Sony KDP-57XBR2 Training Manual page 28

V Model Video Troubleshooting
These models have several additional features not found on the lower-end sets. A 3D comb filter provides higher
quality cross-talk separation along with noise reduction circuitry for the Y component. This is why the S video
inputs are routed through the comb filter. Only the component inputs will bypass this circuit. A decoder circuit
has also been added to the main video path after it exits the comb filter since it is going to be routed to a Picture
and Picture processing IC along with direct input to Y/C Jungle IC206. This will provide twin picture viewing in a
side-by-side fashion rather than a main picture with a small inset box. There is also an additional component
source available at the video 5 input. Figure 6-5 illustrates the basic paths of the main and sub video and
provides the key source for isolating video problems. Figures 6-6 and 6-7 illustrate block diagrams with more
detail to aid in isolating problems.
CV
IC1702
C
INPUTS
SWITCH
Y
COMPONENT
Y
UV4 UV5
IC1704
UV
SWITCH
U BOARD
No Video
As the initial steps mentioned in the previous section dealing with the T and S models, loss of high voltage and
AKB errors must be ruled out. If either one of these has failed, refer to Chapter 5 for high voltage and Chapter
27 for AKB troubleshooting
Checking for OSD should still be your first check. If it is present, you can tell if the RGB output path from IC206
all the way to the CRT is OK and if IC206 is probably working correctly. If no OSD is present, you will need to
work from IC206 forward (assuming the OSD circuit has not failed, but it is highly unlikely that both OSD and
video processing has failed simultaneously).
Using the twin picture feature will be of great help at this point. This is where the video processing differs from
the T and S models. Although the YC from the 3D comb filter and the component video path are routed directly
into IC206, the P&P processor, IC1405, handles the mixing and insertion of the main and sub video paths for twin
Y/
IC204
CV
COMB
A/V
C
FILTER
SY
IC1403
SC
SUB
DECODER
YUV
SY
SUV
IC1405
Y SW
FIGURE 6-5 - V MODELS VIDEO BLOCK
6. RA-3/3A Video Process Troubleshooting: T & S Models
MY
MY
3D
IC1410
Y SW
MAIN C
UV
Y
SUB YUV
YUV
Y
UV
25
IC1402
MAIN
DECODER
Y
MAIN
YUV
YUV
IC1404
YUV
YUV
SW
C
IC1405
Y
P & P
IC1407
YUV
CONTROLLER
COMPONENT YUV OR PIP YUV
FROM B BOARD
PJED
IC1601
VCHIP
IC002
SYSCON
OSD
RGB
R
TO
G
TUBES
IC1206
B
YCJ
6.5TVP14 6/26/02