Only For Training And Service Purposes - LG KU380 Service Manual

4.7.4 Checking PAM Block
TP1. GSM_PA_RAMP : Power Amp Gain Control. typically, 0.2V < Vramp < 1.6V
TP2. GSM_PA_EN : Power Amp Enable
(Power ON : higher than 1.25V , Power OFF : lower than 0.4V)
TP3. GSM_PA_BAND : Power Amp Band Selection Control
(GSM Mode : -0.2V < VBS < 0.4V , DCS/PCS Mode : 1.25V < VBS < 3.0V)
TP4. +VPWR : PAM Supply Voltage Vcc higher than 3.0V
TP3
TP2
TP1
L116
8.2nH
C134
NA
16
DCS_PCS_OUT
9
GSM_OUT
Copyright © 2007 LG Electronics. Inc. All right reserved.

Only for training and service purposes

2
DCS_PCS_IN
7
U102 GSM_IN
SKY77329
1
TX_EN
3
BS
Schematic of GSM PAM Block
- 89 -
4. TROUBLE SHOOTING
TP4
R110
GSM_PA_RAMP
2.2K
C131
68p
NEAR TO PAM
+VPWR
C136 C132
33u
33p
R118 100ohm
GSM_PA_EN
R119 100ohm
GSM_PA_BAND
C143 C144
15p 15p
GSM_PA_BAND
TP2
TP4
TP1
F
TP3
E
M
LOW G
DC
HIGH
LGE Internal Use Only