Barco R9002129 User Manual

DATA 708

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REPLACEMENT OF A PICTURE TUBE

WARNING: CRT HANDLING

The picture tube encloses a high vacuum and care must be taken not to bump or to

scratch the picture tube as this may cause the tube to implode resulting in personal

injury and property damage. Shatterproof goggles must always be worn by individu-

als while handling the CRT or installing it in the projector.

Do not handle the CRT by the neck.

WARNING

TURN OFF THE PROJECTOR AND UNPLUG THE POWER CORD

BEFORE PROCEEDING TO THE REPLACEMENT OF A PICTURE TUBE

I. Removing and disassembling the defective picture tube.

Getting Access to the picture tube

1. Remove the top cover of the projector (please refer to the projector installation manual).

2. Loosen the two locking screws of the module frame.

3. Open the module frame by pivoting it towards the front of projector.

Module frame

Retaining screws

Retaining screws

Replacement of a picture tube

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Electrical disconnection

4. EHT lead disconnection

Pull out the EHT lead of the defective picture tube from the EHT splitter.

EHT lead

Red

Green

Blue

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To pull out

Fig. 1

5. Picture tube drive module removal

Cut the cable-tie indicated with A on the picture below,
loosen it and remove it.

Disconnect the CRT ground plug (indicated with B) of
the defective picture tube.

Loosen the gear clamp of the Picture tube drive module
(indicated with C).

Carefully pull the module (indicated with D) back to slide
the CRT socket off from the end of the CRT.

B

CRT ground plug

A

To secure

To open

Ì

C

D

Replacement of a picture tube

Fig. 2

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CRT unit removal

6. Remove the two bolts, holding the CRT unit
to the CRT main frame.

Pull upwards the CRT unit while using a
screw driver to push the CRT out of the clips
at the bottom, to remove the CRT unit.

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Bolts

clips

clips

Fig. 3

Removing the deflection unit and the stigmator magnets

- Loosen the gear clamp of the stigmator

magnets unit.

- Loosen the gear clamp of the deflection unit.

Clips

- Slide the stigmator off from the end of the

CRT.

- Remove the mu-metal

- Slide the deflection unit off from the end of

the CRT.

Replacement of a picture tube

Gear clamp

Deflection unit

Gear clamp

Stigmator unit

Fig. 4

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II. Placement of the new picture tube.

1. Remove the CRT ground unit from the defective picture tube and reinstall it on the new picture tube.

CRT ground unit

2. Reinstall the two units, stigmator and deflection yoke, on the picture tube neck.

3. Re-install the mu-metal by wrapping it around the neck of the picture tube, then sliding one side a little
under the clamping gear of the deflection unit and the other side under the clamping gear of the stigmator.
Fix it with a cable-tie. Be sure to also fix the discharging wire as indicated.

4. Secure the respective gear clamps (see Fig. 4) of the stigmator and deflection unit.

5. Place the picture tube unit correctly on its two clips and push it downwards to fit. Secure the position with
the two bolts (see Fig. 3).

6. Plug in the EHT lead of the installed picture tube on the EHT splitter and lock the connector (see Fig. 1).

7. Push the CRT Socket module on the picture tube (see Fig. 2).

8. Secure the gear clamp of the Picture tube drive module.

9. Reconnect the CRT ground plug.

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Neutral position

4-pole rings
2-pole rings

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III. Picture tube alignment

Introduction Before starting the alignment of the new picture tube, the projector must warm

up for at least 15 minutes at a medium brightness and contrast.

If a set of three tubes must be replaced, it is advisable to start with the
replacement of the red and blue tubes first, and using the green as the
reference.

Proceed then with the replacement of the green tube, using now one of the
other colors tubes as the reference.

A. Replacement of a complete

set of three tubes

B. Replacement of one or

two tubes

C. Adjustments applicable

to the three tubes

Apply an external crosshatch pattern at 15 kHz or use the internal crosshatch.

Align the optical and electrical focus of the tube.

Rotate the deflection yoke until the horizontal lines of the crosshatch are
levelled on the screen.

Tighten now carefully the screw of the gear clamp of the deflection yoke.

Center the picture on the CRT faceplate (refer to explanation 'Raster
centering').

Note: alignment of the stigmators will change again its position, if so, realign
raster centering.

In such case, the remaining tube can be used as the reference for
centering and positioning of the new tubes.

Preparation

- Proceed to quick optical lens focusing (please refer to the projector
installation manual).

Replacement of a picture tube

- Adjust the 2-pole and 4-pole
magnetic rings on the CRT neck in
their neutral position (see illustra­tion on next page).

- Select a source that will generate
a field of small dots and
crosshairs.

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Adjustment of the stigmators (4-pole magnet ring closest to the deflec­tion yoke)

- Lower the brightness and increase the contrast.

- Overdrive the midpoint focus by adjusting the lens focusing for the respective

CRT.

- Adjust the four pole rings until the defocused dots are circular.

- Realign the electrical and optical focus.

- Reposition the raster as described earlier.

- Due to mutual influence between the stigmators, focus and centering, it is

advised to repeat above a couple of times.

Adjustment of the 2-pole magnets (the rings closest to the CRT socket)

- Underdrive the electronic focus by adjusting the left arrow key of the RCU

for the respective CRT.

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- Adjust the 2-pole magnets rings by rotating one or both up to a point where

the 'shading' of both sides of the vertical and horizontal lines is equal (see
figure).

ab

- Realign the electrical and optical focus.

- Repeat the alignment of the stigmators if necessary, as both adjustments

(stigmator and 2-pole magnets) influence each other.

Re-alignment of the image width coil(s)

- Decrease the contrast and increase the brightness to reveal the background

raster.

- Refer to sheet 'Deflection module R762447' in this manual for the alignment

of the image width coils.

a<b
c<d

c

d

a' b'

a'=b'
c'=d'

c'

d'

Replacement of a picture tube

Note:

When only one tube has been replaced, you can use the image width of one
of the other tubes as a reference, and obviously limit the adjustment to the core
of the corresponding replaced tube.

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CONTRAST LEVEL IS REDUCE D
AND BRIGHTNESS INCRE ASED
TO MAKE THE RASTER
VISIBL E ON THE FACE PL AT E
OF EACH CRT.

US E THE ARR OW KEYS
TO CENTER THE RASTER
ON THE GREEN, RED AND
BLUE CRT RESPECTIVELY

COMM PORT
(800 peripherals )

REMOTE

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S-VIDEO

P2
P1

P2
P1

RED
BLU E

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D. Raster centering

Picture movement when adjusting the arrow keys to

127,&(

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To center the

Center the raster verti call y, using the arrow keys of the RCU ’up’ and ’down ’

The raster must be centered on the CRT
screen surface of each tube, therefore, it is
necessary to look into the lenses.

Raster centering controls (please refer to the
projector installation manual).

center the

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: the RED and Blue raster are tracked with

the GREEN raster horizontally.

press

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To center the

Center the raster vertically, using the arrow keys of the RCU ’up’ and ’down’

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(Two multiturn potentiometers are provided on the module ’Focusing+Shift")

Replacement of a picture tube

press

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