Ntsc/Front_End Troubleshooting - LG HCS6000A Service Manual

3. NTSC/FRONT_END TROUBLESHOOTING

Start
Power is supplied normally?
RF signal is detected?
(using Spectrum Analyzer)
What Voltage is between L303 and ground ?
5V : NO 1V( below) : YES
Check NIM Tuner(TU300)'s output signal
of VIDEO_OUT(pin 16, Fig.04).
END
FIG.04
TU300(16) NTSC VIDEO OUT
YES
YES
YES
YES
YES
Check the power lines(A9V, D5V_2,
NO
D3.3V_2, P_30V_TU)
referring the circuit diagram
NO
NO
NO
3-12
Check antenna connection.
Change Q300.
Change TU300.