Date : 23/04/98
Replacement of a picture tube
1
DATA
808S
R9002031(7)
R9002032(8)
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 individuals while
handling the CRT or installing it in the projector. Do not handle the CRT by the neck.
I. Removing and disassembling the defective picture tube.
1. Removing top cover of the projector
- Turn the lock screw with a
screwdriver or a coin a half
turn counter clockwise.
- Lift up the top cover and
carefully pivot it vertically
(attention: no cover support
provided).
- Carefully push the top cover
downwards (to eliminate lock
spring) and to the left (when
standing behind the projector)
to pull out the hinge-knuckle
of both lift-off hinges.
- remove the top cover.
Date : 23/04/98
Replacement of a picture tube
2
DATA
808S
R9002031(7)
R9002032(8)
2. Removing the picture tube cover
picture tube cover
[A]
[C]
[B]
[B]
[B]
[B]
[D]
[D]
- Remove the 2 retaining screws [A] on both
sides of the projector holding picture tube
cover on main frame.
- Loosen the 4 retaining screws [B] holding
picture tube cover on main frame.
- Loosen the 2 lock screws [C] locking the
picture tube cover on main frame.
- Rotate the picture tube cover towards the
front of the projector and loosen the 2
retaining screws [D].
- Slide the picture tube cover assembly back-
wards until the head of the retaining screws [B]
and [D] match the free gap.
- Pull the assembly out of the main frame.
Picture tube cover assembly removed
Date : 23/04/98
Replacement of a picture tube
3
DATA
808S
R9002031(7)
R9002032(8)
3. Picture tube removal (example GREEN picture tube)
R
G
B
A. Electrical disconnection of the defective
picture tube
EHT lead disconnection
Pull out the EHT lead of the defective picture
tube from the EHT splitter.
Deflection and Magnetic coils disconnection
Pull out the deflection connector J24 and Magnetic coils connector J535 of the G defective picture tube
from main frame.
CRT ground (A) and Unit ground (B) lead
disconnection
Disconnect the plug connection in both ground
wires.
CRT module removal
Disconnect the socket of the defective picture tube by
pulling back the CRT socket off of the end of the CRT.
Date : 23/04/98
Replacement of a picture tube
4
DATA
808S
R9002031(7)
R9002032(8)
B. Mechanical disconnection of the defective picture tube
Disconnection of the CRT from its
support
Remove the 2 bolts, holding the top side of
the picture tube to the support.
Removing the picture Tube
Move the end of the picture tube a little
downwards and clips the front of the picture
tube out of the picture tube lock springs.
Take out picture tube from main frame.
picture tube
lock springs
bolts
Date : 23/04/98
Replacement of a picture tube
5
DATA
808S
R9002031(7)
R9002032(8)
Disassembling the CRT unit
- Loosen the gear clamp of the stigmator magnets unit and slide the unit off of the end of the CRT.
- Loosen the gear clamp on the Deflection unit and on the Dynamic Astigmatism unit and slide both units
together off of the end of the CRT.
gear clamp of the stigmator magnets
gear clamp on the Dynamic Astigmatism unit
gear clamp on the Deflection unit
Date : 23/04/98
Replacement of a picture tube
6
DATA
808S
R9002031(7)
R9002032(8)
II. Placement of the new picture tube
1. Assembling the picture tube unit
8mm
3cm
connection on top
HV Lead reference for lining up
the neck components
Assembling
- Slide the Deflection and the Dynamic Astigma-
tism unit together over the neck of the picture
tube, Deflection unit fully to the end and the
Dyn. Astigmatism unit approx. 8mm from the
Deflection block.
- Tighten slightly the gear clamp of both units
(rotation must be possible for correct adjustment
of the units)
- Slide the stigmator magnets unit over the neck of the
picture tube for about 3cm. Tighten the gear clamp.
Date : 23/04/98
Replacement of a picture tube
7
DATA
808S
R9002031(7)
R9002032(8)
2. Mounting the picture tube unit in the main frame
bolts
Proceed now to the electrical connections and the cover placements (see pages 1 to 3)
Move the socket side of the picture tube below its
output amplifier and place the front of the tube on
the lock springs, lining up the two clearance holes
in the metallic tube support with the threaded
holes in the tube frame.
Push on the top of the tube to lock the tube
between the springs.
Using the two removed bolts, securely tighten the
picture tube into place..
lock spring
foam rubber
Date : 23/04/98
Replacement of a picture tube
8
DATA
808S
R9002031(7)
R9002032(8)
III. Picture tube alignment
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.
1 or 2 picture
tubes replaced
projected picture of the
non-defective tube can be
used as reference
rotate the deflection yoke
until the Horizontal mid-line
is levelled - tighten the
gear clamp
apply an external crosshatch
pattern at 15 kHz or use the internal
crosshatch
Picture tube alignment
proceed to a quick optical
and electrical focus
all picture tubes
replaced
apply an external crosshatch
pattern at 15 kHz or use the internal
crosshatch
rotate the deflection yoke
until the Horizontal mid-line
is levelled - tighten the
gear clamp
centre the picture on the
CRT faceplate (refer to
installation manual)
note: alignment of the
stigmators will change
again its position, if so,
realign raster centring
ç
proceed to the following
adjustments for each picture
tube separately
ç
Set the midpoint focusing
on 57 (see owner's manual)
and the Contrast on 80
move the focus unit slowly
for- or backwards for max
focusing in the middle of the
screen - tighten the gear
clamp and the centring
clamp
Date : 23/04/98
Replacement of a picture tube
9
DATA
808S
R9002031(7)
R9002032(8)
ab
d
c
a<b
c<d
a' b'
d'
c'
a'=b'
c'=d'
realign the electrical
and optical focus
due tu mutual influence between the
stigmators, focus and centring, it is
advised to repeat above a couple of
times
re-position the raster
as described earlier
adjust the 4-pole rings until the
defocued dots are circular.
decrease the Contrast and
Increae the Brightness to
reveal the background raster
see service sheet 'Deflec-
tion switching/Hor Amplitude'
in this manual for the
alignment of the image width
coils
Note: when only one tube has
been replaced, 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
ç
ç
scan width
adjustment
2-pole
4-pole
neutral
position
Set the midpoint focusing
on 100
select a source that
generate a field of small
dots and crosshairs
realign the electrical and
optical focus
adjust the 2-pole magnets rings by
rotating one or both up to a point
where 'shading' of both sides of
the vertical and horizontal lines is
equal.
lower the Brightness and
put the Contrast on its max
with the RCU
Set the midpoint focusing
on 0
/