NEC MultiSync FP1355 FP1355 FP1355, Service Manual

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2.5.1.8 Picture distortion
When the picture distortion is measured, each distortion of the preset timing must be less than
the following values.
4-corner section distortion
Inspect the distortion at the four corners.
• Signal, H character with frame (both normal/reverse)
Item
<Picture performance inspection items> Inspect the following items for the picture distortion.
No. Judgement reference value Input signal
1.
x 1pitch
(=0.3mm)
H character
with frame
(both normal/
reverse)
Left/right
distortion
Top/bottom
distortion
2.
3.
x 0.6mm
* Note
y 1.0mm
Crosshatch
pattern
a. x 1.0mm
b. x 1.5mm
( * )
x
x
y
50mm
x
x
H line
Per 50mm
Scale
Within
n mm
V line
Set scale to V line
Enlarged
Inner distortion
Vertical line X
measurement method
• Distortion x of S-character
distortion, etc.:
Distortion excluding normal pin,
barrel or trapezoid.
Note:There must be no sea-
gull distortion.
• Distortion y:
High frequency distortion
excluding trapezoid.
4-edge distortion
When S-character or seagull type high frequency distortion
is visible, check with the following method.
• Distortion x:
a. Center line
b. Curve of other vertical line
• Distortion x:Curve within
50mm range
• Distortion x:
a. Center line
b. Curve of other vertical
line
• Distortion x:
Distortion in the range of one H
character height.
Judge with the white display G.
(Judge the distortion amount with
a fluorescent material stripe.)
(*) Present No. 1
(31.5kHz, 60Hz) is:
a. x 1.5mm
b. x 2.0mm
x
When Fh < 61kHz,
total area : less than 0.9mm.
When Fh 61kHz,
center : less than 0.6mm,
peripheral : less than 0.9mm.