Ntsc Front- End Circuit - LG LSS-3200A Service Manual

10. NTSC Front- End CIRCUIT

START
YES
Power is supplied normally?
YES
RF signal is detected?
(using Spectrum Analyzer)
YES
What Voltage is between L303 and
ground ? 5V : NO 1V(below) : YES
YES
Check NIM Tuner(TU300) 's output sig-
nal of VIDEO_ OUT(pin 16, Fig. 04 ).
YES
END
FIG. 04
TU300(16) NTSC VIDEO OUT
NO
Check the power lines(A9V, D5V_ 2, D3.3V_
2, P_ 30V_ TU) referring the circuit diagram
NO
Check antenna connection.
NO
NO
3-43
Change Q300.
Change TU300.