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Nokia 2255 Manual

Rm-97, rf description and troubleshooting
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Nokia Customer Care
2255 (RM-97)
Mobile Terminal
RF Description and

Troubleshooting

©2005 Nokia Corporation
ISSUE 1 10/2005
Company Confidential

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Summary of Contents for Nokia 2255

  • Page 1: Troubleshooting

    Nokia Customer Care 2255 (RM-97) Mobile Terminal RF Description and Troubleshooting ©2005 Nokia Corporation ISSUE 1 10/2005 Company Confidential...

  • Page 2: Table Of Contents

    2255 (RM-97) RF Description and Troubleshooting Nokia Customer Care Contents Page Mobile Terminal Components ........................4 Preliminary RF Troubleshooting........................5 Mobile Terminal Cannot Make a Call ....................5 Tx Power Low ..............................5 Transmitter Block Diagram ........................6 Transmitter Schematics ..........................7 Transmitter Troubleshooting ........................

  • Page 3: Mobile Terminal Components

    2255 (RM-97) Nokia Customer Care RF Description and Troubleshooting Mobile Terminal Components Figure 1 illustrates the main components of the 2255. RF connector Cell isolator Rx IC Cell duplexer PA PMIC Cell Rx RF DC-DC SAW filter converter Cell Tx PA...

  • Page 4: Preliminary Rf Troubleshooting

    2255 (RM-97) RF Description and Troubleshooting Nokia Customer Care Preliminary RF Troubleshooting The following sections identify steps to troubleshoot some common RF issues. Mobile Terminal Cannot Make a Call Verify the following if the mobile terminal cannot make a call: 1.

  • Page 5: Transmitter Block Diagram

    2255 (RM-97) Nokia Customer Care RF Description and Troubleshooting Transmitter Block Diagram Following is the block diagram for the Tx RF system. I Figure 2: Tx system block diagram ©2005 Nokia Corporation ISSUE 1 10/2005 Company Confidential Page 5...

  • Page 6: Transmitter Schematics

    2255 (RM-97) Nokia Customer Care RF Description and Troubleshooting Transmitter Schematics The following schematics are for general reference only. See the Schematics chapter for detailed versions. Figure 3: Transmitter schematic 1 ©2005 Nokia Corporation ISSUE 1 10/2005 Company Confidential Page 6...
  • Page 7 2255 (RM-97) RF Description and Troubleshooting Nokia Customer Care Figure 4: Transmitter schematic 2 ©2005 Nokia Corporation Page 7 Company Confidential ISSUE 1 10/2005...

  • Page 8: Transmitter Troubleshooting

    2255 (RM-97) RF Description and Troubleshooting Nokia Customer Care Transmitter Troubleshooting CELL Tx Setup Use the following procedures to prepare for CELL Tx troubleshooting using Phoenix. 1. Connect RF test connector to a call box. 2. Connect the phone to a PC via the bottom connector, and connect a power supply.
  • Page 9 2255 (RM-97) Nokia Customer Care RF Description and Troubleshooting Figure 6: RF Main Mode dialog box 7. Click Set. Note: Be sure that the “RF Main Mode set successfully” message appears in the status bar. 8. Open the Troubleshooting menu, point to RF, and click CDMA Control.

  • Page 10: Failed Test: Tx Pa Detector

    2255 (RM-97) RF Description and Troubleshooting Nokia Customer Care The RF PDM Control dialog box appears. Figure 8: RF PDM Control dialog box for Cell troubleshooting 13. Click Read Phone to update the values. 14. Configure the spectrum analyzer using the following values: •...
  • Page 11 2255 (RM-97) Nokia Customer Care RF Description and Troubleshooting Bad output Good output Figure 9: The output of the mobile terminal on a spectrum analyzer should look like the figure on the left If using the AAS-10 probe with the phone connected to the call box, the amplitude should be approximately -7 dBm at the antenna test point on the top of the PWB.

  • Page 12: Tx Rf Test Points

    2255 (RM-97) RF Description and Troubleshooting Nokia Customer Care Tx RF Test Points Figure 10 and Figure 11 are the transmitter DC/RF test points. See Table 1 on page 14 for test point descriptions and values. TP12 PNMIC DC-DC TP11...
  • Page 13 2255 (RM-97) Nokia Customer Care RF Description and Troubleshooting Following are the Tx DC/RF test points for the N7000 Tx Section TP91 N7000 Tx Tx SAW TP10 Figure 11: Tx DC/RF test points - N7000 section ©2005 Nokia Corporation ISSUE 1 10/2005...
  • Page 14 2255 (RM-97) RF Description and Troubleshooting Nokia Customer Care Table 1 shows the Tx DC/RF test points to probe (see Figure 10 and Figure 11) when troubleshooting the cell transmitter path. It is recommended that you follow the steps in order.

  • Page 15: Tx Agc Tuning

    2255 (RM-97) Nokia Customer Care RF Description and Troubleshooting Tx AGC Tuning Tx power versus IF/RF PDM can be verified against FlaLi specification limits. Make sure that the PA is set in high gain mode (GenIO bits 10, 13, and 12 are set to H).

  • Page 16: Receiver Troubleshooting

    2255 (RM-97) Nokia Customer Care RF Description and Troubleshooting Receiver Troubleshooting Following is the Rx system block diagram. N7160 IC N7100 IF IC CDMA I/Q Down LNA SW Control BB Filter Converter CELL IF SAW BB AMP To BB CDMA...

  • Page 17: Receiver Schematics

    2255 (RM-97) RF Description and Troubleshooting Nokia Customer Care Receiver Schematics The following schematics are for general reference only. See the Schematics chapter for detailed versions. LNA Input RF SAW filter Mixer Output 183.6 MHz LNA Gain Control CDMA IF Out 183.6 MHz...
  • Page 18 2255 (RM-97) Nokia Customer Care RF Description and Troubleshooting Figure 14: Receiver schematic 2 ©2005 Nokia Corporation ISSUE 1 10/2005 Company Confidential Page 18...

  • Page 19: Turning On The Rx Path

    2255 (RM-97) Nokia Customer Care RF Description and Troubleshooting Turning on the Rx Path Use the following steps to turn on the Rx path using Phoenix. 1. Turn on Receiver Only in CDMA mode. 2. On the Phone Control dialog box, click the LOCAL button in the Phone State area to put the phone into Local Mode.

  • Page 20: Switching The Rx Gain, If, And Ip States

    2255 (RM-97) RF Description and Troubleshooting Nokia Customer Care Switching the Rx Gain, IF, and IP States Use the RF Gen I/O dialog box to switch the gain state (Hi and Lo) for CDMA mode. Select the desired state, and click Refresh.

  • Page 21: Receiver Troubleshooting

    2255 (RM-97) Nokia Customer Care RF Description and Troubleshooting Receiver Troubleshooting Use Phoenix to perform the following steps for troubleshooting the receiver. Together with the VCO frequency and level verification, this test should be the first test for a non-working receiver. This test verifies the entire receiver chain, from input connector to baseband output.
  • Page 22 2255 (RM-97) RF Description and Troubleshooting Nokia Customer Care Figure 19: RF Main Mode dialog box for Rx IF troubleshooting 5. Click Set. Note: Be sure that the “RF Main Mode set successfully” message appears in the status bar. 6. Use a Spectrum analyzer to test TP3 (I+,I-, Q+, Q-), Set the S.A to 300KHz Center Frequency, 200KHz SPAN and +10dBm Reference level 7.

  • Page 23: Receiver Rf Troubleshooting Test Points

    2255 (RM-97) Nokia Customer Care RF Description and Troubleshooting Receiver RF Troubleshooting Test Points Figure 20: Receiver Rx troubleshooting test points ©2005 Nokia Corporation ISSUE 1 10/2005 Company Confidential Page 23...
  • Page 24 2255 (RM-97) RF Description and Troubleshooting Nokia Customer Care Figure 21: Receiver Rx troubleshooting test points ©2005 Nokia Corporation Page 24 Company Confidential ISSUE 1 10/2005...

  • Page 25: Receiver If Troubleshooting Test Points

    2255 (RM-97) Nokia Customer Care RF Description and Troubleshooting Receiver IF Troubleshooting Test Points Figure 22: Receiver IF troubleshooting test points ©2005 Nokia Corporation ISSUE 1 10/2005 Company Confidential Page 25...
  • Page 26 2255 (RM-97) RF Description and Troubleshooting Nokia Customer Care Figure 23: Receiver IF troubleshooting test points ©2005 Nokia Corporation Page 26 Company Confidential ISSUE 1 10/2005...

  • Page 27: Cell Receiver Check From Rf To Iq

    2255 (RM-97) Nokia Customer Care RF Description and Troubleshooting Cell Receiver Check from RF to IQ Use the following values to check the CDMA Cell Rx functionality from RF to IQ output. 1. Start Phoenix in Local Mode with only the Rx path turned on.

  • Page 28: Receiver Diagnostic Using Signal Tracing And Call Box

    2255 (RM-97) RF Description and Troubleshooting Nokia Customer Care Cell I Q Output Trace A Trace A 302 kHz -21.2500 dBm -100 Centre: 300 kHz Atten: 10 dB Span: 200 kHz Res BW: 3 kHz Vid BW: 3 kHz Sweep: 100 ms 5/5/2004 3:29:30 PM CellIQ.spt...

  • Page 29: Rx Front-End Ic (N7150) Dc Troubleshooting

    2255 (RM-97) Nokia Customer Care RF Description and Troubleshooting Rx Front-End IC (N7150) DC Troubleshooting There are two common explanations for an N7150 failure consisting of high current in Local Mode with just the Rx turned on: • No presence of an LO signal •...

  • Page 30: Synthesizer Troubleshooting

    Synthesizer Troubleshooting Faulty synthesizers can cause both Rx and Tx failures during tuning, in addition to the VCTCXO tuning. The following synthesizers are used in the 2255: • UHF (CELL) PLL inside N7000 IC. • Tx VHF (457.2MHz) with PLL in N7000 IC.

  • Page 31: Synthesizer Schematic

    2255 (RM-97) RF Description and Troubleshooting Nokia Customer Care Synthesizer Schematic The following schematic is for general reference only. See the Schematics chapter for detailed versions. VCTCXO with AFC control 19.2MHz buffer not installed UHF PLL IC Loop filter Figure 27: Synthesizer schematic ©2005 Nokia Corporation...

  • Page 32: Synthesizer Troubleshooting Setup

    2255 (RM-97) RF Description and Troubleshooting Nokia Customer Care Synthesizer Troubleshooting Setup Use the following steps to troubleshoot the synthesizer using Phoenix: 1. On the Phone Control dialog box, click the LOCAL button in the Phone State area to put the phone into Local Mode.
  • Page 33 2255 (RM-97) Nokia Customer Care RF Description and Troubleshooting Figure 29: RF Register R/W dialog box for synthesizer setup 5. Read register templates N7100 (0) bit 11 for the Rx VHF lock condition. ©2005 Nokia Corporation ISSUE 1 10/2005 Company Confidential...

  • Page 34: 19.2 Mhz Vctcxo Reference Clock

    2255 (RM-97) RF Description and Troubleshooting Nokia Customer Care 19.2 MHZ VCTCXO Reference Clock To N7000 PLL To N7100/BB 19.2MHz @ -24dBm w/production probe 19.2MHz @ -24dBm -14dBm w/HP probe (20dB pad) (CLK19M2_R) VCTCXO Figure 30: 19.2 MHz VCTCXO Reference clock ©2005 Nokia Corporation...

  • Page 35: Vctcxo Manual Tuning

    2255 (RM-97) Nokia Customer Care RF Description and Troubleshooting VCTCXO Manual Tuning 1. The VCTCXO can be manually tuned to verify failed tuned phones, or to verify if a phone cannot make a call. This can be done with the phone in Local Mode and generating a CW signal.
  • Page 36 2255 (RM-97) RF Description and Troubleshooting Nokia Customer Care Use the following steps to set up a CW signal: 1. Open the Phone Control dialog box. Figure 32: Phone Control dialog box for VCTCXO troubleshooting 2. Click the LOCAL button in the Phone State area to put the phone into Local Mode.
  • Page 37 2255 (RM-97) Nokia Customer Care RF Description and Troubleshooting 6. Type 10, 13, 12, and 8 in the fields in the PIN # column. Change to GenIO Output and set to High Figure 34: General I/O dialog box for VCTCXO tuning 7.
  • Page 38 2255 (RM-97) RF Description and Troubleshooting Nokia Customer Care Adjust AFC to center VCTCXO manually Figure 35: Manually adjusting the AFC to center VCTCXO 12. Adjust the AFC value so that the output signal is within +/- 100Hz. If you are using an HP4406 or a spectrum analyzer, narrow the span to 1kHz or less.

  • Page 39: Uhf Synthesizer Test Points

    2255 (RM-97) Nokia Customer Care RF Description and Troubleshooting UHF Synthesizer Test Points Figure 36 shows the UHF Synthesizer layout. 19.2MHz VCTCXO UHF VCO LO coupler Loop filter Lock voltage probe point: N7000 LO/PLL Input RF test point, Tx LO output levels:...

  • Page 40: Uhf Synthesizer Schematic

    2255 (RM-97) Nokia Customer Care RF Description and Troubleshooting UHF Synthesizer Schematic The following schematic is for general reference only. See the Schematics chapter for a detailed version. LO to Rx LO to Tx/PLL UHF VCO Loop filter components Lock voltage (1to 2V)

  • Page 41: Incorrect Uhf Frequency

    2255 (RM-97) Nokia Customer Care RF Description and Troubleshooting Incorrect UHF Frequency Following are possible causes for incorrect UHF frequencies: • Power supplies to PLL N7000 missing or low (VR7) • Loop filter components missing or incorrectly installed • Matching components to N7000 TxLO/PLL input missing or incorrectly installed •...

  • Page 42: Rx Vhf

    2255 (RM-97) RF Description and Troubleshooting Nokia Customer Care Rx VHF Figure 38 shows the Rx VHF test points layout. N7100 IC with Integrated PLL Lock voltage test point DC voltage between 1V and 2 V RF test point: 367.2MHz @ -61 dBm With Production probe -1 dBm with HP Probe.

  • Page 43: Rx Vhf Schematic

    2255 (RM-97) RF Description and Troubleshooting Nokia Customer Care Rx VHF Schematic The following partial schematic is for general reference only. See the Schematics chapter for a detailed version. PLL in N7100 Resonator Loop filter components Lock voltage Figure 39: Rx VHF schematic ©2005 Nokia Corporation...

  • Page 44: Incorrect Rx Vhf Frequency

    2255 (RM-97) RF Description and Troubleshooting Nokia Customer Care Incorrect Rx VHF Frequency Following are possible causes for incorrect Rx VHF frequencies: • Power supplies to PLL portion of IC N7100 missing or low (VR7) • Loop filter or resonator components missing or incorrectly installed •...

  • Page 45: Tx Vhf

    2255 (RM-97) Nokia Customer Care RF Description and Troubleshooting Tx VHF Figure 38 shows the Tx VHF test points layout N7000 IC with Integrated VHF PLL Lock voltage test point RF test point: CELL: 457.2 MHZ @ -18.7dBm DC voltage between 1 and 2 V...

  • Page 46: Tx Vhf Schematic

    2255 (RM-97) Nokia Customer Care RF Description and Troubleshooting Tx VHF Schematic The following partial schematic is for general reference only. See the Schematics chapter for a detailed version. Loop filter Lock voltage N7000 Resonator Figure 41: Tx VHF schematic ©2005 Nokia Corporation...

  • Page 47: Incorrect Tx Vhf Frequency

    2255 (RM-97) Nokia Customer Care RF Description and Troubleshooting Incorrect Tx VHF Frequency Following are possible causes for incorrect Tx VHF frequencies: • Power supplies to PLL portion of IC N7000 missing or low (VR5) • Loop filter or resonator components missing or incorrectly installed •...

  • Page 48: Fm Radio Troubleshooting

    2255 (RM-97) RF Description and Troubleshooting Nokia Customer Care FM Radio Troubleshooting Figure 42 shows the FM Radio layout. FM Radio circuits are located on the top of the PWB. Figure 42: FM Radio layout FM Radio Troubleshooting Setup Use the following steps to troubleshoot the FM radio while using universal headset to the UHJ connector.
  • Page 49 2255 (RM-97) Nokia Customer Care RF Description and Troubleshooting • If a signal is present the radio is functioning properly. • If no channel can be found or no static/sound inspect all FM radio baseband and audio circuits. Refer to the “Audio” section of the Baseband Description and Troubleshooting chapter for more information.
  • Page 50 2255 (RM-97) RF Description and Troubleshooting Nokia Customer Care This page intentionally left blank. ©2005 Nokia Corporation Page 50 Company Confidential ISSUE 1 10/2005...

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