Atsc/ Qam Front- End Circuit - LG LSS-3200A Service Manual

9. ATSC/ QAM Front- End CIRCUIT

START
YES
Power is supplied normally(TU300,
TU301)?
YES
RF signal is detected?
(using Spectrum Analyzer)
YES
Check Error flag(TU300(22)). (using
Oscilloscope) High: normal, Low: Error
High
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 ).
YES
END
NO
Check the power lines(A9V, D5V_ 2, D3.3V_
2, P_ 30V_ TU) referring the circuit diagram.
NO
Check antenna connection.
Low
Check the Voltage between L303 and
Ground. 5V : normal, 0~ 4V : change Q300.
NO
Check the status of connection on
PCB. Change TU300.
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