6255/6255i/6256/6256i (RM-19) RF Description and Troubleshooting Nokia Customer Care Contents Page Introduction ..............................5 Mobile Terminal Components ........................6 Main PWB ..............................6 UI (Secondary) PWB ............................ 8 Preliminary RF Troubleshooting....................... 10 Mobile Terminal Cannot Make a Call ....................10 Tx Power Low ..............................10 Transmitter RF Troubleshooting ......................
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6255/6255i/6256/6256i (RM-19) Nokia Customer Care RF Description and Troubleshooting Rx VHF LO Troubleshooting ........................59 Tx UHF LO (N7000) Schematic ......................60 Tx UHF LO (N7000) Troubleshooting ....................61 GPS Troubleshooting........................... 62 GPS RF Block Diagram ..........................62 GPS RF Schematic .............................63 GPS Troubleshooting Setup ........................64 Self Test Failure ............................
6255/6255i/6256/6256i (RM-19) Nokia Customer Care RF Description and Troubleshooting Introduction When troubleshooting the receiver, first check the RX_AGC PDM value. The AGC value should be close to the typical values in the tables. The RX AGC tries to keep a constant amplitude at the output of the receiver chain;...
6255/6255i/6256/6256i (RM-19) RF Description and Troubleshooting Nokia Customer Care Mobile Terminal Components The mobile terminal includes two PWB boards, the main PWB and the UI PWB. Main PWB Following are the components of the main PWB. Tx I/Q signal test points...
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6255/6255i/6256/6256i (RM-19) Nokia Customer Care RF Description and Troubleshooting Synthesizer IC Cell duplexer Headset jack PCS coupler PCS duplexer Cell coupler Diplexer Rx RF Cell filter Antenna N7160: connector Rx front-end Rx RF PCS filter PCS PA Rx IF AMPS filter...
6255/6255i/6256/6256i (RM-19) 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.
6255/6255i/6256/6256i (RM-19) RF Description and Troubleshooting Nokia Customer Care Transmitter RF Troubleshooting Following are the main Tx RF components. Antenna PCS Tx SAW filter Cell Tx SAW filter Cell PA PCS PA Diplexer connector BOTTOM SIDE TOP SIDE Cell coupler...
6255/6255i/6256/6256i (RM-19) Nokia Customer Care RF Description and Troubleshooting Transmitter Troubleshooting Setup Use the following sets of procedures to troubleshoot the transmitter using Phoenix. Due to the compact layout of the mobile terminal, some of the major test points are not accessible without destroying the shield frames and the EL lamp.
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6255/6255i/6256/6256i (RM-19) RF Description and Troubleshooting Nokia Customer Care 5. Click the LOCAL button in the Phone State area to put the mobile terminal into Local Mode. Figure 9: Phone Control dialog box 6. Open the Troubleshooting menu, point to AMPS, and click AMPS Control.
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6255/6255i/6256/6256i (RM-19) Nokia Customer Care RF Description and Troubleshooting 11. Configure the spectrum analyzer using the following values: • Center Frequency = 836.52 MHz • Span = 100 MHz • Amplitude = 20 dBm • Attenuation = Auto • BW = Auto...
6255/6255i/6256/6256i (RM-19) RF Description and Troubleshooting Nokia Customer Care Cell Tx Setup Use the following procedures to prepare for Cell Tx troubleshooting using Phoenix. 1. Connect an RF test connector to a call box. 2. Connect the mobile terminal to the PC via a test jig. (The bottom connector is a USB port.)
6255/6255i/6256/6256i (RM-19) Nokia Customer Care RF Description and Troubleshooting The CDMA Control dialog box appears. Do NOT select this option Figure 13: CDMA Control dialog box for Cell Tx troubleshooting 9. Select the following values: State = Rho ON •...
6255/6255i/6256/6256i (RM-19) RF Description and Troubleshooting Nokia Customer Care Figure 14: RF PDM Control dialog box for Cell band 12. Click Read Phone to update the values. PCS Setup Use the following procedures to prepare for PCS Tx troubleshooting using Phoenix.
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6255/6255i/6256/6256i (RM-19) Nokia Customer Care RF Description and Troubleshooting 7. Select the following values on the RF Main Mode dialog box: Band = PCS (CDMA) • Channel = 600 • Mode = Rx/Tx • 8. Click Set. Note: Be sure that the “RF Main Mode set successfully” message appears in the status bar.
6255/6255i/6256/6256i (RM-19) RF Description and Troubleshooting Nokia Customer Care Figure 15: RF PDM Control dialog box for PCS band 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.
6255/6255i/6256/6256i (RM-19) Nokia Customer Care RF Description and Troubleshooting 4. Use an AAS-10 RF probe to probe the Cell Tx output of the N7000. • If there is no RF or low RF, look for SMD everywhere around the N7000.
6255/6255i/6256/6256i (RM-19) RF Description and Troubleshooting Nokia Customer Care Tx Output Spectrum Following is the correct output of the mobile terminal on a spectrum analyzer with 100MHz span. Note that if you are using the AAS-10 probe with the mobile terminal connected to the call box, the amplitude should be approximately -7dBm at the antenna test point on the top of the PWB.
6255/6255i/6256/6256i (RM-19) RF Description and Troubleshooting Nokia Customer Care Table 4 shows the values for the test points in Figure 18. Table 4: Tx DC Test Point Description and Values - Main PWB - Bottom Side Test Description Values Point Tx UHF LO Lock voltage: ~1.2V...
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6255/6255i/6256/6256i (RM-19) Nokia Customer Care RF Description and Troubleshooting Table 5 shows the values for the test points in Figure 19. Table 5: Tx DC Test Point Description and Values - Main PWB - Top Side Test Description Values Point Power detector input AMPS: -5dBm at 836.25MHz...
6255/6255i/6256/6256i (RM-19) RF Description and Troubleshooting Nokia Customer Care Tx RF Test Points - Bottom Side Figure 20 shows the Tx RF test points located on the bottom side of the main PWB. Figure 20: Tx DC and RF test points on the bottom side of the main PWB Table 6 shows the values for the test points in Figure 20.
6255/6255i/6256/6256i (RM-19) Nokia Customer Care RF Description and Troubleshooting Table 6: Tx RF Test Point Descriptions and Values - Main PWB - Bottom Side (Continued) Test Description Values Point PCS PA out 11dBm RF out AMPS: +14dBm Cell: +20dBm PCS: +20dBm...
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6255/6255i/6256/6256i (RM-19) RF Description and Troubleshooting Nokia Customer Care Table 7 shows the values for the test points in Figure 21. Table 7: RF Power Supply DC Test Points (Main PWB - Bottom Side) Probe Description Value Point 1.8V VrefRF1 1.4V (Tx)
6255/6255i/6256/6256i (RM-19) Nokia Customer Care RF Description and Troubleshooting Receiver RF Troubleshooting The heart of the receiver is the N7160 Rx IC, which contains two LNAs and mixers. The other components are passive. There are two RF SAW filters for the Cell and PCS bands.
6255/6255i/6256/6256i (RM-19) Nokia Customer Care RF Description and Troubleshooting Receiver Schematics The following schematics are for general reference only. See the Schematics chapter for detailed versions. Cell RF SAW filter N7160 Rx front-end IC PCS RF SAW filter AMPS IF crystal filter...
6255/6255i/6256/6256i (RM-19) Nokia Customer Care RF Description and Troubleshooting RF AGC Status When configuring the values on the RF AGC Status dialog box, note the following: • The RF AGC status functionality only works in Call Mode. • In the PLL Lock Status area, bright green indicates a locked PLL and dark green indicates an unlocked PLL.
6255/6255i/6256/6256i (RM-19) RF Description and Troubleshooting Nokia Customer Care Turning on the Rx Path Use the following steps to turn on the Rx path using Phoenix. 1. On the Phone Control dialog box, click the LOCAL button in the Phone State area to put the mobile terminal into Local Mode.
6255/6255i/6256/6256i (RM-19) RF Description and Troubleshooting Nokia Customer Care Switching the Rx Gain States Use the RF Gen I/O dialog box to switch the gain state (Hi and Lo) for CDMA and AMPS modes. High Gain State (default) Cell AMPS...
6255/6255i/6256/6256i (RM-19) Nokia Customer Care RF Description and Troubleshooting Figure 29: Receiver IQ Level on AMPS band Figure 30 shows the AMPS spectrum and the test points located on the top side of the main PWB. All four test points should be approximately equal. WARNING: Direct current is present on these test points.
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6255/6255i/6256/6256i (RM-19) RF Description and Troubleshooting Nokia Customer Care 3. Measure a 300kHz tone on the analyzer. You should see a typical -21dBm IQ tone for CDMA Cell. Cell I Q Output Trace A Trace A 302 kHz -21.2500 dBm...
6255/6255i/6256/6256i (RM-19) Nokia Customer Care RF Description and Troubleshooting Checking PCS Receiver from RF to IQ Use the following values to check the PCS receiver functionality from RF to IQ output. 1. Start Phoenix in Local Mode with only the Rx path turned on.
6255/6255i/6256/6256i (RM-19) RF Description and Troubleshooting Nokia Customer Care Rx_QP Rx_IP Rx_IN Rx_QN Figure 34: PCS spectrum and the test points on the top side of the main PWB Receiver Diagnostic Signal Tracing Use the following steps to trace the receiver signal.
6255/6255i/6256/6256i (RM-19) Nokia Customer Care RF Description and Troubleshooting Receiver DC Test Points Figure 35: Receiver DC troubleshooting test points on the bottom side of the main PWB Table 9 includes the descriptions and values for the Rx DC test points from Figure 35.
6255/6255i/6256/6256i (RM-19) RF Description and Troubleshooting Nokia Customer Care Receiver RF Test Points Figure 36: Rx RF test points on the bottom side of the main PWB Table 10 includes the descriptions and values for the Rx RF test points from Figure 36.
6255/6255i/6256/6256i (RM-19) Nokia Customer Care RF Description and Troubleshooting Table 10: Receiver RF Test Point Values (Continued) Test Description Value Point PCS channel 600 (to RF SAW) High gain: 1960MHz at -32dBm Low gain: 1960MHz at -49dBm IF MIX OUT (from N7160) High gain: 128.1MHz at -21dBm...
6255/6255i/6256/6256i (RM-19) RF Description and Troubleshooting Nokia Customer Care Table 11: Receiver IF Test Point Values (Continued) Test Description Value Point CDMA_IF_P (to the N7100) Cell high gain: -29dBm 128.1MHz Cell low gain: -45dBm PCS high gain: -29dBm PCS low gain: -45dBm...
6255/6255i/6256/6256i (RM-19) Nokia Customer Care RF Description and Troubleshooting Table 12 includes the measure logic levels for the N7160. Table 12: Rx Front-end (N7160) Logic Levels Logic Input Voltages Mode IF_SEL BAND GAIN_CTL AMPS High Gain 2.8 V 0.1 V 2.8 V...
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6255/6255i/6256/6256i (RM-19) RF Description and Troubleshooting Nokia Customer Care Cell Cell IFAs Buffer Figure 39: N7160 receiver There are two common explanations for an N7160 failure consisting of high current in Local Mode with just the Rx turned on: • No presence of an LO signal •...
6255/6255i/6256/6256i (RM-19) Nokia Customer Care RF Description and Troubleshooting Synthesizer Troubleshooting Faulty synthesizers can cause both Rx and Tx failures during tuning, in addition to the VCTCXO tuning. However, first check for the presence of various LO signals and their proper levels.
6255/6255i/6256/6256i (RM-19) Nokia Customer Care RF Description and Troubleshooting Synthesizer Schematics The following schematics are for general reference only. See the Schematics chapter for detailed versions. 19.2MHz buffer VCTCXO with Not installed AFC control UHF PLL IC Lock voltage Loop filter...
6255/6255i/6256/6256i (RM-19) 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 mobile terminal into Local Mode.
6255/6255i/6256/6256i (RM-19) Nokia Customer Care RF Description and Troubleshooting VCTCXO Troubleshooting Without 19.2MHz, the mobile terminal does not power up. This signal goes to the N7100, N7000, D2800, and the UHF PLL. Check the test points in Figure 43 for the presence of the 19.2MHz signal.
6255/6255i/6256/6256i (RM-19) RF Description and Troubleshooting Nokia Customer Care Table 15: VCTCXO Test Point Output Values (Continued) Test Description Value Point If you do not see the VCTCXO signal at 2.8V test points 1-5, check the voltage at VR3 AFC voltage...
6255/6255i/6256/6256i (RM-19) Nokia Customer Care RF Description and Troubleshooting AFC Voltage Troubleshooting Use the following steps to monitor the AFC voltage. 1. In Phoenix, open the RF PDM dialog box. Figure 44: RF PDM dialog box for AFC troubleshooting Figure 45 shows a partial schematic of the R7205.
6255/6255i/6256/6256i (RM-19) RF Description and Troubleshooting Nokia Customer Care Figure 46: Tx Output for AMPS channel 384, power level 5 UHF Synthesizer The UHF LO frequency varies with the channel and can be calculated using the Frequency Calculator dialog box in the Phoenix RF component. Use the following steps to troubleshoot the UHF LO frequency.
6255/6255i/6256/6256i (RM-19) Nokia Customer Care RF Description and Troubleshooting UHF Synthesizer Test Points N7100 Figure 47: UHF synthesizer layout Table 16 shows the description for each component in Figure 47. Table 16: UHF Synthesizer Layout Components Test Description Value Point...
6255/6255i/6256/6256i (RM-19) RF Description and Troubleshooting Nokia Customer Care Rx VHF LO (N7100) Schematic Following are the main layout components on a partial view of the Rx VHF schematic. See the Schematics chapter for detailed versions. Loop filter components Lock voltage...
6255/6255i/6256/6256i (RM-19) Nokia Customer Care RF Description and Troubleshooting Rx VHF LO Troubleshooting The VHF LO operates at a fixed frequency of 256.2MHz. It is the second LO for down- conversion to I and Q for baseband processing. Use the following steps to troubleshoot the VHF LO.
6255/6255i/6256/6256i (RM-19) Nokia Customer Care RF Description and Troubleshooting Tx UHF LO (N7000) Troubleshooting There are two fixed LOs, 3296.16~3395.88MHz for cell band and 3700~3819.90MHz for PCS band. This is the only LO for up-conversion. Be sure to monitor the control voltage at R7001.
6255/6255i/6256/6256i (RM-19) Nokia Customer Care RF Description and Troubleshooting GPS RF Schematic The following schematic is for general reference only. See the Schematics chapter for a detailed version. GPS RF chip GPS LNA GPS TCXO RF test input RF filter 2...
6255/6255i/6256/6256i (RM-19) RF Description and Troubleshooting Nokia Customer Care GPS Troubleshooting Setup Use the following steps to set up GPS signal using Phoenix. 1. On the Phone Control dialog box, click the LOCAL button in the Phone State area to put the mobile terminal into Local Mode. (See Figure 9 on page 16 for an example of the Phone Control dialog box.)
6255/6255i/6256/6256i (RM-19) Nokia Customer Care RF Description and Troubleshooting 5. In the Test Mode field, ensure that Galvanic is selected. 6. Click Execute. Self Test Failure If the test fails, repeat steps 1—6. If the test fails again, continue with the following self- test failure troubleshooting: 1.
6255/6255i/6256/6256i (RM-19) RF Description and Troubleshooting Nokia Customer Care 2. Click Execute. Figure 56: Turning on the GPS receiver on the GPS Control dialog box 3. Inject a -50dBm tone at 1575.52MHz at the GPS connector (X6250) with a signal generator or a call box.
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6255/6255i/6256/6256i (RM-19) RF Description and Troubleshooting Nokia Customer Care Table 19 shows the values for the GPS DC test points in Figure 57. Table 19: GPS DC Test Point Values Test Description Value Point 1.8V VRF_GPS 2.8V LNA base 0.8V LNA Vcc 1.5V...
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6255/6255i/6256/6256i (RM-19) RF Description and Troubleshooting Nokia Customer Care Table 20 shows the values for the GPS RF test points in Figure 58. All points are 1575.52MHz, except TCXO. Table 20: GPS RF Test Point Values Test Description Value Point GPS TCXO 16.368MHz = -19dBm...
6255/6255i/6256/6256i (RM-19) Nokia Customer Care RF Description and Troubleshooting FM Radio Troubleshooting FM Radio Schematic The following schematic is for general reference only. See the Schematics chapter for a detailed version. Loop filter and VCO FM radio IC Audio output...
6255/6255i/6256/6256i (RM-19) RF Description and Troubleshooting Nokia Customer Care FM Radio Troubleshooting Setup Use the following steps to troubleshoot the FM radio while using a Pop-port headset. 1. Connect the Pop-port headset (HDS-3) to the Pop-port connector (bottom connector). 2. Select the Menu > Media > Radio from the mobile terminal user interface.
6255/6255i/6256/6256i (RM-19) Nokia Customer Care RF Description and Troubleshooting Bluetooth Troubleshooting Bluetooth Schematic The following schematic is for general reference only. See the Schematics chapter for a detailed version. Bluetooth ASIC (N6000) SAW filter Bluetooth antenna strip Inverter Supply line filtering...
6255/6255i/6256/6256i (RM-19) RF Description and Troubleshooting Nokia Customer Care Bluetooth Troubleshooting Setup Use the following steps to troubleshoot the BC02 Bluetooth Control component in Phoenix: 1. On the Bluetooth Control dialog box, select the Tests tab. 2. In the PRBS9 list, choose TX Data 1.
6255/6255i/6256/6256i (RM-19) Nokia Customer Care RF Description and Troubleshooting Bluetooth Troubleshooting Flowchart Bluetooth Is the VREG_IN BT Replace the EXT external supply regulator. Is it OK? voltage 2.8V? Is the VIO bluetooth external supply Replace the R6002. voltage 1.8V? (Probe Is it OK? at the UEM side.)
6255/6255i/6256/6256i (RM-19) RF Description and Troubleshooting Nokia Customer Care Bluetooth DC and RF Test Points Figure 63 shows the bluetooth DC and RF test points on the bottom side of the main PWB. Digital inverter Voltage regulator Figure 63: Bluetooth DC and RF test points on the bottom side of the main PWB Table 23 shows the values associated with the bluetooth test points in Figure 63.