LG KP175 - Page 44

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4. TROUBLE SHOOTING
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(3) Checking RX I/Q
U502
C530
C507
DNI
C507
2V75_VVCXO
C530
DNI
C525
27p
0.1u
C514
VCC_REF
12
VCC_TXVCO
VDD
13
VLDO1
15
16
VLDO2
VLDO3
9
RX1900
RX1900B
25
32
RX850
RX850B
31
30
RX900
RX900B
29
6
SCLK SDATA
5
SEN
7
TXOP_HI
11
10
TXOP_LO
VAFC_NC
18
14
VBAT
4
VCC_BBI
VCC_BBQ
24
VCC_FE
1
17
33
GND
2
I IB
3 8
NC
23
Q
QB
22
REFIN
20 19
REFINB
21
REF_OP
28
RX1800
RX1800B
27
26
U502
AD6548
EUSY0280101
C526
39p
C513
0.1u
IN
QN
QP
IP
TEST POINT CIRCUIT
WAVEFORM
Redownload software and calibration again
Similar?
No
Replace U502
Yes
Check C507, C530.
Check if there is any
Major difference
Refer to graph 4.
2.3
Graph 4.2.3
Figure 4.2.3
CHECKING FLOW