LG GT350 - Page 95

- 96 -
LGE Internal Use Only Copyright © 2010 LG Electronics. Inc. All right reserved.
Only for training and service purposes
4. TROUBLE SHOOTING
LG Electronics 92/115 LGE Property
4.13.1 Checking VCTCXO Circuit
See RX Part “1. Checking DCXO Circuit”
4.13.2 Checking PLL Control Signal
See RX Part “2. Checking PLL Control Signal”
4.13.3 Checking TX I/Q Signals
Check TX I/Q Signals(TP1~TP4)
Signals are
Normal ?
Replace
Transceiver
PMB6272
(
U601
)
Yes
No
T
X Part is OK.
Check Base Band Circuit
or
Re-Download S/W and Cal
TP4(QX
TP3(Q)TP2(IX)
Checking Flow
TP1(I)G
Figure 17. TX I/Q Circuit
LG Electronics 92/115 LGE Property
4.13.1 Checking VCTCXO Circuit
See RX Part “1. Checking DCXO Circuit”
4.13.2 Checking PLL Control Signal
See RX Part “2. Checking PLL Control Signal”
4.13.3 Checking TX I/Q Signals
Check TX I/Q Signals(TP1~TP4)
Signals are
Normal ?
Replace
Transceiver
PMB6272
(
U601
)
Yes
No
T
X Part is OK.
Check Base Band Circuit
or
Re-Download S/W and Cal
TP4(QX
TP3(Q)TP2(IX)
Checking Flow
TP1(I)G
Figure 17. TX I/Q Circuit
X601
26MHZ
TSX-3225
21
3
4
GND2 HOT2
HOT1 GND1
U601
PMB6272
20
19
18
17
16
15
14
13
12
2
1
22
11
32
01
42
9
528 6
2
7
726
8
2
5
924 033
13
2
23
1
33
34
35
36
37
38
39
40
41
GND4
GND3
VDDMIX2V8
VDDTX2V8
TX2
TX1
VDDTX1V5
VBIAS
FE2
A 1EF
XA 8V2SAIBDDV
B X1X
R
XB
1XR
8V2
G
IDD
DV X
2X
R
A
D
2XR
K
L
C 2
DN
G
5V
1GI
D
D
DV
X3
X
R
3SYS
F 3XR
2SYSF X4X
R
OX 4X
R
X
OX 5V
1AN
L
D
DV
GND1
FSYS1
VDDXO2V8
EN
VDDVCO2V8
VCO_RC
VDDRX1V5
VDDRX2V8
0.001uFC616
0.047uF
C617
R612
820
RF_EN
RF_DA
RF_CLK
26MHZ_MCLK
QX
Q
IX
I
26MHZ_BT
TP1(I)
TP2(IX)
TP3(Q)
TP4(QX)