LG GD910 - Page 93

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Only for training and service purposes
5. Trouble shooting
GD910 service manual
Checking Flow
Is the level
of TP4~5 same to Table.1?
TP4: check U102
TP5: check VBAT line
Check TP2,TP3
TP2(GSM) 33dBm over?
TP3(DCS, PCS) 30dBm over?
NO
Y
ES
NO
Y
ES
Setup Test Equipment
Cell Power = -60dBm
T
x
Power Level set
(GSM=5,DCS=0,PCS=0)
GSM T
x
Path is O
K
Remove U402 and
Check the power o
f
pin2,pin7 (on board)
Check TP1
EGSM 900 31dBm
DCS1800 29 dBm
PCS1900 29 dBm
Over?
T
he power of pin2,pin7
is 0~3dBm?
Y
ES
Check U404
or
Replace U404
Y
ES
Replace
U402
Checking Flow
Check TP2,TP3
TP3(DCS, PCS) 30dBm over?
NO
Y
ES
NO
Y
ES
Setup Test Equipment
Cell Power = -60dBm
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TP1
TP3
TP2
TP6
TP4
TP5
Checking Point Checking Point
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TP1
TP3
TP2
TP6
TP4
TP5
Checking Point Checking Point
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TP1
TP3
TP2
TP6
TP4
TP5
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TP1
TP3
TP2
TP6
TP4
TP5
Checking Point Checking Point
GD910 service manual
5.14.4 Checking GSM Tx part
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Checking Flow
Checking Point