LG LM-X120HM Service Manual page 29

3. TROUBLE SHOOTING
3.5 GSM, WCDMA, LTE PART
3.5.1 GSM RF PART
Checking GSM PAM DC Power Circuit
Image
Checking Flow
Main
TP3( 1.8V)
Bot
START TP2(Vbat)
TP1(3.4V -4.3V)
Check TP1 is it 3.4v-4.3v
Check TP2 is it Vbat?
NO
NO
YES
Circuit Diagram
TP1
Rework R1543,
Check TP3 is it 1.8V
TP1/2power=Vbat:
TP2
YES
3.4V-4.3V
YES
Check other related RF path
TP3
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