LG KG800 - Page 57

(1) Checking VCTCXO Circuit
4. TROUBLESHOOTING
- 58 -
C408
R404
Check Pin 3.
Refer to Graph
4
-1(b)
13 MHzO.K?
No
No
VCTCXO Circuit is OK
See next Page to check
ANT SW & Mobile SW
VCTCXO Circuit is OK
See next Page to check
ANT SW & Mobile SW
Yes
Check Pin 4.
Refer to Graph 4-1(a)
2.75V OK?
No
Yes
Changing X601
Check U101
13MHz
2V75_VVCXO
R404
100
1000p
C407
2
GND
3
OUT
4
VCC
1
VCONT
13MHz
X400
C408
1u
C405
1000p
10K
R403
AFC
TEST POINT
CIRCUIT
Waveform
Graph 4-1(a) Graph 4-1(b)
Checking Flow