LG KU730 Service Manual page 86

4.6.4 Checking PAM Block
PAM Control Signal
TP1. GSM_PA_RAMP : Power Amp Gain Control. typically, 0.5V < Vapc < 2.6V,
TP2. GSM_PA_EN : Power Amp Enable
(Power ON : higher than 2.5V , Power OFF : lower than 0.7V)
TP3. GSM_PA_BAND : Power Amp Band Selection Control
(GSM Mode : lower than 0.7V , DCS/PCS Mode : higher than 2.5V)
TP4. +VPWR : PAM Supply Voltage Vcc higher than 3.28V
TP4
VREG_RFRX_0_2.85V
C110
47p
TP1
TP3.
Test Point (RF Tx Level)
L111 7.5nH
C111
0.1u
L117 NA
L119 NA
C121
68p
C125
C126
33p
22p
L123 NA
L125 NA
16
DCS_PCS_OUT
U101
10
GSM_OUT AND0041
Schematic of PAM block
4. TROUBLE SHOOTING
SIM
Connector
TP2
GSM_PA_RAMP
R106
2.2K
TP4
C127 22n
C137
0.01u
C140
51p
1
DCS_PCS_IN
7
GSM_IN
3
TX_EN GSM_PA_EN
2
BS GSM_PA_BAND
- 87 -
MSM6275.
(U200)
TP1
TP2
+VPWR
C129
100u
R115
30
R116
15
R124
51
TP3