BK Precision 1471 Service manual

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10 MHz,

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al

TRIGGERED SWEEP

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Product

A

of DYNASCAN

CORP0RATI0N

West Belle Plaine

1801

.

Chicago,

lllinois 60613

PRTCE

$2.00

lv

INSTRUCTION MANUAL

FOR

b

B

10

MHz,

DUAL.TRACE

K.PRECISION

&

MODEL

L47T

TRIGGERED

OSCILLOSCOPE

SWEEP

v

DIVISION

OF

| 801

DYNASCAN

W.

Belle Ploine

Chicogo,

lllinois 606I3

CORPORATION

Avenue

INTRODUCTION

FEATURES

SPECIFICATIONS

TABLE

OF CONTENTS

\t

Page

OPERATOR'S

OPERATING INSTRUCTIONS

Initial Starting Single-Trace Calibrated Calibrated Time Measurement

External Horizontal Z-Axis Dual-Trace Waveform

DUAL-TRACE

Introduction FrequencyDividerWaveforms Dvide-by-8CircuitWaveforms... 14 Digital Gated Ringing DelayUneTests

Stereo Television

SINGLE-TRACE

Introduction Television Signal Tracing Composite Video Waveform Analysis Sync VITS Vectorscope

CONTROLS, INDICATORS AND FACILITIES

Procedure

Waveform

Voltage Measurement

lnput

APPLICATIONS

. .

Circuit Time

Circuit 14

Amplifier

Servicing

APPLIC

. .

Servicing

and

Pulse

Analysis

(Vertical

Interval Test Signal)

Operation

Observation

(X-Y

Input

Observation

Relationships

Servicing

ATIONS

Peak-to-Peak

Operation)

...

Voltage Readings

. . .

......16

9 9

10

ll l2 t2

t2

14 14

14

v

l6 t7

18 18

t9 t9

r9 2l 23

TELEVISION

Introduction

Importance

Sweep Alignment Methods Tuner IF Alignment ChromaAlignment...

ALIGNMENT

. .

of Sweep

Alignment

26 26 27 28 29 29

v

FM

RECEIVER

ALIGNMENT

TABLE

OF

CONTENTS

Page

,...31

b

PHASE

MEASUREMENT

FREQUENCY

SQUARE

CIRCUIT

WAVE Introduction Testing

Procedure

DESCRIPTION General

Vertical Mode Vertical

Trigger Sync

CALIBRATION

CH

l12

Vertical

Horizontal

Preamplifiers

Iogc

Amplifier

Circuit

Amplifier

I

and CH2 DC

and l/5 Attenuator

Gain

Position

MEASUREMENT

TESTING

.

OF AMPLIFIERS

and Inverter

ADJUSTMENTS

Balance

Adjustment

. . .

Balance

3l

33 34 34

38 38 38

38 38 38 40 40 40 40 40 50

40 40 40

.

. .

40

v

WARRANTY

INSTRUCTIONS

42 43

The B & loscope observing

vertical inputs are

Dual of two waveforms are chopped simultaneous permits

waveforms.

rate

DUAL

K-Precision

is a laboratory-quality,

measuring

and

waveforms. Low-frequency,

viewing. Alternate

simultaneous

viewing

TRACE

FULLY

SOLID STATE

TRIGGERED

SWEEP

LARGE SCREEN

CALIBRATED

VOLTAGE SCALES

CALIBRATED

SWEEP SPEED

WIDE BANDWIDTH

Model

professional instrument

waveforms

provided for

200

a

at

high-speed,

of

input

Two viewed taneously,

the cathode

Only filament.

transistors,

fe

e f

ct Among state construction

o

No stabilization

required.

time o o

o o o

The 147|'s presentations son oscilloscopes. at being they

waveforms ing.

The 130 mm diameter easy-to-read 8

Accurate stantaneous ferent Channel A and

Accurate

DC nSEC free, at

power drain.

Low

Dependability

reliability

Ruggedness. Light

Compactness.

with

until

rest

observed,

are

adjustable

Fully

the

allows

Waveforms synchronized trigger.

x 10 cm

area.

attenuator

different

18

to

l0MHz

rise time assure

high

frequencies.

high

Dual-Trace

l47I

in electronic circuits.

simultaneous

low

kHz rate to

of the two

sweep

waveforms

either singly

desired.

as

other stages

All

diodes,

transistors)

the advantages

weight.

stability

is beyond

non-triggered

The sweeps

triggered always desired

to be

to an

(approx.

cathode

presentation

rectangular viewing

measurement

voltages on l1

Channel

measurements

time

ranges.

bandwidth

resolution

INTRODUCTION

repetition

high

ray tube

are:

-

to assure

trigger

used

ranges

viewing

provide for

repetition-

can

or

FET's

and

of solid

warm-up

waveform

of

comPari-

by the signal

synchronized.

threshold

portion

for trigger-

also

can

external

5.1 inches)

ray tube

of the in-

for

B.

distortion-

presentation

Oscil-

for

rate

inputs

FEATURES

be

simul-

a

uses

use

(field

IC's.

sweeP

remain

that

the

of

be

sync

gives

on an

dif-

both

on

35

and

dual-trace

The width, provided,-make this of applications, electionic laboratorv

wide

WIDE RANGE

SWEEP

SPEEDS

feature,

range

including

equipment,

instruction.

OF

EXPANDED

SCALE

HIGH

SENSITIVITY

TV SYNC

VECTORSCOPE

CALIBRATION

SOURCE

Z-AXIS

INPUT

together

of sweep

the ideal

research

Sweep to speed forms

five

A the horizontal up the magnification mum pSEC/cm.

Permits the impedance, probes

measurements, circuit

A built-in included television SYNC, pulses are automatically at

0.1 vision tal sync selected pSEC/cm

ing

The scope exactly vision

A builtin

o-peak

t checking vertical tional

Intensity included markers.

logic;

low state, state.

with

speeds,

oscilloscope

troubleshooting

0.5

examination waveform.

sweep

mSEC/cm

television

unit

and

range

speed

SEC/cm necessary from DC

magnification

time

sweep

low-capacitance,

to be used

loading.

sync

specifically

signals.

television

times

frames.

pulses are at sweep

to I

lines.

may

provide a color

to

specified

as

manufacturers.

calibrated

square

and

amplifiers

equipment.

modulation for time Compatible

brightness

decreases

MHz band-

the 10

sensitivity

high

for a broad

and

development,

of I

provides

for viewing

to 10

sweep

of

a

In addition,

provides a maxi-

speed

l0:1

for

thus assuring

separator

When

vertical

of 0.5 SEC/cm

for viewing

Television

automaticallY

times

pSEC/cm

be used

by color

wave

recalibration

without addi-

or frequencY

increases

range

repairing

and

ptSEC/cm

every

wave-

MHz.

(5X)

close-

allows

portion of

the

of

highattenuation virtually all

for viewing

I

in logic

less

circuit

using

sync

selected

tele-

horizon-

of

for view-

vector-

as a

displaY

tele-

peak-

volt

Permits

of the

caPabilitY

TTL

with

logic

in

high

of

5X

0.2

is

TV

to

50

v

\,

SPECIFICATIONS

v

b

v

VERTICAL AMPLIFIERS

Deflection

Calibration Accuracy Frequency Response

Risetime Overshoot

Ringing

Input Resistance Input Capacity

Max.

Operating

Chop Frequency Channel Separation

SWEEP CIRCUITS

Sweep System

Sweep Time

Sweep Time Accuracy Sweep

Horizontal

TRIGGERING

Source

Slope

Triggering

Factor

Voltage

Input

Modes

Magnification

Linearity

Range

(Common

(CH

0.01 calibrate sequence.

!

5% on all

DC: DC to 10 AC:

35 3%

display. 3%

display.

I megohm, 22 300

p-p. Channel A only. Channel B only.

Dual-trace automatically chopped at slower; alternate trace automatically times.

2OO kHz Better than 60 dB @ I kHz.

Triggered and automatic. matic mode, without input

pSEC/cm

I calibrated quence.

!

5%.

Obtained by sweep mum

pSEC/cm.

3Vo or less distortion.

INT sensitivity). MODE source of internal signal is the triggering the CH A the CH B source in the CH B mode.

Positive ly variable

AUTO. 20

deflection ray

A aNd CH

V/cm

10 Hzto

nanoseconds.

or less

or

less at 100

(t

pF

3

(DC

V

all sweep times of I

selected

(x

to

CH A and CH B)

5 times

sweep

and

and negative,

Hz

to

tube).

B)

to 2O

range s in l-2-5

d

ranges.

(-

MHz

l0

MHz

kHz squarewave

at 100

kHz

+

5%.

pF).

+

peak)

AC

for

all faster sweep

2Wo).

sweep

signal.

to 0.5 SEC/cm in 18

ranges, in

enlarging

from

speed becomes O.2

EXT

switch selects

trigger;

and DUAL modes,

signal is the

level

control;

MHz

l0

as measured on

Y

in I 1

lcm

3 dB)

dB).

e3

squarewave

or 600

mS/cm

is obtained

center.

(lV p-p

continuous-

(rrrih.

and

In

auto-

l-2-5 se-

the above

Maxi

the CH

source in

and

triggering

pull

I cm

cathode

for

horizontal sync

TV Sync

HORIZONTAL

B Input)

CH

Deflection

V

A

Frequency Input Resistance

Capacity

Input Madmum

Voltage

X-Y

Operation

CALIBRATION

INTENSITY

Voltage TTL

Resistance

lnput

POWER REQUIREMENTS

Input

PROBES

Model No.

Attenuation

lnput Impedances

Connector Tip

(Not

AMPLIFIER

Factor .01

Response DC

Input

VOLTAGE

MODULATION

Included)

Vertical separator any form can be expanded and automatically CM TW mSEC/cm. TVH

pSEC/cm.

megohm

I

pF

22 300

p-p. With SWEEP

CH B becomes the the CH input tion control

position

tal

V

I

frequency.

increases decreases

470 kCl

ll7 or 230 Ifz,

CSA-approved

See

PR-208 Combination l0: I

l0:1

Direct = I megohm, BNC SpringJoaded, hook-on tip.

and

provided

circuit

portion

TW

switch.

V/cm to 800

V

p-p

logic-compatible.

20 watts.

Fig.

=

of

complex synchronized

for

viewing.

(frame)

by SWEEP

=

(Horizontal

(t 3 pF).

(ttC

position,

(horizontal).

square

(nominal).

51.

or

l0

SEC/cm

0.5 pSEC/cm

50

V/cm.

20

to

kHz

e3

(nominal).

+

AC

TIME/CM

the CH A

Y

input

B input

becomes

control.

wave

brightness; brightness.

VAC,

(3-wire

for oscilloscopes.)

PR-24B.

megohms,

Input

peak)

becomes

The

and direct.

so that

TV wave-

TVH

switched

sync

dB).

I

TIME/

to 0.1

to I

through

or 600

switch in

(vertical)

the X

CH B

the horizon-

(+

5%) atline

logic

Low

high logic

lVo,5016O

line cord,

pF.

l8

pF.

120

and

(line)

V

input

and

posi-

-

6 7

8

10

19

18

Fig.

17

1. Front

panel

controls and indicators.

15

\'

OPERATOR'S

CONTROLS.

INDICATORS

AND FACILITIES

v

Cathode Ray Tube

l.

the waveforms

1

Scale. The 8 x marks for voltage measurements.

Pilot

Lamp.

3.

4.

SWEEP TIME/CM Switch. Horizontal selector. Selects

(microsecond steps. In internal sweep

provide CAL I V

5.

peak This is attenuators.

<

>

POSITION

6. position dual cation when

TRIGGERING

7.

determines starts; (+)

equals most positive point switch (PULL generated

EXT TRIG

8. signal.

SYNC

9.

following

SLOPE. The SLOPE waveforms except television composite video

(+)

(-)

TV. In the TV television composite the sweep; the automatically selected to

0.1

automatically

pSEC/cm

(+) (-)

SOURCE Switch.

10.

sweep.

INT

EXT

Lights when oscilloscope

the CH

horizontal

P-P

square

used

of traces

trace mode).

when

pushed

points

(-)

equals

selects automatic

AUTO). When

even without

Jack. Input terminals for external trigger

Switch. Four-position

positions.

Sweep waveform.

mSEC/cm, and horizontal

to I Sweep is Sweep

Sweep is switch

Sweep MODE

Sweep at the

(CRT).

viewed.

are

l0 cm

calibrated sweep times of 1

per

centimeter)

B

generator

sweep.

Provides

Jack.

wave input

for

calibration

Control. Rotation

(both

Push-pull

pulled

in.

LEVEL Control.

on

most

is triggered

is

triggered

vertical sync

selected

pSEC/cm.

triggered on

is triggered on negative-going sync

Selects triggering source

triggered

is in CH A or DUAL

is triggered by

switch is in CH B

is

triggered by an

EXT TRIG

This is the

graticule provides

(vertical)

position,

out

waveform

negative

automatic triggering, a

an

positions

positions,

video signal are used

for

and time

to

this switch disables the

permits

and

calibrated

at the line frequency.

signal

of

the vertical amplifier

traces when operated in the

switch selects

(PULL

Sync level adjustment

point

of triggering. Push-pull

triggering when

input

signal.

lever

are

positive-going

on

negative-going

the sync

times of 0.5 SEC/cm

sweep

sync

for

sweep times

positive-going

CH

by

A signal

position.

Channel

position

jack

external

8.

screen on

is turned on.

0.5 SEC/cm in l8 the CH B input

I volt

adjusts

MAG):

5X

slope

of triggering

switch

for

used

pulses

B signal when

signal applied

which

calibration

(horizontal)

sweep

where sweep

pulses (frame)

when MODE

time

pSECicm

peak-to-

horizontal

5X magnifi-

normal

and

pulled

sync

out

sweep is

with

the

viewing all

signals.

slope

of a

to

trigger

are

(line)

are

of

pulse. pulse.

for

the

to

of

50

Channel B

I l.

ment for adjustment CH

Channel B DC BAL Adjustment.

12. adjustment

Channel B INPUT

13. B. Jack SWEEP

14. Channel B

DC Direct

GND

AC Blocks DC component

Channel B.

15. Channel B. from horizontal sensitivity switch 4 is in the CH

MODE

16. basic operating modes

CH A Only the input signal

CH B

DUAL Dual-trace operation; both

17. Channel A VOLTS/CM Channel A. Vertical from

18. Channel A DC-GND-AC

DC Direct input of

GND Opens signal

AC Blocks DC

19. Channel A INPUT Jack. Vertical input

A.

20. Channel A DC adjustment for

Channel

21.

justment

FOCUS

22.

POWER/INTENSITY

23. rotation

oscilloscope.

Further trace.

POSITION

Channel

when SWEEP

position.

B

for

becomes

TIME/CM switch

DC-GND-AC

input

signal. Opens

signal

amplifier.

position

the

performing

when

VOLTS/CM Vertical

to 20 volts

.01

Switch.

played

Only the played

Channel B input signals are

separate

to 20 volts

.01

signal.

amplifier. This

position

the

performing

when

A POSITION for

Channel A

Control.

of this

Clockwise rotation

clockwise

Control.

B trace. Becomes

Channel

Jack. Vertical input

external

of AC and DC

path

provides a zero-signal

This

of which can

sensitivity

position.

B

Three-position lever switch; selects the

of

as a single

input

single

as a

traces.

sensitivity is calibrated per

AC and

path

provides

of which

component

BAL Adjustment. Vertical

Channel A trace.

Control. Fully

control

rotation

Vertical

TIME/CM switch

B trace.

4 is in the CH B

Switch.

and

DC measurements.

Switch.

per

when the SWEEP TIME/CM

the

trace.

signal

trace.

Switch.

cm. Switch.

and

measurements.

DC

Control. Vertical position

trace.

(OFF

increases

horizontal

Vertical DC Balance

horizontal input

component

grounds

be used

of input signal.

Vertical

is

calibrated

This

cm.

oscilloscope.

to Channel

the

displayed on two

Vertical

DC

component of input

grounds

zero-signal

a

used

can be

of input signal.

position)

turns on oscilloscope.

position

jack

input to vertical

attenuator

control

Channel A

attenuator

input to vertical

jack

counterclockwise

brightness of

adjust-

position

4 is in

the

of Channel

when

position.

of

input

base line,

reference

a

as

for

in 1l steps

adjusts

A is

dis-

B is dis-

and

in

as a reference

of Channel

DC

for

1l steps,

base line,

balance

ad-

turns off

the

INT MOD

24.

25. AC Line Cord

loscopes.

Pro.bi]*9-Fie'

26'

and designed

Jack.Intensity modulation

tu

PR-24B

combination

for

(Z-axis)

(See

Fig.

"6'

2). CSA-approved for oscil-

\s!w

2'' ven-ar,PrvYvu rvr

3-)' The B & K-Precision Model

use with this oscilloscope. However,

l0:1/Direct

probes

CRT

input.

Pl':jt

have

ROTATION ADJUSTMENT

been

any

probe

designed for

nominal input impedance

pF

J5

and capable of

-"

"

ir::l"r

io,

overray

vectorscope

DC (One

(Not

operation.

BALANCE CONTROL

on each

use with an oscilloscope hav

of I megohm

operation up

shown).

side)

rnterchanges

to

10MHz, c

shunte

with

-r>

1.

2.

PULL

APART

ATTENUATION

ROTATE

1O:1

180'

Fig.2.

Rear

and

panel

side

FROBE

COMPENSATION

(PR-2OB

facilities.

ONLY)

PROBE

COMPENSATION

(PR-

ADJUSTMENT

248

ON

ADJUSTM

L.Y)

v

ENT

PUSH

3.

r>-

BACK

TOGETHER

Fig.3.

hobe

details.

v

OPERATING

INSTRUCTIONS

v

INITIAL

l. Set

2. Connect

3.

4.

5.

6. Set

7.

8. Wait

9.

10. Adjust FOCUS

11. Readjust

12. Check

measurements.

STARTING PROCEDURE

POWER/INTENSITY

(fully

counterclockwise).

power

Set control their ranges.

Pull Position. Set CH A

DC-GND-AC

single-trace operation trace

Turn control 3

will light.

warm mode)

If

no trace I\TENSITY observed.

for

the

center the traces.

and CALIBRATION portion ments require

The oscilloscope

POSITION

CH A

I I

and<>POSITION

TRIGGERING

DC-GND-AC

switch 14Io

MODE

operation.

on oscilloscope

a

20 as described in the MAINTENANCE

switch

23

clockwise.

few

seconds

A trace

up.

should appear on the face

appears, increase

control

thinnest,

position

for proper

checking

control 23

25 to

cord

(two

control

sharpest trace.

controls

adjustment of

is now ready

a I l7-vo1t, 50/60 Hz

control

LEVEL

the

16

to the CH A

or the DUAL

by rotating

It will

for

the

cathode

traces if operating in

23

until

22and

6,21

of

only

to OFF

21,

CH B

control 6 to the centers of

control 7 to the AUTO

switch

GND

"click"

(clockwise)

this manual. These periodically.

18

positions.

position

POWER/INTENSITY

on

ray

of the CRT.

the

trace is easily

INTENSITY

11 if necessary,

and

DC BAL

for making waveform

position

outlet.

POSITION

CH

and

position

for

dual-

pilot

and

tube

the setting of

lamp

(CRT)

the DUAL

control 23

controls

AND

adjust-

for

to

12

the l0:l capacitance impedance when

3. SetCH only most measurements and being measured includes a the and

B

frequency The GND ground readings.

4. Connect equipment the measured.

a. If

b.

5. Set CH gives

vertical deflection. probably concerned speed, desired number of waveforms.

duces at least I cm vertical deJlectton develops

ficient

position

in the DIRect (low-capacity position)

possible,

A

the

DC

the

point

the equipment under test less former to

The measurement should

when

2 to 6

which

tigger signal to

to decrease

DC-GND-AC

AC component

position

reference is required, such as

ground

AC

A VOLTS/CM switch

for measuring both

DC reference, and any

.

waveform

position

clip

test. Connect

under

the

in

circuit

powered

prevent

peak-to-peak

using the

(two

cm

be unsynchronized.

with

adjusting

presents

megohm with l20pF shunt

and I

is

WARNING

DIRect

position.

circuit

switch

(this

is

must be used if

large DC component).

(below

required only

of

item, use an

The

5

probe

where the waveform is to be

dangerous

voltage at

not

position

to six large

display

synchronization and sweep

a stable

synchronize

The higher input

should be used

loading.

18 to AC for measuring

the

normal

the AC

time a very low

Hz)

is to be observed.

when a zero-signal

for DC voltage

to

chassis

the tip of the

is a transformer-

isolation trans-

electrical shock.

the

exceed

17 to a

The

Any

600 volts

of the

squares

the

on

remaining

display showing the

signal

the sweep.

position for

the point

Use

component

ground

point

of the

probe

of

probe.

position that

scale)

on the

steps

that

will

are

pro-

suf-

screen

to

v

CAUTION

Never

allow remain few

seconds. The bumed. motion

SINGLE.TRACE

Either

single-trace operation.

following instructions.

the

Perform the

1. with

the

connect

following instructions

The B & K-hecision Model

For

2.

all

set

are

(below

forms DIRect. See Fig. 3

DIRect, or

to input impedance with only l8

a small spot of high

stationary on the screen for

Reduce

by

Channel A or Channel B can be used

MODE

the

except

for

screen intensity or keep the

causing

it to

WAVEFORM OBSERVATION

For simplicity, Channel A is used in

of the

steps

switch

probe

cable

low-amplitude waveforms, the

l0:l attenuation.

0.5 volt for

versa. The

vice

brilliance to more than

may

become

sweep.

"Initial

16

in the

to the CH A INPUT

assume

PR-20B

For low-amplitude wave-

peak-to-peak),

changing

probe

permanently

Starting

CH A

the

combination

set

probes

the

has a

pF

shunt

a

spot in

for

Procedure

position.

the

capacitance

jack

of the

use

probes.

probes

probe

from l0:l

megohm

l0

Then

19.

for

in

Set SOURCE switch

6. provides observed waveforms an switch should cable should be connected

to the

Set SYNC switch 9

7. for observing television to the SLOPE all the the negative-going wave. If the type unknown, the SLOPE

Readjust TNGGERING LEVEL control 7 to

8. synchronized the control that in disappear sweep, such as amplitude

internal sync so

is also

should

external

other types of waveforms.

sweep

(-) position

will

the

sync source

be

external

sync source.

(+)

is to be triggered

display

may

produce

center

portion

if

there

when measuring DC or

waveforms. If no

l0 to the

used to trigger

viewed using

be

placed

or SLOPE

if the sweep

be

a sweep,

is inadequate signal

is required,

in the

from the

to the TV

composite

by a

(+)

position

without

pushed

in

which

of its

INT

that the

the

internal

EXT

(+)

or TV video

(-)

positions for

Use the

positive-going

to

is

be triggered by a

of waveform is

may be used.

jitter.

As a

rotated

and

is usually somewhere

range.

sweep can be obtained,

position.

waveform

sweep.

When

sync.

the SOURCE

position

waveforms

(+)

starting

The

to trigger

extremely

and a

jack

TRIG

(-) positions

observing

position

wave, or

obtain

point,

to

any

trace will

This

being

Most

8

or

if

a

point

the

low

pull

the

triggering. Set SWEEP TIME/CM

9. of waveforms. This a progressively This is because repetition rate does not

When

rates, the operator may intensity conditions, extreme left of the trace. This does not affect the disregarded.

Alter

10.

step 9, it adjustment The waveform (+)

control

portion

of a waveform,

using

control

obtaining

(-)

direction selects

at

direction

dimmer as a smaller

the sweep speed

very

retrace

a

oscilloscope operation and may

is sometimes of the TRIGGERING

which sweep triggering

selects the

(PULL

out

switch

control

fast

toward

the desired

may

change.

NOTE

sweep speed at

wish to operate with the

maximum.

"pip"

the most negative

most

4 for

but

number of waveforms, as desirable to make a

AUTO) fof'automatic

the desired number

for

be set

portion

increases

may appear at the

positive point

viewing only

the trace

low repetition

Under

LEVEL

will occur

becomes

is

displayed.

but the sweep

these

in

any

control

point

way

be

on the

and

on the

in

final

7.

the

waveform control desired

For a

l1'.

CALIBRATED

Peak voltages easily and accurately Trace Triggered

l.

2.

close-up outward on I^he<>POSITION control the sweep by a displays only the

portion

a control clockwise, and center,

the

on non-magnifie d

voltages, of

Adjust controls as waveform to be

CH A VOLTS/CM switch

Set vertical deflection

of the vertical

limits

which sweep

at

may be

portion

turn

control

a specific

adjusted

of the

of

view

factor of five

to the left of center,

center

the

control

return the sweep

to

condition.

VOLTAGE

peak-to-peak

portion

measured on

Oscilloscope.

Sweep

previously

measured.

scale.

triggering

to start the sweep

waveform.

portion

a

portion

view

to

counterclockwise.

MEASLJREMENT

voltages,

of a complex

possible without

will occur. The

the waveform,

of

(5X

instructed

6.

magnification) and

of the turn the portion

sweep.

to the right of

to

DC voltages and

the Model 1471 Dual-

l7 for the maximum

on

This e*puhds

To view

<>POSITION

Push

inward

normal,

the

(See

Fig. 4)

waveform are

to display

exceeding the

any

pull

the

\ V

.} POSITION

POSITI

ON CONTROL

SO THAT BOTTOM OF

FORM

ALIGNS

A

HORIZONTAL

EXACTLY W]TH

REFERENCE

EXAMPLE:

VERTICAL

PROBE ATTENUATION

PEAK-TO.PEAK

TOP OF WAVEFORM CROSSES CENTER VERTICAL AND EASE

ADJUSTED

WAVE-

DEFLECTION = 4.2cm

VOLTAGE/CM

WAVEFORM

CONTROL

SCALE

OF

LINE

ADJUSTED

MARKER

READING

=

.O2

.084V

=

10

=

0€4v

THAT

SO

FOR ACCURACY

OF

o-

@..t

o

Irlo

o

Lz-JB

qfr@H@'

VOLTS/cm

SET TO

.o2v

PROBE

1O:1

ATTENUATION.

Y

l0

Fig. 4. Typiqal voltage

v

measurement.

v

Read the amount

3.

the scale. readjusted reading

if desired. the CH A reference GND deflected The and

Calculate

4. vertical

with the CH

position,

when the

trace deflects

downward

the voltage

deflection 17 setting voltage

1/l0th

probe

displayed

reading

the actual

is

set

when

ment.

5. Calibration occasionally peak

square

jack

5. This calibrated

peak-to-peak.

volt

dicated, see

TION" section

of vertical

The

to shift

POSITION

reference

the

measuring a DC

When

control

POSITION control

CH A

A DC-GND-AC

then

upward

switch

is

for a

the amount

note

for a negative

reading as

(see

example

displayed

for

l0:l

the

accuracy

checked

(in

voltage

by

cm)

in Fig.

on the

being

attenuation.

probe is set

of this

observing

by

wave signal available

source should

need for

If a

"MAINTENANCE

the

of the

manual

deflection

point for

voltage,

to

2l

switch

placed

in the

positive

voltage

input.

follows:

VOLTS/CM control

the

a) Don't

forget that the

oscilloscope measured The actual

for DIRect

oscilloscope

the I volt

the CAL

at

read exactly

recalibration

AND CALIBRA-

for

complete

(in

cm)

may

2l

easier

from

be

scale

adjust

a convenient

l8

in the

trace is

the

position.

DC

Multiply

is

input

the

only

voltage

when the

voltage

is

measure-

may be

peak-to-

P-P

lV

I

in-

is

procedures.

CALIBRATED

Pulse width,

waveform

other measured ments possible. visible moving the

on

from

At low

one time.

at

from left

beginning

to spot.

1.

2.

Adjust

Set

display

controls

of the desired

the SWEEP possible measured,

If necessary,

3.

4. Read

for the most stable

trol

7

the between control

6 may

measurement

reading.

easier

Calculate

5.

MEASUREMENT

TIME

waveform

durations

time

oscilloscope.

this

second

.5

sweep speeds,

However,

to right

ending

and

as

TIME/CM

display

usually

of

one

readjust

amount

points

the

be

points

time

the

(See

periods, circuit

easily and

are

Calibrated

down

the

entire

0.1

to

the bright

the

across

points of the

time measure-

microsecond

waveform is

spot

screen,

measurement

previously described

waveform.

for

contrcI

waveform segment

the

4

cycle. the TRIGGERING

disPlaY.

horizontal

of

measurement.

of

readjusted

with a

duration

deflection

to

vertical

follows:

as

The oPOSITION align

scale

Fig. 5)

and

delays

accurately

be seen

can

which makes

easy

for a stable

largest

the

to be

(in

of

con-

cm)

LEVEL

one

marker

Multiply

the

all

are

not

the

for

v

<>

POSITION CONTROL

LEADING

THAT

ALIGNS

FORM REFERENCE LINE. MAY NOT BE FAST ALIGN BEGINS.

POSITION THAT TRAILING EDGE OF WAVEFORM CROSSES

FOR ACCURACY

EXAMPLE: HORIZONTAL DEFLECTION

(or

PERIOD)

VISIBLE

PULSES; lN

WHEREVER

CONTROL ADJUSTED

HORIZONTAL

SWEEP

TIME

OF

FREOUENCY = 1

ADJUSTED

EDGE

WITH A

OF

VERTICAL

EDGE

ON

THIS CASE

WAVEFORM

SCALE

AND EASE

TIME/CM

DURATION = 63.5pSEC

WAVEFORM

TrME

WAVE-

VERY

OF

= =

10pSEC

.0000635

=

15,750

SO

MARKER

READING

6.35cm

HORIZONTAL

DEF LECTION

SEC

Hz

6.35 cm

@

o

3@fr@f@'

TYPICAL

DISPLAYS RECEIVER

HORIZONTAL

SHOW

WAVEFORM

OUTPUT

TIME/CM

SWEEP

'l

set to

0p sec

set to

.SLOPE

(to

start

sweep

negatlve-going

INT

TELEV!SION

AT GRID OF

TUBE

Q

on edge)

v

5. Typical time

Fig.

measurement.

ll

horizontal

switch 4 setting

when the

divided by 5 to obtain the

Time

6. especially started by a waveform

measurement and the subsequent waveform. urements using external sync,

a. b. Connect a

c.

d. Readjust

e.

Another excellent method for

7. with the manual.

EXTERNAL HORTZONTAL

For

tion signal is required. This is also referred to measurement, where the Y tion and the X horizontal phase

measurement,

input must be

voltage of 100

any satisfactory

the following

use

1. Set the SWEEP CH

the

2. Use Channel

3. Adjust the CH B VOLTS/CM

The

4. horizontal control is disabled.

Do NOT X-Y operation. to adjust horizontal

5. All

Z.AKS

The modulated marks

are INT MOD oscilloscope will of the trace.

deflection

5X magnification is

measurements often require

true

measured in

of the

Set the

source of sync Set

position

necessary for If measuring a delay, measure

start of the

dual-trace operation. The

"DUAL-TRACE

some

the Channel A

CH B

sync

INPUT

trace displayed

SOURCE

the SYNC

for

the TRIGGERING LEVEL

measurements.

input

may

input

mV

l0

operation. To use an external horizontal input,

procedure:

position.

B

probe

B

amount

POSITION

position

use the PULL 5X MAG

controls are disconnected

(Z-axis

required.

(intensity

provide

See Fie. 6.

(in

(see

when measuring

sync signal

cable

the

a stable

sweep

or an

TIME/CM

for

Use

input) where frequency A TTL

modulation)

cm) by the SWEEP TIME/CM

example in Fig.

used, the result must be

time duration.

actual

external

delays. The

from

a subsequent

display between the

switch l0 to the EXT

from the EXT

Use

signal.

switch

proper polarity

waveform.

to the

APPLICATIONS"

rNPUT

an

input

provides

be a sinusoidal

external sweep voltage.

per

control

of deflection or

cm

mV or

probe

for

the horizontal input.

horizontal

of

15.

control

control, and the

NOTE

the CH

gain.

the

on

compatible

alternate brightness

one

circuit.

perform

To

the following

use

TRIG

a short shielded

9 to the

start of

external

horizontal

greater

switch

B VOLTS/CM

SLOPE

for the

the time

the

measuring

procedures

(X-y

OPERATTON)

horizontal deflec-

provides

wave,

is sufficient

fully

4

the vertical input

deflection

I I now serves

control during

and have no effect.

screen

may be intensity

signal

jack

24 on

5). Remember,

circuit and the

jack

waveform.

time delays

section

vertical deflec-

deflection.

<>

or time-scale

applied at the

the rear

and blanking

This

sync.

This

sync such meas-

(+)

sync signal.

control 7

are

as an

such

greater;thus

clockwise

POSITION

control

is

sweep is

allows

pulse

steps:

position.

8 to the

cable.

(-)

or

if

from

the

is

given

in

of the

X-Y

The

for

as

This

for

to

the

and

with

the

as

the

of

f

\

I

l

t

Fig.

6.

Oscilloscope trace with

DUALTRACE

(Refer

to

observing

In and B, it is necessary frequency the

other although An example multiplier. on Channel A, for of this reference frequency

In this way, when

eynchronized,

with the Channel phase

or

simultaneously,

waveforms

both

To display

tion,

use

Perform

l.

2. Connect oscilloscope and CH B INPUT

If the recommended

3. PR-24B should be used except for waveforms peak-to-peak forms for

changing the Whenever capacity

4.

Set traces should

5.

Adjust CH

place

to trace, mark

6. Set both and most measurements being measured

WAVEFORM

Fig.

7) simultaneous waveforms

or that

frequency

the following procedure:

the DIRect

MODE

and adjust

on

14 to

one of the waveforms

of this

The reference,

example,

the

display A display. If two

will

it

in

sync

two waveforms

the

steps of the

oscilloscope

or

possible,

position

I

l0:

switch

appear

A

and CH B

the

Channel A

the scale.

the CH

the

AC

a

\

t

I

that

the basic frequencies

in

is

the waveform

relationship to each

be

for

jacks

less. For the lower

position

probe

16 to the DUAL on

both traces to

A

and

position.

include a large DC

\

OBSERVATION

waveforms

the

checking a frequency

"clock"

or

the multiple

and

will

be displayed on

display of Channel

on Channel B will

difficult if

useful observation.

any

simultaneously for

"Initial

probe

cables to

19

and 13.

B & K-Precision Model PR-20B

probes

and

are used,

should be used.

from

l0:l to DIR or vice

the

use

to minimize

the screen.

CH B DC-GND-AC

high impedance,

POSITION

trace

This is the

must

be used if

t

\

,

t

a

t

Z-axis

input.

on

channels A

be synchronizedto

may be different.

frequency

waveforms having

other

not impossible

Starting Procedure."

circuit

controls 2l and above the a

convenient reference

component.

divider or

be

can

or

also be in

are displayed

both the CH

l0:l attenuation

of

amplitude wave-

loading.

position.

switches l8

position

used

submultiple

Channel B.

sync

to lock

observa-

0.5 volt Fig.

See

versa.

Two

Channel B

used

the

ooints

A is

no

A

or

low

1l

for

v

in

b

3

v

r2

v

Connect

7. gound of waveforms waveform

Channel

the

of

probes

will

A

the equipment

are to

input for

a. If the equipment

less

AC unit,

prevent

b.

peak-to-peak

The measurement the probe

8.

Set

the VOLTS/CM and B deflection.

to

a

The unsynchronized. to those

outlined the procedure displays.

Set

9.

the

provides

SOURCE

internal being observed in

dual-trace

measurement

10.

case set position 8 to

Set positions

the

and

sync

SYNC

for waveforms-, positions

for

ground

clips of the probes

points

to

be measured.

be

synchronized

internal

WARNING

under test

use an isolation

dangerous

should

is

used in

controls

position

displays

The

remaining

for

obtaining

switch

sync so that

is

also used

operation,

point

for

SOURCE

connect

a cable from

source.

switch

observing

or

to

the

observing

under test.

in the

The

must

sync

operation.

is

electrical

voltage

shock.

at

not exceed

the DIR

position.

15 and

gives

that

on the

2 to

screen

steps,

single-trace

stable,

l0

to the

the

Channel

to trigger

a sync

Channel

switch to

9 to

source

A is required.

the EXT

the

television

SLOPE

all other

(+)

types

to

the

Connect

circuit

signal

be

applied

where

to which

a transformer-

transformer

the point

600 volts,

17 for

Channels

3

cm vertical will probably although

operation,

describe

synchronized

position.

INT

A waveform

the

sweep.

other

fhan

(external)

the EXT

TV(+)

TRIG

or

composite

or-SLOPE

of waveforms.

chassis

the

tips

tle the

to the

to

of

if

A

be

similar

This

Often

the

In

this

jack

TVe)

video

e)

Use a sweep is

(+)

the

positions

positive-going

to be

triggered by

wave, or

I l. Adjust TRIGGERING

stable,

control may will the if there as when no AUTO)

12. Set of waveforms. a progressively

13. After step adjustment The point will

positive triggering start the

synchronized

pushed

produce

center

be

a sweep, which

portion

is

inadequate

measuring

sweep

can be obtained, pull

for

automatic

SWEEP TIME/CM

This

portion

of a waveform,

dimmer

obtaining

12,

ft is

the desired

sometimes

of the

(-)

direction

on

the

occur

point

will

sweep

of

sync waveform

the

and

on occur. The

on

of its range.

extremely

control

TRIGGERING

the sync waveform

waveform.

14. The observed

be expanded on the be

left

<>POSITION

rotated

and right

desired. Push

to

sweep

15. Calibrated urements

waveforms

by a

clockwise

extremes

inward

the

normal,

voltage measurements,

and operation

if the

sweep

is to

be

to the

(-) position

a negative-going

LEVE!

sweep. As

in

signal

control 7 to

a starting

and rotated

is

usually

trace

The

to

trigger the

low

amplitude

out

the

to

any

control

triggering.

switch 4

as a

for

may

be set for

but the

smaller

portion

number desirable

the

desired

trace

of waveforms

to make

LEVEL

rotation

(+)

selects the

which

at

direction

sweep triggering

selects

at which

control may

be adjusted

any desired portion

of

factor

control 6. This

Channels A

of

5

by

pulling

control

or counterclockwise

of

the waveform

on

the

non-magnified

control to

condition.

calibrated

with Z-ans

input

triggered

if

by

the

wave.

obtain

point,

the

point somewhere will

that

in

disappear

sweep, such

signals. If

(PULL

number

viewing only

becomes

is

displayed.

as in

a final

control

7.

most negative

the

most

sweep

to

of the

and

sync

B can

outward

can then

to

view

displays

return

time

the

as

the

meas-

are identical

a

v

CHA

A. REFERENCE

(1OOO

PULSES

LEADING EDGES

VISIBLE AT FAST

CHB

.

l

.

l*to

.BY

BY

B.

DIVIDE LEADING EDGE

cHB

C. DIVIDE

TRAILING EDGE

FREOUENCY

PER

SECOND)

MAY

.TWO

OUTPUT

REFERENCE

OF

.TWO

OUTPUT

OF REFERENCE

CHANNEL WAVEFORM

A

f;,iit|5hfr

PULSE

TRAIN

NOT BE

SWEEP RATES

SYNCHRONIZED

PULSE

SYNCHBONIZED

PULSE

Fig.

7. Waveforms

TO

WAVEFORM

A

HEIGHT

in

divide-by-two

WAVEFORM

HEIGHT

circuit.

l

mS/cm

B

WAVEFORM

B

WAVEFORM

A

l3

to those Either the controls the horizontal

previously

Channel A

be used as required in conjunction with

can

sweep

amplitude or time

done either the DUAL reverting to CH B

by using

position

single-trace

positions

of the

described

interval

the

MODE

for

or

Channel B vertical

controls

single-trace

to obtain the required

measurements.

dual display

of the MODE

operation, using the

switch.

DU AL-TRACE APP LICATION S

INTRODUCTION

yet

The most obvious and

the dual-trace oscilloscope is viewing or voltage,

"Cause circuit

tions

detail

of this

simultaneously

phase-related,

such as in

Effect" waveforms is

and

designer of the dual-trace oscilloscope to familiaize

oscilloscope.

or that digital

or

the

two

circuitry. Simultaneous

repairman.

user

FREQUENCY DIVIDER WAVEFORMS

Fig. 7

divide-by-two circuit. "clock"

illustrates the

pulse

train.

Fig. A indicates the

Fig. outputs of the divide-by-two circuitry. the settings of specific

waveforms. In

these the TRIGGERING

A and Channel B

required to

the

7

,

waveform may be either

B In Fig. the case going shifted frequency pulse

produce

waveform levels of

the divide-by-two output

7C

where the

waveform.

with respect to

pulse

by a

width.

oscilloscope controls

addition

LEVEL

vertical

suitable

output circuitry

this

In

the

time

the

most useful

has the

that it

waveforms

have

a common synchronizing

invaluable

an

Several

will

further

in the basic operation

waveforms involved in- a basic

Fig. C indicate

B and

to

these basic control settings,

control,

position

as

controls should

displays. In the drawing

are indicated. The Channel

2 cm

that indicated in Fig.

waveform is

responds to a negative-

the output waveform

case,

leading

interval

edge

corresponding

adjustment

This

facilities

switch or by

capability

that are

frequency-

possible

be reviewed in

reference

the

Fig.7 also

for viewing

well

the

as

the reference

of

operation.

can

be

as

such

A or

CH

feature

of

for

viewing of

the

to

aid

applica-

or

possible

indicates

Channel

be set as

of Fig.

or

7C.

7B

for

shown

the

to

In an application where the logic

or near its maximum

at rise time time

effects of

propagation circuit and must possible frequency loscope the

imposed to

delay in

time

divider

input

determine the exact

that

occurs.

any circuit with procedures given be

calculated. A

the Tp

may

portion

be done

be

if

This

also may

waveform at a faster

DIGITAL

CIRCUIT TIME RELATIONSHIPS

A dual-trace oscilloscope is a necessity manufacturing oscilloscope

permits

between two waveforms.

In digital equipment of

circuits

to relationship to frequency are

dynamic

upon the

dividers

often time-related

state, some of the waveforms change, depending

input or mode of operation. Fig. digital circuit and identifies waveform ing Fig. l0

measurements

shows each of these individual waveforms relationship known comparison

is

would be displayed No. 8

to one or

to

be correct. The dual-trace oscilloscope

to

No.

and Channel B, although other desired. be displayed 8 or No.4 on

Waveforms

on

Channel A.

circuitry is operating

frequency,

design

the

consecutive

delay which

be

compensated

delay which

can be significant in

for. Fig.

may be introduced

stages

produce

circuit. By use of the

and output waveforms can

amount

Significant

several cdnsecutive

for

calibrated

more precise

propagation

stages.

time

measurement,

measurement

of the waveform is expanded

possible

to view the desired

pulling

by

sweep

and servicing digital

easy

PULL

the

5X MAG

speed.

equipment.

comparison of time relationships

it is

common

for a large

be synchronized, or to have

each other. Many of the

previously

as

in many other

described, but waveforms

combinations. In the

9 shows a

several

of the

are appropriate. The accompany-

the

points

normal

and their

waveforms

timing

relationships.

to be expected

have limited value unless their timing

of the other waveforms

more

made.

be

In typical

on Channel A and

would

10,

No. l l through No.

Channel

B in relationship to

fashion,

waveform

be successively

timing

comparisons

13

the

accumulated

a built-in

a critical

8C indicates

the

into a

dual-trace oscil-

be super-

propagation

of

delay may occur

Using

the

Tp can

can

obtained

be

horizontally.

control. It

poition

of

the

in designing,

A dual-trace

number

a specific time

circuits are

typical

points

at

which

at

The

is

this

allows

waveform

No. 3

No. 4 thru

displayed

would

waveform

on

may

be

probably

No.

v

b

rN

Fig. 8. Waveforms

DIVIDBBY.EIGHT

8 indicates

Fig.

divide-byeight

identical

Fig. 8A is divide-bycight

circuit.

to those

supplied

output

used in Fig. 7. The

Fig. B indicates the

input

pulses

the output

and

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WAVEFORMS

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oscilloscope

reference frequency of

to

is

applied

ideal

the

time

Channel

A input, and

to the Channel B

relationship

pulse.

circuit.

for a basic settings are

between

the

lnput.

the

family

In the

waveform No.8

10,

for

viewing

pulse per

of time-related

all of

the

frame.

or

waveforms;there is but one

For convenience, waveform No. 8 or No. desirable. displayed Waveforms No. 4 source start entire there portion cases, while the expand the waveform

GATED

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without

because they

of the

frame.

waveforms

many times when

are

readjustment

No.

thru

do not contain a

would not

It

as shown in

of the waveforms would

it is recommended

sweep speed or 5X magnification be used to

display.

RINGING

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The circuit and waveforms

demonstrate the

oscilloscope is

type

effective

of circuit

waveforms

shown

No. l0 is an excellent

external

the

10 as

sync,

7

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should

sync source

waveforms

of the

not be used

sync

triggering

be necessary Fig. a closer

that the sync

in

l0

all cases.

examination

appropriate. In

be

remain

of Fig.

1l

are

in which the

both in design and

troubleshooting

in

Fig.

sync source

triggering

sync using

may

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may be

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to

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v

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applied

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examined more

oscilloscope

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7. to

Channel A input.

control settings are

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dual-trace

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trigger

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ANY DATA DEPENDING

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the

can be determined by

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settings as

and output

display. Any

evaluated.

and output terminations

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found

in color television

oscilloscope settings

well

waveforms

pulse

stretching and

the basic test circuit. Typical

as

are

on the oscilloscope

shown

ripple

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observed directly.

can be

application of the delay line chedks is

receivers. Fig.

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FUNCTION

POSITIVE OR NEGATIVE

time-related

OR

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also be

can

INPUT

waveforms

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pulse

A

to

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pulses

pulse

B.

should

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examina-

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the

typical oscil-

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can

observed

and

13 shows

the

Fig.

9.

typical

from

the

check section.

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composite video signal

digital circuit

"Y"

delay line

input

for

waveform and the output

delay time, using

in

employed

in

the horizontal

for reference.

the

delay is approximately one microsecond. determining the delay

waveform reveals

characteristics

distortion that

any

from an impedance mismatch

output

resulting

STEREO

Another

in troubleshooting

is amplifiers are used

from

AMPLIFIER

convenient

and the output of one

an open

line.

SERVICING

for

use

amplifiers.

stereo

or otherwise abnormal, the dual-trace efficiently used identical side-by-side progressively amplifiers. been

signal applied

comparison of both units can be

sampling

When

located, the

to

localize

the defective

effects

the defective

to the inputs of both amplifiers, a

identical signal

or malfunctioning

whatever troubleshooting

of

repair methods are employed can

the line, the output

of

may

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or

a

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oscilloscope

points

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immediately.

video amplifier

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INT

TELEVISION

Many

performed later in the apptcations tions. One interval test effectively the

single-trace applications section and

and 21, the information vertical

detail in Fig. 20. Also, because the synchronized to.

Field

the onto each other operation, the signal can be viewed separately indicates alternate

The color television receiver

1. information is to be viewed

SERVICING

of the television servicing using

single-trace

operation. These are outlined

section

of using a dual-trace

blanking interval

#l

procedures,

these

signal),

the

Field

and

as shown

can be accomplished

oscilloscope. As

on

the

pulse

is different.

vertical blanking

waveforms are superimposed

#2

in Fig.

information on each blanking

without

the oscilloscope

control

VITS.

procedures

covering single-trace viewing

the VITS

much more

outlined in

as shown in

Field

and Field

#l

This is shown in

oscilloscope

interval

22, With

waveform,

dual-trace

overlapping. Fig.

setting

for viewing the

on which the VITS

must

be set

to a station

transmitting a color broadcast.

2. T\e control obtain

With the oscilloscope and television receiver operating,

3.

settings

a 2-field vertical display on Channel A.

connect the Channel A detector test

the

4. Set If the

a.

video

point.

SYNC switch as

sync and blanking

signal

of Fig. 14 are

(set

probe

follows:

positive,

are

those required

at

pulses

to the

l0:1)

of the observed

use the TV+ switch

position. If the

b.

the TV-

Adjust the

5.

fields Connect the

detector test

the MODE

7. Set

waveform

and

sync

switch

blanking

position.

SWEEP TIME/CM control

are displayed on the oscilloscope

Channel B

probe (set

point.

to the DUAL

switch

displays

should

pulses

are negative, use

so that 2

screen.

to 10: I

to

)

position.

the

Identical

now be obtained on

Channels A and B.

the

Set

8.

position. sweep

the displays.

SWEEP TIME/CM control

This expands the display by increasing

speed.

right hand

The

appear as

there display

no

is

to either of complete vertical field

display will appear on the

the VITS information will

portion

waveform

shown

provision

of

information on

in the

drawing

for

synchronizing

the

the two fields

frame,

it

cannot be

to

the

.1mS/CM

appear

expanded

of Fig.

waveform

each

trace may

21. Because

the oscilloscope

which.comprise

predicted

Channel A or Channel

B display.

can

be

opera-

(vertical

Fig.

20

*2

sweep

pulse

14

to

video

vertical

video

the

toward

which

is

a

v

5OOO lpSec

PPS

PULSE

Fig. 12.

DUAL

ULTRA SONIC

DELAY LINE

(5pSec)

WIDTH

Delay line measurement

AC

OUTPUT

Pull

9.

the <>POS

tional

5X

counterclockwise

left

until the expanded VITS information

shown in Fig.

control outward to

magnification. Rotate the

direction moving the

15.

NOTE

Because of

the low repetition rate sweep speed combination, the the

signal displays will

be

brightness level of

reduced.

obtain an addi-

control in a

traces to the

appears

and the high

as

t7

CH

1IJ

(INPUT}

A (OUTPUT)

B

DELAY

S

b

1pS/cm

a

o

VI

DEO

AMPLI

FI ER

10. Once the identified information,

Channel A

and Channel B displays have

as being either Field

the

Channel B signal-tracing and trgubleshooting, probe

should be left at the insure that the sync signal reverse provision

two

vertical fields

Fig.

l5

and Field#2

#l tion

displayed

is

because,

shows the dual-trace

sync signal is

is interrupted, the waveform

previously

as

in the oscilloscope

which

comprise a

VITS

information.

on the

trace.

SINGLE.TRACE APPLICATION

INTRODUCTION

In addition to the

outlined,

applications

oscilloscope is required.

oscilloscope,

there are, of

where

the user will be able to make the

dual-trace

course,

only

single-trace

After

SET

BOTH

10:I

ATTENUAT|ON

OELAY

*NOTE'-rrrl

ATTENUATORS SAME, DEPENDING

Fig.

13.

Checking

or Field

#l

probe

may

be used

the

and

video detector test

not

interrupted. If the

displays may

explained, there

to identify either

complete

presentation

The

Field

of the #1

applications

many

service

and

operation of' the

gaining

experience

judgment

PROBES

BUT MAY VARY WIDELY,

"Y"

#2

Channel A

point

FOR

INE

L

NG O F VERTICAL

SHOULD BE THE

ON

CIRCUIT

line

delay

been

VITS

for

in

to using the The tion

to

alternate method

color

described

no

of

is

the

TELEVISION

frame.

Field

informa-

servicing also includes make These

S

previously

laboratory

with

the

as

AMPLI FI ER.

CLIP ON

PLATE

CLOSE

VI DEO

TO

OUTPUT

AMPLI

PROX.

F I ER

more

CAP

efficiently

TYPE.

television

whether

a

job

HORIZONTAL

TO

TO NOTE: NO ELECTRICAL CON-

NECTION;PLACE INSULATION OF LEAD OR IMITY LIFIER TUBE.

IN

HORIZONTAL AMP-

OF

receivers.

performed

be

can

single-trace or the dual-trace method of operation. following is adequate. In

are applications in which

several cases,

the

for

using

the

same application.

dual-trace application has been

single-trace opera-

it will

be

found

SERVICING

A triggered

and

sweep

aligning

several

television servicing

features

o

include

SWEEP TIME/CM control

vertical

sync at sweep speeds appropriate

viewing frames

speeds appropriate

o

Vector

o

pulse

Wide

bandwidth

presentation.

overlay for

oscilloscope is advantageous in

television receivers.

features

that were incorporated to

easier

and more comprehensive.

This

:

automatically

horizontal

and

for

viewing lines.

sync

color demodulator checks.

for

high

resolution

by

that an

oscilloscope

selects

for

at

sweep

video and

j

3

l8

v

VI DEO

2mS/cm

I

o

VERTICAL

SYNC

PULSE

VERTICAL BLANKING

DETECTOR

Fig.

SET

14.

TELEVISION

VIDEO

Set-up

[@?@e@'

for viewing fields I and

mere peak performance peak accompanying service data usually includes waveform pictures peak-to-peak readings on the oscilloscope with those shown on the waveform followed until the The ments are MEASUREMENT

VIDEO

AMP

VITS

2 of

However,

presence

voltage measurement

voltage measurements. The schematic diagram or

procedures

information.

the

or

can

include the required sweep

voltage. Compare

pictures.

by additional

trouble is isolated to as

for

given

PICTURE

TUBE

oscilloscope

absence

often

earlier

paragraph.

of of the

located

be

on the equipment

Any abnormal

readings in the

making

the

in

much more than the

shows

signal.

pictures.

peak-to-peak

CALIBRATED

provides a peak-to-

It

signal. The cause

making

by

These waveform

time

peak-to-peak

the

readings

suspected

an area as

small

of

peak-to-

such

being serviced

and the

voltage

normal

voltage

should

circuits

possible.

measure-

VOLTAGE

poor

be

Fig.

SIGNALTRACING VOLTAGE

television receivers ment for that matter), the oscilloscope is an indispensable instrument. It presence may the

path, When this happens, the

Oscilloscope

15. VITS

READINGS

general

For

of normal

used to trace

be

path.

signal

point

a

information.

may be

presentation

AND PEAK.TO-PEAK

troubleshooting and isolation of troubles in

(or

almost any

provides

As measurements

a visual display of absence

signals. This

a signal by

found where the

source

of fields

other electronic

method

measuring

proceed

of trouble has been

I and

(signal-tracing)

points

several-

along the

disappears.

signal

located.

2 of

equip-

or

signal

in

COMPOSITE

Probably servicing signal, and 17 show composite pulses

be observed

can to determine Knowledge of waveform makeup, the

normal waveform, and the

waveforms help the technician locate problems. television

VIDEO WAVEFORM ANALYSIS

the most important waveform in

is the

the

and

composite

blanking

typical

video

signals

vertical blanking

at various

whether

The

technician should study such

receiver

waveform

pedestals

oscilloscope

synchronized

pulses.

stages

circuits are

known to

and

causes

be

consisting of the

the

traces

with horizontal

Composite video

of

the performing

of

good

in

television

pulses.

sync

when

television

appearance of

various abnormal

and correct many

waveforms operating

video

Fig. 16

observing

sync

signals

receiver

normally.

con-

a

in a

l9

HORIZONTAL

PULSE

SYNC

HORIZONTAL

BLANKING

PULSE

@l

[,

l--

L,lElr-

@i@flo'

10pS/cm

TV_

INT

s

VIDEO

VERTICAL

SYNC

PULSE

TELEVISION

Fig.

16. Set-up

VERTICAL

BLANKlNG

SET

for

viewinghorizontal

of composite

fields

video signal.

fl@fr@3

START

WITH CHA

2mS/cm

(See

INT

WITH

text)

START

TV+ or TV-

20

DETECTOR

TELEVISION

Fig. 17. Set-up

VIDEO

SET

viewingvertical

for

VIDEO

AMP

fields of

composite

video

PICTURE

signal.

TUBE

b

v

U

dition, noting

the waveform

amplifier.

To

composite video

1. Tune

2. Set

3. Set position

mS/cm

4. Set

5.

Set Pull

6.

up the oscilloscope

set

waveforms,

the television set to a

the MODE switch

the

SWEEP

for observing

position for observing TV

the

SYNC

switch to

the SOURCE switch

the TRIGGERING

sync.

7. Set the CH

8. Connect Connect the

chassis. With

set connect output

the

Set

9.

deflection

If

10.

necessary,

to a

If the sync and

11. signals

position; use

the

Push

12.

to a Adjust

13.

desired

A DC-GND-AC

probe

a

ground

tip of the

the

of

television set.

the

A VOLTS/CM switch

CH

possible

rotate

position

are

that

positive,

if the sync and blanking

position.

TV-

in the TRIGGERING

position

that

the

INTENSITY

brightness

14. To view a specific pull

burst,

color for 5X rigfrt to

magnification.

the desired

select

be viewed.

15. Composite video points

on the video circuits

points

those

setting

the

of

required

as

scale,

and

and by

LEVEL control

the observed

of

moving fore,

from one monitoring

may

it

be

SYNC.

at various

use-the

points

for

viewing

following

local channel.

position.

to the CH

TIME/CM

TV

A

switch

to

horizontal lines

vertical

the TV+

to the INT

position.

LEVEL control

to the AC

switch

to the CH A INPUT

cable

clip

probe

the

without

of the

set

probe

going

probe

for

10:l

the

to

for

the

off-scale.

the TRIGGERING

provides

blanking

a synchronized

pulses

of the

set the SYNC

switch

pulses

control and

FOCUS

the waveform, such

provides

and best

portion

outward

LEVEL

a well-synchronized

and

focus.

of

on the <>POSITION

Rotate the same control

portion

waveforms

changing

to keep the display

readjusting

maintain stabilization. The

to

of the waveform

may be checked

moving the

by

the VOLTS/CM control

within the limits

the

waveform may be

point

to another;

necessary

to reverse

the

in the video

television

procedure:

10

pS/cm

the

or to the 2

frames.

for

automatic

position.

jack.

to the television

attenuation,

detector

video

largest

vertical

LEVEL

control

display.

displayed video

to the TV+

negative,

are

rotate

display.

controls

for the

as the

control

left or

to

other

at

probe

tip

to

TRIGGERING

polarity

reversed when

there-

polarity

of

the

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Fig.

19.

OVERALL

FREOUENCY

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pulse

Sync

R€CEIVER

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distortion.

waveforms.

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PULSE ANALYSIS

SYNC

The IF amplifier

be evaluated to some horizontal sync

sync

pulse

waveform is affected

response of a television receiver can extent by careful

pulse

waveform. The appearance

bandpass characteristics. Some and their relation Fig. positive shown in

Sync

18. or negative limiting

Fig.

pulse

19.

to

IF amplifier

waveform distortions

in IF

observation of the

the

by

typical waveform

IF amplifier

symptoms

response are indicated

prdduced

overload

conditions

of the

in

by

are

(VERTICAL

VITS

Most

network

(the

signal

VITS) troubleshooting locaLize and

ing

scope

trouble

when

shows

procedures

displays

of the VITS.

The VITS interval. On the white line

above

INTERVAL

television

that

and

servicing

signals

can be a

television

to the antenna,

realignment may

show how

is

transmitted

television

the

to analyze

set,

top of the

TEST

SIGNAL)

contain a built-in

very

sets.

tuner, IF or

be required.

and interpret

during the

it

can be seen

picture,

valuable tool

This MTS

video

sections

The follow-

oscillo-

vertical

when the

blanking

as a

vertical

bright

test

in

can

2l

linearity

or height

interval (on

the

blanking

*TITT FLAG

BOTTOU

I ,I

PICTURE

rr!

wxrrEJ

BLACXl

is

TV

adjusted to view the

with

sets

circuit must

I T l'r"ttil'

Fig.20.

oF

FIELO

IF

IZING

VITS

I

VERTICAL

internal retrace

disabled to

be

fields

signal,

ELANXING

INTERVAL

vertical

blanking

the VITS).

see

1and2.

blanking

t+t

SLAC(

H0Rt2

PT

Oi

circuits,

ITt

SLAi(lr{G

STAL

279 andline 18

appears

just

at the

before the first line of video.

followed

is

bottom

line

by

of

the vertical blanking

280. The

Each of the multi-burst frequencies is transmitted

equal strength. By observing the

frequencies

these

television receiver,

the

after

frequency response

the

comparative strengths

signal is

processed

of the set is

checked.

Set up the oscilloscope

l. Connect the CH A

the

video detector or other video section of the television

lf the

2.

television

set

circuit, bypass this

the MODE

3. Set up

4. Set waveform frames

5.

Reduce ms/CM) with expands the

the oscilloscope for will be

switch to CH A.

analysis

as

visible.

time to

sweep

the

display by increasing the VITS information will expanded waveform

Further

6. (pull the

ion,

VITS

expand the

outward

<>POSITION

on the {} POSITION

control

moving the trace to the left,

appears.

follows

as

probe (set

to

view

the VITS:

at 10:1) to the output of

desired test

point

set.

has

a vertical retrace blanking

circuit during the measurement.

TV vertical composite video

previously

.l

SWEEP

described. Two

millisecond

TIME/CM

per

centimeter

switch. This

sweep speed. The

appear

to the right

display.

with the 5X magnification

sweep

control). Rotate

in

a counterclockwise direct-

until the

NOTE

The brigfrtness level of the reduced only 60 Hz speed is

because, although

(a

pSEC/cm

20

16,000

pSEC

(.1

mSEC/cm magnified five

signal

repetition

the

period)

display will

the writing

times).

7.

The

waveform

should

be similar

to

shown in Fig.

that

22. For the oscilloscope display, each vertical pulse

(mnti-burst)

279

starts a new

sweep. This causes

to

be superimposed,

line 17

as

entire

pulse

through

in

vertical

on the

expanded

be

rate is

and

lines 18

are

VITS

and

the

(.1

sync

line

of

at

l.r

t*

-

\

t

Fig.21.

Vertical

blanking interval, showing

tion.

The transmitted VITS is a specific Fig. signals sion

evaluate television

VITS followed by sine wave

MHz, 3 MHz,

sequence first multi-burst. This portion

second contains staircase

frequency,

20 and 21. The

for

adjustment and checking

equipment,

(line

amplitude,

television networks use the

but the

performance.

set

17) begins frequencies of

MHz,

3.6

of frequencies is

frame

of

Field

#2

multi-burst that frame

the

of

can be

most valuable

of the

VITS

sine-squared

MHz

3.58

shading, are valuable to

technician.

the interlaced

As seen

with Field

lf2

22

VITS

informa-

precision

and waveshape

sequence

as shown

precision

of network transmis-

technician

with a

(3.58

called

(Iine

279) also portion

can use them to

The first

"flag"

MHz,

0.5

MHz)

and 4.2

"multi-burst."

the

contains an

of the

of

frar,ne

white

l

.5MHz,2

MHz. This

identical

VITS

of the video,

is the

to the technician. The

(lines

ptrlse,

window

bursts at

18 and 280),

pulse

progressively

which

and the

lighter

the network, but have less value

on the televiSion

that line

so

17

screen,

is

Field

followed

#1

by line

of

in

The

to

t

is

Fig.22.

Oscilloscope

single-trace

presentation

operation.

of

VITS

inforniation,

5

and 280. The multi-burst reinforces

identical

the trace.

and

However,lines

both signals are superimposed

other.

ry

8. The

presentation

preceding paragraphs

of the

is the limit of observation

oscilloscope. With the ever,

a single-field VITS

by

placing

the

MODE

Model

presentation

switch causes the Channel B information alternate sweeps, as are Field Because or Field (Fig.

15)

there

#2

will

provision

is no

information,

appear. The

either

the VITS is the most valuable for troubleshooting television Field troubleshooting

Now to multi-burst not

be response good

color

I

the multi-burst attenuation reference

receivers and Field,+2 VITS, either can be used for

#l

and, because

and signal

tracing.

analyze the waveform. All

arc tiansmitted

equally

coupled through the receivei

curve. Fig. 23

at

shows

television receiver, identifying each

and showing

for

each. Remember

voltage

(the

2.0

MHz

are identical,

signals

18 and

280

over

possible

with

a single-trace

l47l oscilloscope, how-

can be obtained

in

the dual

position.

to be displayed

and Field

#1

preselecting

for

Field

multi-burst

it is

+2

or

#7

information in

present

frequencies

the

same

but should

level.

due to its

the

desired response

frequency

the

allowable

-6

that

modulation

amount of

dB equals half the

should be used

which

are not

(Fig.

VITS. Field Field

on

of

each

22)

This

on

#1 #2

both

the

for

chance response video the

on shows except that bursts on

into

below

channel carrying reasoning is right, If the

channels, misadjusted, traps at the or faulty.

for [,ook bridges across

a

of

the antenna system

on

detector on

amplifier

IF

As

another example, let us assume that we have

channels. If the VITS

some

all channels,

stages.

the bench with a very

the VITS

passband,

the

poor

at the video

the burst

either

side. This suggests an IF

2.0 MHz

at

chopping

picture

maybe

carrier

VITS.

the

and

response

an

If the

IF

at 2

FM trap

causing a bite on

input of

the VITS response

If

channels,

all

for

open

foil

the

set could similarly be

the trouble

peaking

patterns,

GRATICULE

causing

the trouble

poor picture.

detector

out frequencies

frequency.

same

amplifier requires

MHz

only one

at the detector

will

be in the video

coils, off-value

etc.

"holes"

is

or

tilted

abnormal at the

probably

is

a

in

set

Our oscilloscope

to be about normal

low

is

compared to the

trap

is detuned

about 2

MHz

Switch to another

thing

is seen,

then our

realignment.

is not seen on other

at the tuner input is

channel.

Other

misadjusted

output

is normal

amplifier.

resistors,

solder

for reference).

o

PICTURE CARRIE R

i.t7

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MOOULAT]

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Fig.24.

\

VECTORSCOPE OPERATION

Performance

in

circuits

the

color

vectorscope operation

tional .equipment needed is a color

& K-Precision color bar

B

this.

First the

must

scope

be

Installation

testing and

television

horizontal

equalized

(see

l. Attach vector overlay

mounting attach bezel

2.

Connect and

screws and lift off bezel.

(see

Fig. 24).

the

tune in

the color bar

bar.generator to

color

3. Adjust the television set's

VECTOR

OVERLAY

vector

of

adjustment

receivers

overlay.

of the

is simplified by

of the oscilloscope. The

generator.

generators

vertical

and

bar

are ideally suited

gain

of

the oscillo-

Fig. 25).

to

scope.

Remove

Insert overlay

the

television set

pattern.

hue and

brilliance controls

4

color using

addi-

The

for

bezel

and

to

mid-range.

I

4t 42 43 44 45 46

FREOUENCY-MHz

Fig.23. Color

TV IF

amplifier

response

curve.

gun,

the

A and CH B

CH

both

usually

4.

47

Set SWEEP

5.

Connect

jacks.

the horizontal

TIME/CM control to

probe

cables

to the

Channel A is the vertical input and Channel B is

input. Connect

driven element of the red

CH B

probe

the

position.

IMUT

tips to the

grid.

If the

cathode is the driven element, then connect to the

To localize

detector. This

video

trouble,

start

will localize trouble to a before or after. the detector. the detector, check channels

look

okay

the

others do not,

but

VITS

tuner or antenna-system

by observing the

multi-burst is normal

If the

other

on

VITS

point

channeld.

at the either

If

you probably

troubles. Don't overlook

at

some

have

the

cathode. the output

Adjust the

6. gain)

VOLTS/CM controls io obtain a compressed 45" pattern oscilloscope is

(The

signal

CH

that

approximately

now set

element is

driven

the

of

color amplifier

(vertical gain)

A

up for vectorscope

fills

element to which

the

is

applied.)

and CH B

the

vector overlay. The

(horizontal

operation.

23

^tE@--l

@ @

COLOR

BAR

GENERATOR

For

7.

probe vector

television

vector

presentation,

to

the driven

pattern

set

is the

manufacturer.

displays obtained

the

either

picture

systems with

If will appear on the right rotate

the vector overlay 180" so the BURST

on

is

the right side.

with the

measurement in a color

vector overlay.

The

vector

of the

TV

set. iarize himself with the produced

that the

of control changes their

elliptical

by the

color amplitude

petals

the

amplitude.

pattern

but

the

Fig.

merely move

element

of the

same

for

gid

using i05o

sets

drive or

NOTE

tube uses

cathode

side

The

color bars will then

display

provides functions The

serviceman

effect on the

color controls.

control

not

their

position

Iastly,

than

of the

105"

sets

90" sets.

CHASSIS

25. Equalizing scope

horizontal

operation.

the horizontal gun.

type

blue

as

The color

given

by the

Fig. 26 shows typical

cathode

drive,

of the

systems

screen.

and

drive.

the burst

Just

90"

label align

quick

very

a

of the demodulators

should

famil-

pattern

He

should observe

will vary the

position.

petals

size

The hue

but not'

will have a more

The

table below

and

ADJUST REOUIRED

GREEN

vertical

lists

A

RED

gain

some common troubles

pattern.

The vector range of possible

axis. petal

the color

to

At

the

should CHROMA oscillator

is

tors.

A

slight is necessary position. on

the

Do not

chroma are aligned by general

If

be

aligned by

the

set has adjustable demodulators, vector display alignment. procedure

to locate counting bars simply between

R-Y

PICTURE

TUBE

for

Vector-

their

and

display

rotate

set's hue

the

can

R-Y

be used

control. It

petal

center of the hue

be vertical. If

reference

oscillator. In

it is

transformer-coupled

effect

to

about the

control

not,

most

to the demodula-

touch-up of this transformer

to

bring the

attempt

petal

R-Y

to make

to

any

adjustments

bandpass amplifiers. These

a

can

Follow

and

B-Y.

generator

sweep

just

alsb

vector

a

be

used

and

display.

for demodulator

the manufacturer's

proper

the

adjust

coils and instead

for

the

correct angle

on the

the

check

should be

vertical

the R-Y

locate

the

sets this

is

all that

a vertical

amplifiers

cannot

in

the

alignment

of

b

24

v

GR

DRI

ID VE

CATHODE

DRI VE

Nn na/

,",=Rv1

v

\as

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U

VECTOR

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VECTOR DISPLAYS

TROUBL E

Loss Overloading Color

weak

Lack

Demodulator

DISPLAY

GRI D

DRIVE

of color

amplifiers unbalanced

of range

sync

of color

hue

of

out of alignment

,

FOR

90'PICTURE

BY

Tq}\*Y'/l

\z\

\

;

FOR 105"

GENERATOR

amplifiers

control

r'os"

coLoR.

BAR

or

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TUBE

CATHODE

DR IVE

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*i4N

/U

*

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EFFECT Petals

of

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are

Flower

petal

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vertical

Angle

between

petal specification General

\

CHASSIS

PATTERN

ON

pattern

crushed

pattern

very elliptical

cannot

R-Y

not

manufacturer's

to

(90'

Specif ication ) .

%f

rotate

will

flattened

or

be made to

petal

and

or 105"

OTu

be

B-Y

Ol^t

RED

L(JE

E

-

GREEN

EFFECT ON T.V. Varying colors

distortion

Color

distortion

Color Hue

control

f leshtones

Wrong colors

PICTURE

TUBE

won't

V

I

PICTURE

adjust

U

,4

Fig.26.

Vectorscope operation and

patterns.

25

INTRODUCTION

Alignment circuits in oscilloscope, of

test equipment sweep, IF supplies alignment

of

television

such as

sweep and RF

and a VTVM.

displays

of the oscilloscope

books instructions

and in

75 38

the television

(typical

?3 72 7t 70

4t 4?

40

tuners,

the

video

receivers

this instrument.

required

are sweep, The

a bandpass

of

sweep

response

the type

set manufacturer's

response.

43 44

CHANNEL 6

69

MxZ

68 45 46

wr0€

4

curves

67

IF

required

The

sweep

marker

generator

always

are shown

TELEVISION

strip, and

a high-quality

additional pieces

generators

generators,

curve on the

shown in

for

method

alignment

inFig.

chroma

video

DC

bias

of

screen

theory

27).

ALIGNMENT

For

a

comprehensive

ment,

we

the B & K Model

"handbook

This

not only the

all the

but alignment

generators, valuable make

alignment easier

many

illustrations step approach textbook. Copies

B & K-Precision

NOTE

analysis of

recommend

the instruction

415

Sweep/Marker

of television

procedures

how

and

general.

in

this

comprehensive manual

procedures,

for using the

why answers

Even

insights and tips

and

qualify

it as the

easy-to-understand

and

are available

distributor or the factorv.

television

alignment"

about television

you

if

use

professional.

more

"how

align-

manual

Generator.

includes

instrument,

other

sweep

provides

that

will

The

step-by-

to

align"

from

your

v

for

a

]8 MHZ

(75

MHZ)

Fig.27.

TV

technique.

The

ideal

oscilloscope

tor. The B

necessary

1ll from

one and precision

television ever, use of the

emphasized.

is equipment

instruction

instrument.

calibrated

alignment.

For

complete

set,

the following

oscilloscope

In

this manual,

required

manuals

Ill r r\

til ||

ut tl

T|ll

I||l

tttl

rlll

6A66

!Ooo

;e33

zFFF f@-@

N^,

-

o

qc-

oq

ci6io

response

instruments

curves

for

obtained

television

and the B & K-Precision

& K-Precision

sweep ranges,

accuracy

follow

Proper

Sweep/Marker

markers

The

of the

alignment

the

manufacturer's

general

set-up instructions

for

sweep-frequency

only

the

use

of the

for

alignment

for

those

simplified

instructions

proper

sweep

instruments.

CONSTANT

AMPL I T

UOE

R.F

SWE€P

MHZ

)

OVERALL

RESPONSE

OVERALL RESPONSE

CHROIIA TA(E_CFF

COIL RESPONS€

OVERALL R€SPONS€

o 2

o q

by sweep-frequency

alignment

Sweep/fuarker

Generator provides

and

DC

bias voltages,

operating

instrument

each particular

of

instructions.

demonstrates

alignment.

use

of the

oscilloscope

generator

should

provided

be

TUNER

I- F

CHROUA

are

this

Genera-

pro-edure iesults

How-

and

oiher

in the

all

in

IMPORTANCE

The most of the tuner, IF receiver

sweeps

through the entire channel at a processed

shaped by the sections. Because tuned

circuits to another has at

proper

the

certain

bandwidth

Fig.

OF

rapid way

provide

is to

controlled,

through

gain

the

characteristics.

points

and the

properties

27 shows

SWEEP ALIGNMENT

and chroma

a

the tuned

and

bandpass

signal is

up to that

the sweep signal with curves of the tuner, IF circuits to

below

scale.

These be obtained receiver were oscilloscope. Because

response

is

Some importance of frequencies area is

the most this area will response

curve

Notice constant-amplitude spectrum.

Notice

The

it.

bandwidths

outlines

are similar to the

if the outputs

demodulated and the

of the

least critical.

reference frequencies

proper

are on the

alignment.

slope

critical because improper IF alignment

the

affect

and this

that

amplitude and

in turn

the chroma information is located

portion

that the relative information are modified circuits This

Notice

chroma

plitude the chroma for overall between the chroma

of

the television receiver tuner

is shown by

that the

frequency

with

frequency-versus-amplitude

this

IF

portion

reference to

signal information at the

range respect frequency

response

IF output

the

to

range

curve, a chroma takeoff

and the bandpass amplifier

of the

receiver.

tuned to the upper end

and

The

provides chroma

result of

usually 4.08

27. This

MHz

compensates for the amplitude-versus-frequency characteristic of the response

curve.

to determine the

portions

constant-amplitude

bandwidth of

repetitive rate.

portions

properties

channeled

overall

condition

of the television

signal which

given

a

fu

television

this

of the receiver,

of

the various

from

one

it is important that each

If the

envelope

signal is demodulated

observed, the

point

can be determiped.

basic response

amplifiers and

chroma bandpass

shown are approximately

curves

of the various

that would

sections

of

curve observed

relative

of

bandwidths, the

are identified to

Notice

the

that the

IF response

show the

curve.

shape of the

color

picture

television

affects

of the transmitted

amplitudes of the

passing

by

through the tuned

and IF amplifiers.

the

(4.08

MHz)

IF

overall

is reduced in

response

upper

end

signal level at the lower end

(3.08

MHr).

To

compensate

characteristic of the

coil is used

The

of the

a response

portion

combining

chroma

takeoff

frequency

as shown in

of the

the

response

overall IF

signal is

it is

series of

section

gain

and

the TV

on an

tuner

chroma

This

chroma

quality.

on a

chroma

curve. of the

run-

of the

coil

range

Fig.

the

of

in

of

is

b

26

IF curve and the produce

range applied to the bandpass indicated

specified as a separate step

cedures. takeoff coil the bandpass transformer.

SWEEP

ing frequency signal at the tuner antenna bias gounding

circuits to

receiver require alignment. is

problem strip and

response and the

likely that response is

a flat overall response

(3.08

by the overall

Alignment

In other

ALIGNMENT

The

best

which

line must be

are

the manufacturer's recommended

The

technician can

satisfactory but the

is

response of the

MFIz

to 4.08

of

performed

is

method of

require alignment

stages

AGC

the

qbserved

then

between the video detector

the output of the bandpass

chroma

the

IF

poor

on

MHz). The resultant amplifier which

chroma

the

chroma

procedures,

METHODS

checking

clamped

line. The

then decide which

chroma

response are

requires

the

slope

chroma

in the

response

takeoff

in manufacturer's

adjustment

together

on an oscilloscope

For example, if the IF response

with the adjustment of

alignment and

is to

application of bias

by

outputs of the IF and chroma

response

response is

touch-up,

affecting chroma

takeoff

chroma

has the response

curve.

coil

inject

terminals.

output of the

amplifier. If

poor

particularly

coil

frequency

signal

is sometimes

test

of the chroma

determinRF

an

The AGC

and

compared

curve.

portions

not,

then

it

response.

is to then

is

pro-

sweep

or

the

of

the

IF

the

IF

is most

if the

The alignment thah that circuit, attention. between the tuner and pre-alignment some

mined, ed. The alignment Some terminals quencies done One way of doing this generator picture selected is the sweep the for the alignment of these stages.

injected alignment. then modulated before this is detected receiver and chroma circuit alignment.

problem

of

the

which is located on

This

procedure

manufacturers.

Once the

an

suggest signal

by selecting the right combination

VSM, or video

modulation

TV receiver

Other

deficient

alignment check

which

in

the

for IF alignment.

carrier

and

at the

frequency for the channel

this is modulated by a

and applied

manufacturers recommend

mixer

The IF

with a video

the

of the tuner

because

IF

part

is

can

receiver so

sweep

is demodulated

picture

recovered

the

section;

of the

the first

given

is

portion

of that section

procedures

combinations

generate

that overall alignment

is to first connect

modulation

to the

grid

(or

carrier

sweep voltage

at the video detector

sweep

however, the mixer output

After this is complete,

base, if transistorized) for IF

portion

RF

passband

seldom creates an

is so

the tuner, tuned matching

IF

stage.

for

of the receiver is deter-

vary

IF

video sweep signal

at the video detector of

chroma

frequency

voltage

link

the

can be

manufacturers.

with

the tuner antenna

at

video sweep

and

of input signals.

method). This video

bandpass

IF

an

sweep frequency

(45.7

(VSM

is used for the

greater

much may require

network

A separate

circuits

perform-

can be

RF

an

being used is

sweep

circuits

5 MHz)

again). As

of the

by

fre-

the

(this

is

TV

U

ANTENNA

TERMINALS

CHANNEL

SELECTOR

cr62

SWEEP/MARKER

GENERATOR

RF SWEEP

OUT VOLTAGE

TELEVISION

SET

.0'lV/cm

o-

o

Ir-l

@

L==]g

ADJUST

HORIZONTAL

SIZE

t

lb

Fig. 28.

Typical

tuner

alignment

set-up.

27

Another method chroma circuits directly. sweep modulation used to of IF of the final

manufacturers spot test tuned

his manual procedures manufacturer's procedure. apparently response, ponent troubleshooting pr

TLJNER

check the

alignment

chroma

overall

In

conjunction

frequencies

point).

circuits in the IF

In

all

cases

particular

is

the technician

failure

ALIGNMENT

l. Connect

antenna

generator

sweep

2. Tune

the TV

circuits

chroma response.

recommend pre-tuning

fther

receiver

preferred

are also

deficient

has

the

terminals

is to first video-sweep

The IF

IF

of the

combined effect

and

chroma alignment. Usually

is

with

into

the

procedures

before

manufacturer's

the

and

for

alignment.

reliable

receiver

must

occurred

ocedures.

(Refer

output of

of the television

to

sweep one of the TV

set to the

then

is

frequency

pix

necessarv

IF

alignment,

(usually

IF

outline

sweep alignment

the

and in most

If

complete realignment

does not

then

and must employ

to Fig.

the sweep

same

channel.

aligned

(45.7

of

the

chroma response

to obtain

IF traps

at

a specified

prealignment

a

method

manufacturer's

SAMS

cases repeat the

restore

consider that

28) generator

set.

channels.

align the

video

and

5 MHz)

a touch-up

the

desired

practically

by injecting

tuner of

procedures.

is the best for

service

PHOTOFACT

of an

the required

a

com-

standard

to the

Adjust

the

all

Connect the

3. directly to the tuner shield to

is

Connect the Channel DIRECT)

normally the

is where a demodulated

4. Set the sensitivity to avoid overloading the television receiver, which would erroneous screen.

5.

The oscilloscope exact

synchronization

presentation

proper

accomplished for

setting the oscilloscope (SWEEP

horizontal

the

Channel

to the

6. Select the marker measure the

The tuner

7. oscilloscope. See the response adjustments for realignment.

ground

the

to

CH A VOLTS/CM

and

operate

distort

picture

TIME/CM

sweep

B input terminal

upper and

response

curve specifications and

clip

A

tuner test

grid

of the

signal

the

response curve and

the

of alignment

sweep and sweep

and

of the response

sinusoidal

for external

to CH

voltage

generator

lower response of the tuner.

curve

the manufacturer's

of the oscilloscope

minimize hum

(Vertical)

point.

mixer tube or equivalent,

present.

is

control

sweep

phase

or

position)

B

from

on the oscilloscope.

frequencies

is now displayed

probe

The tuner test

for maximum

generator

on

the

generator with each

curve.

sawtooth sweep by

horizontal input

and connecting

the

sweep

instructions for

the

probe pickup. (set

point

at low level

provide

oscilloscope

must

be in

for

other

This

is easily

generator

required

on the

necessary

to

v

an

to

EPlMAR

SWE

GENERATOR

VOLTAGE

KER

SWEEP

ffi

AGC BIAS

.01Vlcm

VI DEO

DETECTOR

@il

@

o

@F

ADJUST

HOR IZONTAL

SI ZE

DI R ECT

b

CHB

28

Fig.29. Typical

IF alignment

b

set-up.

ry

ALIGNMENT

IF

1. Connect injection

signal generatoi

has been

tuner applied at

Synchronize

2. generator

ALIGNMENT Connect

3. probe

to the

4. Connect video detector

5. Set the CH viewing

Keep the sweep

6. overioading.

tions Select

7. check A the Model

8.

of the

on

the

the critical

sweep

markgrs simultaneously,

415, is a

Follow

response

the

(Refer

output of

the

sweep

to

the

antenna

the

previously described in

as

procedure.

ground

the

television set chassis.

vertical

the

output.

A

response curve.

Fo[bw the

disabling

marker

and

manufacturer's

the

curve

42.67 MHZ

Fig.29)

to

the sweep

point

of the

the

properly

terminals.)

oscilloscope

clip

probe

VOLTS/CM

generator output

manufacturer's

AGC.

generator

frequencies

generator

advantage.

big

making

and

/

I

L

VALLEY

57"

generator to the

mixer.

IF frequency

aligned,

of the

gain

such

instructions

MAX

Adjust the sweep

RF

with

sweep

oscilloscope

control

level-

frequencies

of interest

capable

the

as

alignment.

the

45.OO MHZ

85%

-+15"/or-lO"/o

-50o/o tso/o

45.75

(If

band.

sweep

the

for suitable

low to

recommenda-

required

(see Fig. 30.)

9f -digppVing B &

for

ADJ

47.25

PIX

MHZ

the

may be

the sweep

TUNER

vertical

to the

prevent

K-Precision

evaluating

SND

MHZ

to all

3 o8 MHz

gf/"

ttOo/o

Typical

31.

Fig.

2.

3.

4.

ranges

sweep

to

frequenCies,

for IF alignment.

used

Apply the

color

the manufactureis

Synchr

described Use a demodulator

(Channel A) to the curve

5. Set the A

CH the screen.

A response

6.

should of interest. bandpass specifications

-l

chroma

resPonse

of

approximately

Use the same

proper DC bias

ampfifiers

the

onize

for tuner

input

the

at

vertical

(VOLTS/CM)

curve

be seen.

Refer to

MHZ

3.58

I

4.O8 MHZ

I

'l

\-

t\

I VALLEY

instructions

oscilloscope alignment.

to the

gain

Select

MAX

15'/"

TILT

response

levels.

(bandpass

probe for the

oscilloscope.

for a convenient

similar

the

MAX

IOO/"

MHZ

4.50

curve,

4I to

lhe

IF injection

the color

to

amplifiers).

the correct

for

sweep

Measure

demodulators. controls

that

to

marker

manufacturer's

alignment

and

showing

of the

shown

generator frequencies

gs"h

_

*l5o/o,-?Oo/o

tolerance

MHz band

44

procedure.

that

level

to

killer

Rgfer

bias

previously

as

vertical

response

the

oscilloscope

viewing

Fig.31

in

instructions

was

enable

to the

level.

input

on

size

for

of

ry

response

Typical

30.

Fig.

ranges

CHROMA

The IF alignment before starting injection injection specified drastically. for alignment.

l.

of

such

kave the sweep/marker connected

IF

response

of

ALIGNMENT

this chroma

video

sweep

herein,

Follow

direct

the

injection

for IF alignment.

as

curve,

levels.

(Refer

must

is

manufacturer's

Fig. 32)

to

be

satisfactorily

alignment

rather than the

used

the response curve

of video sweep

generator

Set the sweep

showing

procedure. If direct

procedure explicitly

tolerance

completed

IF

is altered

for chroma

,

AGC bias

and

generator

sweep

NOTES

29

@-

v

SWEEP

VOLTAGE

ilru

ilrrTmt

ilm

:

@-i-@

ADJUST

VERTICAL

SlzE

VIDEO

DETECTOR

VIDEO

AMP

@

['l@

@

lo-lg

un=J

ADJUST

HORIZONTAL

S;ZE

DEMODULATOR

PROBE

@

b

,

30

TELEVISION

Fig.32.

Typical

COLOR

chroma

FI

RST

AMP

alignment set-up.

SECOND

COLOR

(BANDPASS

AMP)

COLOR

KI

LLER

AMP

U{

Procedure:

1. Connect

FM receiver.

centered

Connect

2.

generator to Jtopt horizontal

Connect

3. input

Adjust

4. coritrols

Set the

5. marker

Aligl the

6.

specifications. Move

7.

curve should

RECEIVER

FM

a sweep

sweep.

and

the

of

the oscilloscope

for display

marker

"pip"

the

strotitO

appear

Refer

generator

Set the

sweep

the

IF amplifiers

Cliannel

the

oscilloscope

the

set

(SWEEP TIME/CM

sweep

vertical

FM

receiver.

generator

ihould

probe to the

displayed,

be

exactly

ALIGNMENT

Fig. 33

to

sweep

voltage

B input

probe to

input

vertical

similar

to that

precisely to

the

be in

according

demodulator

the

in

mixer

the

generator for

output

center

and

center

of the

jack-

of

controls

CH

to

the

horizontal

and

shown

10.7

of

manufacturer's

the

to

output-.-The

10.7

the

(See Fig. 338).

of the

input

for

demodulator

the

10.7

a

sweep

oscillo-

the

external

B).

Fig.33A'

in

MHz.

bandpass'

"pip"

MHz

gain

The

"S"

Adjust faciurer's distances increased

MHz center

10.7

measurements

Phase scope. produce a shift Distortion in

tested. input ciicuit The amount

can

procedure

Typical applications

-specifiC

distorti,on

due to

oscilloscope

the

A

wave input

sine

The same

of the

is applied

be calculated

make

To

(Refer

Using an

1. signal, frequenry

demodulator^

the

instructions

center

from

decreased

and

frequencY.

PHASE

phase

in audio

nonlinear

waveform.

wave

sine

oscilloscope,

to the phase

of

audio

apply

from

phase

Fig.

to

a sine

the

to

the

signal

audio

according

marker

the

so"

as

the

equal

marker

amounts

MEASUREMENT

made

be

may

shift,

amplifiers

is applied

horizontal

difference

resulting

measurements,

34).

wave

in circuits

ate

measurement

and

other

or

amplification

audio circuit

the

to

applied

is

input

and

generator with

network

outp^ut

the

of

input

between

waveform.

use

test signal

being

to

moves

frequency

with

audio

is also

to the

of the

the oscilloscope.

the two

the

pure-

a

the

at

tested.

equal

from

oscillo-

an

desigled

phase

of

networks.

displayed

being

vertical

tested

signals

following

sinusoidal

desired

the

test

manu-

the

to

is

-

b

I

7

J

MARKER

GENERATOR

.-

I

\

@

CHB

[rl@

I

\

I

L

ffi

o

L=jA

@B

SWEEP

MARKER

INPUT

GENERATOR

RF

OUT

'-l

SWEEP

VOLTAGE

VERTICAL

SIZE

r--

I

DEMODULATOR

HORIZONTAL

SIZE

DTRECT

FM RECEIVER

Fig. 33. Typical

FM

receiver

alignment

set-up.

31

AUDIO

SI

GNAL

GENERATOR

ffi'6tr

CHB

v

o

Fig.

34.

Typical phase

3Fj6

ll|Lffijjl

r-t-lrl

AUDIO

NETWORK

BEING

TESTED

measurement

VERTTCAL

srzE

\_

alignment

HORTZONTAL

stzE

LOAD

set-up.

I

)

b

NO AMPL

ISoO

AMPLITUOE

Fig.35.

ITUDE

NO

PHASE

oUT oF

PHASE

Typical

DISTORT ION

SHIFT

PHASE

OISTORTION

SHIFT

phase

measurement

AMPLITUDE

NO PHASE

NO AMPL

ITUOE

PHASE

9oo

OUT

oscilloscope

OISTORTION

SHIFT

DISTORTION

SHIFT

PHASE

displays.

NOTES

i

I

i

1

V(

32

generator

signal

the

Set

2.

''

lii""el;";1-Jtie .ii'iii"

test

the

theoscilloscopeisclippedandthesignallevelmustbe reduced.

Connect

3. circuit.

SWEEP

the

Set

4. Connect

5. thetestcircuit.(Theinputandoutputtestconnections to

6.AdjusttheChannelAandBgaincontrolsforasuitable

7.

-

pattern.

ellipticai ;ff6;;.6"lut.O Fig. 36.

vertical

the

reversed.)

be

viewing

typical

Some

ire

sigrals

diagonal

;;;"e.;it

g0.

A

shift

Phase

oscilloscope

may

outpui

is

circuit

Channel

the

TIME/CM

Channel

the

and

size.

results

ph?se,the

in

If

line.-

adlusteO,

phase

of

fto.

shift

less

output

circuit

observjg

be

overdriven,

probe to

B

A INPUT

horizontal

are

oscillosco,Pf

vertical

the

line

this

produces

(or

more)

puitttn'

the

for

being-tested.

control

shown

is at

The

oscilloscope

the

on

wave

sine

the

output

the

CH

to

probe

oscilloscope

Fig'

in

tr.ace

horizontal

and

angLe'

45"

a

circular

a

90"

than amount

trace

If

oscilloscope-

B'

to

35'

of

normal

the

opgr-

display

the

of

input

the

If

galn

phase

shown

as

the

on

test

may

two

are

shift

desired,

the

inputs

i,1,a^ttt:iq!l

oscilloscope

produces

If

of

an

in

UNKNOWN TO

STANDARD TO

FREqUENCY

ICAL

VERT

IZONTAL

HOR

INPUT,

FREqUENCY

INPUT

SEENOTE((E))

sEEN'TE

/7O$t

S E

THE

NOTE :

Fig.37.

AN YONE

UPON

Lissajous

ment.

OF

PHASE

RELATIONSHIP

waveforms

used

IGURE

F

for

IO

RAT

KNOl.J

UN

TO

STANDARD

>2:

l:l

lDz:

PE ND

S DE

frequency

OF

N

l

I

NG

I

measure-

I

b

AMPLIFIERS

SQUARE

INTRODUCTION

A square

\l

B

_A

f,

v

Procedure:

Connect

1.

B INPUT

CH SWEEP external

connect

2. unknown

Adjust

3. convenient,

resulting

The

4. ratio

the

Phase

36.

Fig.

FREQUENCY

the sine

TIME/CM

horizontal

the

frequencY.

the

betiien

wave

of

iack

control

inPut.

vertical

channel

easy-to-read

input

pattern, called

two

the

=

PHASE

il

calculation'

shift

MEASUREMENT

known

of

oscilloscope

the

A and

display.

CH

to

(cH A

probe

gain

B

a Ussajoul

frequencies'

ANGLE

frequenc,y

and

provides

This

B.

INPUT)

controls

Patlern,

Fig' 37

See

to

set

to the

for a

shows

'

the the

scope. ;;;i;r

il;-

odd

of ;;;

kHz,

1 .5

and

tubes

;rpr"duce

;;a

.'

tigt.f

capacitances

stiav ;;t';;;;-;

t.p""',i".ti;; amplifier fi*ituiions. introduce

unsatisfactorY.

is

As stated

number

un

inlo

Hz onli,

500 frequency i.r1io"O

harmonic.

21st

Theneedforsquarewaveevaluationbecomesapparent

we-realize

if Juring Oiff.i"tnt r""ii"iirO

;;;;ta

t uiironi.i

r..t instruments

WAVE

wave

as

such

"tffir

of

#u'ur

harmonics" ;i;;t;a

kHz,3.5

2-.5

transistois

a

interelectrod

;f

can

Poorly

distortion

odd

of

amplifier,

but

we

inptit

io

normal

frequenciet.

rig""t

quafity

ihe

of

utnphfying

when

or

TESTING

generator

instrument,

this

distortion

given.frequency

a

into

square

as

i;;

a

tnitti-ii.

before,

harmonics.

by

tun

signals

thii

use

with

of

square

voices.

present

that

of

circuit,

a

kHz,

non-linear,

are

wave

e capacitanges,,

as

well

the

of square.

the

designed

lhe

to

a

can

we

injecting

"dtt6tminE

from

audio

iotnt

pass simultaneously

to

Witl'

which

signal,of.

a

iave)

co-pltx

OF

low-distortion

a

and

can

in

contains

frequency'

frequenry

provided'

are

also

square By

it

is identical

which

limited

factors

signal'

wale

distortion

defective

or

where

point

wave

injecting

evaluate

square

a

how 500

amplifiers

square

a

we cin

many

which

j,ungtlon device which

waveforms

used

be

electronic

a

500

a

If

,c{,nnonents

difiicult

is

ancl prevent

A

caused

amplifiers

their

contains

500

a

amplifier

wave

amplifier-

the

to

up

Hz

will

large

a

.wave?,

evaluate

frequencies

what

is

oscillo-

display

to circuits.

large

Hz

sll:t

to

-,til::ilii:?

translormer

Y:11-,1:signed

performance

Hz sine

response

,9:

the

be

number

w9

the

of

number

square

vacuum

amplify

input

the

.faithful

these

by

can

large

a

wave

same

tnt

would

15th

required

have

input

-(lhe

amplifier

musical

A

of

at

or

of

and

a

33

The extremely flat distortion that response. The oscilloscope vertical input should be DC

as it frequencies. When quency low end of the amplifier bandpass of the bandpass; however, of the square end of the

amplifier should

especially important

amplifiers). of amplifier overall some wave signal.

testing

specifications better

TESTING

of the

It

should

amplifier

deficiencies not readily

the

judgment

Connect the

1. the input

2. Connect output of

wave output of the

square

will

introduce the least

amplifier bandpass

The

amplifier, it is

PROCEDLJRE

that

so

may

be observed when

checking

wave input

square

wave,

distortion

be noted that

made using a sine

be

in limited bandwidth

wave

square

performance

quality.

Whether

on

of the

the CH B test

the

of its

output of

the

amplifier

a sine

amplifier

performance.

amplifier

it does not

distortion, especially

amplifier response,

should

because

will

is reached.

the

actual

signal

will

and

The

square apparent when

wave or square

important

be

(Refer

to

the square

being tested.

probe

being

generator

signal

contribute

evaluating

be varied from the

up toward the

of the harmonic

occur before

response

wave

amplifiers

provides

gve

an

wave also will reveal

wave is used

that the manufacturer's

known in order to

Fig.

38) wave

of the oscilloscope

tested.

must be

amplifier

the

upper

the upper

check

signal.

quick

a

estimate of, using a sine

generator

to any

to

set

low

at

fre-

end

content

of an

This is

(voice

check

for

make

to

to the

If

3.

4.

5.

6. use the

ANALYZING

half-cycle is

and high

true

a

maximum amplitude ?o half-cycle amplitude alone of the high produce of one

Dstortion can be classified

categories:

DC

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

Adjust viewing height.

Adjust the sweep wave display on the

For

The

for the rapid drop at the end of the half-cycle from

the vertical

a close-up

5X magnification.

short

created

frequency

point.

rounding of the

a

wave

square

component

to

be viewed,

switch.

affecting the results

(below

view of a

THE WAVEFORMS

rise time which

by the in-phase

sine

Therefore,

cycle

of the

allow

use

However, Ht\.

5

gain

control

time control

screen.

portion

occurs

wave

components.

zero

amplitude

a theoretical

frequency

square corners

(See

Fig.

circuit being tested is

both the

the

the AC

for one

at the beginning of the sum

39).

into

AC

and

position

DC

position

except

for

cycle

of the

of all the medium

The

at the 180" or

components should

at aIl

three

may

at very low

a convenient

of

square

same holds

reduction in

points

four

distinct

DC

of the

be

v

wave,

SOUARE

GENERATOR

o

WAVE

I

o

INPUT

AMPLI FI ER

CIRCUIT

BEING TESTED

^\m---l

cHB I o.

ADJUST VERT

CONVE.NIENT

FOR

GAIN

VIEWING

HEIGHT

OUTPUT

ADJUST SWEEP

SPEED

CYCLE DISPLAY

FOR 1

SLOPE INT

+

b

I

34

Fig.

Equipment

38.

set-up

for

square

wave

testing

v

of amplifiers.

1. change complex

an amplifier filters created will create fesponse

The second

2.

change waveshape

vacuum

as extreme case, clipper

The third

3.

distortion more components

Fig.39.

5t

Fig.40.

Square wave response loss.

-

Response and

high

curve

ends.

amplifier

of

with high

with

frequency

low

Poor

ln actual

component

wave

frequency-selective

a inductince

difference

phase

distortion

testing

wave

distorled

the amplitude

accuratelycircuit. revealing compeniafed

applied

+[n.

response low applied f1g. +tB. th; overcompensation rise at

wave

up

+O times

ty rute

require the 100 about

10,000

and

In a typical

The response

poor

to the

This

(approximately 1

frequency

to

region

top of

the

As a rule

be used

can

the 15th or

to

thumb,

of

at

complete

Hz

square

4000

llz, a 1000

normal

from

waveform.

circuit

by

peaks

or dips

curve.

non-linear

is

in waveshape

non-linear

to

tubes,

a deliberate

network.

delay

is

produced

practice

(sinusoidal harmonic)

or both. in

ieveals

figure indicates

the

This

of

the

least

The

phase

angle

or delay

practical

of

iquare

phase

distortion

wide

many

low-frequency

high-frequency

ol

input

response.

of this

input

figure displays

t00O

at the

leading

the

of thumb,

to reveal

20th

fundamental

is

it

two-frequency

a

spectrum.

wave

tlz. To analyze

Hz

frequency

is

first

The

distortion

amplitude

words,

other

ln

resonant

of

combination

in

an

distortion

produced by

components

an iron

of a reduction

network

band

of an

to

odd

will

core

non-linear

phase distortion,

or

by a shift

a complex

presence

between

distortion.

circuitry,

includes

wave

clues.

amplifier,

distortion

amplifier

response

boost.

amplifier

this

satisfactory

to 2

kHz

Next, a

same

glod

FIz but clearly-

4000

l0

higher

edge of

be

can

it

response

harmonic

the

of

that

seen

the case

In

encompass

above

wave

square

and

component

of a

the introductign

networks

reactive

of

otherwise

and

application

or

transformer,

circuit

phase

in

waveform.

in amplitude

is usually

which

check

includes

or L introduces

C

the

of

components,

Therefore,

usually

will

we

a combination

a square characteristics is indicated

a19-ng

A 100

will appear.as

medium

t'Ilz)--but

Hz

1000

amplifier

frequency

kHz region

the square

said

safely

phase

and

up

or

square

wide-band

pro-p-etly-analyze

to

illustrated

componen-ts_

4000

should

of

in

or selective

components

ffequency

flat

to

refers

elements

between

wave check

Hz

square

shows

square

appear

will

response

by

wave.

that

relationships

to approximateryav9.

circuitry

by

Hz and

be satisfactory.

the

of

such

an

in

and

as

such

which

of a

caused

in square

in

with over-

frequency

reveals

Using this

is

one or

square

by

capacity,

creating

that

find

of

the

of

Fig. 40,

wave

Fig.

in

poor

wave

as in

in

the

the sharp

a square

will

Fig. 40,a

to

up

beyond

a

the

to

refers

Hz

Fig.40

Hz

Now, the region

rise

shows flattening we can

Hz

roo

souAR

E

100 and same low-frequency

mvE

such the obtained.

\,

Fis.4l.

Resultant from amplifier

100

Hz and

in

I kHz

Fig.45.

square

waves

ponent, element, causing, producing

a

out

expect that the

Hz

square

phase

but

square

the

If

combination

only depress

as to

square

wave, a

However, reduction

already

as

the strong

between

from

beyond

will be

wave

the

that

wave will

response

noted,

in turn, a

poor

curve

100

low-frequency

1000 and

frequency

higher

relatively

frequency components

lower

be strongly

amplifier.

of this

elements in this

of

low

the

similar

in amplitude

is usually caused

phase

Fig.

of

tilt

4000

and

4000

components

normal

modified

See

frequency components

Fig.

to

of the component,

shift

Fig. 43 reveals

41A.

in

the

to

to a

the

in

in this

poor

were

be

a com-

reactive

response

Hz. Therefore,

in amplitude

by

Fig. 41A.

amplifier

42 would

by a

in

a

35

Fxl

OUT-OF-PHASE

v

Fig.42. Reduction

frequency

Fx3

Fig.

OL)T

43.

PHASE

OF

Square phase

shift.

wave

of square

component in a tuned circuit.

(LEAD)

tilt resulting from

wave

fundamental

3rd harmonic

resulting

Fig.

graphical tilt is phase-shifted very the square wave.

by a 10" direction. frequency opposite in the two polarity checked

been reduced noted that these examples characterized by the square wave.

Tilt

45. frequency

development

seen to be

3rd

slight shifts in

Fig.44

Fig.

indicates the tilt

phase

shift of a low-freque^ncy element in

Fig.

45

component in a lagging direction. The

of the

through

46

phase algebraic

indicates low-frequency components which have

in amplitude

change in shape

from phase

lagging

in a

of a

caused

harmonic.

phase

indicates a 10"

cases because of

angle

addition of components.

shift of

direction.

similarly by the strong influence

are

in square wave

and shifted in

of low-frequency distortion

tilted

It

also

quickly

phase

in the two

of the

fundamental

square wave.

becomes evident that

shown

shape

shift

the

cases as

phase.

flat top

of the

by tilt

up

produced

a leading

in

a low-

tilts

difference

can

It

will be

portion

The

in

are

in

be

v

are

of

FXI

OUT

M. Tilt resulting

Fig.

36

PHASE

OF

frequency

(LEAD)

from

leading

in a

phase

direction.

shift of

fundamental

Fig.

overshoot higher frequencies. overshoot edge explained square wave, the the

summation of components. occurs

the

in greater

sum along

l,ow-frequency

46. shift.

Fig.

of the

at

previously

41B,

produced

makes

square wave. This

by remembering

If

high

frequencies,

square wave

than other

the leading

itself evident

sharp

a

an

components

component loss

discussed,

by

rising amplifier response

It

should again be

rise of

practically

abnormal rise in

the high-frequency

will be amplified disproportionately

edge.

revealed high-frequency

at the top

characteristic relationship

that

in a normal

the

leading edge

infinite number

amplifier response

creating a higher

phase

and

at the

that

noted

of the leading

well-shaped

is created by

of harmonic components

algebraic

this

is

v

Fig.

47.

Effect of high-frequency

damping.

Fig.

indicates

47

accompanied

square

nQ"

transition

relatively

type wave indicates

network in

sinusoidal the

high

sudden rising, low-frequency

high-frequency

by a

of

lightly

diminishing

damped

a

transient

the amplifier

in the square

high-frequency

voltage, supplies

boost and

boost

"shock"

oscillation

oscillation circuit.

potential

wave

voltage,

energy

the

poor

in an amplifier

transient.

the top of

along

a relatively

in

this

In

case,

from a strarply

to a level

oscillation

for

The

the

value of

in

Fig.

48.

resonant

the reasonably oscillation

Fig.

49 summarizes

a handy

as

serves

Effect of high-frequency

damping.

network

network.

heavily damped,

may be

If this

produced

the

then

as indicated

preceding

reference.

boost and

good

the amplifier

in

a single cycle

Fig.

48.

in

explanations

is

transient

and

A. Frequency

reduction ponent). No

D. Low

G. High

frequency

shilt.

distortion.

low

oI

phcse

(crmplitude

lrequenry com-

shift.

phcse

shilt.

phose

snd

loss

Fig. 49.

Summary

B.

H. Domped oscillotlon

of waveform

oted

Iow

shiIt.

lundqmentql).

lrequency

analysis

frequency

Low

boost

loss cnd

for

square

(qccenlu-

phcse

wave

frequency

High

C.

shiIt.

High lrequency

F.

quency phose

lrequency

Low thickend

testing of amplifiers.

loss-No

cnd low lre-

loss

shilt.

phcse shilt

by hum-voltoge).

Phcrse

(trace

37

The

block

breakdown

reference

by

GENERAL

Basically, vertical network. switched, switching mined LOGIC. OUTPUT plates

amplifier. Drive calibrated CH

converter to

VERTICAL PREAMPLIFIERS

identical both. CH A will

transistor fier with

side

Ql04 gain

provide control VRl02 vertically

MODE

from ICl01

MODE

controlled by IC103 and ICl04. When the LOW, turning

amplifier.

goes amplifier. When DUAL IC103 are CHOPPED mode,

ALTERNATE amplifier sweep circuits.

the

amplifier.

VERTICAL

the vertical output

preamplifiers,

The outputs

as desired,

by the

The

AMPLIFIER,

of

the CRT.

Horizontal

preamplifier

B

All

supply voltages

the

provides

CRT.

Channel A

circuitry and

The

vertical

Ql0l

output

panel

drive

is

changed

gains

across the

Transistor

LOGIC

Trigger

LOGIC

The mode

panel

front

When

low turning

is

When

the SWEEP TIME/CM

CH B

trigger

The

selected

diagram, Fig.

of

the oscilloscope.

to the

schematic

the

oscilloscope

each having

of

of the

main

sweep speed

DC BAL

the differential

of 5, 2,

amplifier

and delivers

switched

turned on,

AMPLIFIER

into the main

CH A

position

vertical

deflection to

the horizontal

when X-Y

a regulated,

and Channel

be described

preamplifier

which forms

signals of opposite

control.

in the emitters

provides

array

circuitry.

of

MODE

mode. When

amplifier

and 1.

screen.

IClOl

Ql07

operation

switch, the Q output

on the CH A

CH B

is selected the Q output

on the CH

is

on and

and after each

from

signal

stage

50,

Circuit

diagam.

consists of two

the vertical

and

of the MODE

which

circuits or

are

circuit operation

amplifier

DC

a

the

selected

providing

signal

consisting of

its

vertical

preamplifiers

CH B

amplifier feeds

drives

provided

is

amplifier

by the

operation

fully

regulated

2kV,

preamplifiers

B

below.

consists of

balanced

a

polarity.

Emitter followers

Ql05

of

The front panel

component to move

is

turned on or off by the

and

Ql08

signal to the trigger

(CH

A, CH B,

preamplifier

preamplifier_and

B

the

off

at a 2}OkHz rate DUAL, the

in

a trigger

switch

is applied to

preamplifiers

the

CIRCUIT DESCRIPTION

outlines

details

own

preamplifiers

switch and MODE

the vertical

is

accelerated

Q105

CH A

Q

is

transistors

the

are

obtained

input

by the

selected.

is the

dual

differential

and

buffers the

and Q outputs sweep when in

in CH

identical

attenuator

amplifier. The

is deter-

the VERTICAL

deflection

horizontal

is furnished

signal from

and a DC-to-DC

potential

same for

FET

VRl0l

Q103

Ql06.

and

Q106

POSITION

the

amplifier.

DUAL)

and

is selected by

IC103

of

and trigger

of

CH A trigger signal

position,

B

horizontal

the

is applied to

Ql13

circuit

can be

by

the

contain

input

ampli-

is the

and

Stage

to

trace

signal

is

goes

IC103

trigger

of

for the

the

to

which amplifies

Q120, drive the vertical DC

balance control,

frequency

TRIGGER

The MODE enables trigger output is fed thru on in all CH

SYNC

preamplifiers) is then fed inverted

selected by SYNC adds a

SYNC

routed to Q320

voltage developed value of the out of cutoff. The output tips of

switch

filter vertical

TV-H

removing C33l sweep circuit.

SWEEP CIRCUIT

and gates SWEEP the turning off

and resistors

form ramp voltage. is

of pulses ramp IC set input

Q307,

trigger

switch 5105.

trigger

amplifier

positions

B.

AMPLIFIER

Source

(SLOPE

DC

COMPONENT

SEPARATOR

When TV+

and

the

When

(.lmS

out

sync

positions,

The

trigger

to the SCHMITT TRIGGER

of IC303.

CONTROL flip-flop

clock

Transistors

MILLER

a

fed to the

As

soon as

IC301

is

until the

exceeds

places

302

forces

terminating the

deflection

while VR104

compensation adjustments.

CIRCUIT

source,

amplifier

Ql27

transistor switch

of the SWEEP TIMErcM

AND

switch 5303

EXTERNAL

or

to differential

-)

or non-inverted

switch 5304. LEVEL

or TV- is

the SYNC

Q319.

input

composite video

the

in

to .5 sec),

the

pulses

waveform,

Q307

selected by

The

holdoff

held low

the

low

a

SEPARATOR

Q320

across

signal.

TW

horizontal

to

SOpSEC

and allowing horizontal

passes

signal

The output

the Q output of IC301

to

initiate

and

Q308

INTEGRATING

sweep

circuit

the Q output of IC301

by IC303 to exclude

ramp

sweep

level set by VR309

on the set input

the

output of

Q

sweep.

the

signal to the

plates

either

CH A or

Selecting

Q107

and

INVERTER

selects

to the output of IC305.

selected, the output of IC305

is

C332 corresponding

Positive-going pulses

of

positions

Q319

pass

to

Q309

ramp

lC3O2

either

and

Q128.

either

triggering.

amplifier

held

at

Q320

signal.

of the SWEEP TIME/CM

is

pulses, permitting

sync

to the

lpSEC,

thru

circuit

pulses

IC30l. On the negative

the

sweep.

and the

the SWEEP

circuit

from

and IC303.

is terminated. When the

IC301

levels required

the

of

CRT. VRl05

and TCll3

B,

CH

is

selected by

CH A or DUAL

and CH

Q108,

The

trigger

Q313. Q:13

cutoff by a negative

corresponds to the

on; this

sweep circuit. In

emitter

from IC303

the

of

switch except

INTERNAL

The trigger

IC305. Either

(SLOPE

circuit

Q319

goes

(SWEEP

IC301. A

high which

+)

control

consisting of

to

an average

drive

allows C331

is turned

pulses

sync

follower

consisting of two

timing

TIME/CM

to

collector of

clock

goes

capacitors

provide

low, the reset

any new

LENGTH),

low on the

to

is a

are

high-

B enables

amplifier is turned

(from

signal

the

signal is

VR310

is

Q320

sync

to

only

the

off,

to

Q303,

the

edge

of

low,

switch,

a linear

Q309

clock

sweep

turns on

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AUTO

SWEEP

Transistors

SWEEP (AUTO) C303 reset of IC301

determined SWEEP TIME/CM transistors off and enabling signal.

circuit.

charges

Q304,

When

and no

and turns

and allows

by the

Q304

Q305,

the trigger

present

is

signal

Q306

resistor

switch.

and

the

When

Q305

sweep to trigger

and

level

at the

on,

this

a

sweep to recirculate

and capacitor

a trigger

discharge

form

Q306

control is

trigger

places

selected

signal is

C303, turning

on the

the AUTO

pulled

amplifier,

a low on

at a rate

by the

present,

Q306

incoming

out

the

CHOPPING

Two NAND gates

200 kIIz CHOPPING

positions

selected.

during

I VOLT CAL

Transistors

wave. VR2l2

OSCILLATOR

of the IC304

retrace

SWEEP TIME/CM

provides

and when

SIGNAL

Q301

adjusts the amplitude

from

IC304

OSCILLATOR

pulse

a

chopping.

Q302

provide

and

and IC305

activated in the CHOP

switch when DUAL

for

blanking

a 60llz

of the CAL

form

the trace

square

SIGNAL.

a

is

v

HORIZONTAL

The

VR306

thru amplifier VR305 the horizontal

thru IC303 and the horizontal

Q317

plates adjustment adjustment.

which equipment. compensation attempted specified test equipment. information for this

cedure can be located

is a horizontal

When

and

of

The

can be

Internal

AMPLIFIER

ramp from

sweep

(timing

consisting

position

in the

and

Q318

the

and

calibration adjustments

performed

Additional

and horizontal

without

B

& K.PRECISION

DYNASCAN

adjustments

adj.)

of

centering adjustment

control.

X-Y

mode,

the

CH B

amplifier. The

is

applied to the horizontal

CRT. VR303

VR304

with a minimum

internal

complete

oscilloscope

SERVICE DEPARTMENT

2815 W.

Chicago, Illinois

by reference

the

collector

to the

Q314,

Q315, Q317,

transistor

signal is applied

is the

is the magnification

of

input of the horiZontal

Q309

Q3l3

output

X5

CALIBRATION

outlined

adjustments

linearity

sweep

service information

Requests

should be

TEST EQUIPMENT

CORPORATION

Park

Irving

60618

outlined in

to

of

for

Road

the

Fig.

here

specialized

complete

addressed to:

calibration

5l

is applied

and

and VR307

to both

of transistors magnification

should not

and 52.

Q318.

is turned

deflection

centering

are those

frequency

of

service

off

Q312

test

be

and

pro-

POWER

operating the oscilloscope.

is

provided output stages

DC-to-DC output of T101 voltage fed provide operating

SIJPPLY

power

The

Regulated

The

accelerating

dividers to

to a regulator

a

supply

output

for

all logic

require the

converter

is rectified

constant accelerating

conditions.

the CRT. A

circuit consisting of

ADJUSTMENTS

VERTICAL GAIN ADJUSTMENT

The following a square accuracy

Procedure:

l. Set

2.

3.

4.

wave

is

available.

CH A

Apply lkHz

CH A input

Adjust VR103 for

Repeat

5 CM deflection.

adjustments should

generator

CH B VOLTS/CM

and

square

connector.

steps 2 and 3

provides

voltages

and amplifier

180V.

voltage for

consisting

and

portion

with

wave of

Set mode

exactly 5

for CH B and

all

voltages necessary

+10,

of

the CRT of

Ql42

filtered

potential

l% or better amplitude

switch

5OmV

CM of deflection on

-8,

and

circuits.

is derived from

a-'1d

and

of the high voltage

29 and

Ql

be

attempted

to

peak-to-peak

to CH A.

switch

adjust

+5

and

Amplifier

T101.

applied thru

Ql30

under varied

only

.01V/CM.

CRT.

VRll3 for

for

are

a

The

is

to

if

U

into

CH A AND

1. Adjust

CH B DC

controls

cH B).

2. Adjust

CH A

trace vertically

Rotate

3. 2V

4. lf

the V

5V/CM

to

ICM

the trace moves performing (

side panel

vertical movement

performing

while

40

BALANCE

to

obtain a horizontal

or CH B

on the CRT.

ATTEN.

while

vertically

STEP

3, adjust

screwdriver

of the trace

STEP

POSITION

control

SWITCH from

observing the

more

the CH A or

adjustment)

does not exceed 5mm

3.

(CH

trace

to

center

IV/CM to

trace.

than 5mm

CH B DC BAL

that

so

A or

the

while

the

HORIZONTAL POSITION

<

>

I . Set

2.

3.

4.

POSITION

rotation.

SWEEP TIME/CM

Set

Adjust VR305 horizontally

Turn the amount minimum

centered

<>POSITION

of deflection in both directions should be a

of 4 CM.

control to

that the line on the

so

on CRT.

ADJUSTMENT

the mechanical

to lmS/CM.

switch

control

full CW and CCW.

center

scope

The

of

is

v

\.

]-Fl

t+to

l2

'EJ

ROTATE

PLUG

TO

CHANGE

VOLTAGE

Fig.

Calibration

51.

diagram,

vR107 VR108

@@

VRLO9

e-'->Q

CH.

GAIN

TC105

VrcroaV

@@@

vertical

amplifier

@

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@

VRl13

TC106

BACK

t/

r

@vatoz

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WARRANTY

SERVICE INSTRUCTIONS

1. Refer to

the

ments that

2.

Check common Always

check

replacement.

3.

Defective period number These

4.

If

the above-mentioned the A

detailed name B

& K-Precision

Contact

your

of

parts

should

of

parts

product

and address. Forward

your

local

nearest service

B

& K-PRECISION

maintenance

may

be

applicable.

electronic

instruction

removed

sent

be

product

will

securely

list of

from exchanged

be

(preferably

troubles

authorized

B & K-Precision

agency,

2815

section

parts

manual for

from

to the

of the instruction

such

as tubes, transistors

applicable

units

factory

which removed

no

at

charge.

procedures

do not correct

in original carton

encountered

prepaid

service

(express

agency.

Distributor

or write

Seruice Department

DIVISION

West

Chicago, Illinois

Irving

to

OF Park

manual

adjustments

which are within

prepaid

and

with model

date

product

of

the difficulty,

or double-packed).

must be enclosed

preferred)

for

the name

DYNASCAN

Road

60618

for adjust-

and batteries.

after such

the warranty

and serial

purchase.

pack

as well as

your

to the nearest

location

and

CORP.

42

'\-'

:r:d

.'B

& K-Precision

workmanship under

authorized placing

and shall

clusiue

or implied. Such other approval; which installed or reserves and product

marhed,

authorized. B

B & K-Precision

product

any

which is returned to

not otherwise

in lieu of all

and.

than B & K-Precision

(ii)

tampered

has the serial

adjusted

the right

incurring any

without

comrynent if a B

or

B &

to the

K-Precision

&

warranls

that

normal usage

distributor.

or cumponent

our factory

for any

be liable

other warronties

warranty shall

to discrntinue

or its authorized

with or altered

number altered,

otherwise than

obligation.

&

K-Precision

d.istributor."

WARRANTY

product

each

and service

which we are satisfied

not apply to

any

K-Precision warranty

factory

manufactured

for a

obligation under

Our

or our authorized darnages, consequential

(including

product

any

service contractor

way or subjected

in any

or removed;

defaced

in accordance

model at any

The warranty

within

it

by

period

of one

this

does not conform

contractor,

service

or otherwise.

warranty

any

or component

(iv)

or

with B &

time

ten days

K-Precision's

or change specifications

be void. ond

shall registration

atter

will

free from

be

year

after. its

warranty is limited

ol merchantability),

without B &

to

which has been

card.

the

with the

transportation

The

(i)

repaired

K-Precision's

misus6, negligence

instructions.

there

sll,a,ll

properly

is not

purehase

defects in purchase

to repairing, foregoing

foregoing

whether expressed,

or altered.by

improperly

design

or

be no

completed.

of the

material and

from an

new

wairanty

prepaid,

warranty is

prior

or accident;

eonnected,

K-Precision

B &

without notice

uarranty

and

product

lrom

or re-

and

anyone written

(iii)

ql

any

post-

we

ex-

an

o

54210

PRINTED

JAPAN

lN

85C1446-OO

(G)

43

*..{

NOTES

4

it' ti

F

1..

I

t li

i

;

I

T t t

I

l

t

a

, t

l.

-:

F:.

F-

DIVISION OF

t

8OI

Chicogo,

DYNASCAN

W. Belle Ploine

lllinois

60613

CORPORATION

Avenue

480.169-9-001

BK Precision 1471 Service manual

Specifications and Main Features

Frequently Asked Questions

User Manual