Sony KDS-R50XBR1 Training Manual page 91

Can
Yes
any OSD be
Displayed?
No
On-Screen Displays (OSD)
Reference Figure 5-5
• User Menu
• QM Service Mode
TV Service Mode
•
• WE Service Mode
• Panel Service Mode (DE Microprocessor)
For a detailed diagram showing the location of each OSD generator
reference Figure 5-5. The various OSD's are very usefully in
troubleshooting a video problem. As shown in the diagram the video
system can be divided into four areas or boards (ASU-Board, DSU-
Board, Q-Box, and C-Board), by verifying that the particular OSD can be
displayed. For example, if the ATI Service Mode OSD were the only OSD
missing (all other OSD's are OK) then this would point to a defective Q-
Box module.
Another important OSD test is to attempt to display the ROOK test
patterns. Note that the ROOK is located on the C-board, and therefore,
is at the end of the video path just before the Optical Block (the C-board
is part of the Optical Block). Consequently, if the ROOK test patterns can
be displayed then this effectively indicates that the Optical Block is OK
and the defective exists in the circuits before the Optical Block (e.g. the
ASU/DSU Assembly).
If no OSD's are displayed then you should go to the Optical Block
Troubleshooting Flowchart F next will be discussed in an upcoming
flowchart description section.
TVP-21
Can
Yes
User Menu or
QM OSD be
Displayed?
No
If some OSD's can be displayed then depending on what OSD's are
displayed will determine the defective area. As previously mention check
the User Menu, which is developed in the Q-Box module, to determine if
the defect is in the Q-Box module or in the ASU/DSU Assembly.
5. Video Processing System
88