LG S5000 Service Manual page 57

4. TROUBLE SHOOTING
(2) Checking VCTCXO Circuit
Test Points
X500.4
(VCC)
X500
Figure 4-7
CIRCUIT
C541
NA
Waveform
Check Pin 3.
Refer to Graph 4 -1(b)
Check Pin 4.
Refer to Graph 4 - 1(a)
X500.3
(OUT)
2V75_VVCXO
R515 100 3
4
C543
2.2u
(1608)
Graph 4-4(a)
Checking Flow
26 MHzO.K?
No
2.75V OK?
No
Check U103, PMIC
X500
R514
1
OUT VCONT
15K
2
VCC GND
C542
26MHz
1000p
TCXO_26MHz
Graph 4-4(b)
- 58 -
VCTCXO Circuit is OK VCTCXO Circuit is OK
Yes
See next Page to check See next Page to check
Mobile SW Mobile SW
Yes
Changing X500
AFC