LG S5000 Service Manual page 56

(1) Checking Regulator Circuit
Test Points
CIRCUIT
Checking Flow
Regulator Circuit is OK
See next Page to check
U503. 5
(OUT)
Figure 4-8
RF LDO
R517
CLKON
0
R518
100K
Voltage at NO
Pin5 of U503
Is 2.85V?
YES
VCTCXO
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4. TROUBLE SHOOTING
U503
U503. 3
(EN)
VBAT
RF2V85
U503 MIC5255-2.85BM5
1 5
IN OUT
2
GND
3 4
EN BYP
C544 C545
1u 0.01u
Level at NO
Pin3 of U503
Is high?
YES
Replace U503
C546
4.7u
Change main board