Transmitter Rf Troubleshooting Procedures - Nokia 6255 Rf Description And Troubleshooting

6255/6255i/6256/6256i (RM-19)
RF Description and Troubleshooting
14. Click Read Phone to update the values.

Transmitter RF Troubleshooting Procedures

After Phoenix is set up using either the AMPS, Cell, or PCS setup procedures, use the
following steps to troubleshoot the transmitter.
1. Using a voltmeter, check to see that all VR2, VR6, and VR1B are on the transmit
system. (See "Tx DC Test Points - Bottom Side" on page 25.)
• If any are missing, look for SMD problems around the N7000 and the UEME.
• If SMD is good, replace the UEME.
2. Once all DC voltages are present, check the AGC control voltages. (See "AMPS Tx
Setup" on page 15, "Cell Tx Setup" on page 18, or "PCS Setup" on page 20.)
• If the voltages are incorrect, check the SMD around TX_AGC1 and TX_AGC2.
• If the SMDs are correct, replace the D2800.
3. Using an oscilloscope, check the input modulation BBIQ wave forms at R7021,
R7022, R7023, and R7024. They should all be present with an AC swing of about
500mVpp, with an offset of +1.2V.
• If one or more waveforms are missing, look for SMD problems around these
resistors.
• If the SMD is good, replace the UEM.
Page 22
Figure 15: RF PDM Control dialog box for PCS band
©2005 Nokia Corporation
Nokia Customer Care
Company Confidential Issue 2 05/2005