
6.14.1 Transmitter Circuit
√
Check point of PAM
- Transmitter output power (=R505, L572) is approximately 3dBm.
Fig 13 Transmitter circuit (U104)
LGE Internal Use Only
Copyright © 2008 LG Electronics. Inc. All right reserved.
Only for training and service purposes
6. Trouble shooting
- 114 -
Does Power
(TP1 & TP2)
seem like
about 3dBm?
Check
U102
Check the next part
YES
NO
Transmitter Circuit
TP1
TP2
4
5
VRAMP
3
BS
BY_CAP1
13
9
BY_CAP2
DCS_PCS_IN
1
12
DCS_PCS_OUT
GND1
14
11
GND2
8
GND3
GSM850_900_IN
7
GSM850_900_OUT
10
MODE_SELECT
2
PGND
15
6
TX_EN
VBATT
TQM7M5005
U500
C512
100p
C527
VBAT
820p
1
R510
1
R507
33 uF
C511
1000p
C523
C526
100p
100p
C525
4.7nH
L572
27p
C524
2.7nH
L501
L500
NA
1
R509
1.2K
R508
1
R505
PA_BAND
PA_MODE
PA_EN
TXLB
TX_RAMP
TXHB
TP2
TP1
Summary of Contents for KC550
Page 1: ...Date May 2008 Issue 1 0 Service Manual Model KC550 Service Manual KC550 Internal Use Only ...
Page 182: ...Note ...
Page 183: ...Note ...