LG KG245 Service Manual page 56

(2) Checking VVCXO Circuit
TEST POINT
X400.3
(OUT)
X400
Figure 4-7 (a). VVCXO Circuit
CIRCUIT
C443
NA
WAVEFORM
Graph 4(a)
Check Pin 3.
Refer to Graph 4 -1(b)
Check Pin 4.
Refer to Graph 4 - 1(a)
X400.4
(VCC)
2V75_VVCXO
R416
3
100
4
C442
2.2u
Figure 4-7 (b). VVCXO Circuit
- 57 -
4. TROUBLE SHOOTING
CHECKING FLOW
26 MHzO.K?
No No
2.75V OK?
No
Check U101, PMIC
X400
R417
1
OUT VCONT
15K
2
VCC GND
26MHz
C441
1000p
Graph 4(a)
VVCXO Circuit is OK
Yes
See next Page to check See next Page to check
Mobile SW Mobile SW
Yes
Changing X400
AFC