Filter
Top Products
Date : 08/06/99
Replacement of a picture tube
DATA 708
6
R9002120
R9002129
Adjustment of the stigmators (4-pole magnet ring closest to the deflec-
tion 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.
- 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).
- 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.
ab
d
c
a<b
c<d
a' b'
d'
c'
a'=b'
c'=d'
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.
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.