NEC Multisync Plus JC-1501VMA Service Manual page 26

d) Sequentially cancel the short-circuit created between TP401 and TP402 and between
TP901 and TP902.
NOTE: The darker the environment where cutoff adjustment is performed, the better
white tracking can be achieved later. Be. sure to perform cutoff adjustment in as
dark a place as possible.
(4) Adjustment of SUB. BR IGHT VR
a) Receive Signal 1 (44.8.kHz) H gray scale (16 gradations).
b) Rotate the Contrast V R fully to the right.
Rotate the Brightness VR fully to the left.
c) Use the SUB. BRIGHT VR (VR905) to adjust the 5/16th grade so that it is faintly
illuminated.
After this step, do not change the setting of VR905.
d) Rotate the Contrast VR fully to the left.
Rotate the Brightness VR fully to the right.
e) Receive all-black signals.
f) Rotate VR904 and VR906 to adjust the back rasters until they are all white.
(5) Fine Adjustment of White Balance
Color temperature: Center
X
= 0.310
y= 0.325
Hue: A slightly bluish white.
a) Receive Signal 1 (44.8 kHz)
H
gray scale (16 gradations). (the window pattern should
be in the range where the ABL circuit is not applied.)
b) Rotate the Contrast V R fully to the left.
Rotate the Brightness V R fully tothe right.
Check that the white balance is satisfactory at each gradation. If the white balance is
not satisfactory, perform fine adjustment of the SUB. BRIGHT VRs (VR904 and
VR906).
NOTE: Do not change the setting of VR905 (GSUB. BRIGHT).
c) Rotate the Contrast VR fully to the right.
Rotate the Brightness VR to the position where no back rasters appear.
Check that the white balance is satisfactory at each gradation. If the white balance is
not satisfactory, perform fine adjustment of the GAIN VRs (VR701 and VR703).
NOTE: Do not change the setting of VR702 (G GAIN).
If the back rasters and the white balance at each gradation are not satisfactory, per-
form fine adjustment ofthe SUB. BRIGHT VRs (VR904 and VR906).
NOTE: Do not change the setting of VR905 (G SUB. BRIGHT).
(6) Focus Adjustment: Use Signal 1
[All-white signals or those with four dots missing]
a) Rotate the Contrast V R fu lIy to the right.
Rotate the Brightness VR to an appropriate position ..
b) If the focus is markedly weak and if the moire effect appears, rotate the SUB BIAS VR
(VR907) fully to the left and perform readjustment of (31. (4), and (5).
N.OTE: After turning VR907 fully to the left and performing readjustment, confirm
the following:
All-white signals of Signal 1 (44.8 kHz) are being received.
Brightness VR: Rotated fully to the left (MIN)
Contrast VR: Rotated fully to the right (MAX)
Confirm that the entire screen is free from any distortion.
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