Hitachi DV-PF73U Service Manual page 30

FLOW CHART NO.10
Video E-E does not appear.
Is the Video signal inputted to Pins(38,40,42) of
IC301?
Is the C-SYNC signal outputted to Pin(34) of IC301?
Is the C-SYNC signal inputted to Pin(41) of IC501?
Check the line between Pin(34)
of IC301 and Pin(41) of IC501,
and service it if detective.
Yes
Is the video signal inputted into Pin(1) of IC751?
Is the video signal outputted to Pin(15) of IC751?
Is approximately 6.8V voltage supplied to Pin(16)
of IC751, or approximately -8V voltage supplied to
Pin(7) of IC751?
Is the "H" pulse inputted into Pin(9) of IC751?
Replace IC751.
Yes
Yes
No
Replace IC301.
Yes
No
Yes
Yes
No
1) In the external input mode
Check the line between the video input
terminal (rear) and Pin(38) of IC301, and
service it if detective.
Check the line between the video input
terminal (front) and Pin(40) of IC301, and
service it if detective.
2) In the U/V tuner mode
Check the line between Pin(18) of the U/V tuner
and Pin(42) of IC301, and service it if detective.
Is 5V voltage supplied to Pin(21) of IC301?
Check the P-ON+5V line and service it
if detective.
Yes
Is voltage with each inputted signal supplied to
Pin(71) of IC301?
Yes
Check the line between Pin(71) of IC301 and
Pin(16) of IC501, and service it if detective.
No
Check the line between Pin(35) of IC301 and
Pin(1) of IC751, and service it if detective.
Yes
Is the video signal outputted to the emitter of Q391?
Check the line between Pin(15) of IC751
and Q391, and service it if detective.
Yes
When only Line signal is not outputted...
check the line between the emitter of Q391 and the
video output terminal (JK751), and service it if
detective.
When only RF signal is not outputted...
check the tuner (TU701), and the line between the
emitter of Q391 and Pin(6) of the tuner, and
service it if detective.
No
Check the AL+12V line (R779, D702) and the
AL-30V line (R777,R778), and service it if detective.
No
Check Q760 and the OUTPUT-SELECT line,
and service it if detective.
No
No
No
No
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