CC Technical Documentation NPM-10 (3595) Series Transceivers Troubleshooting - RF Issue 2 03/2004 Confidential ©2004 Nokia Corporation
NPM-10 (3595) Troubleshooting - RF CC Technical Documentation Contents Page RF Troubleshooting ....................................................................................................... 3 Abbreviations in Troubleshooting Charts ....................................................................3 Introduction ..................................................................................................................3 General Description of the RF Circuits .............................
NPM-10 (3595) Troubleshooting - RF CC Technical Documentation RF Troubleshooting Abbreviations in Troubleshooting Charts Table 1: Troubleshooting Abbreviations Abbreviation Definition BB Base band DC Direct current ESD Electrostatic discharge FEM Front End Module LF Low frequency LO Local oscillator LPF Low pass filter PA Power amplifier PLL Phase-locked loop PWB Printed wiring board RCT Radio communication tester RF Radio Frequency Rx Receiver Tx Transmitter UHF Ultra-high
NPM-10 (3595) Troubleshooting - RF CC Technical Documentation Always make sure the measurement set-up is calibrated when measuring RF parameters on the antenna pad. Remember to include the loss in the module test jig when realigning the phone. Most RF semiconductors are static-discharge sensitive. Use ESD protection during repair (ground straps and ESD soldering irons). Mjoelner is moisture-sensitive, so parts must be pre-baked prior to soldering.
NPM-10 (3595) Troubleshooting - RF CC Technical Documentation The output from the mixer is fed to the Mjoelner BB where the signal is amplified in the BBAMP, and the low pass is filtered in LPF1 before the DC compensation circuits in DCN1. The DCN1 output is followed by a controlled attenuator and a second low pass filter (LPF2). The output from LPF2 is DC centered in DCN2 before being fed to the BB for demodulation.
NPM-10 (3595) Troubleshooting - RF CC Technical Documentation The reference frequency is generated by a 26 MHz, voltage-controlled X-tal oscillator (VCXO), which is located in Mjoelner. Only the X-tal is external. Twenty-six MHz is supplied to the BB, where a divide-by-2 circuit (located in the UPP IC) generates the BB clock at 13 MHz. The reference frequency is supplied to the reference divider (RDIV) where the frequency is divided by 65.
NPM-10 (3595) Troubleshooting - RF CC Technical Documentation As Table 2 indicates, the PLL must be able to cover the frequency range from 3296.8 MHz to 3979.6 MHz.
NPM-10 (3595) Troubleshooting - RF CC Technical Documentation Figure 4: Key RF Component Locations Power Supply Configuration All power supplies for the RF unit are generated in the UEM IC (D200). All power outputs from this IC have a decoupling capacitor at which the supply voltage can be checked.
NPM-10 (3595) Troubleshooting - RF CC Technical Documentation Figure 5 shows the power supply configuration used in the NPM-10 (3595) phone. PA UEM Battery MJOELNER Vtx VR2 VddTX Vdddig VR3 VXO VddXO Vddbbb VddPLL VddLO VddPre VPLL VR5 VCP VR1A Vrx VddRXF VddRXBB VddCP Vbext Sel_addr VddDL VR6 Vbb VIO Vref1 Vref01 VR7 VCO module Vvco Figure 5: Power supply configuration The names in bold are signal names, which are used in the RF schematics.
NPM-10 (3595) Troubleshooting - RF CC Technical Documentation Figure 6 shows the measuring points at the UEM (D200). VR2=Vtx (C643) VR5=Vpll (C226) VR7=Vvco (C224) VR3=Vvcxo (C227) VR6=Vrx (C225) Vref01=Vref2 (C231) Figure 6: Supply points at the UEM (D200) Figure 7 shows the supply point at the Mjoelner (N600). Vio=Vbb (C621) Figure 7: Supply point at the Mjoelner (N600) Receiver General Instructions for GSM 850 Rx Troubleshooting Use the following steps to troubleshoot the GSM 850 Rx: 1.
NPM-10 (3595) Troubleshooting - RF CC Technical Documentation 4. Open the Maintenance menu, point to Testing, and click RF Controls. 5.
NPM-10 (3595) Troubleshooting - RF CC Technical Documentation Troubleshooting Chart for the GSM 850 Receiver 1 1 4 3 2 Apply -55 dBm 881.6 MHz, offset 67.71 kHz from generator to antenna connector YES 2 Oscilloscope at RX I/Q signal 704 mVpp DC offset 1.38 V freq. 67.
NPM-10 (3595) Troubleshooting - RF CC Technical Documentation Figure 10 shows the results of measuring with an oscilloscope at RXIP or RXQP on a working GSM 850 receiver. • Signal general frequency = 881.66771 MHz • Amplitude = -55 dBm • Signal amplitude peak = 704 mV • DC offset = 1.38 V Figure 10: RX850 I/Q signal waveform General Instructions for GSM 1900 Rx Troubleshooting Use the following steps to troubleshoot the GSM 1900 Rx: 1. Connect the phone to a PC with the module test jig. 2.
NPM-10 (3595) Troubleshooting - RF CC Technical Documentation • Rx/Tx Channel = 661 • AGC = 9 Figure 11: GSM 1900 values on the Rx RF Controls dialog box Page 14 ©2004 Nokia Corporation Confidential Issue 2 03/2004
NPM-10 (3595) Troubleshooting - RF CC Technical Documentation Troubleshooting Chart for PCS Receiver 1 1 4 3 2 Apply -55 dBm 1960 MHz, offset 67.71 kHz from generator to antenna connector YES 2 Oscilloscope at RX I/Q signal 416 mVpp DC offset 1.35 V freq. 67.
NPM-10 (3595) Troubleshooting - RF CC Technical Documentation Figure 13 shows the results of measuring with an oscilloscope at RXIP or RXQP on a working GSM 1900 receiver. • Signal general frequency = 1960.06771 MHz • Amplitude = -55 dBm • Signal amplitude peak-peak 416 mV • DC offset 1.
NPM-10 (3595) Troubleshooting - RF CC Technical Documentation Measurement Points in the Receiver VANT1 Z700 VANT3 N700 RF Antenna (RX in) N700 VANT2 Z700 Figure 14: Rx measurement points at the front-end module PA (N700) RX850 Mjoelner input INML L602 RX850 Mjoelner input INPL L603 RX1900 Mjoelner input INMM L611 RX850 Mjoelner input INPM L601 RX850 SAW filter bal output Z602 RX1900 SAW filter bal output Z601 RX850 SAW filter unbal input Z602 RX1900 SAW filter unbal input Z601 Figure 15: Measur
NPM-10 (3595) Troubleshooting - RF CC Technical Documentation RXQM D200 RXIP D200 RXIM D200 RXQP D200 Figure 16: Rx I/Q Signals, baseband shielding can Transmitter Measurement Points for the Transmitter VANT1 VTX_B_P VANT3 OUT_D_TX DET ANT (Tx out) VPCTRL_G VANT2 VTXLO_G Figure 17: Tx measurement points in the PA (N700) shielding can Page 18 ©2004 Nokia Corporation Confidential Issue 2 03/2004
NPM-10 (3595) Troubleshooting - RF CC Technical Documentation VTX TXQM TXQP TXIP TXIM Bal_Input2 PCS OUT_D_TX Bal_Input1 PCS Bal_Input1 GSM Bal_Input2 GSM OUT_G_TX Figure 18: Tx measurement points in the Mjolner (N600) shielding can General Instructions for GSM Tx Troubleshooting Use the following steps to troubleshoot the GSM Tx: 1. Apply an RF cable to the RF connector to allow the transmitted signal to act as normal.
NPM-10 (3595) Troubleshooting - RF CC Technical Documentation • Tx Power Level = 5 • Tx Data Type = All 1 Figure 19: GSM 7 Page 20 Tx values on the RF Controls dialog box Measure the output power of the phone; it should be around 32.0 dBm. Remember the loss along the end launch connector in the test jig (around 0.3 dB).
NPM-10 (3595) Troubleshooting - RF CC Technical Documentation Troubleshooting Chart for GSM 850 Transmitter Use a high impedance probe for the spectrum analyzer measurements in the following chart. Set the trace to maxhold because the signal is bursted. Measure power on ANT with power meter or RCT >31dBm No Measure pin 1 of FEM: -0dBm No Yes Measure BAL input to Z603 0dBm No Check VTX with scope: 2.
NPM-10 (3595) Troubleshooting - RF CC Technical Documentation Figure 21: TXP, VPCTRL_G and TXC Page 22 ©2004 Nokia Corporation Confidential Issue 2 03/2004
NPM-10 (3595) Troubleshooting - RF CC Technical Documentation Troubleshooting the Modulation The following plots show different situations of Tx IQ measurements. Depending on the time, the modulation may cause the signal to look differently.
NPM-10 (3595) Troubleshooting - RF CC Technical Documentation 6. Select the following values on the RF Controls dialog box: • Band = GSM 1900 • Active Unit = Tx • Tx Power Level = 0 • Tx Data Type = All 1 Figure 23: PCS Tx values on the RF Controls dialog box 7. Measure the output power of the phone; it should be around 29.5 dBm. Remember the loss in the test jig (around 0.7 dB).
NPM-10 (3595) Troubleshooting - RF CC Technical Documentation Figure 24 shows a troubleshooting chart for the PCS transmitter Measure power on ANT with power meter or RCT >28dBm No Measure Pin_PCS: -2dBm No Yes Measure BAL input to T600 -4dBm No Check VTX with scope: 2.7V + discretes around Yes Yes Check T602 (PCS Balun) Check TXIP and TXQP (See Figure 22) No Yes Check R759, C746 Check FEM with scope: Vant1,Vant3 = 0 Vant2, Vant4= 2.4 to 2.8V VTX_B_P and VTXLO_G= 2.
NPM-10 (3595) Troubleshooting - RF CC Technical Documentation The following applies to Figure 25: • PCS 1900 band, Power level 0, Channel 661 • Red trace: Vpctrl_P @ R713 output Figure 25: VPCTRL_P Note: TXIQ signals look the same in PCS and GSM Synthesizer There is only one PLL synthesizer generating local oscillator frequencies for both the Rx and Tx in both bands (PCS and GSM). The VCO frequency is divided by two for PCS operation or by four for GSM operation inside the Mjoelner IC.
NPM-10 (3595) Troubleshooting - RF CC Technical Documentation • Operation Mode = Continuous • Rx/Tx Channel = 661 Figure 26: Synthesizer values on the RF Controls dialog box It is not possible to measure the output of the VCO (G600) directly because this component is placed underneath a shielding can without a detachable lid. However, it is possible to get an indication if the VCO outputs the correct frequency with a spectrum analyzer and a high impedance probe. To do this, probe R656 and C654.
NPM-10 (3595) Troubleshooting - RF CC Technical Documentation Example Signal Measured at VCXO output (R420) Figure 27: VCXO 26 MHz waveform VCO The VCO generates frequencies in the range of 3296.8 MHz–3979.6 MHz when the PLL is running. The output frequency from the VCO is led to the local oscillator input of the Mjoelner IC (N600), where the frequency is divided by two or four so that they can generate all channels in GSM and PCS respectively.
NPM-10 (3595) Troubleshooting - RF CC Technical Documentation • Operation Mode = Continuous • Rx/Tx Channel = 661 Figure 28: RF Controls settings for PLL troubleshooting 5. Troubleshoot using Figure 29.
NPM-10 (3595) Troubleshooting - RF CC Technical Documentation Spectrum analyzer VCO frequency (R656) 3920.0 MHz Yes PLL block functional No Check UEM, Software, phone not in function No VCXO is not functional, check crystal (B600) No Check UEM, software, phone not in function No Check UEM, software, phone not in function No VCO (N601) is not functional No Check loop filter R618, R619, C639-C641 No Oscilloscope VCXO power supply (C620) 2.
NPM-10 (3595) Troubleshooting - RF CC Technical Documentation If the phone stops working a short time after the power is turned ON, the 26 MHz system clock signal might not be getting to the UPP clock-input in the baseband. In this case, turn on the phone and verify the following: • VCXO power supply (C620) = 2.
NPM-10 (3595) Troubleshooting - RF CC Technical Documentation Measurement Points at the PLL/VCO PLL Vcc (C634) VCO Vcc (C654, R656) Be careful - do not short this point with shield. The VCO Out put is also detected here.
NPM-10 (3595) Troubleshooting - RF CC Technical Documentation Frequency Lists GSM 850 Ch 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 TX 824.2 824.4 824.6 824.8 825 825.2 825.4 825.6 825.8 826 826.2 826.4 826.6 826.8 827 827.2 827.4 827.6 827.8 828 828.2 828.4 828.6 828.8 829 829.2 829.4 829.6 829.8 830 830.2 830.4 830.6 830.8 831 831.2 831.4 831.6 831.8 832 832.2 832.4 RX 869.2 869.
NPM-10 (3595) Troubleshooting - RF CC Technical Documentation PCS 1900 Ch 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 TX 1850.2 1850.4 1850.6 1850.8 1851 1851.2 1851.4 1851.6 1851.8 1852 1852.2 1852.4 1852.6 1852.8 1853 1853.2 1853.4 1853.6 1853.8 1854 1854.2 1854.4 1854.6 1854.8 1855 1855.2 1855.4 1855.6 1855.8 1856 1856.2 1856.4 1856.6 1856.
NPM-10 (3595) Troubleshooting - RF CC Technical Documentation Ch 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 TX 1860.2 1860.4 1860.6 1860.8 1861 1861.2 1861.4 1861.6 1861.8 1862 1862.2 1862.4 1862.6 1862.8 1863 1863.2 1863.4 1863.6 1863.8 1864 1864.2 1864.4 1864.6 1864.8 1865 1865.2 1865.4 1865.6 1865.8 1866 1866.2 1866.4 1866.6 1866.8 1867 1867.
NPM-10 (3595) Troubleshooting - RF CC Technical Documentation 3. Open the File menu, and click Choose Product. 4. Select NPM-10. 5. Attenuation in the test jig RF connector alone is 0.3 dB for GSM 850 and 0.7 dB for GSM1900. 6. Use an RCT (radio communication tester), spectrum analyzer, or another suitable device for tuning or testing the phone. The default channels are 190 for GSM 850 and 661 for GSM 1900.
NPM-10 (3595) Troubleshooting - RF CC Technical Documentation Figure 34 shows the current values stored in permanent memory. Figure 34: Rx Band GSM 850 calibration values 4. Adjust the signal generator settings to the frequency and amplitude specified in the Calibration with band GSM850 message box. 5. Click OK. The 850 band is calibrated and automatically stored in PM. 6. Phoenix prompts for the 1900 MHz calibration while displaying the current values in PM.
NPM-10 (3595) Troubleshooting - RF CC Technical Documentation 7. Adjust the signal generator settings to the frequency and amplitude specified in the Calibration with band GSM 1900 message box. Figure 35: Rx Band GSM 1900 calibration values 8. Click OK. 9. New RSSI values are calculated and stored in PM.
NPM-10 (3595) Troubleshooting - RF CC Technical Documentation Rx Channel Select Filter Use the following steps to calibrate the Rx channel select filter: 1. Open the Maintenance menu, point to Tuning, and click Rx Channel Select Filter Calibration. 2. Choose whether you want to load values from the phone on the Phoenix - (Rx Channel Select Filter Calibration) window. 3. Click the Auto Tune button. Figure 36: Phoenix - Rx Channel Select Filter Calibration window 4. When finished, press the Stop button.
NPM-10 (3595) Troubleshooting - RF CC Technical Documentation Rx Band Filter Response Use the following steps to calibrate the Rx band filter response: 1. Open the Maintenance menu, point to Tuning, and click Rx Band Filter Response Compensation. 2. Click the Start, Read from PM area button. 3. Choose whether you want to load values from the phone on the Rx Band Filter Response Compensation dialog box. Figure 38: Rx Band Filter Response Compensation dialog box 4. Click the Manual Tuning button. 5.
NPM-10 (3595) Troubleshooting - RF CC Technical Documentation 7. Click Yes on the Tune ending message box if you want to save the values to the phone. Figure 39: Tune ending message box 8. Repeat steps 1-7 for the GSM 1900. Note: This calibration requires a lot of different frequencies from the generator. If you have a signal generator with a frequency list option, you can use Auto Tuning (the dwell should be around 10 ms).
NPM-10 (3595) Troubleshooting - RF CC Technical Documentation Tx Tuning Use the following steps to tune the Tx: 1. Open the Maintenance menu, point to Tuning, and click Tx Power Level Tuning. 2. Press the Start, Read from PM area button. 3.
NPM-10 (3595) Troubleshooting - RF CC Technical Documentation Figure 41: GSM 850 values on the Tx Power Level Tuning dialog box Use the following steps to tune the GSM 850 Tx: 1. Set the Tx data type modulation to 1, 0, or Random. (Select Random if a GSM tester is used so it can be synchronized to the burst.) 2. Select High in the Tx PA Mode field. (Do not use Low PA Mode tuning.) 3. The first power tuning should be setting the base level to –30 dBm. 4.
NPM-10 (3595) Troubleshooting - RF CC Technical Documentation Tx Power Tuning PCS 1900 Repeat steps 1-6 from the “Tx Power Tuning GSM 850” section above for the 1900 MHz. After you tune the power levels, which appear bold in Figure 42, click OK. Phoenix calculates the coefficients for the remaining power levels and saves them to permanent memory. Figure 42: GSM 1900 values on the Tx Power Level Tuning dialog box Tx I/Q Tuning Use the following steps to tune the Tx I/Q: 1.
NPM-10 (3595) Troubleshooting - RF CC Technical Documentation • VBW = 1 kHz • Sweeptime = .5 seconds • RF attenuation = 20 dB • Reference level = 30 dBm • Trigger = free run 3. Select where to get the values. Typically, you would click Load From Product. 4. Push the Start soft key. 5. Use the sliding arrows or the + and - keys to adjust the Tx I DC offset and Tx Q DC offset values to reduce the carrier frequency to a minimum. The carrier must be at least –30 dBc.
NPM-10 (3595) Troubleshooting - RF CC Technical Documentation 6. Use the sliding arrows or the + and - keys to adjust the Amplitude difference and Phase difference values to reduce the lowest sideband frequency. The sideband must be reduced at least –35 dBc. Typically, sideband suppression is better than -40 dBc. 7. Ensure that the IQ tuning values meet the specifications for both 1 and 0 data types.
NPM-10 (3595) Troubleshooting - RF CC Technical Documentation 8. Select the Save to Product box if you want to save the tuning values to the phone. 9. Push the Stop soft key. This ends tuning and saves the values to the phone if you have selected the Save to product box. 10. Repeat steps 1-11 for the PCS 1900 using channel 661. Figure 45 includes typical tuning values for the PCS 1900.
NPM-10 (3595) Troubleshooting - RF CC Technical Documentation RF Control Use the following steps to check the receiver or transmitter without going in a call. This process is similar to a call, but you have control through the PC instead of the tester. Ensure that the GSM 850 Tx PA mode is set to High. 1. Open the Maintenance menu, point to Testing, and click RF Controls. 2.
