Hitachi CM801U Service Manual - Page 27

ADJUSTMENTS

1.

Power

supply

1.1

Power

switching

frequency

(1)

(2)

(3)

(4)

(5)

(6)

(7)

(8)

Turn

the

switch

of

the

unit

off.

Place

a

jumper

wire

across

R9C6

on

power

sub-p.w.b

2

to

disable

+

B

output

voltage.

Turn

the

switch

of

the

unit

on.

Receive

reverse

cross

hatch

pattern

of

signal

70A.

Connect

frequency

counter

between

D984

anode

and

GND.

Adjust

R95F

to

a

frequency

of

60.3

±

0.01kHz.

Turn

the

switch

of

the

unit

off.

Remove

the

jumper

wire

from

R9C6.

1.2

Heater

voltage

adjustment

for

color

display

tube.

(1)

(2)

(3)

(4)

(5)

(6)

(7)

(8)

Turn

the

switch

of

the

unit

off.

Place

a

jumper

wire

across

R9C6

on

power

sub-p.w.b

2

to

disable

+

B

output

voltage.

Turn

the

switch

of

the

unit

on.

Receive

reverse

cross

hatch

pattern

of

signal

70A.

Connect

a

Digital

multimeter

between

the

T1(GND)and

T2

on

the

CRT

neck

board.

Adjust

CDT

heater

voltage

to

6.2

±

0.05V

using

R942.

Turn

the

switch

of

the

unit

off.

Remove

the

jumper

wire

from

R9C6.

1.3

+

B

voltage

adjustment

(1)

(2)

(3)

(4)

(5)

(6)

(7)

Turn

the

switch

of

the

unit

off.

Adjusting

horizontal

free

running

frequency

must

be

finished

before

this

adjustment.

Receive

a

reverse

cross

hatch

signal.(See

table

1.for

proper

signal

timing)

Connect

a

Digital

volt

meter

between

Q800

collector(or

R807

on

the

side

of

Q800)and

GND.

Turn

the

switch

of

the

unit

on.

Adjust

R973

to

the

proper

+B

voltage

value

as

outlined

in

table

1.

Receive

reverse

cross

hatch

pattern

of

signal

30C

and

verify

that

the

+B

voltage

is

at

53.5

±

3.0V.

Table

1

Model

signal

+B

voltage

CM800U

80A

127±1.0V

CM801U/802U

94A

149±1.0V

CM803U

112A

179.0±

1.0V

fl

2.

Deflection

circuit

adjustment

2.1

Horizontal

free

running

frequency

adjustment

(1)

Turn

the

switch

of

the

unit

off.

(2)

Place

a

jumper

wire

across

R9C6

on

power

sub-p.w.b

2

to

disable

+

B

output

voltage.

(3)

Connect

a

10

Kohm

resister

between

1701

2

pin

and

C714

+

Pin.

(4)

Connect

a

1

Kohn

resister

between

R71B

and

1702

1

Pin.

(5)

Connect

frequency

counter

between

R71B

and

GND.

(6)

Turn

the

switch

of

the

unit

on.

(7)

Receive

the

signal,

as

indicate

on

table

2,

for

frequency

Horizontal

high(fHH),

and

adjust

R724

to

the

value

indicated

on

table

2.

(8)

Receive

the

signal

43W

for

fHL

and

adjust

the

fHOL

to

43.3

±

0.1

kHz

using

R721.

(9)

Repeat

(5)

and

(6)

until

fHOH

and

fHOL

meets

the

values

indicated

on

table

2.

(10)

Receive

the

signal

36W

for

fHLL,

which

is

on

table

2,

and

adjust

the

fHOLL

to

36.1

±

0.05kHz

using

R726.

(11)

Turn

the

switch

of

the

unit

off.

(12)

Remove

the

adjustment

jig.

Table

2

R726

R721

R724

fHLL

fHOL

fHL

fHOL

fHH

fHOH

CM800U

36W

36.1±0.05kHz

43W

43.3±0.1kHz

80A

80.5±0.2kHz

94A

94.3±0.2kHz

CM

801U

CM802U

112A

113.3±0.2kHz

CM803U

2.2

High

voltage

adjustment

(1)

(2)

(3)

(4)

(5)

(6)

(7)

Turn

the

switch

of

the

unit

off.

Connect

a

high

voltage

meter,

whitch

is

capable

to

measure

up

to

40kV,

between

CDT

anode

and

GND.

Receive

normal

cross

hatch

pattern

of

68A

signal.

Turn

the

switch

of

the

unit

on.

Adjust

high

voltage

level

to

27.5

±

0.3kV

using

R756.

Turn

the

switch

of

the

unit

off.

Remove

the

adjustment

jig.

Hitachi CM801U Service Manual - Page 27

Adjustments

Page 27 highlights