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CN602

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CN604

CN1102

CN312

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CN321

CN305

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CN303

CN1

CN

CN1103

CN1400

CN605

CN701

CN501

CN904

CN2601

Picture tube

US board

A1 board

D board

H1 board

AC inlet

HV Regulator
Circuit Check

HV Protector
Circuit Check

Beam Current
Protector Circuit
Check

When replacing or repairing the shown below table, the

following operational checks must be performed as a

safety precaution against X-rays emissions from the unit.

3-1

Part Replaced (

[)

RV901

HV ADJ

*

Confirm one minute after turning on the power.

1) Turn the RV901 slowly, and adjustment so that high

voltage is in the specified range.

[Specification]: 27.00 ± 0.05 kV

2) Check that the voltage of D912 cathode on the D

board is 17.0 V or more.

1) Using external DC Power Supply, apply the voltage

shown below between cathode of D912 and GND,

and check that the RASTER disappers.

[Specification]: 19.95 + 0.00/– 0.05 V

1) Connect constant current source to a section between

T901 (FBT) qa pin and GND, and check that the

RASTER disappers when the specified current flows

to the qa pin.

[Specification]: 2.12 + 0.00/– 0.01 mA

Part Replaced (

])

D Board C925, IC901, R901,

R902, R905, R924,
R925, R926, RV901,
T901 (FBT)
• Mounted D Board

D Board C920, C923, D911,

D912, R903, R917,
R918, R919, R920,
R923, T901 (FBT)
• Mounted D Board

N Board IC1001, RB1001

• Mounted N Board

D Board C930, D917, R921,

R932, R933, R935,
T901 (FBT)
• Mounted D Board

N Board IC1001, RB1001

• Mounted N Board

1. Display all white pattern (or black dot pattern).
2. Set contrast to 255.
3. Display green plain pattern.
4. Side back DY and roughly adjust green plain pattern to be

centered on the useful screen with Purity Magnet.

5. Adjust DY tilt.
Note: Set ROTATION to 128 and LCC_NS to 128 when

adjusting DY tilt.

6. Lightly tighten the DY screw.

Note: (1) After adjust W/B (9300k), measure the average of 

Σ

IK

with all white video input, while CONTRAST is
maximum and BRIGHTNESS is center. And
adjustment shall be made so that the miss-landing
become least after aging 2H with the IK 30% of
measured value shown above.

(2) The magnetic field shall be BH = 0.
(3) When adjusting at other than BH = 0, calculate the

shifted value from BH = 0.

1. Put the monitor in helmholz coil.
2. Set as follows;

LCC_SW = 0

(LCC Correction Current = 0)

FUNCTION_SW bit1 =

(Auto Degauss = On)

CONTRAST = 255

3. Display green plain pattern.
4. Degauss the iron part of chassis with a hand degausser and

degauss coil.

5. Degauss CRT face with a hand degausser again.
6. Input AC 230V to AC IN and turn the monitor off and on.

Then auto-degauss works.

7. Reset FUNCTION_SW bit1 to 0 (auto-degauss = off)
8. Degauss CRT face with a hand degausser again.
9. Attach wobbling coil to the specified place on CRT neck.
10. With landing checker, adjust DY position, purity, DY center

and landing of the 4 corners.

11. Check landing of the 4 corners, and adjust using magnet if

they are not in the specification.

4-1

Note: (1) Do not attach more than 2 magnets on one corner.

(2) Attach magnets within the range of 80 - 100 mm from

DY.

(3) Be sure to degauss and check when used magnets.

12. Tighten DY screw within specified torque, and auto-

degauss.

Note: Torque 22 ± 2 kgcm (2.2 ± 0.2Nm)
13. Adjust the vertical angle of DY to make top and bottom pins

equal (a = b). The horizontal angle shall not be changed
(straight). Settle DY upright without leaning, and insert
wedges firmly so that DY shall not move.

 ± 6

 ± 6

 ± 6

 ± 6

 ± 6

 ± 6

 ± 6

 ± 6

 ± 6

<Specifications>
Adjust so that the green is within
the specification given right.
4 corner adjust target : within ± 1

The red and blue must be within
the specification given right with
respect to the green.

A difference between red and blue
must be within the specification
given right.

0 ± 3 0 ± 7.5 0 ± 3

0 ± 3 0 ± 7.5 0 ± 3

0 ± 3 0 ± 7.5 0 ± 3

(µm)

(µm)

10

10

10

10

7

10

10

10

10

(µm)

a

b

c

d

<How to place wedge>
Green plain crosshatch pattern

a and b should be equal.
c and d should be equal.

Plaster RTV to both sides for the upper wedge.

Make sure that they settle inside DY.

Plaster RTV to one side for other wedges.

14. Adjust top and bottom pins correction VR.
15. Adjust the horizontal trapezoid distortion by DY horizontal

trapezoid correction VR.

16. Check landing at each corner and in case not in specification,

adjust landing of 4 corners with landing magnet.

17. Remove the sensor and wobbling coil.
18. Switch signals to R, G, and B, and then check that the pure

colors have good color purity.

19. Fix purity magnets with white paint.

4-2

Connect the communication cable of the computer to the connector located on the D board. Run the service software and then follow
the instruction.

IBM AT Computer

as a Jig

1-690-391-21

1

A-1500-819-A
Interface Unit

2

*The parts above (                ) are necessary for DAS adjustment.

1

3

D-sub
(9 Pin [female])

mini Din
(8Pin)

4 Pin

3-702-691-01
Connector Attachment

3

To BUS CONNECTOR

4 Pin

4 Pin

•

(1) Display white crosshatch pattern.
(2) Pile the convex parts of 6-pole magnet for convergence

together.

(3) Roughly adjsut H.CONV and V.CONV with 4-pole magnet.

•

1. 9300 K

x = 0.283 ± 0.005
y = 0.298 ± 0.005

(All White)

2. 6500 K

x = 0.313 ± 0.005
y = 0.329 ± 0.005

(All White)

3. 5000 K

x = 0.346 ± 0.005
y = 0.359 ± 0.005

(All White)

•

•

Adjust the focus volume 1 and 2 for the optimum focus.

•

B

a

a     1.8 mm
b     1.8 mm

a

b

b

A

MODE

A

B

4 : 3

352

264

5 : 4

330

264

B

A

A

0.20 mm

B

0.24 mm

V

XBV

XCV

B

R

B

R

R
B

B
R

R

B

B

R 

TLV

TLH

YBH

YCH

R B

R B

H.TRAP

TB-PIN

TLH

XCV

Purity

4-pole magnet

6-pole magnet

2-pole magnet

Focus 1

Focus 2

FBT