Checking Vctcxo Circuit - LG KE600 - Cell Phone Service Manual

5.15.3 Checking VCTCXO Circuit

Checking Points
Pin 3: 26MHz
Figure 4. VCTCXO
VCTCXO Circuit Diagram
2V7_VCXO
C641 C632
NA
1u
100p R620 0
Figure 5. VCTCXO
Checking Flow
of Pin3 similar to
of Pin4 similar to
Pin : 2.7V
VCTCXO Circuit is OK.
X601
See next page to check
26MHz
VCC GND
4 2
OUT VCONT
3 1
X601
- 105 -
Is the waveform
Yes
No
Is the waveform
Yes
PLL Circuit.
Waveform
Pin 4
Pin 3
Figure 6. VCTCXO Waveform
5. Trouble shooting
No
Replace X601
Checking U201
(PMIC)