Unique Main Video Board (Bm5-Board) Or Lvds Cable Effects; Unique Lcd Panel Assembly Effects (& Tcon Board); Common Main Video Board (Bm5-Board) And Lcd Panel; Assb. Effects - Sony KDL-40SL140 Training Manual

the distortion.

Unique Main Video Board (BM5-Board) or LVDS Cable Effects

A video distortion that has soft edges and/or is moving through the video
is most likely caused by a defect in the video processing circuitry. All video
processing circuitry is located on the BM5-Board. Therefore, replace the
BM5-Board if the video distortion has soft edges and/or is moving through
the video on the screen. Macro-Blocking is a good example of this type
of distortion. Be careful though, macro-blocking can also be caused by a
weak RF signal when the TV is in the tuner mode.
• Poor Picture Detail - Loss of overall picture detail. A loss of
information on the LVDS lines from the Xilleon IC will cause poor
overall picture detail.
• Abnormal Picture Size or Geometry- The video signal scaler
circuit is located on the main video board BM5-Board. Therefore,
if either the picture size or geometry is abnormal the BM5-board is
defective. Only the BM5-Board can cause such a distortion.
Color Distortion - A color distortion can be cause by a defective
•
Xilleon or LVDS cable. The individual color signals are spread out
over the LVDS twist pair wires. For example, the Red signal may
be broken up into three components and sent over three different
LVDS twisted pairs. Therefore, this distortion will display as a poor
reproduction of a particular color not a overall lost of one color.
Use a Red, Green, and Blue raster generator to confi rm a poor
reproduction of a single color.
• Loss of a Single Color Loss of a Single Color - A loss of a single color can only be Loss of a Single Color - A loss of a single color can only be
caused by a defective Xilleon IC (IC7000). Use a Red, Green, and
Blue raster generator to confi rm a complete loss of a single color.
Unique LCD Panel Assembly Effects (including TCON Board)
• Line(s) of Pixels (Fixed Position) - Poor physical connection (or
bonding) between the LCD Panel and the fl ex cables will cause a
loss of line(s) of pixels. The pixel drive lines can be open (no drive)
or shorted (drive all the time). Depending on the type of failure the
CTV-51
line(s) or pixel(s) will be black, white, or colored (red, green, or
blue). These lines and pixels will also be very sharp in detail.
• Random Line(s) of Pixels (Random Movement) - The TCON
board controls the charging and timing of the pixels. If the TCON is
partially defective random lines and/or pixels will be seen randomly
fl ashing across the screen. These lines and pixels will be very
sharp in detail, like a specifi c line of pixels are randomly turned off
and on.
• Loss of Half Screen Video - Half the screen will have live video
and the other half will be a white raster.
• Half or Full Screen Video Distortion - Reference Figure 4.5 for
half-screen example. In this case, the key distingishing factor is
the presence of undistorted video behind the color distortion. The
distortion is basically an overlay in front of the good video coming
from the BM5-Board.

Common Main Video Board (BM5-Board) and LCD Panel

Assembly Effects
• White Balance (WB) Irregularity - A WB irregularity will show
up as an overall poor reproduction of white. A white raster can be
used to determine if a WB or gamma irregularity has occurred. WB
will cover the complete picture, where as, gamma will be in specifi c
zones or specifi c color areas in the picture. WB adjustment data is
stored in the EEPROM IC7402 on the BM5-Board. The WB data
stored in IC7402 is set to the middle value (e.g 255) of the data
span. The TCON also contains WB data, which is specfi cally set
for the associate LCD Panel. This is why the TCON is not fi eld
replacable.
• Gamma Irregularity - Gamma Correction affects the overall
picture brightness level and individual color (RGB) brightness
levels. Gamma adjustment data is stored in the EEPROM IC7402
on the BM5-Board. The TCON also contains GAMMA data, which is
specfi cally set for the associate LCD Panel. This is why the TCON
is not fi eld replacable.The data may become corrupted causing
irregular gamma adjustment. The gamma adjustment is divided up
Troubleshooting
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