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Video Signal Flow
Refer to figure 40. Most of the video processing is performed on the H and DG (digital)
boards. In the analog (H, G, and TU) boards, the video signal is approximately 1Vp-p
throughout. The analog video signal can be traced using the service manual block
diagram. Thus, the details are not shown here.
W
ithin the digital board, the main video signal path takes one of the three routes below:
1. If the input is composite video
, the main signal takes the path from IC4609, IC4611-3,
and IC4401 to the LVDS transmitter. The sub picture takes the lower signal route via
IC4201, to IC4401 to be joined with the main picture.
2. If the input signal is component video, the main signal is diverted to IC4201 that
contains a higher resolution 10-bit A/D converter before entering IC4401.
3. If the input is component video and the split (PwP) picture feature is selected, the
signal path is the same as the composite video path (via IC4609).
Troubleshooting tips - Use the PwP feature to identify a problem in the DG board. If the
left main picture is defective, the IC4609 - IC4611-3 composite video signal path is
defective. If the right sub picture is defective, the IC4201 GC3FS path is defective. If
both component and composite video pictures are defective, the problem is in the H
board. All the analog video passes through connector H5. If these contacts are
intermittent, loss of analog video may be difficult to identify.
Figure 40 - Video Signal Flow Block
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