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Copyright © 2009 LG Electronics. Inc. All right reserved.
Only for training and service purposes
LGE Internal Use Only
4. TROUBLE SHOOTING
Copyright © 2008 LG Electronics. Inc. All right reserved.
Only for training and service purposes
LGE Internal Use Only
(3) Checking TX I/Q
U500
Redownload software and calibration
again
Similar?
No
Replace U500
Yes
No
Graph 4.4
Check C505(TP1), C507(TP2).
Check if there is any
Major difference
Refer to graph 4.2
TEST POINT
CIRCUIT
CHECKING FLOW
WAVEFORM
TP1
TP2
TP1
TP1
Figure 4.6
TP2
TP2
(GP
(GP
(GP
39p
C505
3
VSUP_BBI
VS
UP_BBQ
31
VS
UP_FE
40
4
35
RX1800
RX1800B
34
33
RX1900
32
RX1900B
39
RX850
RX850B
38
37
RX900
RX900B
36
28
SCLK
SDATA
27
SEL 26M
5
26
SEN
U500
GND
41
I
1
2
IB
Q
30
29
QB
REF_SEL
0.1u
C507
39p
100p
IP
IN
QP
QN
6M
S_CLK
S_DATA
S EN
TP1
TP2