Hitachi CM801U Service Manual - Page 28

3.

Video

Circuit

Prior

to

the

video

circuit

adjustment,

all

Sync.And

Deflection

circuit

adjustment

must

be

completed.

The

monitor

must

have

been

warmed

up

for

more

than

60

minutes.

Video

signal

must

be

terminated

with

750

and

should

provide

the

correct

voltage

at

the

monitor

end.

(Pre-setting

before

adjustment]

*

Output

voltages

of

DAC

Function

Pin

No.

Output

Voltage

R

Color

#9

pin

(1051)

5V

(FF)

G

Color

#6

pin

(1051)

5V

(FF)

B.Color

#8

pin

(1051)

5V

(FF)

Contrast

#7

pin

(1051)

5V

(FF)

Brightness

#5

pin

(1051)

0V

(FF)'

Sub

Brightness

#4

pin

(1051)

2.5V

(7F)

Sub

Contrast

#5

pin

(1051)

2.5

V(7F)

R.BKG

#15

pin

(1051)

5V

(00)

G.BKG

#14

pin

(1051)

5V

(00)

B.BKG

#16

pin

(1051)

5V

(00)

Note

1)

ACL

Adjustment

R264

is

set

to

Mechanical

center.

Note

2)

Color

Analyzer

:

Minolta

CA

100

or

equivalent.

3.1

Cut

off

adjustment

(1)

Receive

a

signal

of

80A

with

a

blank

signal

pattem.(Black

video)

(2)

Connect

a

high

impedance

voltmeter

(more

than

1000M0)

to

the

Screen

terminal

(G2)

on

the

CRT

neck

board.

Adjust

the

Screen

voltage

pot

on

FBT

to

see

400

±

10V.

(3)

Adjust

R,G

&

B,BKG

to

show

the

CIE

coordinate

of

X

=0.313

±

0.03,

Y=0.329

±0.03

at

0.25

cd/m

2

(0.07ft-L).

If

it

looks

difficult

to

obtain

X

and

Y

readings

mentioned

above,

do

the

followings

to

obtain

these

numbers.

1)

Reset

Sub

Brightness

to

1.57V

(BF)

or

3.4V

(40).

2)

Reset

Sub

Brightness

to

0.63V

(DF)

or

4.4V

(20).

3)

Reset

G2

to

430V

or

370V

4r)

3.2

White

balance

adjustment

(Color

2)

(1)

Receive

a

signal

of

70A

with

a

full

white

pattern.

(2)

Set

Brightness

Control

to

the

center

(2.5V

:

7F).

(3)

Adjust

the

light

output

to

80

cd/m

2

(23ft-L)

at

the

center

of

screen

by

adjusting

Sub

Contrast

Control.

(4)

Adjust

the

white

balance

of

high

light

output

by

Green

and

Blue

color

adjustments

to

read

CIE

coordinate

of

X=0.313

±

0.015,

Y=0.329

±

0.015.

(5)

Adjust

Contrast

Control

to

read

3

cd/m

2

(1

ft

-L).

(6)

Adjust

Red

and

Blue

BKG

to

read

the

same

CIE

coordinate

shown

in

3.3.4.

(7)

Adjust

Contrast

Control

to

read

80

cd/m

2

(23ft-L)

and

then

confirm

CIE

coordinate.

If

it

shown

out

range,

go

back

to

3.3(4)

Register

the

readings

of

R/G/B

BKG

and

Color

data

(Color

2)

to

the

microprocessor.

(8)

3.3

White

balance

adjustment

(Color

1)

(1)

Receive

a

signal

of

70A

with

a

full

white

pattern.

(2)

Set

brightness

Control

to

the

center

(2.5V

:

7F).

(3)

Adjust

the

light

output

to

80

cd/m

2

(23ft-L)

at

the

center

of

screen

by

adjusting

Sub

Contrast

Control

in

Color

2

mode.

(4)

Select

"Color

Select"

to

Color

1.

(5)

Adjust

the

white

balance

of

high

light

output

by

Red

and

Blue

color

adjustments

to

read

CIE

coordinate

of

X=0.283

±

0.015,

Y=0.298

±

0.015

Note)

The

reading

of

G

color

should

stay

in

the

same

as

in

Color

2.

(6)

Register

the

readings

of

Color

dada

(Color

1)

to

the

microprocessor.

3.4

White

balance

adjustment

(Color

3,

User

area)

(1)

Receive

a

signal

of

70A

with

a

full

white

pattern.

(2)

Set

Brightness

Control

to

the

center

(2.5V

:

7F).

(3)

Adjust

the

light

output

to

80

cd/m

2

(23ft-L)

at

the

center

of

screen

by

adjusting

Sub

Contrast

Control

in

Color

2

mode.

(4)

Select

"Color

Select"

to

color

4.

(5)

Adjust

the

white

balance

of

high

light

output

by

Green

and

Blue

color

adjustments

to

read

CIE

coordinate

of

X=

0.336

±0.015,

Y=0.352±0.015.

Note)

Value

of

R

color

should

be

the

same

as

in

Color

1.

(6)

Register

the

readings

of

Color

data

(Color

3,

User)

to

the

microprocessor.

3.5

Brightness

adjustment

(1)

White

balance

adjustment

must

have

been

done

before

Brightness

adjustment.

(2)

Receive

signal

of

70A

with

a

blank

signal pattem.(Black

video)

(3)

Set

Brightness

and

Contrast

Control

to

their

maximums.

(4)

Ambient

light

on

the

surface

of

the

CRT

should

show

lower

than

50

lux.

(5)

Select

"Color

Select"

to

Color

1.

(6)

Adjust

the

light

output

to

0.95

cd/m

2

(0.07

ft

-L)

at

the

center

of

screen

by

adjusting

Sub

Brightness

Control.

(7)

Receive

a

signal

of

70A

with

a

window

pattern

(100

X

100

mm)

(8)

Adjust

the

light

output

to

120

cd/m

2

(35

ft

-L)

at

the

center

of

screen

by

adjusting

Sub

Contrast

Control.

(9)

Receive

a

signal

of

70A

with

a

full

white

pattern.

(10)

Set

R/G/B

color

to

the

maximum

(5V

;

FF)

(11)

Adjust

the

light

output

to

110

cd/m

2

(32ft-L)

at

the

center

of

screen

by

adjusting

ACL

adjustment.

(12)

Register

the

readings

of

Sub

Brightness

and

Sub

Contrast

to

the

microprocessor.

Hitachi CM801U Service Manual - Page 28

Hitachi CM801U - RasterOps - 21" CRT Display Manual

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