LG KE820 - Power saving; Display; Wallpaper

5. Trouble shooting
- 100 -
5.12.3 Checking VCTCXO Circuit
Checking Points Checking Flow
Circuit Diagram
Waveform
Figure 4.
Figure 5. VCTCXO
Figure 6. VCTCXO Waveform
C430
22p
X401
GND
2
3
OUT
VCC
4
VCONT
1
26MHz
R425 620
2V7_VCXO
C431
1uF
NA
C455
0
R449
AFC
Pin 4
Pin 3
VCTCXO
Pin : 2.7V
Pin 3: 26 MHz
X401
Is the waveform
of Pin3 similar to
Is the waveform
of Pin4 similar to
Replace X401
Checking U203
(PMIC)
Yes
No
No
Yes
VCTCXO Circuit is OK.
See next page to check
PLL Circuit.