LG KG920 - Page 77

(1) Checking Regulator Circuit
4. TROUBLE SHOOTING
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U504
U504. 5 (OUT)
U504. 3(EN)
Regulator Circuit is OK
See next Page to check
VCTCXO
Voltage at
Pin5 of U502
Is 2.85V?
Level at
Pin3 of U502
Is high?
YES
NO
Replace U502
YES
NO
Change main board
C543
4.7u
C544
27p
U504
BYP
43
EN
2
GND
IN
1
OUT
5
MIC5255-2.85BM5
C545
27p
2V85_RF
1uF
VBAT
C546
0.01u
C547
CLKON
TEST POINT
CIRCUIT
CHECKING FLOW
Figure 4-3.
Figure 4-4.
Figure 4-5.