Atsc/Qam Front_End Troubleshooting - LG HCS6000A Service Manual

2. ATSC/QAM FRONT_END TROUBLESHOOTING

Start
Power is supplied normally(TU300)?
RF signal is detected?
(using Spectrum Analyzer)
Check error signal(TU300(22)). (using
Oscilloscope) High:normal, Low:Error
Check NIM Tuner(TU300)'s output
signals of DATA(Fig.01)
(pin 28,29,30,31,32,33,34,35),
packet clock(Fig.02)(pin 27) and
Byte clock(pin 36)(Fig.03).
END
YES
YES
YES
YES
YES
Check the power lines(A9V, D5V_2,
NO
D3.3V_2, P_30V_TU) referring the circuit
diagram.
NO
Check the Voltage between L303 and
NO
Ground.
5V : normal, 0~4V : change Q300.
NO
Check the status of connection on PCB.
Change TU300.
3-10
Check antenna connection.