LG EC970W - Tunner;IF Circuit; No picture on the TV screen

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5. Tuner/IF circuit
(1) No picture on the TV screen
No picture on the
TV screen
Does the Video signal at
the TU701 Pin24?
Check 34V line.
Check 5.2V line.
Check the liC Clock
signal of µ-com Pin 71.
Is +30V applied to
TU701 Pin 16?
Is +5.2V applied to
TU701 Pin 13?
Does the Clock signal
appear at TU701 Pin 11?
Does the data signal
appear at TU701 Pin 12?
Replace Tuner
Check the signal flow
from TU701 Pin 24 to
IC301 Pin 48.
Does the Video signal at
the IC501 Pin50?
Check the signal flow from
IC501 Pin52 to JK301.
YES
YES
YES
YES
YES
YES
YES
NO
NO
NO
NO
NO
Check the liC Data signal
of µ-com Pin 72.
NO