LG MG210 Service Manual page 83

4. TROUBLE SHOOTING
Checking VCTCXO Circuit (Tx pass continued)
Checking Points
PIN1
PIN4
Crystal Input
LDO Output
Crystal Output
VCTCXO Circuit Diagram
X400 26MHz
R418 15K
1
AFC
VCONT OUT
2
GND VCC
C439
1000p
PIN3
RF2.85V
C437
3
TCXO_OUT
1000p
4
C438
1u
- 82 -
Checking Flow
Check Pin 3 of X400
Yes VCTCXO circuit is OK
26MHz ? See next page to check
No
Yes
Pin 4 2.85V ?
No
Check U403
Waveform
Pin4
PLL circuits
Replace X400
Pin3