Optical Block - Sony KDS-50A2000 Training Manual

Optical Block

Troubleshooting
The primary objective of this troubleshooting flowchart is to determine if
the Optical Block, Video Circuits, or the Power Supply System is causing
the abnormal TV operation. The very first step is to eliminate or confirm
the Optical Block as the defect component. The quickest and surest way
to confirm proper Optical Block operation is to access and display the
Panel Service Mode (ROOK IC) test patterns.
PANEL SERVICE MODE
Internal Signal Generator
Because the ROOK (located on the C-Board) generates the test patterns,
the patterns are applied directly to the SXRD panel drive IC's and SXRD
panels bypassing all other video processing circuits.
Optical Block is isolated for troubleshooting purposes. If the patterns are
displayed then the Optical Block is OK and the video processing circuits
need to be examined.
Yes
OSD or Patterns
Dark Raster is
Optical Block
A-1203-196-A (50")
A-1203-195-A (55")
A-1203-194-A (60")
The next step is to check the raster intensity (or Overall SXRD Panel
Lighting) when the ROOK test patterns are turned off and the TV is in
TVP-23
Optical Block
Turn ON
Does
Display?
No
In this case there is no
Displayed & LCD drive to the panels.
Audio OK
Replace
normal display mode. If the raster is dark, then this indicates no drive to
the SXRD panels and indicates a defective Optical Block assembly.
Therefore, the
On the other hand, if the test patterns do not display and the raster is bright,
then the SXRD panels are receiving drive signals from the SXRD driver
circuits. However, no video is reaching the SXRD panels. Therefore, the
next step is to check the power supply to the C-Board video circuits.
The voltage at CN6901/pin 1 on the G-Board should be 16.5V. If the
voltage is missing then you need to troubleshoot the power supply system,
go to Power On Troubleshooting Flowchart B. The Main Power Supply
develops the 16.5V.
If the 16.5V is present and a bright raster is displayed then the defect
exists on the B1-Board (video processing circuits). In this case, replace
the B1-Board.
6. Video Processing System
In this case there is LCD
Bright Raster is
Yes
drive, however, no video.
Displayed &
Audio OK
Check Voltage at
CN6901/pin 1
G-Board
"Before Shutdown"
Replace Is voltage
Yes
B1-Board 16.5V
A-1205-147-A Present?
No
Replace
G-Board
A-1186-654-A
Does
OSD or Patterns
Display?
No
73