LG KE800 Service Manual page 72

4.19.9 Checking Transceiver Output Signals
R514 10
R505
C524 C525
47n 0.1u
1K
GND15
26
GND14
25
GND13
24
GND12
23
GND11
22
GND10
21
GND9
20
GND8
19
GND7
18
GND6
0 17
EN
8
GSM_IN
7
VRAMP
6
VBATT
5
RSVD1
4
BS
3
S_PCS_IN
2
MODE
1
Figure 20. Transceiver Output Circuit
Checking Points
U601
Figure 21. Transceiver Output
MODE Transceiver Output
GSMK VRAMP controls output power
8PSK VRVBIAS sets PA bias
Table 3. Transceiver Output Operation
- 73 -
4. Trouble Shooting
FE2
33
VBIAS
34
VDDTX1V5
35
TX1
36
TX2
37
VDDTX2V8
38
VDDMIX2V8
39
GND3
40
C526 C527
5600p 10p
GND4
41
R507
C531 0 C532
NA NA
R509
0
C534 C535
NA NA
VSUPPLY
DCS_PCS IN (R509)
GSM IN (R507)