Only For Training And Service Purposes - LG KF305 Service Manual

4. TROUBLE SHOOTING
(4) Checking TX I/Q
TEST POINT
SW601
TP1
U602
Figure 4-3-4
WAVEFORM
Graph 4-3-4
CHECKING FLOW
LGE Internal Use Only
TP2
TP2
Check if there is
Any Major Difference
¨ Refer to Graph4.3.4
Re-download the Software
And calibrate
- 72 -
CIRCUIT
QN
82p
C617
QP
VLDO1
C618
47p
25
RX1900B
26
RX1900
27
RX1800B
28
RX1800
29 AD6548
RX900B
30 U602
RX900
31
RX850B
32
RX850
33
GND
VLDO1
C636
39p
IP
C642
82p
IN
No
Replace U602
Similar?
Yes
Copyright © 2009 LG Electronics. Inc. All right reserved.
2V75_VCXO
R611
AFC
10K
C619
1u
2V93_VEXT VBAT
C622
16
VLDO2
15
220n
VLDO1
14
VBAT
13
VDD
12
VCC_TXVCO
11
TXOP_HI
C626 C627
10
TXOP_LO C629 0.1u 0.1u
C630
9
27p 0.1u
VLDO3
C634
0.1u
(GPIO_072)
S_EN
S_CLK (GPIO_074)
S_DATA (GPIO_073)
C639 C640 C641
100p 100p 100p
TP1

Only for training and service purposes

VLDO1
C625
0.1u