LG GD510 Service Manual page 85

5. Trouble shooting
GD510 Operational Description
GD510 Operational Description
5.13.3. Checking TX I/Q Signals 5.13.3. Checking TX I/Q Signals
FE2
33
VBIAS
34
VDDTX1V5 VDDRX2V8
35 20
TX1 VDDRX1V5
U602
36 19
TX2 VCO_RC
PMB6272
37 18
VDDTX2V8 VDDVCO2V8
38 17
VDDMIX2V8 EN
39 16
GND3 VDDXO2V8
40 15
FSYS1
14
GND4 GND1
41 13
X601
4
GND2
1
HOT1
TP1(I) TP4(QX)
TP1(I)
TP1(I) TP3(Q)
TP2(IX) TP3(Q)
TP2(IX) TP3(Q)
TP2(IX)
Figure 17. TX I/Q
Figure 17. TX I/Q
Figure 17. Tx I/Q
;
;
Checking Points
Checking Points
U401
Figure 18. TX I/Q
Figure 18. TX I/Q
LG Electronics
LG Electronics
LGE Internal Use Only
C650 C649 C623
100n 100n 100n
C627 47n
R603 820
RF_EN
C619 1n
26MHZ_MCLK
TSX-3225
3
HOT2
2
GND1
26MHz
TP4(QX)
TP4(QX)
BT_CLK
RF_CLK
RF_DA
QX
Q
IX
I
TP1(I)
TP4(QX)
TP3(Q)
TP2(IX)
TP1(I)
TP3(Q)
TP2(IX)
U401
91/113
Checking Flow
Checking Flow
Check TX I/Q Signals(TP1~TP4)
Check TX I/Q Signals(TP1~TP4)
Signals are
Signals are
Normal ?
Normal ?
Yes
TX Part is OK.
TX Part is OK.
Check Base Band Circuit
Check Base Band Circuit
or
Re-Download S/W and Cal
Re-Download S/W and Cal
I
I
Q
Q
TP4(QX)
I
I
Q
Q
Figure 19. TX I/Q Waveform
Figure 19. TX I/Q Waveform
91/113
- 86 - Copyright © 2009 LG Electronics. Inc. All right reserved.
Revision A
Revision A
Replace
No
No
Transceiver
PMB6272(U602)
Yes
or
TX
TX
LGE Property
LGE Property
Only for training and service purposes
Replace
Transceiver
PMB6272(U602)