Audio Troubleshooting - Sony KDL-32BX320 Service Training Manual

TCON: Since the TCON allocates the RGB video information based
on specific timing information, the distortions tend to be fixed and
usually appears as symmetrical patterns that occupy most (or a
significant portion) of the display. The TCON circuits in this chassis
are integrated within the LCD panel which requires replacement of
the entire panel to remedy a TCON failure. Some examples of TCON
errors:
• No video
• Thin vertical lines spanning most or all of the display
• More that one column of wide vertical columns which may
appear black or any color, or may contain distorted video.
• Multi-colored vertical line patterns with a repetitive pattern
Service Tip: Whenever vertical lines of distortion appear, select an
inactive input or disconnect the antenna in the tuner mode. The idea
is to not have a high-definition signal as the source. This allows the
picture zoom functions to operate.
Change the zoom mode from the remote commander. If the lines
follow the normal and zoom modes the problem resides on the main
board. If the lines remain fixed throughout the various zoom modes
the TCON is at fault.
LCD Panel: Distortions originating from the LCD panel tend to be
localized with the exception of horizontal line issues. A failure of a
gate driver can cause a horizontal distortion with all video content
below that point appearing distorted. Depending on which gate driver
has failed, the distortion may only cover a small area of the bottom of
the screen if the driver failed near the bottom of the panel, or a large
area of the screen if the driver failed near the top of the panel. With
the exception of visible physical damage, the following are some
examples of LCD panel related distortions:
KDL-32BX320/32BX321/32BX420/32BX421/40BX420/40BX421/46BX420/46BX421
SECTION 4 - TROUBLESHOOTING
• Any single, thin vertical line (regardless of color)
• Any thin vertical lines isolated to a specific area of the screen
• A singe vertical column of lines of any color or containing
distorted video
• Any fixed horizontal lines
• Blotches of black or improperly colored areas
• Ghosting of images in which the entire image is repeated one
or more times
A thorough understanding of how the video is processed throughout
the chain of circuits all the way to the panel is important. A past
article written for the Sony Newsletter described, in detail, how this
process works.
Figure 5-2. Video Distortion Flowchart on page 32
which component is causing the distortion.

AUDIO TROUBLESHOOTING

Since all audio signals are input, processed and amplified by the
main board, any issue involving the loss of audio or audio distortions
which are present at all inputs would dictate that the issue can be
resolved by replacing the main board. It is possible that a software
update might also resolve the issue, but it is very unusual for a
software update to affect all sources. Once again, always check
the Sony Authorized Servicer Portal at
known and/or listed issues that are software related.
Audio problems that are input specific (especially the HDMI and
digital sources such as the USB input and tuner) are more likely to
point to the need for a software update and this is especially true if
the problem is intermittent.
will assist in isolating
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