LG KE820 Service Manual page 103

5. Trouble shooting
5.12.6 Checking RX I/Q Signals
R426
0
R427
0
R428
0
C432 C433
NA NA
R429
0
R430
0
C434 C435
NA NA
R431
0
Figure 14. RX I/Q Circuit
Checking Points
Q
I
Figure 15. RX I/Q
RF_CLK
RF_DA
QX
Q
IX
I
U40
- 104 -
Checking Flow
Check RX I/Q Signals
Signals are
Normal ?
Yes
RX Part is OK.
Check Base Band Circuit
or
Re Download S/W and Cal
I
RX
Q
Q
I
I
Q
Figure 16. RX I/Q Waveform
Replace
No
Transceiver
PMB6272(U402)