LG KE820 Service Manual page 106

5.12.10 Checking TX I/Q Signals
R426
R427
0
R428
0
C432
NA
R429
0
R430
0
C434
NA
R431
0
Figure 19. TX I/Q
Checking Points
Q
I
Figure 20. TX I/Q
RF_CLK
0
RF_DA
QX
C433
NA
Q
IX
C435
NA
I
U40
Checking Flow
Check TX I/Q Signals
Signals are
Normal ?
Yes
TX Part is OK.
Check Base Band Circuit
or
Re Download S/W and Cal
I
TX
Q
Q
I
I
Q
Figure 21. TX I/Q Waveform
- 107 -
5. Trouble shooting
Replace
No
Transceiver
PMB6272(U402)