LG U310 Service Manual page 82

+VPWR
L1023
4.7nH
TP3
C1082
33p
TP2
L1028
56nH
FL1003 LP69A
ANT TX
RX
GND1 GND6
GND2 GND5
GND3 GND4
C1062
C1061 1000p C1063
4.7u
1000p
WS2512_TR1G U1002
10 1
VCC2 VCC1
9 2
GND4 RFIN
8 3
RFOUT GND1
7 4
C1070 GND3 VCONT
6
1p
GND2
11 5
BGND VREF
C1074
NA
R1027
PA_ON
10K
U1004 U1003 LMV228TLX-NOPB
0 C1079
1 4 A1
OUT 50OHM RFIN_EN VDD
R1028 100p
B1
GND OUT
2 3
IN COUP
HDET
CP0402A1880EL
L1029
L1030
C1093
100nH
2.7nH
100p
For testing, Max power output is needed.
Set the Phone Tx is ON
and PDM is 450
Check TP1
Over 21dBm ?
NO
Check TP2
Over 19dBm ?
NO
Check TP3
Over 16dBm ?
NO
Check TP4
Over -5dBm ?
NO
Change the board
- 83 -
4. TROUBLE SHOOTING
+VPWR
R1025
6.2K
PA_R0
Q1000
UMC4N
C1071
15p
PA_ON
VREG_RFTX_2.85V
C1077 C1075
4.7u
0.1u
A2
VREG_RFTX_2.85V
B2
HDET1
C1084 C1085
27p 1200p
YES
RF Tx Level is OK
YES
Check FEM
YES
Check Duplexer
Check PAM Block
YES
Refer to 3.5.4
WCDMA
FL10
L1301
SAFEB1
3.3nH
4
C1068
NA
TP4
C1086 C1087
100000pF 10p
C1088
C1091 10p
100000pF
13
PLNA_OUT
14
ILNA_OUT
15
PLNA_BIAS
16
PLNA_IN
17
ILNA_BIAS
18
ILNA_IN
19
R
VDDRF3