LG -MC2670 Service Manual page 15

LG-MC26 70
2.1.3 Checking VCTCXO Circuit
Test Point
X100. 4 X100. 3
Figure 2.1.3
Circuit Diagram
Waveform
Graph 2.1.1(a)
Check X100 Pin 3
◆ Refer to Graph 4-1(a)
U400. 32
Check X100 Pin 4
◆ Refer to Graph 4-1(b)
12
Checking Flow
VCTCXO Circuit is Ok
Yes
19.2MHz OK? See next Page to check
Rx VCO
No
Yes
+2.85V_TCXO OK?
No
Check Q701
Graph 2.1.1(b)
Changing X100