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LGE Internal Use Only
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Only for training and service purposes
4. TROUBLE SHOOTING
GS290 Operational Description Revision B
LG Electronics
88/136
LGE Property
4.12.1. Checking DCXO Circuit
Replace X500
No
Yes
DCXO Circuit is OK.
See next page to check
PLL Circuit.
TP1(C516) : 26MHz
Figur2. DCXO
DCXO Circuit Diagram
Figure 3. DCXO Cicuit
Waveform
Is the waveform
of TP1(C516) similar to Fig.4?
TP1 (C516)
X500
Figure 4. DCXO Waveform
Checking Points
Checking Flow
26MHz
X500
TSX-3225
2
1
3
4
GND2
HOT2
HOT1
GND1
U500
PMB6272
19
18
17
16
15
14
13
2
1
1
1
0
1
9
8
7
6
5
4
3
2
1
A
X
A
B
X
B
8
V2
GI
D
D
D
V
A
D
KL
C
5
V1
GI
D
D
D
V
3
S
Y
SF
2
S
Y
SF OX
X
O
X
GND1
FSYS1
VDDXO2V8
EN
VDDVCO2V8
VCO_RC
VDDRX1V5
1n
C516
C517
47n
R508
820
RF_EN
26MHZ_MCLK
TP1(C516)