LG FM300 Service Manual page 37

(2) Insert SIM Card &check (TP1)
LGE Internal Use Only
START
(1) Check voltage(TP1)
TP1= 3.3V
Yes
TP1= high -> low?
Yes
(3) Check voltage(TP2)
TP2= 2.6V(high ->low)
Yes
(4) Check signal(TP3)
TP3= 2.6V pulse
(When insert SIM card)
Yes Yes
(4) Check voltage(TP4)
TP3= 3V
Yes
FINISH
No
Check the R306 Soldering
Check the Soldering
No N
R308&S300
If soldering is fine, replace
S300
Check the Soldering
No
IC303&U103
If soldering is fine, replace
IC303
No
Check the Soldering
R350&CN300&S300
No
Check the Soldering CN300
If soldering is fine, replace LTE
module
- 37 - Copyright © 011 LG Electronics. Inc. All right reserved.
4. TROUBLE SHOOTING
g
Only for training and service purposes