5. Trouble shooting
- 100 -
5.13.3 Checking VCTCXO Circuit
Checking Points
Checking Flow
Pin 4 : 2.7V
Pin 3: 26MHz
X401
Is the waveform
of Pin3 similar to
Fig.6?
Is the waveform
of Pin4 similar to
Fig.6?
Replace X401
Checking U201
(PMIC)
Yes
No
No
Yes
VCTCXO Circuit is OK.
See next page to check
PLL Circuit.
VCTCXO Circuit Diagram
Waveform
10p
C440
C442
0.1u
0
R418
26MHz
X401
2
GND
3
OUT
VCC
4
VCONT
1
R421
0
VRF2V7
R417
1.8K
AFC
Pin4 (R418)
Pin3 (R421)
Figure 4.
Figure 5. VCTCXO
Figure 6. VCTCXO Waveform
Summary of Contents for Prada KE850
Page 1: ...Date March 2007 Issue 1 0 Service Manual Model KE850 Service Manual KE850 ...
Page 3: ... 4 ...
Page 5: ... 6 ...
Page 71: ...4 PCB layout 72 Main PCB bottom Main PCB bottom placement ...
Page 115: ... 116 6 Download S W upgrade 6 Press the START button ...
Page 117: ...6 Download S W upgrade 118 KE850 KE850P40 7 V09a KE850 KE850P40 7 V09a ...
Page 127: ... 128 LGMC 8 pcb layout ...
Page 128: ... 129 LGMC 8 pcb layout ...
Page 129: ... 130 LGMC 8 pcb layout ...
Page 130: ... 131 LGMC 8 pcb layout ...
Page 131: ... 132 8 pcb layout ...
Page 132: ... 133 8 pcb layout ...
Page 133: ... 134 8 pcb layout ...
Page 134: ... 135 8 pcb layout ...
Page 135: ... 136 8 pcb layout ...
Page 136: ... 137 8 pcb layout ...
Page 137: ... 138 ...
Page 149: ... 150 ...
Page 151: ... 152 ...
Page 172: ...Note ...
Page 173: ...Note ...