LG LG-V909DW - Page 77

4. TROUBLE SHOOTING
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206LF
12 02 91
12
81
01
16
13
8 9 7 6
11
5
414
315
2
117
UMTS1
UMTS3
GSM1800/1900RX1
ANT GSM1800/1900RX2
GND1 GND2
GSM850RX1
3CV 2XR058MSG 1XT0091/0081MSG 1CV
XT009/058MSG
VDD
GND3
2CV
4DNG
VC4
2STMU
5DNG
DNGP
p081
812C
SW200
4 2 1 3
1G
A C
2G
100n
L202
4.7K
R129
TRX_W2100
TRX_W900
TRX_AWS
TP1

ͽ͸Ͷ ͺΟΥΖΣΟΒΝ ΆΤΖ ΀ΟΝΪ

4.5 GSM Receiver Block
GSM Receiver stage is configuring of both FEM stage and MDM RF Receiver.
So, we need to just consider FEM operating and matching components.
Set the Phone Rx to be on
Check TP2, TP3
Signal exist?
Check FEM Block
yes
no
Change the board
Check TP1
Signal exist?
Check RF Switch (M/S)
no
yes
Set the Phone Rx to be on
Check TP2, TP3
Signal exist?
Check FEM Block
yes
no
Change the board
Check TP1
Signal exist?
Check RF Switch (M/S)
no
yes
Chart 4 GSM Receiver Block sequence
FIG 23 GSM Rx Block
{wGY{wGZ
{wGX

ͽ͸Ͷ ͺΟΥΖΣΟΒΝ ΆΤΖ ΀ΟΝΪ

4.5 GSM Receiver Block
GSM Receiver stage is configuring of both FEM stage and MDM RF Receiver.
So, we need to just consider FEM operating and matching components.
Set the Phone Rx to be on
Check TP2, TP3
Signal exist?
Check FEM Block
yes
no
Change the board
Check TP1
Signal exist?
Check RF Switch (M/S)
no
yes
Set the Phone Rx to be on
Check TP2, TP3
Signal exist?
Check FEM Block
yes
no
Change the board
Check TP1
Signal exist?
Check RF Switch (M/S)
no
yes
Chart 4 GSM Receiver Block sequence
FIG 23 GSM Rx Block
{wGY{wGZ
{wGX

ͽ͸Ͷ ͺΟΥΖΣΟΒΝ ΆΤΖ ΀ΟΝΪ

FIG 24 Schematic of the FEM
FIG 25 Schematic of the GSM Rx Path
TP3
TP2
nztG_\WG
k
jzVwjzG
TP1