LG KP260 - Page 44

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4. TROUBLE SHOOTING
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(3) Checking RX I/Q
TP7
TP8
Y0280101
VLDO2
16
9
VLDO3
30
RX900
29
RX900B
SCLK
6 5
SDATA
7
SEN
11
TXOP_HI
TXOP_LO
10
18
VAFC_NC
VBAT
14
VCC_BBI
4
24
VCC_BBQ
1
VCC_FE
VCC_REF
17
12
VCC_TXVCO
13
VDD
15
VLDO1
GND
33
I
2 3
IB NC
8
Q
23 22
QB
20
REFIN
REFINB
19
REF_OP
21
RX1800
28
27
RX1800B
RX1900
26
25
RX1900B
RX850
32
31
RX850B
AD6548
U502
82p
C542
C521
0.1u
C519
82p
IN
IP
QP
0.15MM
QN
TEST POINT CIRCUIT
WAVEFORM
Redownload software and calibration again
Similar?
No
Replace U502
Yes
No
Check TP7,8.
Check if there is any
Major difference
Refer to graph 4.2.3
Graph 4.2.3
Figure 4.2.3
CHECKING FLOW
TP8
TP7