0!r

,SLOPE

(to

negative-going

start

sec

set

to

sweep

Q
on

edge)

o

@

CHB

POSITION
THAT

TRAILING EDGE

CROSSES HORIZONTAL

FOR

ACCURACY

EXAMPLE:
HORIZONTAL DEFLECTION

(or

PERIOD)

FREOUENCY=

waveform

measured
measurement of
and the
urements

a.
b.

subsequent

using

the

set
Connect

the

source

souRCE

a

cable.

c. Set the

position
Readjust

d.

SYNC switch

for

the TRIGGERING

necessary for

e.

If

measuring

start of the

8. Another excellent
with

dual-trace operation.

"DUAL-TRACE

the
manual.

EXTERNAL

For

tion

signal is
measurement,
flection
horizontal

HORTZONTAL

some measurements,

required.

where

and the X rnput

input may

CONTROL

SWEEP

TIME DURATION

OF WAVEFORM

ADJUSTED

OF WAVEFORM

SCALE MARKER

AND

EASE

TIME/CM - 1OpSEC

1

TtN/iE

in a subsequent

the

display

between

waveform.

external

cable from

of

the

sweep

sync, use

switch

12

the EXT

sync

signal.

1l

proper

a stable

a

delay, measure

to

method for

to the

polarity

waveform.

the

start

measuring

The

APPLICATIONS"

rNpUT

external

an

This is

the

provides

be a

also referred

Y

input

horizontal

sinusoidal

SO

READING

OF

=

6.35cm

-

63.5uSEC

=

1

^0000635€EC

=

15,15O

Hz

Fig.

circuit. This

the

perform

To

following

the

to the EXT

TRIG

Use

a shori

SLOpE

for

the

LEVEL

the time from

of

the waveform.

time

procedures

section

(X-y

OPERATTON)

horizontal

to

provides

deflection.

wave,

6. Typical
allows

pulse

sync

such meas-

steps:

position.

10

iack

shielded

(+)

(-)

or

sync signal.

control

9

the

delays is

given

are

of

the

deflec-

as

an X-y

vertical

de-

The

such

as

for

to

in

measurement.

time

phase

measurement,

input must

voltage

any
satisfactory operation.
use the

following procedure:

t.

Set the
the

2.

Use

Channel

3. Adjust

if

CH B VOLTS/CM

4.

The

as the
TION

Do NOT
X-Y
VOLTS/CM

5.

All sync controls

DISPLAYS
RECEIVER
HORIZONTAL

SHOW TYPICAL TELEV!SION

WAVEFORM

or

mV

100

per

mV or

be

10

of

To use

CH

B

the

Channel A

the

SWEEP

B

TIME/CM

position.

probe

for

amount

and VARIABLE

(vertical)

CH B

horizontal position

control

operation.

is

disabled.

use

the PULL

Use

controls

are

AT

OUTPUT

external

an

GRID OF

TUBE

cm of deflection

greater

an external

switch 5 fullv

probe

for

the

vertical

the horizontal
of horizontal

POSITION

control now

control,

NOTE

5X

the CH B

to

MAG

adjust

horizontal gain.

VARIABLE

disconnected

voltage.

sweep

greater;

or

is sufficient

horizontal

clockwise

input

input.

deflection

controls 17

and the

conrrol

and

<>

durins

have

input,

and

with

and 18.

serves

POSI-

and

no

effect.

This
thus

for

to

the

the

13

6. Set both the
l6

and
most measurements

measured include

being

CH A and CH

AC

to the

position.

and must be

a

large

B DC-GNDAC switches

This is the

DC

position

used if the

component.

used

points

22

for

Fig. 7. Oscilloscope

ZA)flS IMUT

The trace
modulated
marks are
applied at

the rear of the oscilloscope will

and blanking
DUAL{RACE

(Refer

In observing

it

B,
frequency

other

the

example of

An
multiplier. The
on Channel A,
multiple
Channel
Channel A is synchronized,
also be
waveforms
each other are

impossible

not

if
useful observation.

To display
tion, use the

Perform the

l.

2. Connect
and CH

If

3.
oscilloscope
be used except
or

position
probe
possible,
position

4. Set MODE switch
should appear on the screen.

5. Adjust CH A and CH
to
trace. and adiust both traces
mark on the icale.

displayed

(Z-axis
required.
the INT MOD

Fig. 8

to

is necessary that the waveforms

or that one of

although the basic

of

this

B. In

in

having no

B

the recommended

less. For

from

place

input) where
A 2O-volt

of

the trace.

WAVEFORM

)

simultanedus

is in checking a

this

reference,

for example, and the multiple

referenie

Way, when

this

qync

with

displayed

to

two waveforms

following

steps

oscilloscope

INPUT

probes

for
lower amplitude

the

should be

10: 1 to DIR or

use

the

to minimize

the

Channel

trace with

on the screen may

(intensity

See

OBSERVATION

waveforms on channels A and

the

waveforms by synchronized to

frequencies

"clock"

or

frequency

the display

the Channel

phase

simultaneously,

lock

both

procedure:

of the

probe

jacks

23 and

B &

used,

are

waveforms

used. See

high impedance,

circuit

19

to the A &

POSITION

B

A trace above

Z-axis input.

frequency

peak-to-peak

modulation)

provide

Fig.

7.

the waveform

frequency

or

waveforms

simultaneously

"Initial

cables

15.

K-Precision

10:1

of 0.5

Fig. 3

loading.

to a convenient

or

alternate brightness

may

frequency

frequency

will be

on Channel B will

A display. If two

it will

in sync

Starting

to both the

attenuation should

volt

waveforms

for changing the

vice versa. Whenever

low capacity

position.

B

controls

the Channel

intensity

be

or time-scale

greater

signal

jack

3l on

related

be

be different.

divider

can be

displayed

display

relationship to

be difficult

for

Procedure."

Model

peak-to-peak

the DIP.ect

Two traces

25 and

in

or

used

or

sub-

on

of

for

any

observa-

CH A

PR-35

10:1

13

reference

ground

7. Connect
ground
of the
waveforms
signal
applied

a.

b.

8. Set
and B to a
deflection.
unsynchronized.
to those
the
displays.

Set the SOURCE

9.

provides

being

desired,
trigger the sweep by setting the SOURCE
CH

source
A or B is
to
from

Set

10.

positions for
waveforms,

positions
Use the

a

sweep
Adjust TRIGGERING LEVEL

11.
stable,
control

will
the center
if

as when measuring extremely low

no

AUTO)
Set SWEEP

t2.

control
controls

waveform,

as a smaller

After obtaining the

13.
step 12, it is sometimes

adjustment of the

The
point

will
positive point

B

triggering

start

waveform.

the

of the equipment under test.

probes

are to

to which the

to the Channel A input.

equipment

If the
less AC unit, use an isolation transformer
prevent
The
measurement should not

the

the

B

the

the SYNC

positive-going

produce

there is inadequate signal

sweep

(-)

dangerous electrical

peak-to-peak

probe

VOLTS/CM

The

outlined

procedure for

internal sync so that the

observed is also

the Channel B waveform

position.

other than the measurement

required.

(external) position

EXT

EXT

the

or

for

(+) positions

is

to

be

synchronized sweep. As
may

be

a

portion

can

for

automatic triggering.

for

6

may

but

portion

direction of

on the

occur

the sweep on any

sync waveform

and the

will

clips of the

points

to

be measured.

waveform will be synchronized be

WARNING

under

voltage at

is used in

position

displays

Often in dual-trace operation,

TRIG

observing television

to the SLOPE

observing

triggered

pushed

sweep, which

be

TIME/CM switch 5 and VARIABLE

the

be

the trace

on the
occur.

the DIR

controls

that

on

remaining

The

for

single-trace operation,

obtaining stable,

12 to the

switch

used

In this

jack

l0

switch

wave, or to the

obtained,

1l to the TV(+) or TV(-)

all

if

the sweep is to

by

in

and

its

of

range. The

desired

set

number of waveforms.

for

viewing only a

becomes

displayed.

is

desired number

TRIGGERING LEVEL

rotation

(+)

sync

The

desired

probes

to the

in the

test

exceed

l7

gives

the screen

to trigger the sweep. If

case set

to

other types of

a negative-going

rotated

is

to trigger the sweep,

pull

desirable to

selects the

at which

direction

waveform at which sweep

control

Connect the tips

circuit

preferred

It is

is

a transformer-

shock.

the

600

position.

and 20

steps, although similar

the

out the

for

2 to 3 cm

will

CH A

Channel A

may be used to

point

ttre

SOURCE switch

and connect a cable

sync source.

composite video

(+)

or

be

(-) position

control 9 to obtain a

a starting

to any

usually

trace will

amplitude signals. If

control

progressively

of waveforms

sweep triggering

selects the most

may

be

portion

chassis

where the

that the

to

point

of

volts,

if

Channels

vertical

probably

describe

synchronized

position.

waveform

switch to

a

for

Channel

SLOPE

waveforms.

triggered

if

wave.

point,
point

somewhere in

disappear

(PULL

These

portion

dimmer

make

a

control

negative

most

adjusted to

of the sync

A

be

This

the

sync

(-)

by

the

the

that

such

of a

in

as
final

9.

a

3

l4

14. The observed
expanded

<>

the
rotated

waveforms of

by a

POSITION

clockwise or

and right extremes

desued.
sweep

15.

Calibrated voltage
urements

to

Either the

controls can
the horizontal

Push

inward on the

to the normal, non-magnified

and

operation

previously

those

Channel A or Channel B

used as required in

be

sweep controls to obtain
amplitude or time
done

the A

either

& B

using

by

position

to single-trace operation,
positions

The

16.
be
the
A-B

of the

Channel A and

added

algebraically

position,

tr+B

position.

MODE switch.

factor

control

of 5

pulling

by

8.

This control

counterclockwise to view

Channels A

of

the

waveform

control to

condition.

measurements,

with

described

calibrated time

Z-axis input

for

single-trace operation.

vertical

conjunction with
interval
of the MODE

or subtracted

measurements.

the

dual display

using the

by

placing

B waveform

Channel

facilities

switch

CH A or

the MODE switch

algebraically

and B can

outward

can then

the left

displays as

return

identical

are

adjustment

required

the

This

can

such

reverting

or

by

displays can

the

meas-

CH B

in

the

be

on

be

be

as

in

FREQUENCY

Fig.
divide-by-two
"clock"
outputs of the
the settings of specific

waveforms.

these
the TRIGGERING
A

and Channel B vertical
required
8, the waveform
voltage amplitudes of
waveforms are desired,
VARIABLE
The Channel B

Fig.

88 or 8C.

waveform

responds

output

waveform
of the
corresponding to

DIVIDF-

Fig.

{

DUAI-TRACE

APPLICATIONS

INTRODUCTION

The most obvious
dual- trace oscilloscope
viewing simultaneously two waveforms that

phase-related,

or
voltage, such as
"Cause
circuit
tions

and

designer

of the dual-trace

in

Effect"

or

detail to familiarize
of this

oscilloscope.

yet

and

or

that

digital

waveforms

the repairman.

the

most useful

that it has the

is

have

a common synchronizing

circuitry.

Simultaneous

an

is

Several

invaluable aid

oscilloscope will be reviewed

the user

further

in

the

feature

of the

capability

frequency-

are

viewing of

to the

possible

applica-

basic ooeration

for

divide-by-eight

identical to those

Fig.

divide-by-eight
Fig.
input

In an
or near
rise time
time

circuit

in

possible

frequency
scope the

94

B

indicates the

pulses

propagation

and must

DIVIDER

8

illustrates

circuit.

pulse

train. Fig.

WAVEFORMS

the waveforms

Fig.

B

divide-by-two

oscilloscope

In

addition to these

LEVEL

position

produce

to

suitabie displays.

levels of

2 cm are

the

the

controls must be

waveform may be either

Fig.

In

is shown

for

the

to a negative-going

shifted

reference

BY-8

9

is

is

frequency

pulse

the

width.

CIRCUIT WAVEFORMS

indicates waveform

circuit.

supplied

output

used

The

Fig. 8.

in

to

the Channel

applied to

is

ideal

and the

application

output
where

its maximum

effects

of the

delay

be

time

divider

compensated for.

delay which

circuit. By use of the

input and output

pulse.

the logic

design

consecutive

which

waveforms

A

indicates the reference

Fig.

and

C

circuitry.

controls

basic

indicate

Fig. 8

the

also

for

control settings,

control, as well as the

controls should

involved in a

In the

drawing of Fig.

indicated. If the exact

Channel A

Channel A and

placed

8C

the divide-by-two

case where the

waveform. ln

with respect to the

pulse

relationships

basic oscilloscope

The reference

time

relationship

frequency,

stages

can be significant

may

be

and Channel

the

in

that

output

by a time

A

input, and

the

Channel

circuitry

the

produce

Fig. 9C

introduced

Channel

CAL

indicated

this

leading edge

for

settings

frequency

between

operating

is

accumulated

in a critical

indicates the

dual trace

can be superimposed

basic

or

possible

indicates

viewing

Channel
be

set as

position.

in

output

circuitry

case, the

interval

a

basic

are

of

the

B

input.

the

at

a

built-in

into a

oscillo-

B
B

J

CHA

^REFER

A.

cHn

B. DIVIDE

ENCE FREOUENCY

(1OOO

PULSES

LEADING

VISIBLE

,/r-

u

-

LEADING

BY

- l*ro

cHB

l

C. DIVIDE-

TRAILING EDGE

BY.TWO

PER

SECOND)

EDGES

AT FAST

-TWO

EDGE

OF

OF REFERENCE PULSE

MAY NOT BE

OUTPUT

REFERENCE

OUTPUT SYNCHRONIZED

CHANNEL A
WAVEFORM

fi,itt|3hfr

PULSE

TRAIN

SWEEP

RATES

SYNCHRONIZED

PULSE

Fig.

8. Waveforms

TO

TO

WAVEFORM

HEIGHT

in

divide-by-two

A

WAVEFORM

circuit.

OG
o

0

@

B

HEI

t

GHT

t5

zontally.

control.

waveform

of the

This may be done by

It also may be

at

faster

a

possible

sweep speed.

pulling

to view the desired

PULL 5X MAG

the

portion

"-"iVuurforrns

g.

fig.

determine

to
occurs.

PROPAGATION

An
circuit
propagation
consecutive

simplify

resultant

the
combined

or A-B

A+B
position the two

display. Similarly, in

trace

algebraically subtracted.

are

precise
procedures
be calculated.

the Tp

if

the exact

TIME

example

was

measurement

display of

of

given

in

delay may

stages. This

waveforms

a single-trace

into

position

inputs

given for

portion

the

A more

propagation

in

divide-by-eight

propagation

amount

MEASUREMENT

the

occur in any

propagation

of

when

of

are

propagation time

calibrated

precise

of

the

of

delay

previous paragraph. Significant

oscilloscope

the dual-trace

presentation

MODE

the

algebraically

position

A-B

the

Either position

time measure^m€nt, Tp

measurement

waveform is

circuit.

in a divide-by-eight

circuit

features which

has

Fig. 10

delay.

presentation

by selecting

switch.

added in a single

the

(Tp).

can

expanded

that

delay

with several

shows

is

the

In the A+B

two

inputs

provides

Using the

obthined

be

^

car

hori-

DIGITAL

A
manufacturing
oscilloscope
between

ln

circuits
relationship
frequency
are
dynamic
upon
typical
which
accompanying
expected at
ships.
their
waveforms
scope
fashion,
and

successively
comparisons
No. 13

relationshio

CIRCI.JIT

dual-trace

permits

waveforms.

two

equipment it is

digital

to

be

dividers

time-related

often

state,

the input

digital

waveform

each

individual

The

timing

is known

allows

wavefornr

waveform

displayed

would

to

to each

circuit

relationship

may be

TIME RELATIONSHIPS

necessity in

oscilloscope is

servicing digital

and

easy comparison

synchronized,

some of

Fig. l2 shows

this comparison

No. 4 thru

waveform No. 8 or No. 4 on Channel

other.

previously

as

many

in

the

or mode of operation.

and identifies several

measurements

of these

waveforms
to

be correct.

No. 3 would be displayed

on Channel B, although
desired.

probably

a

equipment.

time

of

common

waveforms

the

points

to one or

No. 8,

be displayed

for a large number of

to have a specific

or

Many of

described,

other combinations.

change,

are appropriate.

normal waveforms

their timing

and

limited

have

more of

dual-trace

The

and

made. In

No. 10,

on

to be

Waveforms No. 11 through

designing,

A dual-trace

relationships

the

circuits

but waveforms

depending

Fig. 11 shows a

points

of the

relation-

value

the other

oscillo-

on Channel

would be

other timing

Channel B in

time

are

In the

at

The

to

be

unless

typical

A

A.

CHA

CHB

A&B

A-B

EXPAND THrS

MORE PRECTSE

FOR

T|ME MEASUREMENT

PORTTON

Il*to

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I

/

-(
\_

/\

/

+l

/ ll

\-

n

I

L

-t'

_

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/

/

I

I

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\

I

,

1

I

/

I

,

I

\--

--/

/-\.

/\

\

\

\

_.

\

\l

I

I

I

/

./

\

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I

/

/

rb.

16

Fig. 10. Using

A+B or A-B m-odes

propagation

for

time measurement.

family

the

In

ll. waveform

viewing

ior
pulse per
waveform
desirable.

all

frame. For convenience,

No.8

With

displayed without

time-related waveforms shown

of

No.8 or

No.

l0

is an

excellent

of the waveforms; there is

external

No. 10

or

external sync, any of

as

the

sync

the

readjustment of the sync

sync

but one

source may be

waveforms

Waveforms No. 4 thru No. 7 should not be used

Fig.

in

source

triggering

sync using

may

be

controls.

the svnc

as

SECURITY

8tT I

SECU R

IT Y

BIT 2

source

because they

of

start

entire

the frame.

waveforms

there are many
portion
cases, it

of the

recommended

is

while the sweep

do not contain a

[t

as shown

times

waveforms

speed or

expand the waveform

not

would

in

when a

would be

that the sync

5X

display.

triggering

be necessary

Fig.

12

in all cases. In fact,

examination

closer

appropriate. [n

remain

magnification

pulse

at

the

to view the

of
such

unchanged

be used to

a

CODEO

FUNCTION

DATA

INPUT

(8-8rrS)

START

INPUT

LINE DRIVER

- - --15

ui48

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u.2

MULTI

PLEXER

-

N16

13

RUN

4

5

6

7 8

SE CURI T Y

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OATA ENABLE

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ur3A

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Fig. I l.

Typical

circuit using several

digital

time-related

waveforms.

t7

DISTORTION MEASUREMENT

An amplifier
tested for distortion
measurement

is

or

stage,

with

entire

an

amplifier

this oscilloscope.

especially valuable when the
waveform must be faithfully reproduced
Fig.

l3

wave,

such as is

typically

audio output of a limiting

shows the testing of such a

modulator
using any type
testing
normal

of a transmitter. The measurement may

that

normally applied to the

is

operation.

of

signal;

The

merely

procedure

circuit using a

encountered

use

which

the type

for

distortion testing

circuit

follows:

1. Apply the
amplifier

2. Connect
and

preferable

is

relationship to each other,

type of

under test.

Channel A

Channel B

probe

the

if

normally encountered

signal

probe

to

the

to the

two

input

output of the

signals

are not inverted

but

inverted

used.

3.

Set CH A and

sranr

I

DC-GND-AC

CH B

- .,

switches to AC.

I

couNTER

2

-

ENAELE

rnay

unit,

type of

This

slope of a

by an amplifier.

triangular

the recovered

in

precedes

of signal

be

the

rnade

for

ampiifier during

the

in

of the

amplifier

amplifier. [t

signals

can

be

in

be

MODE

4.

Set

5.

Set sync
described
chronized

Adjust

6.
superimpose

Adjust the

7.
(VOLTS/CM
are as large
the scale,

switch to A

SLOPE

in waveform

waveforms.

the CH

the

CH A

and

as

and so that

same height.
Now

8.

set the MODE
waveform
the

A+B

(CH

maining

VARIABLE)

B

waveform.

distortion;

amplitude

is inverted

position).

the

if

and there
will cancel and there
line remaining

& B.

switch

A

and

waveforms

and

CH B

VARIABLE)

possible

without

both

switch to the

in relationship

Adjust the fine

slightly

Any

two

waveforms

is

will be only

the

screen.

on

to

CH A

viewing

POSITION

CH B

directly

vertical

so that the

exceeding

waveforms

for

waveform
no

distortion,

and adjust

controls

procedure.

controls to

over each other.
sensitivity

*aveforms

the limits

are exactly

position (if

A-B

to the

vertical

other, use
sensitivity

the minimum

that remains

are

exactly the

the waveforms

a straight

horizontal

as

for

syn-

controls

of

the

one

re-

equals

same

DArAsELEcr

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18

12. Family of time-related waveforms

Fig.

from typical digital

circuit

in

Fig. 1 l.

A.B = DISTORTION

ADJUST
TO SUPERIMPOSE
DIRECTLY

POSITION CONTROLS

EACH OTHER

OVER

AC I

ADJUST SO
WAVEFORMS
SAME

WAVEFORMS

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Fig. 13. Distortion

GATED RINGING

The circuit
demonstrate
oscilloscope
applications.

identical

to
waveform and
waveforms

are sampled at Channel B

CIRCUIT

waveforms of Fig. 14

and

the type of

effective both

is

The

basic oscilloscope

those

Fig. 8. Waveform

of

applied to Channel A

is

reference waveform of Channel A.
signal can be

examined

the sweep time

pulling

or by

magnification.

times
desired to

out on the

center

per

more

centimeter

This control

the desired waveform

measurement.

circuit in

in

which the dual-trace

design

and

control settings

A is

and compared

The frequency burst

closely either by increasing

to

mSEC

.5

POSITION

<>

can

control
then

information

oscilloscope screen.
DELAY

used to determine the delay

delay lines
pulse
display
Channel
synchronize the displays.
pulses

LINE TESTS

The dual-trace

as

feature of the

well

as ultrasonic type

can be used to trigger or

and the delay line

B. A repetitive type

should be

large

compared to the delay

oscilloscope

times

of transmission

delay lines.

synchronize the

output

pulse

The

can

make

will

interval between repetitive

investigated. In addition to determining
pulse

distortion inherent

by examination

of
Channel B waveform display. Figure
typical

oscilloscope settings as well

the delay line

in

the delayed

can

pulse

15 demonstrates

as the basic test

are shown to

troubleshooting

reference

the

All other

input.

to the

per

centimeter

to obtain 5

be rotated as

on the

can also be

type

The

input

Channel A

be observed

possible

it

time to

delay time,

be determined

observed

on

circuit.

are

on

to

be

the
the

the

Fig. 14. Gated

CHAN NE

CHANNEL

A

(INPUT

PU

LSE

L

)

B

(

OUTPUT

PU

LSE}

ringing

__:,@

Lol-,
t#

PULSE

GEN

PPS

5OOO

PULSE

lpSec

Typical

input and
oscilloscope display.
observed

and

and output terminations

WIDTH

Fig.

15. Delay line
output

Any

evaluated. The results of modifying

circuit and

o

ULTRA

DELAY LINE

(

5p Sec)

SONIC

waveforms.

o(E---:-------l

o61

o

zL==*ll-

@

t\zzf-ii-

['-l@ ll

_5sE

?^"'ll

OUTPUT

measurements.

waveforms are shown on

pulse

stretching and ripple

be observed directly.

can

1pS/cm

SLOPE+
CHA

can

the

input

the

be

t9

A

common

color

in

settings

*op.
*y;

drluy

waveform

input

ariuy

time,
composite
approximately

O.t.y chiracteristics

t|6

reveals

impedance

from

sulting
STEREO

Another
troubleshooting

in

amplifiers

btherwise

or
efficiently

application

televisi,on

and

empl-oyed

liie

using

uidro

one

distortion

iny

mismatch

an open

AMPLIFIER

convenient

ured

ute

abnormal,

used

identical'signal
iide-by-sidi
progressively

i*ftifirtr.
been

repair

compirison

When the

located.

methods

sampling

the

immediately.

of

receivers.

typical

circuit

in

utiO

signal

the

for

hbrizontal

output

itt.

microsecond.

of

that

a

or

line.

SERVICING

use

stereo

the

and

the

localize

to

applied

to

of

-identical

defective

effects

employed

are

the

Figure

16

shows

line checks

delay
connections

the

waveform

reference.

In

line,

the

may

are

-qVn9 .pulse.
The indicated

addition

output.waveform

the

be introduced

amplifier

video

greatly attenuated

dual-channel

for

amplifiers.

ou_tput

dual

the

the inputs

both

whatever

of

can

If identical

of one is

oscilloscope

trace

defective

both

of

can

units

points

signal

malfunctioning

or

troubleshooting

observed

be

found

is

oscillo-

the

to

section.

compared

check

of

the

The

for

the

delay

determining

to

an

from

output

re-

oscilloscopes

channel

distorted

weak,

state.

be

can

With an

amplifiers,

be

both

in

stage

has

by

made

and

analyzed

and

IMPROVING
DESIRED TO

ln

large

a
possible

undesired

is

control
display
dofted

responding
B
identibal-phase

With

vertical

B
Channel

is

and
Hz component.

AMPLIFIER

a

In

phase
in

distortion
components

shifti
signal
output

some

undeiired

minimize

to

component.

settingi

Channel

of

line indicates

the

indicates

MODE

display

attenuator

A signal

desired

the

single-trace

the

measurements

shift

addition,

is

be

can

the

to

signal

RATIO OF

THE

I.JNDESIRED

applications,

the

signal component

for

or

Fig. 17 indicates

such an

for

A indicates

the average

undesired

to an

waveform

a

to the average

set

switch

controls,

cancelled

can be

waveform

PHASE

SHIFT

application

square

the

in

explained

terms of

in

which comprise

verified

directly

amplifier

and observing

with respect

SIGNALS

may

desired

signal

such as

practical

purposes eliminate

application.

desired

the

amplitude

component.T!..

60Hz

of'equal

the Channel

of

to A-B,

the

be observed

can

by adjusting

and

Hz component

60

the

by

MEASUREMENTS

section
using
wave

a single

testing

trace

section,

phase shift

the square

providing a

by

wave.

the

input

signal.

to

the

b-e riding

Hz. It

60

oscilloscope

the

waveform

The

signal

variation

amplitude

waveform.

I

Channel

without

this

of

described.

are

square

the signal

of
These

wave input

sine

phase

on

is

the

the

and

cor-

Channel

and

the CH

the

of

B.inpu-t

the 60

manual

wave

phase

of the

tL,

CH

CH

B

AMPLI FI

DE

1rr

S

(INPUT)

A
(OUTPUT)

VI DEO

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CAL

PROBES

BOTH

SET

ATTENUATION

1O:1

D

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L

o

o

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I

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INE

FOR

1pS/cm

HORI

TO

NO

NOTE:
NECTION;PLACE

INSULATION

OR

LEAD

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IMITY

TUBE.

LIFIER

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IN CLOSE

AMPLI

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CLIP

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OUTPUT

AMPLI

CON-

ON

CAP

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ER.

FI

AMP-

20

16. checking

Fig.

*NOTE

:-SETTING
ATTENUATORS
SAME,

DEPENDING

BUT

"Y"

MAY

ON

delay

F VERTICAL

O

SHOULD

VARY

CIRCUIT

color

in

line

BE THE

DELY,

WI

TYPE.

television

receivers.

CHANNEL

CHANNEL

A

B

@

ADJUST FOR

COMPLETE CYCLE

AT

60Hz

o

o
o

@

@fi@

Hz

WITH

START

A&B

A_B

TO

CHANGE

Fig 17. Improving desired-to-undesired signal ratio.

In

amplifiers,

all

amplitude

change
response
illustrates
directly.
made
audio
CH A

provide

in

points,

a method

In
at approximately
amplifier

INPUT

VARIABLE control is

The

a complete

phase

a

response.

phase

a

determining amplifier

of

particular case, the nteasurements

this

5000 Hz. The

used as a reference

is

jack.

cycle

is always

shift

For

shift of

of the input

60

associated

example, at

45" occurs.

input

applied to

and is

adjusted as

waveform

phase

signal

required

ONE

1mS/cm

AUTO

SLOPE+
CHA

with a

-3

the

Fig.

shift

are being

to the

displayed

dB

18

the

to

8

horizontally.

cm

on
The 8 cm

display
frequency and
waveform.

The signal

audio amplifier

The vertical

as required
shown

The CH
Channel
axis as
distance
axis for
between
points of

attenuator controls

to

Fig. l88.

in

POSITION

B

waveform is

B

the

Channel

between corresponding

the two waveforms

two waveforms. In this case,

the

the two waveforms are compared.

produce

A waveform
represents

each

centimeter

developed across

applied

is

to the Channel

peak-to-peak waveform of 2 cm

a

control

displayed

waveform as shown in

A

a difference of I centimeter
as a

phase

shift of

45o.

of 2

height

3600 at

represents

the output

B INPUT

Channel B are adjusted

of

is

then adjusted so that the

the same

on

points

on

then represents

the

It

This

exists.

is

then

is used.

cm

pisplayed

the

45o of

the

of the

jack.

as

horizontal

Fig.

l88. The

the horizontal

phase

the

shift

zero crossover

that

shown

is

interpreted

TELEVISION SERVICING

Many of the television servicing

performed

using single-trace

operation.

procedures

These are outlined

can be

later in the applications section covering single-trace opera-

procedures,

tion. One of
interval

effectively using

the single-trace

these

test signal),

a dual-trace oscilloscope. As

applications

can

and 26, the information

vertical blanking interval

detail
synchronized
the Field
onto

Fig. 25. Also, because the oscilloscope sweep is

in

each

to

and Field

#l

the

vertical

other as shown in

viewing the

be accomplished

section

on

pulse

and as shown in

Field

the

different. This is shown

is

blanking interval

waveforms are superimposed

#2

Fig.

operation, the signal information on

be viewed separately without

can
indicates
alternate

1.

the oscilloscope

VITS.

The

color
information
transmitting

control

setting for viewing the

television receiver on which

to

viewed must

be

is

a color broadcast.

27A.

VITS (vertical

much more

outlined in

Field

and

#l

waveform,

With

each

dual-trace

blanking

overlapping.

the

to

be set

a station

Fig. 25

#2

in

pulse

Fig. 19

VITS

A

CHANNEL

A

CHANN

EL

B

e^3@+@!

AUDIO

FIER

AMPLI

Fig. 18. Measuring

ADJUST
FOR

2OpS/cm

OUTPUT

LOAD

AS REOUIRED

COMPLETE CYCLE

lN

CHANNEL

CHANNEL B

amplifier

Bcm

A

phase

-t

shift..

/

l<-

+so

\

\ / /
\

\ a

t
?

/

2l

The control

2.
obtain

With the oscilloscope

3.
connect
detector

the SYNC

4. Set

If

A.

video
position.

If

B.

the

5. Adjust
veriical

Connect

6.
detector

the

Set

7.
waveform

Channels
Place

8.
position.

g.

Set

position.

i*.tp
the
displays.
apfeai

th6re

settings

vertical

2-field

a

the Channel

point.

test

switch

sync

the

signal

sync

the

switch

TV-

the sweep

are

fields

the Channel
test

Point.

MODE switch

displays

A and

the sweep

SWEEP

the

This

The

speed.

hand

iight

is

The

shown

as

provision

no

waveform

Fig.

of

display

television

and

probe

A

follows:

as

blanking

and

positive;

are

blanking

and

Position'

VARIABLE

time

displayed

probe

B

the

to

should

B.

VARIABLE

time

TIME/CM

expands

portion

the

VITS

information

of

information

drawing

the

in

for synchronizing

those

19 are

Channel

on

receiver

(set

pulses

use

pulses

the oscilloscope

on

(set

A &

now

control
display

the

l)

l0:

at

of

the

are

control

10:1)

to

position.

B

be

control

to

by increasing

will

?Ppear

expanded

each

on

Fig.

of

the

required

A.

operating,

to

th-e- observed

TV+

negative,

to

obtained

in

the

26'..Because

oscilloscope

to

video

the

switch

use

2

that

so

screen.

video

the

ldentical

on

CAL

the

.1mS/CM

the

toward

waveform

may

trace

display
.o*pltt.
field
B

Pull

10.
tional
counterclockwiie
left

shown

Because
sweep
the

once

11.
identified
information,

Fig.

and

displayed

is

to

display

display.

<) POS control

the

5X

until

in

speed

signal

the

display
troubieshooting
should
that
signal
re-verse

provision
iwo

Field

which

be

the

is

because.

vertical

20 shows

#2

on

either

vertical

will appear

magnification.

expanded

the

20.

Fig.

low

the

of

combinatibn,

displays

channel

being

as

probe

the

is

can

left at

signal

sync

interrupted,

the

in

fields

dual-trace

the

VITS information.

trace'

the

it

frame,

on

outward

direction

VITS

NOTE

repetition

reduced.

be

will

channel

A and

either

corresponding

used

be

to

used'

be

the video

as

oscilloscope

not

is

the

previously

which comprise

two

the

of

which

iields

cannot

the

Rotate

moving

the

Field

and

detector

interrupted.

waveform

to identify

presentation

The

predicted.which

be

Channel

obtain

to

the

the

information

and

rate

b-rightness

displays

B

or

#1

to the

ior signal-tracing

remaining

the

point

test

explained'

a

complete

of the

Field

#1

comprise

Channel

or

A

an

control

to

traces

appears

high

the

of

level

have

Field

#2

waveform

to

If

-the

displays

there

either

frame'

Field

information

a

addi-

a

in

the

as

been

vlTS

and

probe

insure

sync

may

is no

of the

#1

VIDEO

VERTICAL

SYNC

PULSE

VERTICAL
BLANKING

TELEVISION

VI DEO

DETECTOR

SET

@

o

@

@

t-

o

cL

o

L

o

@

?@!@[oP

VI

DEO

AMP

START

TV+ or

(See

CHA

PICTURE

TUBE

WITH

2mS/cm

(See

text)

TV-

text)

22

19. Set-up

Fig.

for viewing

fields

I and

2 of

vITS

information.

Fig. 20. Oscilloscope

of VITS information.

SINGLE-TRACE

INTRODUCTION

In

addition to the dual-trace
outlined,
applications where only single-trace
oscilloscope
oscilloscope.
to
using
The
tion is adequate. In
alternate method
described
applications the most
the Channel B vertical
switch
complete triggered sweep
of the
switch
switch
obtained
operator.

TELEVISION

servicing and
also
make television
These

SIGNALTRACING
VOLTAGE

television
ment

instrument.

there

are, of course, many service

is requrred. After

user will

the

whether

the

following are applications

in the CH B

oscilloscope, and, in

in

A triggered

includes several features

features

o

SWEEP TIME/CM
vertical sync
frames
propriate

o

Vector

o

Wide
presentation.

general

For

for that matter),

job

a

single-trace or the dual-trace method

for the same

the A-B

the GND

in

can be

SERVICING

sweep oscilloscope

aligning

servicing easier and

include

and

for viewing lines.

overlay

bandwidth

READINGS

troubleshooting

receivers

provides

It

presentation

APPLICATION S

gaining

be

cdn be

several cases.

the

using

application.

flexible operation will

amplifier

position.

as well

position

position),

inverted

television receivers.

:

at sweep
horizontal

for

color

high resolution

for

PEAK.TO.PEAK

AND

(or

almost
the oscilloscope

a visual display

to make

abie

performed

in which single-trace

it

duai-trace

is

This

as free running

addition, by

(with

the

polarity

in

that were

control automatically selects

speeds

sync at

demodulator

and

any

of fields

applications

experience
more efficiently

will

application

For

used

arrangement

whatever

is advantageous

more

appropriate for viewing

isolation of

other

I and

2

previously

laboratory

and

operation

the

be found that

all

with

placing

CH A DC-GND-AC

if desired by the

This

incorporated

comprehensive.

sweep speeds

checks.

video and

electronic equip-

an indispensable

is

of absence

of the

with the

judgment

of operation.

opera-

has been

the

following

be

achieved iT
the MODE

provides

operation

MODE

the

waveform

oscilloscope

ap-

pulse

troubles

as

by

an

is

in

to

in

or

presence
may
the
path, a point

When

mere presence
peak
performance
peak

accompanying
usually
pictures
peak-to-peak
readings
waveforrn pictures.
followed
until the
The
ments
MEASUREMENT

COMPOSITE

servicing
signal,
and 22
composite video
pulses
can
to determine
Knowledge
normal
waveforms
problems.
television
dition,
amplifier.

posite

1. Tune

2.

3.

4.

5.

6.

7.

8.

9.

10. tf

I l.

of normal

be

signal

However,

voltage

voltage

procedures

Probably

be

To

Set the
Set the

position
mS/cm position

Set the SYNC
Set the

Pull

sync.
Set the CH
Connect a probe

Connect
set
connect the
output of

Set
deflection possible

to a position
Adjust the

horizontal
video display.

to

used

this

include the

are

the

and

observed

waveform,

noting the

set

video

chassis. With

the

necessary,

trace

path.

As

measurements proceed

may

happens,

the

oscilloscope shows much

or

absence of

measurement

can

often be located
measurements.
service

inciudes waveform

voltage.

on the

by

trouble

is the

show typical

the television

the TRIGGERING

oscilloscope

additional readings

is

isolated to

for making

given

earlier

paragraph.

VIDEO

the

most

composite

blanking

signals

vertical

help

The technician

receiver known

up

MODE

SOURCE switch

CH B VOLTS/CM

blanking pulses.

at various

whether

of

waveform

the

waveform

the

oscilloscope

waveforms,

switch to the

SWEEP

for

observing

switch

B DC-GND-AC

ground

the

tip

the

television

rotate the

that

sweep

lines or

signals. This method

a signal by measuring

be

found where

the

source of trouble has

of the signal. The

data

on

required

Compare

Any

abnormal

peak-to-peak

the

in

WAVEFORM

important

waveform

pedestals

oscilloscope

synchronized

stages

circuits

makeup,

and the

technician

should

'to

at

the

use

set to a local

TIME/CM

TV

for

observing

to the

to the
LEVEL

cable to the

clip

of the

probe

the

of the probe

set.

without

TRIGGERING

provides

time VARIABLE

two

vertical

the signal disappears.

signal. It

The

the

pictures.

sweep time

with

as small

CALIBRATED

and the

causes

be in

various points

for

following

horizontal

TV+

switch

switch

going

a synchronized

provides

by making

schematic

equipment

peak-to-peak

the

those

readings

in the

an area

ANALYSIS

waveform

consisting

sync

traces

with horizontal

Composite

the

of

performing

are

the

of various

locate

study

such

good

viewing

channel.

position.

CH B

switch to

TV vertical

position.

CH

B

control for

to the

CH

probe

set for

to

the

for the

off-scale.

frames

(signal-tracing)

several points

the

along

been located.

more

cause

such peak-to-

being

These waveform

and the

shown

suspected

voltage

pulses.

when

television

appearance

and

correct
waveforms
operating

television

procedure:

the

lines

frames.

position.

B INPUT
to the

10: I

video

largest

LEVEL

control

of

signal

than the

peak-to-

a

poor

of

diagram

serviced

normal
voltage

on the

should
as
VOLTAGE

in television

of the video

video

in

or to the

AC

attenuation,

display.

composite

be

circuits

possible.

measure-

Fig.

observing

sync

signals

receiver

normally.

of a

abnormal

many

in a

con-

thc

video

com-

l0

uS/cm

automatic

position.

jack.

television

detector

vertical

control

for

two

in

or

2l

2

23

BURST

VIDEO

HORIZONTAL

PULSE

SYNC

HORIZONTAL

BLA\KI

TELEVISION

Fig. 21. Set-up

NG

PULSE

SET

@ff@3

VI DEO

AMP

viewinghorizontai fields of composite

for

L\

o

-{T-l

I

,El'-

PI

CTU

TUBE

video signal.

RE

1Opr

TV­CHB

S/cm

t"

VI DEO

VERTICAL
BLANKI

TELEVISION

NG

SET

pcil@l@l

VI

DEO

AMP

@m

oG

PI

CTU RE

TUBE

2mS/cm

TV­CHB

24

Fig.22. Set-up

viewingvertical fields of composite

for

video

signal.

t2.

13.

If

sync

the

are

signals
position;

the TV-

use
Push

to a

the TRIGGERING

in

position

and blanking

positive,

the sync and

if

position.

provides

that

pulses

the

set

blanking

LEVEL control

a

the displayed

of

SYNC

pulses

switch

to the TV+

negative,

are

and rotate

well*ynchronized

video

display.

NORMAL

SYNC

PULSE

14. Adjust
desired brightness

To view a

15.
color
for
right
be

16. Composite
points on
those
setting
of
LEVEL control
of
moving from one
fore, it

the INTENSITY and

and best

specific

burst,

5X

magnification.

to

select

portion

pull

outward on

desired portion of the

the

viewed.

waveforms

video

the video

points

the

and changing

as required

and

scale,

to

to

observed waveform

the

monitoring

may be

necessary

circuits

by readjusting

maintain stabilization. The

SYNC.

PULSE

SYNC

ANALYSIS

The IF amplifier response of

evaluated

to some

horizontal sync

pulse

sync
bandpass

their

and

waveform is affected

characteristics.

relation
Fig. 23. Sync
positive
shown

or negative limiting

inFig.24.

qrcUIT

O€FECT

Normal

Crrcutt

hrgh

ol

shilt

low

frequency

frequercy

Fig.

23. Analysis

Loss
respon$

Excessive hrgh frequency

response, non-lrnear
phase

Loss of

respons

extent by

pulse

waveform.

to

IF amplifier

waveform distortions

pulse

froRtzoilTAL

PULSE

DISTORTION

FOCUS

controls

focus.

the waveform, such as

of

Rotate the

the <)

POSITION

same control

waveform to

keep

may be

by

the

the

checked

moving the probe

VOLTS/CM

display within

the TRIGGERING

be reversed when

may

to

reverse

point to

another;

polarity

the

a television receiver can

careful

Some typical

observation

The

appearance

by the

IF

waveform symptoms

response are indicated in

produced

in IF overload conditions are

RECEIVER

CAr'ERALL

FREOUENCY

RESPOiISE

Plcture

EFFECT

PICTURE

Normal

.1

prcture

Loss ot

\

Frne vertrcal
whrte stlatrons

change

a

sharp

ng

A

A-

shadr

Change
prcture

prcl

ure

rn shadrng of large

areas,

al

of

sync

pulse

distortion.

for the

the

control

left

or

at other

tip to

control

the limits

polarity

there-

the

of

be
of the
of the

amplifier

by

ON

detarl

black and

tollowrrg

prcture

In

smeared

SYNC

PULSE

COMPRESSION

CAUSED

LIM

BY

ITING

,,WHITE,'

SATURATION

CAUSED

LIM

Fig.24. Sync

VITS

The
interval.
white line above
iinearity
interval
the

frequency, amplitude,

and
adjustment
ment, but the technician can use
set
begins

frequencies

On the television set, it

height is

or

(on

TV sets

blanking circuit

The transmitted

26. The television networks
and checking

performance. The first frame of

with a "flag" of white video,

of 0.5

I+I

ITT

I

I

BY

ITING

pulse

is transmitted

the top

adjusted

with

must be disabled to see
VITS

MHz,

FLAG

I'5

1.0

0.,

,.n

|

I

the

of

internal retrace

a

is

waveshape

and

of

MHz, 2MHz,3

1.5

''.2

l.e

I

during the vertical

to view the vertical blanking

precision

network

lT ll lil

'l-

I

IIJTTI.SURST

waveforms.

blanking

can be seen as a bright

picture,

when the

blanking circuits,

VITS).

the

sequence

of

as shown in

use the

precision

signals

transmission equip-

them to

the VITS

evaluate

television
(line

followed by sine wave

MHz,

3.6

-sQrARt0

:ttrt

(rrAY

/

8t

INTtRCHAXGt0)

.vlN00u

\

RltSt

PuL\t

I

HOR

*,r',

,,,o, *

|

I1 SLAi(ITiG
PT

Ot

vertical

specific

Fig. 25

for

17)

MHz,

STAL

(VERTICAL

VITS

Most network

(the

signal
troubleshooting

VITS)

and
localize trouble to
and shows
ing
scope

when

procedures

displays

of

show

INTERVAL

TEST SIGNAL)

television signals contain

that can

servicing

the

realignment

how

VITS.

the

be a very valuable
television sets.

may

to

analyze

tuner,

be

antenna,

IF

required.

and

built-in test

a

tool

in

can

sections

or

This

video

VITS

The follow-

interpret oscillo-

FttL0

\

2

Fig. 25. VITS signal,

fields I and

2.

25

a

BOITOM

-r,JiurE

-

oF

FIELD

PUuSES

I
]

If

sYNC

VERTICAL

wrNDOw

srNE - SO,AREO

l::l; ?:::l i i

wxrrtrrac--',

iouaLrzrNG

PULSES

T-

ELANXING

INTERVAL

PUt
Or.*

SE

-

-----l

ll

iil

-t:&3;,

il

Prcrul

vrDEO

The brightness

reduced because,

onlv 60

speed is 20
times).

8.

The waveform

21 . For the

pulse

starts a new

(multi-burst)

279

280.

and
reinforces

level

although

(a

Hz

16.000

trrSEC/crn

should

oscilloscope

sweep. This

to be

The rlulti-burst

the trace.
identical and both signals
other.

NOTE

the

of

signal
the repetition rate

pSEC

(.1

be

periodt

mSECicm

sirnilar to that

display. each

causes line l7

superimposed.

signals

However,

lines

are superimposed

display will

the writrng

magnified fivc.

shown

verticai

as

are

are iines

identrcal.

18

and 280

over each

be

rs

Fic.

in

svnc

anil irne

lt

whrcli

are

not

Fig.26.

Vertical
information.

(3J8

MHz)

and

"multi-burst".

the

called

279)

also contains
portion
valuable
(lines

the VITS

of

to

the technician.

l8

and 280),
window pulse
progressively
but

have less
television
that

line
by line
vertical

lighter

value

screen.

l7

followed

is

280.

The

blanking

video.

Each
equal
these
teievision

of the

strength.

frequencies

receiver,

checked.

Set

up the

oscilloscope

1.

Connect

the video

video

2. If

section

the

television

the

detector

circuit, bypass

3. Set the MODE

4.

Set

the

up
waveform
frames will

5. Place

oscilloscope for

analysis

be

the

sweep

position.

6. Reduce
ms/CM)
glpands
VITS
expanded

7. Further
(pull
the {}
tion,
VITS

sweep time

with

the

information

waveform

expand

outward

POSITION

moving

appears.

blanking interval,

4.2

MHz.

This

sequence

The

an

identical multi-burst.

the portion

is

The

which

contains the

the

and

staircase

shading,

to

Field

entire

pulse

the technician.

#l

line

by

VITS

and

multi-burst

By

observing

the

after

the

signal

frequency response

as

probe

CH

B

or

of

other desired

television

the

frame

first

second frame

of

are valuable

is interlaced

219

appears

just

before

frequencies

the

comparative
is

follows

(set

at
set.

set has a vertical retrace

this
switch to

circuit

CH B.

during

TV verticai

previously

as

visible.

VARIABLE

time

to

.l millisecondper

the

display

SWEEP TIME/CM

by increasing the

will

appear to the

display.

the sweep

on

the

control

the trace

with

{}

POSITION

in

a counterclockwise

to the left,

showing

VITS

of frequencies

Field #2

of

This

that

can

sine-squared

3.58 MHz
to

the

As

seen on

with Field

and line

at

the

the

18

bottom

first

(line

multi-burst

be most

VITS

of the

oulse.

bursts

network.

#2 so

followed

is

of the

line

is transmitted

strengths

processed

to view

10:1)

through

of

the VITS:

to the

point

test

the

set

output

in

the

the

blankine

the measurement.

composite

described.

control

Two

in

video

vertical

the

CAL

centimeter

switch.

sweep

right

This

speed.

on the

The

the 5X magnification

control).

Rotate

direc-

until the

expanded

is

at

the

of

at

of

is

of

(.1

Fig.27.

9. The
is
oscilloscopy.
however, a single-field
obtained by
position. This
displayed
Field
preselecting the Field
Field
multi-burst information in

valuable for troubleshooting

because
VITS, either

Oscilloscope presentation

informatio

presentation

the

limit of

With

single-

n,

preceding paragraphs

the

of

observation

Model

the

VITS

placing

causes

on alternate

VITS. Because

#2

Field

or

#l

present

it

is

can be

MODE

the

the Channel B information to

sweeps, as are the

there

Field

or

#1

(Fig.

#2

on

both

used for troubleshooting and signal

trac

e

oper ation.

possible

with a single-trace

1472C

presentation

switch

is

no

1*2rnformation,

22)

will

the VITS

television receivers

Field

#l

tracing.

Now

multi-burst

not

response
good

to analyze the

are transmitted at

be equally coupled

Fig. 28

curve.

color television receiver, identifying each frequency
the multi-burst and showing the
attenuation for each.
reference voltage
for

reference).

To localize

detector.

video
before or

the

channels

after

detector,

look

tuner or

(the

trouble, start by observing

This

the detector.

check the

okay but

antenna-system

waveform. All frequencies

the

same

level,

through the receiver

the desired response

shows

allowable amount of

Remember

MHz

2.0

-6

that

dB

modulation

equals

should be

the

will

localize

trouble

to

[f the multi-burst

VITS

on other channels.

do not,

others

troubles.

you

Don't

a

probably

of VITS

(Fig.

27)

oscilloscope,

be

can

in the A &

be

Field

provision

#1

and

for

either

appear. The

the most

is

and,

Field

and

#2

of the

but should

due to

its

for

half the

used

VITS

at the

point

either

normal

is

some

If

have

overlook

the

t

I

B

a

of

at

26

n

ct
!30

I

(t

z
$oo

(l

t25

Fig. 28.

the

chance
response
vid^eo
the

the bench

the
that
either
passband,
ihe
carrying
,s
poor-

maybe
a
set

for

L,ook
bridges across

VECTORSCOPE

in
vectorscope

of

on some

detector

tF amplifier

another

As

with a

VITS at

burst

the

side.

chopping

picture

VITS. If the
and

,igtrtl

response

ptVt

ari

only

on

bite

similarly

could

VITS response

the

If

all channels,

open

for

Performance

television

color

equipment
B'&^K-Precision

this.

the

First

equalized

be

must

Attach

1.
overlay,

CnftgRATION

AND

Connect

2.
and

tune in

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)

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il

MODULATI

l

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ATION

DUL

MO

4.?-MHz

MOOULATION

FREOUENCY-MHz

TV

Color
antenna

channels.

all

on

stages.

example,

veiy

video

the

This

carilei

2.0

at

suggests

MHz

-out
frequency.

same

IF amplifier

the

at

trap

MHz is

2

the

at

one channel.

misadjusted

be

trouble

th-e

peaking

patterns,

foil

OPERATION

testing

receivers

operation

needed

color

horizontal

(see Fig.

overlay

vector

re-attach

color

the

the color

2o-MH

;

ON

43

44

IF amplifier

system

the

If

channels,

us assume

let

picture. our

poor
detector

low compared

is

iF

an

frequencies

thing is

requires

not

tuner input

Other

the detector

at

will

coils,

etc.

adjustment

and

is

oscilloscope.

the

of

color

a

is

generators

bar

verticai

and

30).
to scope.

bezel-

section

generator

bar

bar

Pattern.

450

I

I

l.

LI

-Mo

O'5-MHz

MODULATION

response

causing

VITS

trouble

the

that

about

to be

is

trap

about

Switch

to

seen,

realignment.

seen

misadjusted,

is

traps

faulty.

or

the video

be

in

off-value

of

simplified

bar

are

gain

Pull off bezcl,

(Refer to

graticule

for

to

TURE

PIC

R

CARRIE

1

-i

\

\

\

curve'

"holes"

is

oscilloscope

detuned_into

'another

then our reasoning

on other

at

output

ideally

of

or tilted

abnormal

is

we have

at the

probably in

on

a set

shows

normal

to the

except

bursts

on

the

MHz below

2

channel

If the

channels,

causing

input

is

of the

normal

the

amplifier.

resistors,

the color

by using

solder

circuits

thg

The additional

generator'

oscilloscope

the

The

suited

for

insert

MAINTENANCE

removal')

the television

set

Adjust

3.
mid-range.

SWEEP

Set

4.
Connect

5,

iacks.

horizontal

ihe

driven
cathode
cathode.

output

the
Adiust

6.

gaiir)
io*or.rt.d

vector
vectorscope

4

For

vector
orobe
vector
television
displays

sysiems

If the
will appear
rotate

on the right

is
with

The

measurement

a color

in

tarrze
produced
ihat

of the
control
their
elliptical
lists
pattern.

The
range
possible

axis.
petal should
CHROMA
oscillator
tors.

A slight

necesiary

is
position.

ments

Fig.29.

the

Installation

television

TIME/CM

probe cables

Chinnel

A is

input.

the red

the

is

(The

signal

CH

of

driven

driven

oi

(vertical

A

and

pattern

45o

The oscilloscope

element

the

VOI-TS/CM

overlay.

operation.
presentation,

driven

to the

pattern is

set manufacturer.

obtained

with

picture

for sets using

either

tube

on the right

vector

the

side.

overlaY.

vector

the

vector

display

of the

TV set.

the color

by

color

with

amplitude

himself

the

petals but

changes

amplitude.

the

Lastly,

pattern than

common

some

vector

of

display can

the color set's

to rotate

the

At

center

be vertical.

reference

transformer-coupled

is

touch-up

to bring

not attempt

Do

the chroma

on

RATI

G

of

hue

set's

control

the CH

to

vertical

the

Connect

gun,

element,

eiement

the color

VARIABLE

that

merely

element

same

the

grid drive

NOTE

uses cathode

overlay

The color

functions

serviceman

The

the

controls.

their

not

position

l05o sets

90o

troubles

hue

R-Y

the

the hue

of

oscillator.

this transformer

of

the

bandpass

CULE

VECTOR

OVERLAY

m

vector overlay.

brilliance

and

position.

B

CH

the

to

CH

input

both

usually

then

the

is

amplifier

gain)

and

A and

Channel

and

probe

the

connect

element

applied.)

is

B

CH

controls

approximately

now

is

the

move

gun.

blue

the

of

type

given by the

as

Fig 31 shows

l05o systems

drive,

the

the

will

drive.

the burst

screen'

BURST

then

or cathode

side of

so

180"

bars

provides a very

demodulators

of the

should

effect

control

on the

He

should

will vary

position. The

petals but not

the

of

sets.

and

be used

control.

petal

will

The

their

about

have a
table

effect

to check

It should

the

control

it

is

not,

If

locate

[n most

demodula-

to the

is

petal to a

R-Y

to make

any

amplifiers'

BEZEL

controls

to

B INPUT

B is

the

to

tips

grid.

If

the

to the

which

to

(horizontal

obtain a

ro
set up

fills

the

tor

horizontal

The color

typical

90o

and

Just
label
align

quick

famil-

pattern

observe

size

the

hue

more

below

on the

the

be

vertical

the R-Y

the

this

sets

that

all

vertical

adju.st-

This

27

@

o

COLOR

BAR

GENERATOR

CHASSIS

q

U

ADJUST
REOUIRED

GREEN

A

o
o

@

@

I

l@,

PICTURE

TUBE

amplifier
c-annot
display.

display
ment.
cedure to
counting
between

in

If the

can

Follow

R-Y

is

aligned

general

set has

also

the

locate

bars

simply

and B-Y.

Fig.

30.

by

a sweep

be

aligned

adjusted

be

the

demodulators,

used

manufacturer's

for

proper

adjust

for

Equalizing

generator

just

by

demodulator

coils and

the

a vector

the

alignment

instead

correct

horizontal and vertical

and

vector

alisn-

pio-

of

angle

gain

for Vectorscope

operation.

NOTES

28

GRI

DRI VE

R-Y

F=\

t-\

D

CATHODE

VE

DRI

--------Rt

1y.-

ID

GR

DRIVE

DISPLAY

VECTOR

R-Y,*-_-

VECTOR DISPLAYS

TROUBLE

otA n/

,"=Rvr

Y\A

\

6/U\

,

FOR

90"

HN4

;

FOR 105"

COLOR

BAR

GENERATOR

\___r\_

PICTURE TUBE

\>..\\i

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PICTURE

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CATHODE

DRIVE

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| ,/1

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RED

BLUE

EFFECT ON T.V.

PICTURE

TUBE

e

U

I

PICTURE

Loss

of color sync
Overloading
Color amplif

weak

Lack

Demodulator

of

iers unbalanced

range

of

color

hue

of

out of alignment

amplif

control

iers

or

Fig.

Petals
Petals
Flower

R-Y

Angle

31. Vectorscope operation and

pattern

of
are

pattern

petal

vertical

between

petal

not

ication

specif

General Specif ication

will rotate

crushed

cannot be made to be

to

f

lattened

or

very elliptical

petal

R-Y

manufacturer's

(90"

or

and

105'

).

NOTES

B-Y

patterns.

Varying colors

distortion

Color

distortion

Color

Hue

control

fl eshtones

Wrong

won't

colors

adjust

29

TELEVISION

ALIGNMENT

INTRODUCTION

Alignment
circuits in
oscilloscope,

television

such as this

of

tuners,

the video IF strip,

receivers requires a

instrument.
of test equipment required are sweep
sweep,
supplies
aligrment

IF

sweep and

and a

displays a bandpass response curve on the screen

of the oscilloscope of

RF

VTVM.

the
books and in the television set
instructions

f5 74

40 4r

38 39

(typical

75 7?

response

70

69

4l

44

Fig. 32. TV response

frequency

The

oscilloscope

instruments

ideal

and the

Generator. The B &

technique.

B &

K-Precision Sweep/Marker

provides all necessary sweep

from one

voltages,
procedure and
in

television set,
ever,
use of

television

all

calibrated accuracy

precision

For

alignment.

complete

follow the

the following

the oscilloscope for

manual,

In this

emphasized.

is
and other equipment
provided

in the

instrument.

alignment instructions

general

the

only

required

instruction

marker

sweep,
The sweep

generator

type always shown in

manufacturer's alignment

curves are shown in

curves

for

obtained

television alignment are

K-Precision Sweep/Marker

ranges, markers and

The simplified

the

of

manufacturer's

set-up

instructions

sweep-frequency

proper

use

Proper use of the sweep

for alignment should be

manuals

for those instruments.

and chroma

quality

high

The additional

generators

generators,

for video

DC bias

method

theory

Fig.

CONSIANT

AMPL I T

UO€

R_F

SWEEP

OV€RALL TUN€R
R€SPONS€

I-F

OVERALL
RE

SPOai

S€

CXROYA TAXE_OFF

RESPONSE

COIL

OVERALL

CINOilA

RESPOf{S€

by sweep-

Generator

DC bias

operating

instrument

of

each

results

particular

instructions.

demonstrates

alignment.

of the

oscilloscope

generator

pieces

,of

32).

this

How-

in

NOTE

For

a comprehensive analysis of
ment, we recommend the
the B &
This
not only the
but
alignment
generators,
valuable
make
many.
step

textbook.

K Model 415

"handbook

the

all

how and why

general.

in

this

procedures,

alignment

illustrations

approach

Copies are

of

procedures

comprehensive manual

easier and more

and

qualify

instruction

Sweep/Marker Generator.

television

alignment"

for using the

answers about

if

you

Even

insights and tips that will

easy-to-understand step-by-

it as the

available from

B & K-Precision distributor or the

IMPORTANCE

most

The
of the tuner,
receiver
sweeps through
channel at a

processed

shaped by the
sections. Because
tuned circuits to

has the
at

proper

certain

bandwidth properties

Fig.

32
curves of
circuits below
to

scale. These

be

obtained if

receiver

were

oscilloscope.

response

Some reference
importance
frequencies
area
this

the

is

area

response

Notice
constant-amplitude portion
spectrum.
information
circuits of

This

is shown by

Notice

that
chroma
amplitude with

the

of

chroma frequency
for this frequency-versus-amplitude
overall
between
chroma
tuned

yryally

IF

the IF

portion

to the

4.08 MHz

32. This
characteristic

curve

(3.08

curve. The
and

g

Jqsponse
IF

produce
range

OF

SWEEP ALIGNMENT

rapid

way

to

and chroma

a

is to

IF

provide

the entire

controlled, repetitive

through

the

gain

tuned

and bandpass properties

the

signal

another

characteristics.

points

and the

up

shows the

the

tuner,

it. The

sweep

IF

bandwidths

outlines are similar

the

outputs

demodulated

Because

least

is

of the

critical.

frequencies

proper

of

are on the

most

will

affect

curve and this

that

Notice

critical

the

the

chroma

that

alignment.

slope

because

amplitude

in turn

the

are modified

the

television

reference to the

the

signal

frequency

information

range

respect to

range

response

compensates

output

of the

upper

and

the

of

curve,

and the

receiver.

end

provides

for the

chroma

result

the

response

q4

overall

MHz

response

4.08 MHz).

to

determine

portions

constant-amplitude

bandwidth

rate.

portions

is channeled

it

is

important

If fhe signal

envelope observed,

to that point

signal

amplifiers

and

shown

to

of the

and

the

various

the curye

relative bandwidths,

are identified

Notice

the

of

IF response

improper

and

affects

color

information

the transmitted

of

relative

by

passing

amplitudes

receiver tuner

overall IF

the

at

(4.08

MHz)

the

signal level

(3.08

MHz).

characteristic

a

chroma takeoff

bandpass

The

of the

chroma takeoff

chroma

a

response

amplitude-versus-frequency

portion

of combining

of the

chroma takeoff

in the

The

resultant

television

align-

manual for

includes

instrument,

television

use

other

sweep

provides

professional.

"how

The

to align"

your

factory.

the overall

of

condition

the

television

signal

given

a

of

of the

from one

that

As this

receiver,

of the

each

television

signal

various

series

section

is demodulated

gain

the

be determined.

can

with

basic response

chroma bandpass

are approximately

curves that

sections

of

would

the

observed

the

to

show

that

the chroma

curve.

IF

alignment

shape

the

of

picture

chroma
quality.

is located

television

the

of

through

and IF

response

uppei

is

at the

To

chroma

the

amplifiers.

curve.

end

of the

reduced

lower

compensate

of

coil is

amplifier

of

coil is

frequency

as shown

of the

the

response

range,

in

overall

of the

coil

chroma

frequency

signal

is their

which

it is

and

TV

on

an

tuner

the

This

on a

tuned

in

end

the

used

the

Fig.

If;

to

is

of

in

t

is

-

-

!

30

applied to the bandpass

indicated by the overall

Alignment

specified

;edures.

iakeoff
the

bandpass transformer.

as a

[n

coil

of

separate

other

performed

is

amplifier which

chroma response

the

chroma takeoff

step in manufacturer's

procedures,

adjustment of the

together

SWEEP AI,IGNMENT METHODS

The best method

*'hich

stages require
irequency
bias
grounding
circuits
to

the manufacturer's

signal at the tuner

line must

the

then

aie

The technician
receiver
rs
problem
strip and
response

require alignment.

satisfactory but

is between the video detector

the output

and the

likely that the IF

response

The RF
ment
that of
which

part

the

poor

is

portion

problem

the IF section; however,

located

is

of the tuned

IF

first

of checking

alignment

antenna

be clamped

AGC line. The

by application

outputs

observed on an oscilloscope

recommended

then decide

can

For

example,

the chroma

the

of

bandpass

chroma response are

requires

on the

of

because the

on the tuner,

matching

stage. A

touch-up,

slope affecting

the

tuner

passband

may

network between the

separate

has the

response

curve.

coil

is sometimes

test

pro-

chroma

with the

alignment

to

is

adjustment

inject

an

RF

determining

and

terminals. The

sweep

AGC

of bias

the

[F

of

response
which portions

response

and

curye.

the

if

is not.

and chroma

compared

of the

[F

response

then

the

output of the IF

amplifier" if the IF

poor

then

particularly

it is

most

if

the

chroma response.

seldom

creates

is so much

the mixer

require

attention.

an

align-

greater

than

output circuit,

This

tuner and

pre-alignment procedure

of

given

for the link

Once the

alignment

an
aiignment

deficient portion

procedures

suggest signal

can

generate

which

circuits by some

that

of

check

vary

combinations

IF

and

manufacturers.

of the receiver

section

can

performed.

be

with manufacturers. Some

the

at

tuner

video

antenna

sweep frequencies

receiver so that overall alignment can be done by selecting

right

the
this
alignment.

frequency for
modulated by
video

or

modulation is

receiver and applied t'o the

alignment

injected at the mixer

alignment. The

then

before

receiver

chroma

circuits
modulation
check
alignment and chroma

is

chroma circuits
overall

is

combination of

tirst

to

is

After this

connect

the

channel being used is selected and this is

video

a

input

an

is compiete,

sweep signal

sweep modulation method).

demodulated

at

chroma bandpass circuits

of these

Other manufacturers

stages.

recommend an

grid (or

picture

[F

modulated with

this

is detected at the video detector of

and the

recovered

carrier frequency

video

a

sweep
sweep voltage is

circuit alignment

Another method

directly.

of the IF

the

combined effect

to

is

The IF

pix

first video-sweep align

then

is

frequency

on

alignment.

is necessary

chroma resDonse.

signals. One way

sweep

the

(this

generator

picture

is

RF

This video sweep

the video detector

[F

base,

sweep

transistorized)

if

(45.75

voltage

(VSM

aligned and

(45.7

the

Usually

to

obtain the

5 MHz)

chroma

a

touch-up

determined,

is

The

terminals

the

in

doing

of

for IF

carrier

the VSM,

of

or

the TV

for the

frequency

for

IF

MHz)

As

again).

the TV

for the

used

the

chroma

video

sweep

is

to

used

response of IF

of the

desired

final

is

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TERMINALS

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Fig.

33. Typical

tuner

alignment

set-up.

3l

In

conjunction with
facturers
frequencies
point).
tuned

particular
preferred
are
procedure.
deficient
the
has occurred
procedures.

TLJNER

1.

2.

3.

4.

recommend

into

Other procedures

circuits

In

all

cases the

receiver and

for

also reliable

technician

Connect

antenna terminals

sweep
Tune
Connect

directly
Connect
DIRECT)
is_

where

Set the

VARIABLE)

If

receiver

ALIGNMENT (Refer

generator

the

TV set

the

to

normally

a demodulated

vertical

If

alignment,

pre-tuning

the IF

in the IF

alignment.

and in most
complete realignment

must

and must

the

the tuner

the

to the

the

for

(usually

before

manufacturer's

the manufacturer's

SAMS PHOTOFACT

does

not restore

then

consider

employ

output

of

to sweep
to the

ground

Channel A (Vertical)

tuner test

grid

of the mixer

signal

controls

maxirhum

IF

at a specified

outline a

sweep

method

cases

repeat

that

standard

to Fig.

of the sweep

the

television

one of the

same

channel.

clip

of the oscilloscope

shield

to

point.

present.

is

(CH
sensitivity

practically

traps

by

injecting

prealignment

alignment

is the

service manual

the

manufacturer's

of

the

minimize

an apparently

required

a

component

troubleshooting

33)
generator

set.

TV

channels.

hum pickup.

probe (set

The tuner

tube

or equivalent,

VOLTS/CM

A

and operate

all manu-

spot

tuner

test

of

procedures.
best for

procedures

iesponse,

Adjust

test

all

his

is

iailure

to the

the

probe

to

point

and

the

generator

sweep

television receiver,
curve and
the

oscilloscope screen.

5.

The

oscilloscope sweep
exact synchronization
proper presentation.
accomplished

lgtltlg
(SWEEP

the
to

6.

Select the marker generator
measure

7.

The tuner

oscilloscope. See
the

adjustments

IF ALIGNMENT

l.

Connect the
signal
generator
tuner has

applied at the

2.

Synchronize
generator
ALIGNMENT

the

TIME/CM

horizontal

the

Channel B

the

response

injection

at low

provide

oscilloscope

upper and lower

response

for

to
been

as previously

which

an

erroneous

of the

for sinusoidal

to CH B,position)

sweep

input

the manufacturer's

curve specifications

realignment.

(Refer

to Fig. 34)

output

point

sweep

properly

antenna

the

oscilloscope

procedure.

level to

would distort

picture

and sweep

phase

and

response

or sawtooth

for

external

voltage from

terminal

frequencies

response

curve

is now displayed

the

of
of the mixer.

the

terminals)

sweep

tF frequency

aligned,

sweep

described

avoid

overloading

of

generator

with

each

curve.

horizontal

and

the sweep

on

the

oscilloscope.

of the

instructions

the

and

generator

Adjust

band.

RF

sweep

with

in the

the response

alignment

This

connectlng

required

the

the

on

must

be

other

for

is easily

sweep

tuner.

by

input

generator

to

on the

for

necessary

to the

the

sweep

(If

the

may

sweep

TUNER

in

be

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32

Fig.

34.

Typical

IF

alignment

set-up.

ground

Connect
probe to the

t

t-

Connect
video

Set

VARIABLE) for suitable
curve.

(-r

Keep
overloading.
tions

1.

Select
check
A sweep and
the
B &

x

Follow
the

85"/"

the

television

the vertical

detector

the

the sweep

on

the

markers simultaneously,

K-Precision Model

response curve

output.

generator

Follow

marker

critical

marker

gain

AGC.

generator

frequencies

and

vertical

disabling

the

the manufacturer's

of the oscilloscope

clip

set chassis.

probe

controls

the manufacturer's

generator

415,

making the

the oscilloscope

of

(CH

A VOLTS/CM and

viewing

output

is a

instructions

of the

level low

frequencies

of

interest

advantage.

big

alignment.

of

capable

such as the

for evaluating

vertical

the

to

response

prevent

to

recommenda-

required

(see

displaying

to

Fig. 35).

all

Use a demodulator

4.
(Channel

curve
Set

5.
VOLTS/CM and

size on
A response

6.

should
of
bandpass

9e/"

A) to the oscilloscope.

the

at

input

the

vertical

the screen.

curve

be seen. Select

interest.

3.OB

Refer to

specifications

-l

MHZ

*lo"/"

probe

to the demodulators.

gain

controls

VARIABLE) for a convenient

similar

the

the manufacturer's

I

I

I

I

for the vertical input

Measure

of the oscilloscope

to that shown in

marker

and alignment

_

generator

MHZ

3.58

r

I

I

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procedure.

4.O8 MHZ

the response

frequencies

instructions

(CH

A

viewing

Fig. 37

for

:ts"h-

5o"/"

I

/l

-^/

souND

.?5 MHZ

Fig. 35. Typical IF response curve, showing

CHROMA ALIGNMENT

The IF alignment
before starting this chroma
urjection
injection

drastically.
for

such

alignment.

l. lrave the sweep/marker

connected
to
frequencies.

used

2. Apply the
the color
manufacturer's

3. Synchronize
described for

-----)

CHRoMA

42.t7 MHZ

ranges of response

of video sweep is

specified herein,

Follow

direct injection

sweep

for IF

I

I I

|

I

I

I

levels.

(Refer

must

manufacturer's

the

as for IF alignment.

approximately

Use

the same

alignment.

proper DC bias

amplifiers

(bandpass

instructions

the oscilloscope sweep as

tuner

alignment.

Fig. 36)

to

be

satisfactorily

alignment

rather than

used
the response curve

of video sweep

generator

Set

4l to 44

the

tF

injection

to the

amplifiers).

for the

procedure.

procedure

the sweep

color

tolerance

completed

the IF

is altered

for

AGC bias

and

MHz

level that was

killer to

Refer

correct

bias

previously

direct

[f

sweep

explicitly

chroma

generator

band

of

enable

to

the

level.

Fig.

37. Typical

VALLEY

t-_

t5

"/"

ILT IOTO

T

tolerance ranges

chroma response

NOTES

MAX

MAX

4

MHz

so

of response levels.

i
I

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curve, showing

33

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Fig. 36. Typical

FI

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chroma aiignment

COLOR

(BANDPASS

set-up.

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AMP

AMP)

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Procedure:

1. Connect
FM receiver.
centered

2.

Connect

generator

scope

horizontal

.)

Connect

of

input

4.

Adjust
controls

5. Set

6. Align

7.

the

marker

specifications.

Move the

curve

FM RECEIVER

Refer

generator

sweep

a

Set the

sweep.

sweep

the

the Channel B input

to

set the

and

the

the

the oscilloscope vertical

for display similar

marker

"pip"

the

should

(SWEEP

sweep

vertical input

FM

receiver.

generator precisely to 10.7

should

IF amplifiers

probe

to the

displayed.

be

ALIGNMENT

Fig.

to

to the

generator for a 10.7

sweep

voltage

oscilloscope contrcls

TIME/CM

probe

to

be

the

in

according

demodulator output.

and

FM RECEIVER

38. Typical

Fig.

38

mixer

output

that shown in

center

of the sweep

jack

of the oscillo-

to CH

to the

horizontal

and

the

of

the

to

manufacturer's

the 10.7

FM

the

of

input

MHz

for external

B).

demodulator

gain

Fig. 38A.

MHz. The

bandpass.

"S"

The

"pip"

MHz

receiver

Typical
spetific

distortion

Dstortion

the oscilloscope

in

tested.
input
circuit is
The amount
can

cedure

alignment

should
Adjust
faciurer's
distances
increased

MFIz center

Phase measurements

A sine

be calculated

To

set-up.

appear

exactly

the demodulator

instructions

from center

decreased

and

frequency.

PHASE

applications

phase

in audio

due

wave input

The same

of the

applied

of

phase measurements,

make
(Refer

are in

shift,

amplifiers

to

non-linear

waveform.

sine

oscilloscope,

to

the horizontal

phase difference

from the

Fig.

39).

to

MEASUREMENT

may be

and

is applied
wave input

in the center

according
the marker

so

as

equal

circuits

measurement

amplification

and

resulting

marker

the

amounts

with an

made

desigrred,to

other audio

or

the audio circuit

to

is applied

output of

the

input

between

waveform.

use

(see

Fig.

to the

moves

frequency

from the

oscilloscope.

produce

phase

of

networks.

displayed

also

is

to the

the

the

of

oscilloscope.

the two signals

following

the

38B).

manu-

equal

is

10.7

a

shift

being

vertical

tested

pro-

35

AUDIO

SI

GNAL

GENERATOR

(t

m

#

W
ffi

ffi

ffi
ffi

o'
0

@

o

@

@

[.

cr'

I

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I

@l

CHB

f

I

Using

l.

2.

3.

4.

5.

6.

7.

an
signal,
frequency

Set the
operating level
the circuit'sr output may
scope. If the
display on

level must
Connect the

circuit.
Set the
Connect the

the test
to
be reversed.)

Adjust the
viewing size.

Some typical
signals
diagonal
properly

A

.90o

pattern.

audio signal

apply

a sine wave test signal

to the
signal

test

the

be

reduced.

Channel B

SWEEP TIME/CM

Channel A INPUT

(The

and horizontal oscilloscope

Channel A

results

phase,

in

line. If

adjusted, this line

shift

the

circuit.

vertical

are

phase

audio network being tested.

generator

of

oscilloscope

the vertical

Fig.

39. Typical phase

generator

the

circuit

circuit is overdriven, the

probe

input

and B

are shown in

the

oscilloscope

produces

with a pure

at the desired

output for

being

be observed

is

control

and output

gain

at

is

tested. If desired,

on the oscillo-

clipped and the signal

to

the

output

to CH B.

probe

to

test connections

controls for

Fig.

40.

trace

and horizontal

a 45"

angle.

a

circular

the normal

the

is

oscilloscope

N ETWOR

BEING

sinusoidal

test

sine wave

the

test

of

of

input

inputs may

a suitable

If the two

a straight

gain

are

VERTICAL

AUDIO

K

TESTED

measurement

alignment

NO AMPLITUDE

NO PHASE

ISoO

AMPLITUOE

Fig.40. Typical

SIZE SIZE

PHASE

HORIZONTAL

set-up.

DISTORTION

SHIFT

PHASE

OF

oUT

OISTORTION

FT

SHI

displays.

phase

AMPLITUDE

NO PHASE

AMPLITUDE

NO

PHASE

90" oUT oF

measurement

DISTORTION

SHIFT

DISTORTION

SHIFT

PHASE

U

oscilloscope

36

Phase

elliptical

be

can
Fig. 41.

calculated

shift

of less

oscilloscope

from the

(or

more)

pattern.

The

oscilloscope trace

90o

than
amount

produces

phase

of

as shown

an

shift

in

UNKNOWN

TO VERT ICAL

STANDARD FREqUENCY

TO HOR

FREqUENCY

INPUT,

IZONTAL

INPUT

sEE-"'((

E

))

RAT

STANDARD

IO

KNOWN

UN

TO

,-r:

OF

I

Fig.4l.

FREQUENCY MEASUREMENT

Procedure:

1.

Connect the sine

INPUT

B
TIME/CM
horizontal

2.

Connect the vertical
unknown frequency.

3. Adjust
convenient,

4.

The resulting pattern,
the

jack

control to

input.

the

Channel A and

easy-to-read

ratio between

B

_A

6

WHE

RE

Phase

wave

of

of the oscilloscope

CH

input

size

called a Lissajous

the

two

=

PHASE

il

shift

calculation.

known

frequencies.

B.

This

probe

B size

display.

of

frequency

and set the

(CH

ANGLE

to

provides

A INPUT)

controls for

pattern,

See Fig.42.

the

CH

SWEEP

external

to

the

a

shows

sEE -rrrr/0o$,

NOTE:

Fig.42.

As stated
of odd harmonics. By
amplifier, we can evaluate
only,
we can determine
input

The need

we

if
during normal use to
different
controlled signal with
output
harmonics
sees

instruments

ANYONE
UPON PHASE

Lissajous
measurement.

before, a square

but by injecting a

from

signals

for

realize

frequencies. With

quality

of the square

when amplifying

or

OF

waveforms

injecting a 500 Hz

how the amplifier

Hz

500

square

that some

pass

which

of a

voices.

THESE

RELATIONSHIP

square wave of the

up

wave

audio amplifiers

simultaneously

signal

wave)

complex

l:1

lta: I

6:l

FIGURES

used for frequency

wave contains a large

amplifier response

to

the l5th or 2lst

evaluation

a

square

we can evaluate the

of

many

which

DEPENDING

sine wave

same frequency

respond

would

becomes apparent

will be required

a large

wave, we

frequencies

what the

is

waveforms of

number

into an

500

at

num6er

Hz

to

harmonic.

of

have

input

and

(the

amplifier

musical

a

t

il

SQUARE WAVE

INTRODUCTION

A

square wave
scope, such
various types
square

wave

of

odd harmonics

wave

in injected

1.5

kHz,
tubes and
and reproduce
signal. Interelectrode
stray capacitances
response are a few
reproduction
amplifier

limitations.
introduce
is unsatisfactory.

2.5kH2,3.5
transistors

can
distortion

generator

as this

of distortion present

given

of a

of

into

are non-linear,

a square

as well

of

of a square

minimize

Poorly

designed

to

TESTING

instrument,

frequency

that

frequency.

a circuit, frequency

kHz,

also

wave

capacitances,

as

the

the

the

OF AMPLIFIERS

and a low-distortion

can be used

in

electronic

contains a large

If

provided.

are

it

which

limited device

factors

wave signal.

or defective

point

is difficult to

is

identical to the

junction

which prevent

distortion

where

oscillo­display

to
circuits. A

number

500 Hz

a

components

and transformer

A well-designed

caused by these

amplifiers

their performance

square

of

vacuum

Since

amplify

capacitances,

input

faithful

can

The

extremely flat so that

distortion
response. The
DC as it
frequencies.
quency of
low end
of
of the
end

amplifier
especially important in limited
amplifiers).
of amplifier
overall
some
wave signal.
testing the amplifier,
specifications
better

square

that

introduce

will

the

the amplifier

of

the

bandpass;

square

the

amplifier

of

It should be

should

The square

amplifier

deficiencies not

Whether

judgment

output

wave

may be

oscilloscope

When

checking

square wave

however, because

wave,

bandpass is reached.

noted that the

be made

performance

quality.

on

the

of its

of the

does not contribute to

it

observed

vertical input

the least

input should

bandpass up toward the

distortion

using a

wave signal provides a quick

and

The square

readily

a sine

wave or

it is

important

amplifier be known

performance.

generator

signal

evaluating

when

distortion,

amplifier response, the

of

will occur

actual response

bandwidth amplifiers

will

apparent

should

especially

be

varied

the

harmonic

before

sine

wave

give

an

wave

when

square wave is used

that the manufacturer's

in

order

must

amplifier

be set to

at

from the

upper

content

the

upper

check of an

signal. This

also will reveal

(voice

check

estimate of

using a

to

make

be

any

low

fre-

end

is

sine

for

a

37

TESTING

1. Connect the

2. Connect the CH B test probe

3. tf the DC

4. Adjust the

5.

6.

PROCEDURE

the input

output

sufficiently low to
component to be
AC-GND-DC
used without
frequencies

viewing
Adjust the

wave display
For

use

of the amplifier being

the amplifier being tested.

of

component

switch.

(below

vertical

height.

sweep time

on the screen.

a

close-up

the 5X

magnification.

(Refer

output

of the square wave

of

allow both

viewed,

However,

affecting the

5 Hz).

gain

controls for

of a

view

to Fig. 43)

tested.

the

of

oscilloscope to the

the

circuit being tested

the

the

use

the

results

controls for

portion

position

DC

position

AC

except

one cycle

of the square wave,

generator

AC

at very low

a convenient

and

of

may

square

of

to

is
DC
the

be

maximum
half-cycle
amplitude alone
produce
of one

amplitude to
point.

a rounding

wave

square

Therefore,

the

of

high frequency

the square

of

(See

cycle

zero

amplitude at

a theoretical reduction

Fig.

components should

corners at all four

).

the

l80o

points

or

in

v

ANALYZING

The
half-cycle
and high
true for the

short rise time which

is created by the

frequency sine wave

THE WAVEFORMS

occurs at the beginning

in-phase sum

rapid drop at the end

SQUARE

GENERATOR

components. The same

WAVE

o

the

of all

of the half-cycle

medium

o

the

of

holds

from

P^fr

Fig.44.

g

U

CH

ADJUST

GAIN FOR

CONVENI

VIEWING

Square
loss.

@

o

@

0

@

VERT

HEIGHT

ENT

wave

I

rll-lr

I

response

@

O

with

ADJUST

SPEED

CYCLE

SLOPE

CHB

high

frequency

SWEEP

FOR

1

DISPLAY

+

U

38

l

INPUT

Fig.

43. Equipment

AMPLI FI ER

CIRCUIT

BEING TESTED

set-up

for

square

OUTPUT

wave testing

I

of

amplifiers.

T'

Distortion can

t.

The
change
complex
an amplifier

filters created

will create

response curve.

2.

The
change
waveshape
as
extreme
clipper

3. The
distortion
more components

in actual

component

wave

frequency-selective

a
inductance

difference

phase

distortion or

wave testing

distorted square

the
amplitude

ln a
accurately
circuit.
revealing
compensated
applied
46A. This figure indicates
response
low frequency
applied to
Fig. 468.
the region of
overcompensation at
rise

the top of

at

As a rule of

wave can

to the 15th

up
imately
this rule of
require
the complete

Hz

100

about

10,000

be classified

first

second is

vacuum

third is

typical

The response

poor

to the input

(approximately

be

40

at

square

4000 Hz.

Hz,

frequency

is

from

normal

waveform.

circuit

by combination

peaks or

non-linear

in waveshape

to non-linear

tubes, an iron core

a

case,

network.

delay or

produced

practice,

(sinusoidal

or both. The

phase

in

of

and

reveals

the

This

used to reveal

times

thumb, it is seen

least a

a 1000

delay

practical

phase

distortion

wide band amplifier, a square

many distortion characteristics

low-frequency

high-frequency

response.

input

figure displays
1000 to

the leading edge of the square

thumb, it can be safely said

or 20th

the fundamental of the square

two-frequency

spectrum.

wave will encompass components

To analyze above

Hz

In other

of

dips in an otherwise

deliberate non-linear circuit

by a shift in

of

a complex

a reduction

network which includes capacity,

presence

angle

circuitry,

wave

of an amplifier is indicated in

of this amplifier

of this same amplifier

4000 Hz but clearly

the higher 10 kHz region by

[n the

square

distinct

three

into

distortion

amplitude

resonant

produced by application

components

harmonic) is usually

between components,

distortion. Therefore,

boost. A i00

satisfactory

kHz

1

Next,

response

odd

of a

words,

networks

of

distortion

transformer, and in

phase

phase

waveform.

in amplitude

of the C or

we

includes

clues.

response along

2 kHz) but shows

to

1000

a

good

frequency response

and

harmonic or

that wide-band circuitry

check

illustrated by

case

4000 Hz

wave

should be

categories:

refers

and

component

the introduction

reactive components

distortion,

will usually

a combination

will

medium frequency

to

or selective

flat frequency

refers to a

and

or elements

such as a

which is

between one

of a square

caused

L

introduces

creating

in square

find that

wave check

with

Hz

square

as in

appear

Hz

square

will appear

reveals the

the sharp

wave.

that a square

phase relationships

to approx-

up

wave.

properly

Fig. 45,

and
satisfactory.

the

to

of

in

the

of

such

an

or

by

of

of

the

Fig.45.

over­wave

Fig.

poor

wave

as in

in

Using

will

analyze

to

up

beyond

a

u,

tt,

z
o
c
o

ur

a

poor

Fig. 45. Response curve

and

a

Hz

to0

SOUARE

WAV E

Fig. 46.

a

Resultant 100

from amplifier

high

ends.

of amplifier

I

SOUARE

Hz

and 1 kHz square waves

Fig.45.

in

with

KHZ

WAVE

low

Now, the region
shows
flattening out
we can

100
and
same square
low-frequency response

such
the square wave, a
obtained.
ponent, as already
element, causing,

a rise
expect

Hz square wave

phase

but that

If the combination

to

as

only

However, reduction

between

poor low-frequency

from

from beyond

that the

wave

higher frequency components

will be

lower frequency components in

the

will

of

of

depress the

curve

noted,

in turn, a

Hz

100
1000
relatively normal in amplitude

strongly

be

this amplifier. See

elements in this amplifier

low frequency

similar to

is usually

phase

4000 Hz

and

and

modified by the

in amplitude

shift of the

response to a

Hz.

4000

Fig.

components

Fig. 47 would

caused

by

Therefore,

to

component,

45

Fig.

in

the

in

this

poor

46A.

were

in

be

a com-

a reactive

Fig

47.

Reduction
frequency

of square

component

fundamental

wave

in

a tuned circuit.

39

Fig.48.

Square
phase

shift.

tilt resulting from

wave

3rd harmonic

producin$
graphical
tilt
phase-shifted
very slight shifts
the square wave.

Fig. 49
by a 10"
direction, Fig.
frequency
opposite in the two cases because of
polarity
checked

Fig. 51
been reduced in
noted
characterized by change
the

Fig. 468,
overshoot

higher

overshoot makes itself

edge of
explained by

square wave, the sharp
the summation of a
components.
occurs

the

in
greater

sum

the strong tilt

development

seen to

is

that these

square wave.

along

3rd

indicates the tilt

phase

shift of a low frequency

component in a

of the

through algebraic addition

indicates

previously

produced

frequencies.

the square

remembering that

If

at high frequencies,

square wave

than

other components

the leading

of a

be

caused by the strong

harmonic. It

phase

in

50

indicates a 10o

phase

angle in the two

low

amplitude and shifted

examples

by rising

It

wave.

rise of the leading

practically

an abnormal

will

edge.

Fig. 46A.

of
similarly

are

in square wave shape

lagging

frequency

of

in shape of the flat top

discussed,

should
evident

This

the

be amplified disproportionately

tilted square

becomes

also

quickly

phase

direction.

of

components.

components which have

low frequency

revealed high-frequency

amplifier response

again be noted

the

at

characteristic relationship

in a normal

infinite number of harmonic

rise in

high

frequency

creating a higher algebraic

Fig. 48

influence

shown up by tilt

element

the

cases as

phase.

in

top

edge is created

amplifier

reveals

wave. The

of the

evident that

produced

in a leading

shift

in a

The tilts

difference in

can

It

will be

distortion

portion

at the

that this

the leading

of

well-shaped

response

components

a

in

low

are

be

are

of

is

by

Fil

A)T

tr

Fig.49.

FxI

Tilt resulting from
mental frequency

OUT.OFPIIASE

PHASE

(LEAD)

in a

phase

shift of funda-

leoding

direction.

Fig.

51.

Inw

shift.

frequency

component

loss

and

U

phase

40

Fig.

50.

Tilt

resulting from a phase

mental frequency

in

lagging

a

shift

of funda-

direction.

Fig.

52. Effect
damping.

of high-frequency

boost and

poor

U

52

Fig.
accompanied
sinusoidal

the square
relatively
case,

indicates

by

type of

wave indicates

high

the sudden

from a sharply

low

level value

of

oscillation in

reasonably

amplifier
transient

is

oscillation

53.
54

Fig.

serves

summarizes

as a handy

lightly

a

diminishing

"Q"

network

transition

rising,

frequency

resonant

the

reference.

frequency

high

damped

relatively

voltage,

network.

heavily

may be

the

amplifier

boost in

"shock"

oscillation

a transient

the amplifier

in

the square

in

frequency voltage,

high

supplies

If this

damped,

an

transient.

the

along

oscillation

circuit.

potential

wave

the energy

network in

then a single

produced as indicated

preceding

explanations

The

top of

in ^

this

In

to a

for

the

cycle

Fig.

in

and

A. Frequency distortion.

reduction
ponent).

ol

No

low

phose

lrequenry

(crmplitude

shilt.

com-

B. Low

frequency boost

oted Iundomentql).

Fig. 53. Effect

damping.

(qccenlu-

of high-frequency

frequency

High

C.

shilt.

boost

loss-No

and

good

phcrse

D. Low frequency

G. High

lrequency loss ond

shilt.

phose

shilt.

phose

Fig. 54. Summary of

E.

Iow lrequency loss ond

shilt.

H. Domped

oscillotlon.

waveform analysis

for

phose

square

wave testing of amplifiers.

F.

High lrequenry

quency

Low frequency
thickend by hum-voltoge).

phcse

loss

shilt.

phose

qnd

shilt

low fre-

(trqce

4l

The

block

down

of the

reference
GENERAL

Basically,
vertical
network.
switched,
type of
determined
MODE
amplifier
which drives

Horizontal
amplifier. Drive
calibrated

preamplifier

B

All

supply
converter
the

CRT.

VERTICA

Channel

circuitry

The

section

100:

l, 1000:1.
and 5:1.
provide

The
sistors
FET's
amplifier

VR101
an internal balance

applied

is
the output

and

Ql06

llZ

the
control adjusts the
provides

the

across

'the

emitter

correct deflection

ments.

The trigger
a the emitter
tne

signal to

The
amplifiers
the

CH B signal when

MODE

The mode

B)

is

controlled by lC10l

Dl08

in

When

which

reverse-biases

Dl0l

and D104,

vertical

diagram, Fig.

oscilloscope. Circuit

to the

schematic diagram.

the

preamplifiers,

outputs

The

desired,

as

switching

by

the position

of OPERATION

feeds

the

the

vertical

deflection

to the

sweep speed

when X-Y

voltages

provides

L PREAMPLIFIERS

A and

and

vertical

of the

The

the

vertical

Q102

Q102

pair

the

is

to

and

a

only difference

is

LOGIC

each

CH

amplifier.

Channel B preamplifiers

circuit operation

attenuator has

attenuator provides

The

combined effect

vertical

preamplifier

and

and

with output signals

front panel

emitter followers

impedance to

VR105

Q107.

ll5

DC

component to move the

screen.

circuit of

amplifier Q I l9

of

Q

the trigger

that

the MODE

of operation
of the

A

is selected, the

allowing
At the same time

55,

oscilloscope

each

having

of the

into the main

of the

VERTICAL

horizontal

circuits

are fully

regulated

a

second

attenuator

Ql03

Ql03

control. The

attenuator

gain

Amplifier

factor

108

circuits.

in the A-B

channel

D102

vertical preamplifiers

CH A

of the

LOGIC.

deflection

provided

is

or

operation

2kV

is

section

ratios

consists of

and transistors

form

DC

balance

Q104

drive conventional

VRl06

and

positions.

of

Qlb6

gain

and

Q108

for

and
109

and

Q

between CH A

switch reverses the polarity

(CH

A, CH B, A

and

preamplifiers.

output

and

the

CH A signal

CIRCUIT

outlines

consists of

and

amplifier

by the

regulated

the

two

of the

output of

is adjusted

accurate

Q
and

position.

IC102

Dl03

the

details

its own

vertical

CH B

OUTPUT
plates

selected.

is

accelerating potential

same for

ratios

provides

in a l-2-5

balanced

a

of

and

and

Ql09

120

provides

of IC 102

ICl02

circuit break-

are

obtained

two

input attenuator

amplifier.

preamplifiers

MODE

The main

by the

sections.

control

are

Q107

amplifies

and diodes

and forward-biases

switch

AMPLIFIER,

of the

CRT.

horizontal

furnished

is

signal from

and a DC-to-DC

contain

both.

The

of l:1, l0:

ratios of

two sections

sequence.

FET

input

thru

Q104

differential

opposite

and

and

Ql02

which

Q105

amplifier

balance

VARIABLE

The

while VR101

trace

vertically

VRl07

by

provide

to

voltase measure-

the

portion

a

and CH B

+

& B, A

Pin

the main

into

Pin

11

output

by

identical

can be

The

is

and

vertical

by

the

CH

to

identical

first

l,

2:l

to

is

tran-

Q109.

polarity.

VRl12

Q103
lower

stage

pots

for

in

the

signal

of

pre-

of

-

B, A

-

D10l

3

low,

is

is

DESCRIPTION

high

which
biases D105
main

amplifier. For

selected,

is
at

a rate equal

(200kHz).
simultaneously
operation

switched

VERTICAL

The selected

to

the vertical
IC103­amplifier.

The

Q306

drive the
TRIGGER

_ f!.

SW20l. Selecting
amplifier
amplifier
fed thru
of the

SYNC

Transistors
as a differential
emitter
q?gi
SW202,
DC
of the

When

routed
Q205

cutoff by_
corresponding
Positive-going
of.

Q205

video

When
SEC), capacitor
the horizontal

The trigger
the SCHMITT
IC20I.
SWEEP
the

Q213

Transistors

and

a MILLER
voltage.
to

the RS

transistor

As soon
1C202
until the
on

and

terminates

both

For

is selected,

to the horizontal

The

output

where

vertical deflection

CIRCUIT

trigger

^Ql19

Ql21

transistor

SWEEP

AMPLIFIER

follower

_depending

*

or

to

level

TRIGGER

TV+

to

the

and

Q206.

the negative

corresponds

signal.

in TVV

The
CONTROL

clock

waveform,

to

initiate

resistors

INTEGRATING

The

flip-flop

Q21

as the

is held

sweep

sets pin

the

forward-biases

and Dl08 prohibiting

CH B, the

channels

to the

+

A

applied

AMPLIFIER

signal from

amplifier

signal

level

amplifier

the

signal

source,

CH

and

and

Ql22.The

switch

TIME/CM

AND

Q201

,

amplifier.

Q201

upon

-

respectively.

the

tligg_er

LEVEL

61 TV-

SYNC

Q205

to

an_average

pulses

positions

C207

pulses.

sync
signal

passes

TRIGGER

output pulses

flip-flop

to sweep.

Q216

selected

sweep

ramp from

consisting

1

and

Q212.

output

Q

low

by

Q21

ramp

13

1C202

of

sweep.

D106

reverse

are

alternately

chopping oscillator

B

and A

to the

CH

is amplified

either

Ql20

Q202,

SEPARATOR

drive

to

is

the

and
by

is

main

A is

amplifier.

which

is

consists

A

Q219.

switch

INVERTER

and

the position

signal

control.

is

is

voltage

switched

circuit

Q2l6

the SWEEP

I

terminated.

turned

the preamplifiers

consists of

increased

plates

of the

CH

A or

as

the

and CH

trigger

Q2l9

except

Q203,

The trigger

routed

Emitter

depending

selected,
biased

near

value

out of

Q205
the

sync tips

of time

thru

emitter

consisting

from

1C202.

output goes

Q

and

circuit

the

of

two

of'lC2O2 goes

to

exclude

LOW

which

and Dl07

CH B

is

B, both

amplifier.

to

of transistors

to the

CH

source

amplifier
CH B.

and

to

the
of
follower

the

circuii

cutoff.

developed

of

base switch

in

by

lC20I

On the

the

TIME/CM

provide

to

collector

gates

any new

Transistor

and reverse-

signal from

true. When

switched

channels

on and

then

is

I

23,

Q

drive

levels

CRT.

B,

is

enables

B

enables

is on

in all

are

e204

signal

is applied

base

the

SyNC

e2O4

upon

the position

output

consisting

e205
across

the

input

cutoff.

of

the

(.lmS

to

Q206

follower

of

two

ptN

g

negative

low,

turninf

timing

iwltch

a linear

of

ezIj

from

IC201

low,

the

clock

e2l2

turns

e213

the

A

& B

by ICl0l

frequency

ar-e

When

X-y

CH

B is

applied

and

Ql24

the

output

thru

Q301

required

selected

selected

of-e202

of

ihe

compoiite

e207
clock

capacitors

by
trigger
trigger

positions

connected

switch,

adds

Q203

is held

e205

signal.

outout

to .5

filter

out

and

gates

of

the

edge

of

off

form

ramp

is feb

thru

reset

of

pulses

turns

on and

to

is

to
or

a

is

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43

Transistors
TRIGGER
is adjusted
and

Q9

condition is applied
reset

of

determined by

TIME/CM

sweep ramp

The

the input of

Q220,Q22r - Q225.

When

mode, transistor

B signal is applied to
Thetutput bi transistors
horizontal

Q208, Q209,

SENSE

so that

produce pulses

1C202

switch.

in the CH

deflection

switch.
the

slope

the RESET of

to

allows

the

the horizontal amplifier

Q2tg

a sweep

r.esistor

from the collector of

position

B

is turned

Q220

plates

CALIBRATION

The calibration

can be

which
equipment.

compensation
attempted
specified
information

lnternal adjustments

cedure can

HOUSING

1. Remove
on

230 VAC

Remove housing

1.
Remove voltage

2.
Rotate

3.

4. Replace
Replace housing.

5.

Additional internal

without

test equipment.

for this

B &

be

REMOVAL

top.

OPERATION

plug l80o

0.7A fuse

adjustments

performed

and horizontal

DYNASCAN CORPORATION

2815

Chicago,

located by reference

6 screws,

with a

complete

oscilloscope

Seraice
K-Precision

West

2

from

selector

and

with

and

When

the TRIG LEVEL control

is not

which keep

and

capacitor

SWEEP

of

off thru

and to

and

Q224

the CRT.

of

ADJU

outlined here are those

minimum

adjustments of

sweep linearity should

service

Requests for complete service

should

Departrnent

Product

lrving Park Road

Illinois

outlined

on left

side,

scope.

plug

re-insert

0.3A fuse.

form the

Q2l0

triggered,

Q2tO

lC2O2. A

recirculate at a

to

the horizontal

selected

Q217

consisting of

TIME/CM

IC2O3 and the CH'

is applied-to

Q225

STMENTS

of specialized

information and

be addressed

Group

60618

the

in

to Fig.56 and

(see

plug.

calibration

right side,

on

2

58).

Fig.

AUTO

transistor

The on

ON.

low

on

by

is applied

Q218,

switch,

amplifier.

frequency

not

to:

57.

and

Q8

the

rate

the

to

the

test

be

pro-

AND CH

CH A

l. Adjust

B).

cH

Adjust

2.
trace

Rotate

3.
to maximum

lf the

4.
performing

(front

vertical
while

I

I

&

12

/5

Position

l.

with

B,
GND.

Switch

2.
VRl08

Switch

3.
VRl09

VERTICAL GAIN ADJUSTMENT

following adjustments should

The
square
curacy

2

HORIZONTAL

wave

is

Procedure:

Set CH A and

l.

and set

(fully

Apply

2.
A input connector.

CH

3. Adjust

4.

Repeat

deflection.

CM

l. Set

SWEEP TIME/CM

Set

2.

3. Adjust

horizontally

4.

Turn the

amount of deflection

minimum

B DC BALANCE

controls

A or CH

CH

vertically on

VARIABLE control

the

CW

moves

trace

STEP

panel screwdriver

movement

performing STEP
ATTENUATOR

to vertical center

trace

V

ATTENUATOR

.01

to

(CH

B) until

to

(CH

available.

CH A and

clockwise).

1 kHz square wave

VRl07

steps 2 and

<>

POSITION control mechanical center.

VR206 so that the

V/CM and adjust

,05

unttl

B)

generator

CH

for exactly 5 CM of

PO$TION ADJUSTMENT

centered on

<>

POSITION

4

CM.

of

obtain a horizontal

to

POSITION control

B

the CRT.

from maximum

trace.

while

observing

vertically

3, adjust

the trace does not

of

3.

BALANCE

V/CM

and

trace is

trace ts

with l% or better

B VOLTS/CM switches
CH B VARIABLE

Set mode switch to

3 for

CH B and

switch

CRT.

control

in

the

more

CH A or CH

the

adjustment)

of screen

V/CU

.01

in

VRl05

adjust

vertical center.

at

VRl06

vertical center.

at

attempted

be

50 mV

of

deflection

adjust

EXT.

to

spot on

full

directions

both

than

peak-to-peak into

CW and

(CH

trace

to

center

5mm

B

so

exceed

CH A or CH
and input

(CHA)

(CH

amplitude

to.0IV/CM

controls

CH A.

VRI l0

the

CCW. The

should

A or

the

CCW

while

DC

BAL

that the

5mm

at

or

A) or

only if

ac-

to CAL

on

CRT.

for

scope

be a

a

5

is

GRATICULE

bezel with

Grasp

l.

2. Lift off

3.

M

uniformly forward

bezel

panel.

front
parallel
age of mounting

Reinsert
panel

mounting

REMOVAL

Caution

front

to

graticule

graticule

hands at top

both

to unlock

should

panel

when removing,

legs.

from

bezel.

on bezel and snap

holes.

be used

keep

bezel

break-

into front

Pull

and bottom.

mounting legs from

to

to

avoid

bezel

v

@

u^114,

cRT

cENT ADJ.

VR11O

GAIN

@

@

TC114

ADJ.

HrGH

FREO
ADJ.

CHB

ATTENUATO.R

,i4,

VR103

FRONT

Fig. 56. Calibration

ADJ.

BAL.

DC

I

?

PANEL

diagram,

(o

\:/

rPlo2

a

@

tJot

TC103

@@@

TC104

vertical amplifier board.

TC102

(BACK

6

rtr

TCl06

VIEW)

HrcH

FREO
ADJ.

os

vR107

GAIN

@

@

TC1

ADJ.

1 3

FRONT

PANEL

@

TC2o2

@

vR2o4

@

TC201

i

@

vR21o

VR206

Posrrr

oN

ADJ-

@

VR2O7

h

YJ

@

VR2O8 VR2O9

@

vR212

u9,,

@

@

VR

205

Fig. 57. Calibration

diagram,

horizontal amplifier board.

45

POWER

SUPPLY

BOARD

VR 3O5

ROTATE PLUG TO

CHANGE

VOLTAGE

VAC

240

VAC

1

20

FUSE

A- 1 20 VAC

o.7

0.3A-

Fig. 58. Calibration

240 VAC

diagram,

TC

301 - M ID FREOU
TC 302-UNBLANK
VR 305-HIGH
VR 306­VR

3O7 - INTEN

VR

3OB-Y DEFLECTION

VR 3O9-

power

supply board.

FREOUENCY

1

KV ADJ

9

SITY

1

ADJ.

95V

U

ENCY

ADJ

46

v

Refer

l.

to the MAINTENANCE

adjustments

WARRANTY

that may

be applicable.

SERVICE

section

of

INSTRUCTIONS

your

B & K-Precision

instruction

manual

for

2. Defective parts
period.

should
state the
date the
terms

3. If
with
Enclose
or ship PREPAID

agency
your

If
your

model
unit

Warranty.

the

of

the above-mentioned

your

unit, pack

a letter

(see

list enclosed

list of authorized

local

distributor

removed

be sent PREPAID

and

was purchased.

describing

from units which

serial

number

procedures

it securely

(UPS

for

the

preferred)

with

B

& K-Precision

the name

B & K-Precision

DYNASCAN

2815

These parts

problem

unit).

of

Service

Chicago,

to the Service

of the unit

(preferably

your

West

are within

will

do not

to the

correct the

in the original

and include

nearest

service

nearest

Deportment

Product

CORPORATION

Irving

Park

Illinois

the One Year

Department

from

which

be exchanged

agencies

service

Group

Road

60618

the

problem

your

name

B & K-Precision

has

agency,

Limited Warrantv

listed

below.

parts

were removed

at no

charge, under

you

carton or

been misplaced,

are experiencing

double-packed).

and

address.

authorized

or write

to:

Be

sure

Deliver

service

contact

to

and

the

to,

47

ONE

DYNASCAN
material and
year

from the

option,

its

it
warranty
contracior.

otherwise.
any
pirchase. This ivarranty

and
conneition' or
Instruction
removed.
specifications
warranty,
to

after

and

DYNASCAN

worranty

repairs,

DYNASCAN

t}e encloseii

DYNASCAN

date of

warrants

workmanship

repair

which is returned,

DYNASCAN

misuse,

Manuai.

purchase.

puichase

date of

of

merchantability)

of

negligency

adjustment

This warranty

or

desiAn

DYNASCAN

CORP.,

YEAR

each

that

under conditions

from an

product

any

replace

traniportation

not

shall

no other

makes

does

reserves

without

6460

ore

not

apply

or aiCident;

otherwise

is
the right
notice-and

W. Cortland

LIMITED

product

authorized

or

-otherwise
express

limiied

(i)

to

or

than

void if the

to discontinue

warranty registration

Street, Chicago,

WARRANTY

manufactured by

use and-service

normal

of

DYNASCAN distributor.

component

prepaid,

damage

in accordance

without incurring

to

linble

be

warranties.

in

duration

resulting.from

(ii)

damage
serial number

it will be

conforming

not-

factory or our authorized

our

any

for

implied vwrranties

Any

(1)

to

resulting

with

has

model

any

any

card should

Illinois 60635, within ten

free from defects

p_eriod

for

a

DYNASCAN

with- the

damages,

one

tq1-qqp^tgper

DYNASCAN's authorized

obligation.

consequential

year-fro.m

unauthorized

been altered,

any time

at

To

completed and

be

in

(l)

of one

will,.

foregoing

service

or

(including

date of

the

alterations

installation,

or

(10)

or

change

this

mailed

days

defaced

register

U

48

@

7452

pRINTED

tN

JApAN B5o-2823-oo

v

(c)

F

)

o

a

*

t,

tr

,''

:

il
,6

#

t

J

DYNASCAN CORPORATION

W. Cortlond

6460

Street

U

48G182-9-ml

Chicogo,

lllinois 60635

v