4. TROUBLE SHOOTING
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Only for training and service purposes
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TX Module Mode
Tx ENABLE
GpCtrl1
GpCtrl0
Off
0
0
0
RX 0
0
1
0
RX 1
0
1
1
GSM850/900 TX Mode
1
1
0
DCS1800/PCS1900 TX Mode
1
1
1
Check TP6 & TP7
Control Signal is
(TP3,4,5) OK ?
Check MT6255 (U101)
Yes
Check TP1 of U400 ?
TP1 Signal is OK?
Yes
No
No
Mobile SW & TX module is OK.
TP8 signal same as TP1?
Replace TX module (U400)
No
Yes
Replace SW400
TP6, TP7 Signal is OK ?
Yes
Replace MT6255 (U101)
No