LG KU730 Service Manual page 75

4. TROUBLE SHOOTING
Logic Table of the Antenna Switch
GSM900 TX
GSM900 RX/WCDMA
DCS1800/PCS1900 TX
DCS 1800RX
PCS 1900RX
Checking Switch Block power source
Check Soldering of
ANT_SEL0, 1, 2 High Level
2.5V < Voltgae < 3.0V
Check the Logic
ANT_SEL2
LOW
LOW
HIGH
HIGH
LOW
YES
in each mode
ANT_SEL1
LOW
LOW
HIGH
LOW
HIGH
Check VCC
NO
TP1 VREG_RFRX_0_2.85V
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ANT_SEL0
HIGH
LOW
LOW
LOW
LOW