HP ID5220N, Service Manual

Page: 67 / 96

Service Testing and Qualification 61
15. Inspect the screen to determine whether the configuration passes or fails the alignment procedure for
centering and distortion:
•
Pass: No red border is visible prior to electronic centering. The image rotation must be 5% or less.
•
Fail : A red border is visible.
The lines in the corners have a 5% spacing (used to judge rotation, centering, and distortion). 5% is
approximately equal to 3 mm. The border lines labeled 5, 4, 3, 2, 1% are the indicated % of the overscan
from the image edge. The red border is not symmetric in order to provide more overfill at the top of the
screen.
16. Perform the following calculation to determine if the final configuration passes or fails the keystone test:
Specification: < 1%
Max
% 100
1 2
1 2
1 2
1 2
•
⎭
⎬
⎫
⎩
⎨
⎧
⎥
⎦
⎤
⎢
⎣
⎡
+
−
•
⎥
⎦
⎤
⎢
⎣
⎡
+
−
V V
V V
H H
H H
Vertical Keystone Horizontal Keystone