4. TROUBLE SHOOTING
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Only for training and service purposes
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START
(1) Check (TP1)
No
Check the Soldering Q300 &
R321
START
Connect to PC with USB cable
Yes
TP1 goes from high to low?
(2) Check (TP2)
TP2 goes from high to low?
Yes
If soldering is fine, replace
Q300
No
Check the Soldering R384 &
R309 & R383
(3) Check the signal
TP3
Yes
No
Check the Soldering FL302 &
CN301
If soldering is fine, replace
FL302
Yes
(4) Check the signal TP4
Check the Soldering U300 &
CN300
If soldering is fine, replace LTE
module
No
FINISH
Yes