Focus Adjustment - Hitachi 36SDX88B Service Manual

3.3 Focus Adjustment Adj. point
FOCUS 1
FOCUS 2
Preparation for adjustment Adjustment procedure Notes
(1) Do this adjustment after (1) Turn picture adjust VR. Change Sub- There are 2 Focus adjustment
adjusting horizontal Brightness Data at adjustment No. ,I0 VRs at FBT, THOl, on
and vertical center and so that background become just black Deflection PWB, because this
size is finished. if it's too bright or too dark. chassis uses Double Focus
Picture :Standard factory System.
settings A criteria of Focus adjustment
(2) AC+l2OV+2V (2) Horizontal Line Adjustment should be Halo tendency.
Adjust Focus on Cross-Hatch Circle
Focusing point is shown
Pattern concentrating the center below.
point of the picture.
The top end
(3) Receive Cross-Hatch
(3) Adjust focus while focusing only at
of Cross-Hatch
Signal with Circle Pattern. horizontal line so that it become the
VGA3 group 1 thinnest without any halo and
Black background blooming on the horizontal line.
(4)
White line (4) The focus point is center.
Adjust cut-off after Adjust focus so that there is no halo
finishing coarse Focus
and blooming on the horizontal and
adjustment;
vertical lines with repeating from item
The e
Just Focus is -t2OOV.
2 to 5. Final process should be item 5
Confirm Cut-Off Adjustment of this page.
The end of
if voltage range is out of
k2OOV after re-adjusting (5) Vertical Line Adjustment
Focus. Adjust Focus on Cross-Hatch Circle
Pattern focusing the point as
shown in the right figure.
(6) Adjust focus 2, focusing only at
vertical line so that it become the most
The second vertical line
from
thick; the adjustment point which can
the left end.
be seen the clearest without any
saturation.
Focus 2 FOCUS I
Concentration point:
Inner point of the circle as shown
in the right figure.
Note:
Adjust Horizontal Center Focus
again after adjusting Vertical
Focus.
0
0
FBT
;3
SCREEN
81