BK Precision 1477, 1472C Service Manual

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Bi(F#C!S#J

SERVICE

MANUAL

1472C

1477

lSMHz

Triggered

Sweep

DUAL-TRAGE OSqLLOSCOPE

lllronn'

\,\

Bt(

WARilI1{G

fhis service mantrcrl teclnicions only. yvu

board when tJle oscilloscope is operating. High present present

any

turned off. unit.

t477. arate schematic is

essentially pearzrnce knobs,

1477 is on

qnlified

are

voltage

High

on

the sweep

on the

time the

Always observe caution when

Contacting

This

second edition

Electricaly, Model

apply

from Model

etc.

A

page

To arrcid electnc

to do

up to

power

oscilloscope

exposed high voltage

DIFFERENCE-S BETWEEN

supplied

to both models.

parts

list

34.

is intended

shock,

so.

rfDC

2000

board. Line

transformer, on-off

is

corurected

of the service

1477 is very similar to the

for

l47ZC,

itemizing

using a

present

is

voltage

could

manual is

eadr model.

Model

those

use

for

do

not

on the CRT

of LZO VAC

switch,

to:ur

housing

the

result

MODELS

L477 has several changes

front

new

parts

qnlified

W

perf

orm servrcrng urless

and

voltage up to f95 VDC is

power

and

power

AC

is removed

in

fatal

expanded

Model

The

circuit board

panel,

which are unique

new

electronics

power

(or

240 VAC)

supply

source,

electric

include

to

1472C. A sep-

handle,

supply

board

even if

from

shock.

Model

drawings

in ap-

for Model

is

the

\-

new

\-

TABLE

OF

CONTENTS

b

OPERATOR'S

SPECIFICATIONS..............

CIRCUITDESCRIPTION.................

SERVICING

TROUBLESHOOTING AD

JU

STM ENTS

PARTS

LfST........................

CIRCUIT

PowerSuppIy....................................

Vertical

SweepBoard

VO

LTAGE M

MODEL

I4TZCPRODUCTION

CONTROLS'

...........

. . . .

. .

. . . .

BOARD MAPS

Amplifier

..............

EASUREM

INDICATORS

AND FACILITIES

o.............

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. . . .

. . . . . . . . .

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. . . . .

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ENTS

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CHANGES. .

. . . . . .

. .

. . . . . . . .

. . .

. . . .

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. . . . . . .

. . . . .

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. . . . .

.

30

. 30

3

5

:

MODEL

MODEL MODEL MODEL

I47ZC SCHEMATIC

1477

PARTSLIST................

SCHEMATIC

1477 1477

PRODUCTION

RE'ERENCE

I47ZC

L47ZC

Instructiorr Mantral

Composite

(Schematic

L477 Instructigr Manual

1477

Composite

(SchematicDiagram&

DIAGRAMS

DIAGRAM

. . . . . . . . .

CHANGES......

PUBLICATION

.

. . .

...,.

. . o . .

Diagram

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. . . . .

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. . . . 35

U

\t

11 10

12

2

Fig. l. Front

panel

controls and indicators.

v

\,

OPERATOR'S

l.

Cathode

U

:

-

the waveforms

2. Scale. marks for measurements.

able.

3. POWER

tion lcop9.

Further

illumination

4. Pilot

5.

SWEEP time

pSEC/cm in

CAL position this

permits

6.

Sweep adjustment. the

7.

CAL lV P-P peak-to-peak calibration check the frequency probes

<>POSITION

8. position

dual trace

fication when

9.

TRIGGERING determines points starts; (+) switch (PULL generated

10. EXT signal.

ll.

SYNC switch. following positions:

SI-oPE. waveforms

(+) waveform.

(-) waveform.

TV. In television the automatically to automatically to .5

(+) (-)

Ray

The

8 x voltage (vertical)

ILLUM

of

this Clockwise clockwise

level

lamp.

Lights

TIME/CM

selector.

(microsecond

19

steps

when

switch

sweep

equals

lweep

0.1 mSEC/cm,

Sweep

disables

the

CH

speed

In

time

of

used with

of traces

mode).

when

pushed

(-)

equals

most selects AUTO).

even

jack.

TRIG

The

except

is

Sweep is

the TV

composite

sweep;

pSEC/cm.

is

triggered

is

(CRT).

Tube

are viewed.

l0

Illumination

control.

control

rotation

of

the

when

Selects

VARIABLE

(fully

B input

VARIABLE

extreme

the

is

calibrated.

jack.

Provides

square

wave

the vertical

the oscilloscope.

control.

(both Push-pull

pulled

in.

TEVEL

on waveform

most negative

positive

automatic

When

without

Input

Four-position

SLOPE

television

triggered on

triggered

positions,

the vertical sync

selected for

and

selected for

triggered

This

graticule

cm

of

Fully

(OFF

position) of the

scale. oscilloscope

switch.

clockwise). the internal

comp€nsation

positions

on

Horizontal

calibrated

per

centimeter)

provide

to

control.

clockwise

calibrated input amplifier

Rotation

traces when

switch

(PULL

out

control.

point

triggering

automatic triggering,-a

an

input

terminals for external

on negative-going

video

signal

sweep

horizontal

sweep

positive-going

on negative-going

turns

lever

composite video

positive-going

the sync

CONTROLS.

is the

screen

on which

provides and time the

scale is fully

counterclockwise

control increases

is

sweep

control

In

the CH B position,

sweep

horiiontal

signal.

attenuators

adjustment

adjusts

selects

5X MAG);

Sync level

slope where

point

of triggering.

when

signal.

switch

are used for

are used

pulses (frame) times of sync

times of

calibration

(horizontal)

turns

off oscillo-

on oscilloscope.

turned

on.

coarse

times

to

0.S SEC/cm

6 is

set to the

generitor

sweep.

Fine

sweep

(CAL)

pbsition

I

kHz, I volt

This

used for

is

and

horizontal

operated

5X magni-

normal

adjustment

of

triggering

Push-pull

pulled

sweep

trigger

with

viewing

signals.

slope

pulses

to

trigger

0.5 SEC/cm

pulses (line)

gSEC/cm

50

pulse.

sync

pulse.

sync

INDICATORS

adjust-

rota-

ihe

sweep

of

0.5

and

time

to

of the

in the

sweep

and

out

is

the

all

of

a

-are

are

12.

SOURCE triggering triggered

CH

A Sweep is triggered

CH B

Sweep

EXT

Sweep

at the EXT

13.

Channel ment for adjustment

position.

CH B

14.

Channel B adjustment for

15.

Channel B. Jack SWEEP

16

Channel

17.

Channel Channel sensitivity. Vertical from

l8 horizontal switch

18.

Channel

adjustment In attenuator horizontal gain switch

19. MODE basic

20. Channel channel sensitivity.

TIME/CM

DC

Direct signal.

GND

Opens signal amplifier. the when

AC

Blocks

.01

is set

5

the extreme

5

is

switch. Five-position

operating

CH A

CH B

A &

B

A + B

A-

B

A VOLTS/CU

A

AND FACILITIES

switch.

source

by

POSITION

B

Channel

when

DC

INPUT

B

becomes

B DC-GNDAC

position

B VOLTS/CM B

which

to

20

to

sensitivity

is in the

VARIABLE

B

provides

is

in the CH B

Only the input displayed

Only the displayed as a single

Dual and two

The B inputs as

a single

The from difference is only display

which

vertical

Tfuee-position lever

for

the same source

is triggered

is

BAL

Channel

input of

performing

DC

volts

CAL

clockwise

calibrated.

control

modes

trace operation; Channel B separate traces.

waveforms

waveform

the

a

provides

the sweep. Both

by Channel

by Channel B

triggered

SYNC

B trace.

SWEEP

Jack.

switch

This

component

provides

CH

are added

Channel

is inverted.

sensitivity

by

jack

control. Vertical

Becomes horizontal

TIME/CM

adjustment. Vertical

B trace.

Vertical

external

5 is in

switch

AC and

path

and

provides

of

which

DC measurements.

switch. Vertical

sensitivity

as a single trace.

trace.

step adjustment

per

crnwhen VARIABLE

position.

when

position.

B

control. Vertical

fine

control of vertical

(CAL)

This control

when

position.

of the

signd

input signd to

inpu.t signds are

from

Channel A

displayed

B input is

switch.

coarse

in

an external

grounds

can

of

lever

trace.

and the sum is

is

switch

dual trace operation.

10.

input

horizontal

CH

the

DC component

zero-signal

a

used

be

input

is

calibrated This

the SWEEP

position,

the

SWEEP

switch; selects the

oscilloscope.

to Channel A is

both the

Channel

waveform as a single trace.

Vertical

adjustment calibrated

sweeps

A signal.

signal.

signal

applied

position

switch

jack

B

input to vertical

sigid.

attenuator

control

becomes

Channel

A and

B is subtracted

attenuator

adjust-

posiiion

5 ii in the

DC balance

of

Channel

input

position.

of input

base line,

as a reference

of vertical

in

I I

contrbl

adjusts

TIMETCM

attenuator sensiviti$.

the verticd

the

TIME/CM

Channel A

displayed on

Channel

displayed

and thc

present,

vertical

of

in

I I

selects

are

when

for

steps

-i

line

B is

If

the

for

steps

OPERATOR'S

CONTROI.S.

INDICATORS

FACILITIES

AND

per

from .01

set to the

2l is

21.

Channel adjustment

extreme clockwise

In the attenuator

22.

Channel A

DC

GND Opens

AC

Channel A

23.

A.

Channel A DC BAL adjustment. adjustment

25.

Channel A

for

ment

volts

to 20

YARIABLE control.

A

provides

calibrated.

is

DC-GNIIAC

Direct input

vertical base as a ments.

Blocks

INPUT

for

POSITION

Channel A trace.

position.

CAL

fine control of

switch.

input of AC and DC component

signal.

signal amplifier. This

line, the

reference when

DC component

jack.

Channel

A trace.

control.

when

cm

(CAL)

path

and

position

performing

Vertical

VARIABLE control

Vertical

vertical

position,

provides a zero-signal

of which can be

of input signal.

input

Vertical

ground

DC

jack

position

attenuator sensitivity.

vertical

the

of

input to

used

measure-

of

Channel

DC

balance

adjust-

ASTIG

26. optimum with

28. after

FOCUS control.

27. INTENSITY

28. Fuse

29. AC

30. INT

31.

32. Combination

Probe

33. combination use with

signed input capable

Vector

34. for

adjustment.

spot

FOCUS control

the

little readjustment

Very

line cord. CSA-approved

vectorscope

adjustment.

initial

holder.

jack.

MOD

(see

Fig.

this oscilloscope.

for use

impedance of

of operation Overlay

roundness

control.

Intensity

carrying

3). The l/Direct

10:

with an

(not

operation.

Astigmatism

when used

27 and

this control

of

Adjusts

I megohm up to l5

brightness

for

oscilloscopes.

modulation

and

handle

K-Precision

B &

probe

has been

However,

oscilloscope

shown).

shunted

MHz,

Interchanges

adjustment

in

INTENSITY

tilt

conjunction

of trace.

(Z-axis)

stand.

Model

designed

any

having

by

can be

is required

probe

a

27

used.

with

provides

control

input.

PR-35

for de-

nominal

pF

and

scale

v.

COMBINATION

AND

Fig. 2.

CORD

WRAP

Rear and

FEET

side

panel facilities.

\,

/

I

30

\'

SPECIFICATIONS

(CH

and CH

b

VERTICAL AMPLIFIERS

Deflection

Frequency

Risetime Overshoot Input

Input Tilt Max.

Operating

Chop Ctrannel

factor

Response

Resistance Capacity

Input Voltage

Modes

Frequency

Separation

A

0.01 V/cm I I ranges

adjustment. DC:

DC to l5 MHz

AC:2 Hz 24 nanoseconds. 3% or less. I

megohm

(t3

pF

22

bss than 5%.

alte

rnate

kHz

(DC +

A only.

(dual

(single-trace

of

(n0%')

than

300 V PP.

Channel Channel B only. A & B matically times of

selected for A + B of Channels A - B ference

200 Better

v

SWEEP

CIRCLJITS

Sweep

System

Sweep Time

Sweep Range Variable

Sweep Magnification

Unearity

Length

TRIGGERING

Source

Slope

Control

Sweep

of

v

Triggering

Range

(Common

of

to

CH A

Triggered matic

mode,

without

0.SpSEC/cm (!57") quence. provides

At least Obtained

sweep 5 mum

0.1,/SEC/cm. 3% or

5%

pSEC/cm

102

CH A, sensitivity.

P tinuously pull

2O Hz to 15 MHz deflection as measured on ray tube).

input

in 19 ranges,

Each overlapping

for

2.5 times.

times

swee p speed

less

SEC/cm

or less for

mm to

CH

ositivc

for

AUTO.

B)

V/cm,

to

20

providing

each

(-3

dB)

to 15 MFIZ

(approximate).

pF).

chopped at

I mS/cm and

trace

all

A

Channels

60 dB.

(-3

peak)

AC

trace);

automaticallv

faster

sweep timei.

algebraic

B).

and

algebraic

A

trace

all sweep

and

and CH B)

and

automatic. In auto-

sweep is

signd.

to

0.5 SEC/cm in l-2-5

fine

adjustment.

by enlarging

from

distortion

to

2

pSEClcm

I

ranges.

I l0 mm.

B

and

and negative,

variable

the above

center.

pSEC/cm

EXT:

level

(min.

{%, for

fine

dB)

or

600 V

auto

slower;

sum

dif-

B).

obtained

se-

range

Maxi

becomes

for

0.5

ranges.

and

0.5

p-p

I V

con-

control;

0.5

cm

cathode

in

TV Sync

HORIZONTAL

input) Deflection Factor Frequency Response

Resistance

Input

Capacity

Input Protection

X-Y

Operation

CALIBRATION

INTENSITY

Voltage Input Resistance

POWER

Input

Regulatron

MISCELLANEOUS

Scale

Mechanical

PROBES

Attenuation Input

Connector Tip

REQUIREMENTS

Model No.

Impedances

AMPLIFIER

VOLTAGE

MODULATION

Features

Vertical separator any

form expanded for and

automatically be CM switch. TVV mSEC/cm. TVH

and horizontal

circuit

portion

of complex TV wave-

can be

synchronized

viewing.

(frame)

TW

=

0.5 pSEC/cm

50

SEC/cm to

provided

sync switched

SWEEP

gSEC/cm.

(Horizontal

l0

mV/cm DC to I MHz I megohm

(t3pF).

pF

22

(DC

V

300

input thru

(nominal).

(-3

dB).

(nominal).

+

peak)

AC

p'p. With

SWEEP TIME/CM

position,

CH B

the

CH A input becomes the Y input and

the X input position horizontal position

I kHz

input

CH B

(horizontal).

control

becomes

control.

square

wave of

becomes

(!s%).

p-p

2O

minimum

470 kO

120 (3-wire for oscilloscopes.)

108

Variable illumination.

Carrying handle for

PR-35 Combination

l0:l = l0 Direct = I

BNC Spring-loaded

(nominal)

VAC,

line

132 vAc.

to

(two

megohms, l8

megohm, 120

!2Vo

,

tlz,23

50/60

CSA-approved

cord,

tilt stand.

required).

l0:l

and direct.

hook-on tip.

so that

(line)

TVH

TIME/

to

CH B

or

600 V

switch in

(vertical)

The

CH B

I V p-p

watts.

pF.

sync

and

0.1

0.5

the

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CIRCUIT DESCRIPTION

v

:

U

The down of the reference to the

GENERAL

Basically. the oscilloscope vertical preamplifiers, network. switched, as type of switching of the determined by the position MODE arnplifier which drives

Horizontal amplifier. calibrated

preamplifier when X-Y

B

All

supply converter the CRT.

VERTICAL

Channel A

circuitry and circuit

The

section of

100: l, 1000: l. The second section

5:

and provide

The sistors FET's amplifier

VRl0l an internal

applied

is the output impedance

Ql06

I

the

12 control provides

across

'the

emitter circuit correct ments.

The trigger amplifier the emitter of Q 108 and

a tne signal

The only amplifiers the CH B

MODE LOGIC

The B)

is controlled

Dl08

When which DlOl and vertical

diagram, Fig.

block

oscilloscope.

schematic

each having

The outputs

desired,

OPERATION

of

feeds

the

deflection Drive sweep speed circuits

voltages are fully

provides

PREAMPLIFIERS

and

vertical

the

The

l.

and

in

combined

vertical

the

vertical

and

Ql02

the

and

Ql02

pair

the front

is

balance

to

emitter

Q107.

and I

adjusts

a DC

screen. Amplifier

deflection factor

to the trigger

difference between

is that the

signal when in the A-B

mode

of operation

each

of

CH

A is selected,

reverse-biases

D104, allowing the CH

amplifier.

of the

into the

VERTICAL

the

vertical

to

attenuator

preamplifier

with output

/5

the

deflection

the

horizontal amplifier

regulated 2kV

a

Channel B

operation

attenuator

Ql03

panel

control. The output

followers

to drive conventional

VRl05

attenuator

gain

component

of

Q

circuits.

MODE switch

ICl0l

by

the

channel

D

I 02 and

At the same

3, outlines

Circuit details are obtained

diaeram.

consists

its

vertical preamplifiers can be

main vertical

CH A and CH B

of the

LOGIC. The

OUTPUT AMPLIFIER, plates

provided

is

or by the signal

operation is

regulated

accelerating

preamplifiers

the same

is

has two sections.

provides

effect of the two sections is

ratios in a l-2-5 sequence.

consists

transistors

and

form a balanced

signals

DC balance control

104 and

Q

VRl06

and

positions.

of

Ql06

move the

to gain

is

and

Ql08

for accurate

l9

I

and

Q

109 and

Q

position.

(CH

the

CH B,

A,

ICl02 and

and

preamplifiers.

output

D 103 and

time ICl02

the

circuit

of two

own

MODE

of the CRT.

by the horizontal

selected.

ratios of

provides

of

opposite

of

Q

are

and

Ql07

adjusted Ql09

I 20 amplifies

provides a portion

CH A and

reverses

of IC 102

A signal into

attenuator

input

amplifier.

preamglifiers

switch

main vertical

is furnished by

from the

DC-to-DC

and a

potential

contain identical

for both.

The first

l: l, l0: l,

ratios

FET

input

thru

Ql04

differential

and

102 and Q 103

Q

which lower

105

amplifier stage

balance

VARIABLE

The

while

trace

by

provide

to

voltage

CH B

polarity

the

A & B,

A

diodes

Pin 3

forward-biases

Pin I I

break-

by

identical

The

and

CH

to

of

2: I

to

tran-

Q109.

polarity.

VRll2

pots

for

VRl0l

vertically

VRl07

the

measure-

the signal

pre-

+

B, A

Dl0l

low,

is

main

the output is

which forward-biases

high

D 105

biases main amplifier.

selected, both channels

is

a rate equal to

at (200kHz).

simultaneously operation is switched

is

VERTICAL

The selected

to the vertical

ICl03.

amplifier.

The output

Q306

the

drive

TRIGGER CIRCI.IIT

The trigger

SW20l.

amplifier

thru

fed of the SWEEP TIME/CM switch

SYNC

Transistors

differential

a

as emitter follower

Q203 SW202, r or DC

level

of the

When

routed Q205

cutoff corresponding to Positive-going pulses of

Q205

video signal.

in

of

-

When

SEC), capacitor C2O7 is switched

horizontal

the

The trigger the SCHMITT TRIGGER IC20l. The output SWEEP CONTROL the clock waveform, Q2l3

Transistors

resistors

and

MILLER

a voltage. to the RS transistor

As soon

lC2O2 until on and

terminates

and

For CH

For

A + B and

applied to the main

selected,

to the horizontal

AMPLIFIER

signal

amplifier which consists of

The signal

where the

AMPLIFIER

depending

TRIGGER

and

by

to initiate

is held low

the

amplifier

vertical deflection

Selecting

transistor switch

to the

The

sets

signal is

source, either CH

Qll9

and

Ql2l

Q20l , Q202, Q203,

-

respectively.

to

the trigger

TV+

e1 TV-

SYNC SEPARATOR circuit

Q206.

the

corresponds to the

in TW

sync

signal

to sweep.

Q2l6

selected by the

INTEGRATING circuit

sweep ramp

flip-tlop

I and

Q2l

as the

sweep

ramp

l3

the

sweep.

D 106 and

prohibiting

D 108

CH

and

amplifier.

Q20l

upon

LEVEL

Q205

negative

an average

positions

Q

by

of

the reverse is

B,

are alternately

the

chopping

A B, both channels are

CH A is

amplifier.

from

level

Ql2O

Q122.

AND

drive

pulses.

passes

pulses

flip-flop 1C202. On the negative edge of

the

and

consisting of two

Q212.

output of'lC2O2 Q2l

is

lC2O2 LOW which

preamplifiers

the

is increased to drive the output

consists of transistors

amplified

plates

A as

the

and

trigger amplifier selected is

The

Q219. Q2l9

except

INVERTER

The

and routed to

position

the

Emitter

signal depending

control.

selected, the output

is

biased

is

voltage

value

Q205

qync

of time base switch

thru emitter follower

circuit consisting

from

output

Q

Q2l6

SWEEP TIME/CM switch

from

the collector of

I to

exclude any

terminated.

D 107 and

CH B signal

true.

switched

oscillator frequency

amplifier.

turned

of the CRT.

A or CH B,

trigger

near cutoff.

out of cutoff.

and

on and

to the levels required to

source

CH B enables

on in all

is

CH B.

and

Q204

signal is applied to

the of the follower

upon

developed

of the

tips of

in

by

Q206

IC20l

goes

the timing capacitors

provide

to

gates

goes

Transistor

turns

from the

When

by

When

CH B is

then

is

Ql23,Ql24

Q30l

selected by

is

enables trigger

positions

are connected

base of

low,

from

new

Q202

SYNC switch,

Q2O+

position

the

of

consisting of

Q205 across

input signal.

The

the

composite

(.lmS

to filter

Q207

of two

8

clock the

turning

linear ramp

a

Q2l7

IC20l

low, the

clock

Q2l2

Q2l3

reverse-

A & B ICl0l

X-Y

applied

and

thru

trigger

or

adds

a

is

Q203

is held

Q205

output

.5

to

out

and

gates

of

off

form

fed

is

thru

reset of

pulses,

turns

and

on

CIRCUIT

DESCRIPTION

\r.

Transistors TRIGGER is

adjusted and condition reset

9qlqryin.d

TIME/CM

Q9

of

produce

is applied

1C202

Q208.

SENSE

so that the

switch.

by

allows

the

switch.

pulses which

QlC|().

to the RESET

resistor

and

When

slope is

a

High power

voltage Line transformer, the turned from in

fatal

the

not

keep

sweep to recirculate

and

capacitor

voltage

supply

up

to 195

voltage

oscilloscope

off.

the

unit. Contrcting

electric

fornr

Q2l0

TRIG LEVEL

triggered. of IC202.

up to

board when

of 120

on-off

Always

transistor

Q2tO

A low

selected by the

2m0

volts

VAC

switch,

is

connected to

observe

shock.

the

AUTO

control

ON. The

Q8

on

rhe

on

at a rate

SERVICING

WARNING

volts

the

DC is

lor

and

caution

exposed high

present

DC is

oscilloscope

present

24O VAC)

on the swe€p

power

AC

an

when

The sweep

the

input of the

Q220, Q22t

When mode, transistor B signal

The output horizontal

on

is

operating.

present

is supply power

souroe,

the housing is removed

voltage

ramp from the

-

Q225

in the

is

applied

of transistors

deflection

CRT

the

board.

the

on

board

any

even

result

ould

horizontal

CH B

Q2

to

and

High

power

time

collector of

.

t g is turned

Q220

plates

if

amplifier consisting

position

and

Q224

of the CRT.

Q2l7

of SWEEP

off

to the horizontal

and

TIME/CM

thru IC203

is

QZZS

applied to

is applied to

of

Q218,

switch,

and the

CH.

amplifier.

the

\,

HOUSING

Remove five Phillips head

1. each side, onc

tom of

2. Slide through the

CRT

WARNING: Keep

socket.

Remove

1.

REXIOVAL

from

houring.

complcte oscilloscope chastis

front

of

TILT

hands

High voltage

housing.

screws,

top, and two

housing.

the

from

away

(2000

VDC)

from

one

from

out

CRT

present.

bot-

Loosen the tvvo screws

2. around the

Turn on

3.

to obtrin a

4. Grasp the CRT shicld toward

the rotate the CRT so

horizontal line on the

a

Tighten

5. trace

neck

the oscilloscopc

single trtce.

through

the CRT band,

remains

horizontal.

of

the CRT.

front

the

the tracc

which

clamp the band

diust

rnd

fingpr

the

of the

is

grrticule.

making

controll

holes

CRT and

parrllol

sure that

in

with

the

b

SERVICING

v

230 VAC OPERATION

l. Remove

Remove voltage

2.

3. Rotate

4. Replace Replace

5.

housing from

selector

plug 180"

and

0.7A fuse housing.

scope.

re-insert

with

0.3A fuse.

plug

(see

plug.

Fig.

8).

2.

Lift off Reinsert

3.

panel

graticule

from bezel.

on

mounting holes.

bezel and

snap

bezel

into front

GRATICULE

REMOVAL

l. Grasp bezel with

bezel uniformly

panel.

front parallel

to front panel

age of mounting

Caution

(see

Fis.

a)

both hands at top and bottom.

forward

to unlock mounting legs

should be used

when

removing,

to keep

to avoid

legs.

Pull

from

bezel

break-

o

O,,

o

?,c

O

I ll

\-/ .)i

vl

ol

a

I

v

REAR VIEW

Fis. 4 Removing

the

Bezel

v

TR0ttstEsH00Trl{G

TROUB

r

I

2

'

3

LESHOOTI

Check the

Check ot spot

Check the trace

Check V AMP operat

Check operat

NG

pilot

presence

ron

trace

dual

ron

lamp

Troubleshooting

Flow

b

1

Chart

Check

sync

ro

operat

n

Check

,

/

6

"

v

sync

changeover

video

Check

Check calitrralrnq roltaqe

b"

SLOpE

sync

Bepair

comoleted

Lt

10

TRottrEsHo0Trltc

Y

Notes:

Check pilot

the

lamp

Check the

heck

(at

P3O7

a. LED

Poor

b.

P305

+

195V

terminal I

defective

contact in

(x68)

fuses

suppty

Parts

1.

without

belong

a.

D3O3

b.

C322

Power

c.

def ec t ive

defective(

defective(X68

transf

X68)

ormer

2.

3.

4.

. . ampllfier X74.

.

X68.

. .

X73.

borrd

Check

AC lTOV

(on

)

ply side f

ormer

a.

D3O3 (x68)

b

031l (x6a)

ol

)

secondary

power

open

crrcurted

open

crrcurted

sup

lrans

to

the

denotes

board

d€notes

.

denotes

particular main

sw€€p power

Power defective

notes

body.

vertical

board

supply

transformer

Check

2

of spot

SWEEP

DIV to

presence

(Set

TIME/

CH B

Check (at

terminal 1

ot CRT

-1.9kV

socket)

supply

or

2

+22V,

Check

+1OV,

+5V.

supplies.

(

X68)

+

13V.

-1OV

a. D3O1. b.

c.

Check

collector

(X68)

wave

wave)

-306

v

terminal

end

mlnal

Check terminal GND nal

2 trrminal 3

rd

bctwecn GND,

5

voltages

and

3 and GND.

and

GND,

trrmlncl

and

and GND.

between

1

P3O1

of

between

(X68)

and

termi-

a

o301

def ective

.AMP

H def ect ive

(Refer

V-AMP defective

(Refer

to

(srnusordal

lorm rn

0317

D31 O def ective

(

x68)

I

)

{

}

3O2 defective

(

x68)

Malf

unction in 308,309,310, 314 circuit lC3O1 (

x68)

(X68)

defective

a. Malfunction

0315,

316,

(X681

317

defective

L30l

b.

(

x68)

Q3O7,

313,

in

and

a.

voltage

Check

grid

3

6.3V supply

power

termi-

trans

CRT nal

Check on seconctarY of former.

at

stde

D311,312defective

(

x68)

b.

0318 defective(X68) lC2O2,204

c.

(x741

6.3V broken

terminal

defective

v

C RT

def

ective

11

TR0rtsrEsH0oTtltc

Check the

Jr

.-

trace (with

TRIG

LEVEL knob

PULL

to

set AUTO)

Check collector wave

form (See

F ig

Check

lC2O3, No.

o{ (4vl (xt4l

4217

ol

5)

X Y voltage

(X74\

8

Srveep crrcuit

(

malf

u nctron

C)210-

213,216,

217

and lC2O2l

(X74)

rnvestrgate

yJavelorrns

respectrve pornls (See

lC203

tive ( X 741

F rg

al

5)

defec

Fig. 5

Waveform

(lnput (SWEEP

corrector of o2o3

Signal 2

Tf ME

I

in

SWEEP Circuit

kHz

Sine Wave)

0.1mS/DlV)

W',

b

No. 11

In

No.

8

No.

2

of

"R"

lc2o1

lC2o1

lC2O2

oI

|

':l

lllI

I

:l

,'l

lll

I

n

11

b'

Note 1: Add

sine

vertical

Malfunction in 0218, 221

circuit

225

wave of

input

2

termtnal.

(Xl4l

kHz to

AoTCHB

CH

No. 13

No. 8

lector ol Q.217

Cof

x68

emitter

1

O32 (blanking)

"S"

"O"

of

lC2O2

oI

,,1

lc2,2r"l

40

I

t-l t-

n

,A

t'

0

12

BK Precision 1477, 1472C Service Manual

Specifications and Main Features

Frequently Asked Questions

User Manual