Only For Training And Service Purposes - LG KP105 Service Manual

TX Trouble
TEST POINT
TP2
U401
TP3
X101
Signal configuration
Mode GSM900
VLOGIC (TP1)
TXON_PA (TP2)
BS (TP3)
Copyright © 2008 LG Electronics. Inc. All right reserved.

Only for training and service purposes

SW401
TP1
FL401
U103
DCS1800
TX TX
H(2.7V) H(2.7V)
H(2.7V) H(2.7V)
L H(2.7V)
4. TROUBLE SHOOTING
CIRCUIT
C403 C404
12p 0.01u
TP1
VLOGIC
1K R405
TX_RAMP
TXON_PA
BS
TP3
C408 C409 C410 C411
39p 39p 39p 39p
6
PCS_RX
7
GSM_RX
8
GND1
9
GND2
10
GND3
11
ANT
CHECKING FLOW
Check Control
Signals(TP1,2,3)
Signals are
Normal ?
Yes
PAM Control Signal
is OK.
See next page to
check
Mobile SW Circuit.
- 51 -
VBAT
C401
C405 C406
10u
33p 18p
(2012)
TP2
1
VBATT
20
GND9
19
U401
PCS_IN
SKY77517 18
NC
17
GSM_IN
16
GND8
No
Check
ULC2(U103)
LGE Internal Use Only
DCS_PCS_OUT
GSM_OUT