LG KP260 Service Manual page 44

(3) Checking RX I/Q
TEST POINT
TP8
Figure 4.2.3
WAVEFORM
CHECKING FLOW
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Only for training and service purposes
TP7
Graph 4.2.3
Check TP7,8.
Check if there is any
Major difference
Refer to graph 4.2.3
Redownload software and calibration
4. TROUBLE SHOOTING
CIRCUIT
TP7
C519
82p
C521
0.1u
0.15MM
Y0280101
25
RX1900B
26
RX1900
27
RX1800B
28
RX1800
U502
29
RX900B
AD6548
30
RX900 VCC_TXVCO
31
RX850B
32
RX850
33
GND
TP8
C542
82p
No No
Similar?
Yes
again
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QP
QN
16
VLDO2
15
VLDO1
14
VBAT
13
VDD
12
11
TXOP_HI
10
TXOP_LO
9
VLDO3
IP
IN
Replace U502
LGE Internal Use Only