Only For Training And Service Purposes - LG KG290 Service Manual

(4) Checking TX I/Q
TEST POINT
C541
U501
Figure 4.3.4
CIRCUIT
Checking Flow
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Only for training and service purposes

C514
C519
0.1u
25
RX1900B
26
RX1900
27
RX1800B
28
RX1800
U501
29
RX900B
AD6548
30
RX900
31
RX850B
32
RX850
33
GND
Check if there is
Any Major Difference
Refer to Graph4.3.4
Re-download the Software
And calibrate
- 67 -
4. TROUBLE SHOOTING
Waveform
Graph 4.3.4
QP
C514
39p
QN
0.15MM
16
VLDO2
15
VLDO1
14
VBAT
13
VDD
12
VCC_TXVCO
11
TXOP_HI
10
TXOP_LO
9
VLDO3
IP
C541
39p
IN
No
Replace U501
Similar?
Yes
LGE Internal Use Only