LG G3100 Service Manual page 69

4-3-5 Checking RF TX Level
L401
L405
Check L401(For GSM),
L402(For DCS)
GSM: ~10dBm
To Check TXVCO DCS : ~8dBm
Output
Check R406(For GSM),
R414(For DCS)
To Check Attenuation
Circuit
Check L405(For GSM),
GSM: ~34dBm
C427(For DCS)To Check
DCS : ~32dBm
PAM Output Power
RF TX Level before ANT SW
See next Page to check
ANT SW & Mobile SW
For these RF TX Level test case,
TX Stand alone Mode is needed
U401
No
Yes
No
GSM: ~8dBm
DCS : ~6dBm
Yes
No
Check R401
Yes
To Check TXRAMP
is OK
L402
C427
R414
Changing U401
Soldering check
R406, R408, R409,
(For GSM)
R414, R415, R416
(For DCS)
GSM: ~2V
DCS : ~2V
Yes
GSM: ~2.85V
DCS : ~2.85V
Yes
GSM: ~2.7V
DCS : ~2.7V
GSM: ~0V
DCS : ~2.7V
Changing U402
- 71 -
4. TROUBLE SHOOTING
R405
No
Change the board
Check R403 to
Check 2.85v
No
Change the board
Check R404
To Check TXPA
No
Change the board
Check R405
Yes
To Check Band
No
Change the board
Yes
R406
R401
R403
U402
R404