LG KE520 Service Manual page 58

4.2.2.1 Regulator Circuit
Refer to RF Receiving Path Trouble Shooting
4.2.2.2 DCXO Circuit
Refer to RF Receiving Path Trouble Shooting
4.2.2.3 Mobile Switch & PAM & FEM Circuit
1
SW400
C423
FL401
C425
3
4
U401
U400
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Only for training and service purposes
C421
2
L406 L405
U402
C428
C425
C420
X400 U403 U404
C420
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4. TROUBLE SHOOTING
Check SW400
(Mobile switch)
OK
NO
Check R405, R406
(With spectrum analyzer)
OK
Check C421 NO
(With spectrum analyzer)
OK
Check Control Signal
C423,C425,C428,C431
OK
Re-download SW & CAL
NO
Replace
SW401
Check
U402
Check
FL400
NO
Check U401
LGE Internal Use Only