25
6. RA-3/3A Video Process Troubleshooting: T & S Models
CV
C
Y
COMPONENT
Y
UV4
UV5
Y/
CV
C
MY
MY
SY
SC
SUV
SY
YUV
YUV
Y
UV
COMPONENT YUV OR PIP YUV
YUV
MAIN
YUV
C
Y
TO
TUBES
R
G
B
OSD
RGB
Y
FIGURE 6-5 - V MODELS VIDEO BLOCK
SUB YUV
U BOARD
IC204
3D
COMB
FILTER
IC1410
Y SW
INPUTS
IC1704
UV
SWITCH
IC1404
YUV
SW
IC1405
P & P
IC1407
YUV
CONTROLLER
IC1702
A/V
SWITCH
IC1403
SUB
DECODER
IC1402
MAIN
DECODER
IC1206
YCJ
PJED
IC1601
VCHIP
IC002
SYSCON
IC1405
Y SW
MAIN C
UV
Y
YUV
6.5TVP14
6/26/02
FROM B BOARD
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.
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