XOCECO PS42K8, Руководство по обслуживанию

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3) VGA No Picture
yes no
normal abnormal yes no
normal abnormal
5
．
Abnormal picture :
Peculiar color, which may be caused by the following phenomena:
A certain differential wire pair of LVDS
（
RX0+/-
，
RX1+/-
，
RX2+/-
，
RX3+/-
）
is abnormal,
which may lead to lack of color ( it’s not a complete loss of color);
Failure with resistor rows R550~R555
，
which may lead to loss of corresponding color from
the gray degree corresponding to the picture of all channels. Through self signal check by
PW181, the failure is still there.
Failure with resistor rows R419, R421, R425, R427, R431, R432
，
which may lead to loss of
corresponding color from the gray degree corresponding to the picture of channels
VGA/YPRPB/DVI.
Failure with resistor rows R415, R418, R422, R424, R429, R430
，
which may lead to loss of
corresponding color from the gray degree corresponding to the picture of channel DVI.
Failure with resistor rows R342, R343, R344, R345
，
which may lead to loss of
corresponding color from the gray degree corresponding to the picture of sub-channels
TV/AV/YCRCB, or lead to abnormal brightness.
Failure with resistor rows R207, R208, R209, R210, R211, R212 or R145, R146, R147,
R148
，
which may lead to loss of corresponding color from the gray degree corresponding
to the picture of main channels TV/AV, or lead to abnormal brightness.
If input YPRPB signal is normal
If the mode of VGA (lower right corner
of screen OSD) identifiable
Measure the input line/field synch.
signal of 81 and 82 of N403
Check N402
and its
peripheral
Check N403 and its
peripheral,especially its
output signals (CLK,
line/field synch. and
enable etc.)
Check N403
and its
peripheral
Input interface circuit has
problem
If the two TV pictures are
normal
Check input
circuit of
GPORT of
N501