LG GD910 Service Manual page 93

5. Trouble shooting
5.14.4 Checking GSM Tx part
Checking Flow Checking Flow Checking Flow
Setup Test Equipment Setup Test Equipment
Cell Power = -60dBm Cell Power = -60dBm
Tx Power Level set
(GSM=5,DCS=0,PCS=0)
Is the level
of TP4~5 same to Table.1?
YES YES
Check TP2,TP3 Check TP2,TP3
TP2(GSM) 33dBm over?
TP3(DCS, PCS) 30dBm over? TP3(DCS, PCS) 30dBm over?
YES YES
Check TP1
EGSM 900 31dBm
DCS1800 29 dBm
PCS1900 29 dBm
Over?
YES
GSM Tx Path is OK
Checking Point Checking Point Checking Point Checking Point Checking Point Checking Point Checking Point
TP5 TP5 TP5 TP5
TP4 TP4 TP4 TP4
TP6 TP6 TP6 TP6
TP2 TP2 TP2 TP2
TP3 TP3 TP3 TP3
TP1 TP1 TP1 TP1
LGE Internal Use Only
NO NO
TP4: check U102
TP5: check VBAT line
Remove U402 and
Check the power of
pin2,pin7 (on board)
The power of pin2,pin7
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GD910 service manual
GD910 service manual
NO NO
is 0~3dBm?
YES
Replace
U402
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- 94 - Copyright © 2009 LG Electronics. Inc. All right reserved.
Check U404
or
Replace U404
Only for training and service purposes