LG HB620 Service Manual page 122

4.16.3 Checking PAM Block
TP3
R107
GSM_PA_RAMP
2.2K
TP1 TP1
C136
56p
C137 16
DCS_PCS_OUT
NA
9
GSM_OUT
C138
56p
C141
NA
Test Point Net name
TP1 GSM_PA_RAMP
TP2 GSM_PA_EN
TP3 +VPWR
Copyright © 2008 LG Electronics. Inc. All right reserved.
Only for training and service purposes
+VPWR
C126 C127
1u 33u
C132
68p
TP2
2
DCS_PCS_IN
7
U102 GSM_IN
SKY77329
1
TX_EN
3
BS
C139 C140
15p 15p
[Fig. 4.18] Schematic of PAM Block
[Fig. 4.19] Test Point of PAM Block
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4. TROUBLE SHOOTING
R108
DCS_PCS_TX
68
R109 R110
91 91
4 5
GSM_PA_EN
FL102 O1 G3
1
GSM_PA_BAND IN
G2 G1
EFCH897MTDB1
3 2
Description
Power Amp Gain Control. Typically, 0.2 ~1.6V
Power Amp Enable (ON : >2.5V, OFF : <0.7V)
PAM Supply Voltage (Vcc > 3V)
R112
GSM_TX
51
R114 R115
120 120
LGE Internal Use Only