No Or Low Tx Output Power In Wcdma - Motorola MotoRAZR maxx V6 Manual

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Title: Troubleshooting-Guide MotoRAZR maxx V6

No or low TX output power in WCDMA

Let radio transmit on WCDMA using RepairStudio/Radiocomm. Make sure to provide a
battery voltage via micro clamp-type tests probes to battery contacts J5400.
Measure the power at the output of the WCDMA PA
If output power PA_2100_RF_OUT
- Check to see if PA
- Check the input power
- If input power to PA is low it is most likely a problem with the SYMPHONY U100.
- If input power to PA is ok it is most likely a problem with the PA
If output power PA_2100_RF_OUT
FEM U001 (do a visual check for misplaced parts around FEM U001).
WCDMA TX signals
- TX_WB_2100: modulated input TX signal from SYMPHONY
- PA_2100_EN: logic signal that enables the WCDMA PA
- PA_VBA: controls the gain of the WCDMA PA
- PA_VDET: power detect signal
- PASSKEY_VLD: determines two modes of operation: - Hi Power Mode/Low Power
Mode
WCDMA TX supply voltages
- VRF_TX_2_775V
- BATT+
- VRFCP_2_775V
- VHVIO_2_2_775V
- VRF_LVIO_1_875V
- VMELODY_CORE
- VRF_RX_2_775VV
Repair Support Information
from WCDMA PA is low
U400 is soldered down properly
TX_WB_2100 to the PA from SYMPHONY at
Figure 37
from PA is good the trouble is most likely related to a bad
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U400 at R400-1.
U400
TSG_3G_V6
1.0
23.07.2007
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C408-1
itself.