LG KG110 - Page 34

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4. TROUBLE SHOOTING
Check ANT SW
R418
Vtx
R427
Vmod_en
C441
RX4
C444
RX3
C445
RX2
C446
RX1
~ -62dBm?
Check RX level of
R441 (for GSM850)
R444 (for EGSM)
R445 (for DCS)
R446 (for PCS)
NO
Change U401
YES
Check R418,R427
Check whether Ant SW
Set as RX mode
? Refer to Table 4-2
NO
Change the board
Vmod_en = H?
Vtx = L?
See next page to check
SAW filter
YES
Figure 4-6
Figure 4-6
Vbs2
Operating Mode
Vmod_en Vtx Vbs1
Control Voltage
TX GSM 850/900
RX2
RX3
RX4
Sleep Mode
RX1
TX DCS/PCS
HHLH
L
HLH
HHLL
LHLL
LHHH
LHHL
LLLL