Iiyama A902MT, Service Manual

Page: 16 / 78

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L M R
Fig.1
T Thin
M Thick
B Thin
Fig.2
Thin Thick
Fig.3
Thick
L M R
1-24. FOCUS [PWB-MAIN]
1)
2)
3)
4)
5)
6)
7)
8)
9)
10)
Receive a green cross-hatch signal of MODE 5.
Adjust FOCUS-A VR of T501 (FBT) to make the vertical lines sharpest at
points L, M and R as shown in Fig 1.
Adjust FOCUS-B VR of the T501 to make the horizontal center line
sharpest at points L, M and R as shown in Fig. 1.
If the focus at points T and M is as shown in Fig. 2, adjust V-DBF in the
menu with the front buttons to make the horizontal lines have the same
thickness at points T, M and B. And adjust the FOCUS-B VR again to
make the horizontal lines sharpest at points T, M and B. (V-DBF should
not be adjusted when focus at points T and M is optimum.)
If the focus at points L and M is as shown in Fig. 3 or vice versa, adjust
DBF Para and DBF Phase in the menu with the front buttons to make the
horizontal center line have the same thickness at points L, M and R. And
adjust the FOCUS-B VR again to make the horizontal center line sharpest
at points L, M and R. (DBF Para and DBF Phase should not be adjusted
when focus at points L and M is optimum.)
Repeat 2) to 5) until the focus is optimum.
Confirm no focus variation on the entire screen.
Check the focus with red and blue respectively.
Receive a H-character signal and repeat 7).
Repeat the FOCUS adjustments until the focus with red, green and blue
is optimum.
1-23. RASTER REGULATION (DYNAMIC) confirmation
1)
2)
3)
4)
5)
Receive an entire white signal of MODE 5.
Set the input signal by the signal generator as follows:
V-DISP-TIME: 150 V-POSI-TIME: 450
Maximize the brightness or set the signal level to 0.9Vp-p by the signal
generator.
Confirm that <W of the right hand side figure is 1.0mm or less when
turning the luminance volume on the signal generator to the maximum
and “1” respectively.
Return the brightness to center indication.
n
n
FOCUS-A
FOCUS-B
SCREEN
T501(FBT)
Back-raster
Picture
W
1-22. V-CONVERGENCE confirmation
1)
2)
3)
Receive a cross-hatch inverted signal of MODE 5.
Select V-convergence or DA TEST 2, and press the MENU Button so that
the automatic confirmation program starts.
Confirm that the vertical line is diverged.
n