Sony KD-34XBR2 Training Manual page 49

Flow Charts for locating a defective board
In the Twin Picture Mode the main picture video signal path is always used to display the largest picture. To do
this the MID circuit in the Q box and switching ICs on the B board may interchange paths depending upon which
picture is the largest. Use the flow charts to change the size of the pictures in Twin Mode and isolate the problem
to a board.
Main
pix
IC205
NTSC/480i
SINGLE PIX
HAS A DEFECT?
IS THE DEFECT IN
ALL MODES?
VIDEO, TV?
NO
PROBLEM EXTERNAL,
OR ON B OR U INPUT BDs
FIGURE 11-8 - FLOW CHART 2 - VIDEO TROUBLESHOOTING - NTSC PIX DEFECT
Signal Tracing to prove the problem is on the board
Refer to the following to support the traditional video signal tracing in the HA-3 and RA-5A TV chassis:
•
Figure 11-1 for the signal flow
•
Figure 11-10 for the location of HA-3 chassis connectors.
•
Chart 11-4 shows the Video Signal Levels along the way
•
Waveforms 11-1 – 11-3 that show the signal shapes with an NTSC color bar input to the TV.
Conditions of measurement - Color bars are input to the main (VHF/UHF) and sub (Cable) tuners from two
separate NTSC generators for ease of signal tracing. The color bar signal is followed as it enters and leaves a
board. The Sub signal is always present at the connector even though it is not being used. The TV is tuned to
Channel 3 and Channel C3.
Figure 11-2 - Twin Picture Mode, Analog Inputs
Sub
pix
IC200
a
PRESS "TWIN MODE".
MAKE LEFT PIX
LARGER. DO BOTH
YES
PIX HAVE THE
PROBLEM?
NO
MAKE THE RIGHT
PIX LARGER.
WHERE IS THE
DEFECT?
CHANGED
PIX
WHICH PIX?
RIGHT
MAIN AREA
B BD. IC207,
IC205, QM BD.
IC7807
11. Video Process - HA-3 and RA-5A Chassis
Main pix
S
from IC205
b
RETURN TO 1 PIX.
TURN ON THE INTERNAL
YES
VIDEO GEN. (SERVICE
MODE)
SAME
QM BD.
PIX
PROBLEM
WHICH PIX?
PROBLEM IS IN
LEFT
A/D IC8601
MID IC8703
SUB AREA
B BD. IC200/
IC202
46
Main pix
S
from IC205
c
ANALOG PROBLEM
IN A, B, OR C BD.
YES
DEFECT IN THE
GENERATOR
PATTERN?
*
NO
LARGER
PROBLEM
IN A/D IC7806
DRC IC7804
SMALLER
*
SEE "ADJ. OVERVIEW" SECTION
QM BD.
DEFECT
(MID IC8703)
8/30/01
39TVP12 1355