Fisher AD-530 - Diffraction Grid and E;F Balance Alignment

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ADJUSTMENT

PROCEDURES

(continued)

4.

Place

the

test

disc

YEDS7

on

the

table

load,

and

press

the

PLAY

button.

5.

When

the

disc

begins

to

rotate

a

waveform

will

appear

on

the

oscilloscope.

While

observing

this

waveform,

turn

the

gears

in

the

direction

of

the

arrow

by

hand

to

send

the

pick-up

to

the

outer

edge.

6.

When

the

pick-up

approaches

the

outer

edge,

the

wave-

form

on

the

oscilloscope

will

suddenly

disappear,

and

if

it

is

now

pushed

further

outwards

there

will

be

points

at

which

waveforms

will

appear

again.

These

locations

are

the

multiburst

signal

storage

locations.

If

the

disc

rotates

at

high

speed

at

this

time,

perform

this

step

once

again.

Multiburst

signal

track

Test

disc

YEDS

7

7.

Set

the

oscilloscope

to

X-Y

operation

to

bring

up

the

waveforms.

Insert

the

adjustment

tool

in

the

diffraction

grating

adjustment

hole

on

the

pick-up,

and

rotate

the

adjustment

tool

to

right

and

left.

The

waveform

should

be

almost

a

straight

line

with

a

phase

difference

of

0°

as

shown

in

Fig.

1

below.

This

indicates

that

the

beams

are

arranged

in

one

straight

line.

The

waveform

in

Fig.

2

in-

dicates

that

the

beams

are

not

arranged

along

the

same

Stream.

NOTE:

It

is

important

to

turn

the

adjustment

tool

only

a

little

ata

time.

If

it

is

rotated

too

far,

the

beams

will

be

pushed

over

into

neighboring

streams.

Fu

B40

RN

Aes

u-¥

Fig.

1

Fig.

2

—8-

Pick-up

Adjusting

Hole

Jig

*)

tc

Do

not

Adjust

8.

Next,

when

the

waveform

in

Fig.

1

is

obtained,

turn

the

adjustment

tool

clockwise

from

that

position

at

which

the

waveform

in

Fig.

1

appeared

and

adjust

so

that

the

waveform

is

a

straight

line

with

a

phase

difference

of

180°.

(See

Fig.

3)

Fig.

3

9.

Once

the

state

indicated

by

the

waveform

in

Fig.

3

is

od-

tained,

hold

the

STOP

button

down

temporarily,

and

re-

move

the

connection

between

tester

termina!

(CN9-1.2)

microprocessor

TEST

pin

and

the

TEST

pin

as

well

as

that

between

test

terminal

(CN12-1)

TOFF

pin

and

GND.

10.

Next,

press

the

PLAY

button,

and

set

the

oscilloscope

in

the

DUAL

MODE

so

that

both

E

and

F

outputs

can

be

seen.

Set

the

DISPLAY

TIME

to

5us.

Now,

adjustment

is

com-

plete

if

the

waveforms

shown

below

in

Fig.

4

(Channe:

1

trigger)

are

obtained.

Approximately

m™

~~

E-beam

waveform

m~—~—

F-beam

waveform

(Pe

O4Oms

Ad

4Ome

Sus

1

Fig.

4

NOTE:

Diffraction

grating

adjustment

is

performed

for

a

single

pick-up,

so

if

the

following

checks

are

performed

adjust-

ment

is

unnecessary.

a.

PLAY

the

fourth

item

on

the

test

disc

(Modern

Wave

Il

CA35-1045,

Toshiba-EMI),

turn

the

tracking

servo

OFF,

and

check

that

the

waveform

is

linear

with

a

phase

difference

of

180°.

b.

Next,

apply

tracking

servo,

and

if

the

waveforms

shown

in

Fig.

4

are

obtained

then

adjustment

is

un-

necessary.

E/F

BALANCE

ADJUSTMENT

1.

Place

the

test

disc

(Modern

Wave

II)

on

the

table

load,

and

play

the

fourth

item

on

the

disc.

Short

the

test

termi-

nal

(CN9-1,2)

microprocessor

TEST

pin

to

the

TEST

pin,

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