LG C1150 Service Manual page 51

4. TROUBLE SHOOTING
(2) Checking VCTCXO Circuit
Test Points
X301. 3
Figure 4-3.
Circuit Diagram
R311
100
Waveform
X301. 4
VVCXO
X301
3 1
OUT CTL
4 2
VCC GND
C337
13MHz
2.2u
(1608)
Graph 4-1(a)
Checking Flow
Check Pin 3.
13 MHzO.K?
Refer to Graph 2-1
No
Check Pin 4. 2.75V OK?
Refer to Graph 2-2
No
Check U101, PMIC
R312
15K
C335
1000p
Graph 4-1(b)
- 52 -
VCTCXO Circuit is OK
Yes
See next Page to check
ANT SW & Mobile SW
Yes
Changing X301
AFC AD6535_AFCDAC