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Nokia NPM-2NX, Troubleshooting Manual

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Nokia NPM-2NX Troubleshooting Manual Download Page 66

NPM-2NX

Troubleshooting

CCS Technical Documentation

Page 66

 

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Nokia Corporation

Issue 1 07/02

GSM TX tunings

If some TX tuning fails, start always TX troubleshooting!

TX IQ

• Purpose of this tuning is tune DC offset and phase offset so low as possible

•Typical values Amplitude: -45 to –55 dBc and Phase: –50 to – 60 dBc

If tuning fails there can be following problems:

• UEM or Safari

• Too low output power

TX Power levels

• Purpose of this tuning is tune all power levels (PL0 – PL15)

If tuning fails there can be following problems:

• Broken components: PA, Safari, up converter, some filters

• Missing components

TX crossband

• Purpose to tune ch512 and ch810 equals to mid (ch661) channel power

•Typical values

•Low Comp Factor –0.5 to –1.5

•High Comp Factor  0.5 to 2

Summary of Contents for NPM-2NX

Page 1: ...CCS Technical Documentation NPM 2NX Series Transceivers Issue 1 07 02 ãNokia Corporation Troubleshooting ...

Page 2: ... supply for data cable 20 Sleep Clock 20 Display Keyboard lights do not work 22 Display does not work 23 Buzzer does not work 23 Vibra does not work 24 Keyboard does not work 24 SIM does not work 24 Infrared does not work 25 RF Troubleshooting 26 Introduction 26 Abbreviations in fault finding charts 26 Receiver 27 General instructions for RX troubleshooting 27 Path of the received signal 28 AMPS 2...

Page 3: ...une Tuning 61 TDMA RF tunings 61 TDMA RX tunings 61 TDMA TX tunings 62 GSM RF tunings 64 GSM RX tunings 64 GSM TX tunings 66 List of Figures Fig 1 UEM regulator s filter capacitors 5 Fig 2 BB testpoints 6 Fig 3 Power up sequence 9 Fig 4 Fault tree phone does not power up 11 Fig 5 Fault tree charging 15 Fig 6 Fault tree earpiece fail 17 Fig 7 Fault tree microphone fail 18 Fig 8 Fault tree accessory...

Page 4: ... local or test mode at start up if correspond ing resistors are connected Note Baseband doesn t wake up automatically when the battery voltage is connected normal mode Power can be switched on by Pressing the power key connecting a charger RC alarm function In the local and test mode the baseband can be controlled through MBUS or FBUS FBUS is recommended connections by a Phoenix service software M...

Page 5: ...l Documentation Troubleshooting NPM 2NX Issue 1 07 02 ãNokia Corporation Page 5 Measurement points Figure 1 UEM regulator s filter capacitors VR6 VR4 VR2 VR7 VR3 VR1B VR1A VCORE VFLASH VFLASH VANA VSIM VIO VR5 UEM ...

Page 6: ...cal Documentation Page 6 ãNokia Corporation Issue 1 07 02 Figure 2 BB testpoints SLEEPCLK UEMINT SLEEPX PURX DbusDA CbusDA CbusENX Fbus TX CbusCLK DbusCLK FbusRX DbusENX MbusRX MbusTX RFCLK Init clk 19 22MHz GSM 13MHz TDMA UEM FLASH UPP ...

Page 7: ...ervice The Baseband Troubleshooting instructions consists of the following topics Power up Flash programming Audio Earpiece Microphone Charging Accessory detection Data cable Sleep clock User interface Display Lights Buzzer Vibra Keyboard Infra red Power up faults Power up sequence UEM acts as a HW master during start up Vbatt limits 2 1V for internal state machine 3V triggering whole startup Regu...

Page 8: ...he UEM switching the regulators OFF MCU starts running the Bootsrap Code written in stone UPP internal ROM the program checks if there exists any reason for FDL mode Flash Down Load If there exists executable code in FLASH and there exists no reason for FDL the MCU starts running the MCU program from FLASH MCU runs the FLASH MCU code the phone initialization user interfaces internal blocks etc Cor...

Page 9: ...9 2 MHz running 3 Purx released Purx released by UEM UEMINT goes high for 100 ms and about 500ms RFCLK will change 13MHz GSM mode SleepX goes high and UEM starts feeding SleepClk 32 KHz to UPP NOTE Sleepclock starts running in crystal circuitry B200 immediately when battery voltage is supplied 4 Software running Default value for Vcore is 1 5 volts and if software is running Vcore will rise to 1 8...

Page 10: ...le to force phone on by disabling watch dog Instead measurements should be done immediately when power key pressed or when battery voltage connected to phone local test mode The easist way to check if software is running when phone takes abnormal amount of current is to measure cbusclk and Vcore Dbus clock programmable 9 72MHz TDMA 13MHz GSM is not automatically visible on test and local mode ...

Page 11: ...ash1 Vana Vio Vcore VR3 when pwr key pressed Check 13MHz GSM or 19 44 TDMA RF clock from C420 Check that purx goes up to 1 8V Change UPP D400 Change the UEM D200 OK Measure VBAT from C262 Check R202 R203 R205 C217 C220 Check G801 missing misaligned Measure J406 1 08 MHz TDMA and 1 00MHz GSM Check C420 Check 19 2MHz from G801 See RF troubleshooting FAIL Re flash phone OK OK FAIL VR3 missing FAIL OK...

Page 12: ...by Prommer If bootstrap is not requested bootstrap code jumps to FLASH SW If Bootstrap code is requested UPP enters Flash mode and sets FbusTX to 0 as acknowledgement to prommer This is an indication that UPP can run at least the fixed Bootstrap code although not able to run FLASH code UPP then sends an UPP ID to prommer via FBUSTX line After prommer has received UPP ID it sends corresponding Seco...

Page 13: ...UPP MbusRx SA0 FbusRx from Prommer UEM UPP FbusTx from UPP UEM Prommer C104 MCU ID message sending failed in the Phone FbusTx from UPP UEM Prommer C105 The Phone has not received Secondary boot codes length bytes correctly Mbus from Prommer UEM UPP MbusRx FbusRx from Prommer UEM UPP FbusTx from UPP UEM Prommer C106 The Phone has not received Secondary code bytes correctly Mbus from Prommer UEM UPP...

Page 14: ...ansfer C384 during algorithm download to target phone C584 during erasing C684 during programming Flash UPP Signals between UPP Flash C585 C685 Data block handling timeout C585 during erasing C685 during programming Flash UPP Signals between UPP Flash C586 C686 The status response from the Phone informs about fail C586 during erasing C686 during programming Flash ...

Page 15: ...er and check audios 2 In case of earpiece XMIC fail Feed 1Khz signal to XMIC line and measure signal from earpiece line Audio test box JBA 8 is needed Audio loop Audio test Ext In Hp Out must be switched on by Phoenix service software This loop will connect audios only through UEM In this case UPP is not used Phone doesn t start charging Connect charger and check VCHARIN check CHRG_CTRL if used AC...

Page 16: ...d measure signal from XEAR line Audio test box JBA 8 is needed Audio loop Audio test Hp In Ext Out must be switched on by Phoenix service software This loop will con nect audios only through UEM In this case UPP is not used 4 Run audio loop selftest with Phoenix BB Self tests ST_EAR_DATA_LOOP_TEST This loop will test the eardata micdata lines between UPP and UEM ...

Page 17: ...phone line does not work Figure 6 Fault tree earpiece fail Earpiece doesn t work Run audio loop selftest with phoenix Check R157 L152 L158 C150 C164 C153 C165 R152 C156 C155 R164 R161 R153 R150 C159 C167 V153 Check earpiece Change UEM Feed 1KHz to Xmic by JBA 8 and measure from earpiece Change UPP Fail OK OK OK Fail OK ...

Page 18: ...e does not work Figure 7 Fault tree microphone fail Microphone doesn t work Run audio loop selftest with phoenix Check C151 C152 C157 L151 C162 C168 C169 R156 R162 R166 R159 C154 C158 C161 C166 R163 L159 V152 Check microphone Change UEM Feed 1KHz to Mic and measure from Xear by JBA 8 Change UPP Fail Ok Ok Ok Ok Fail ...

Page 19: ... 50 and hookint value between 0 30 Figure 8 Fault tree accessory detection Accessory detection doesn t work normally Check HeadInt and HookInt ad value with Phoenix No accessory connected HeadInt and HooInt 1000 Change UEM Check headint line L152 C150 R152 C153 R154 C160 R153 R150 C159 Check hookint line L159 R163 C158 R155 R151 C161 V152 Check bottom connector Connect HDC 9 and keep the HDC 9 swi...

Page 20: ...lt tree data cable Sleep Clock Missing non functional sleep clock causes Entering sleep mode fails higher current consumption shorter standby time Baseband self tests cannot be run DLR 3 data cable doesn t work Connect DLR 3 check DLR 3 detection Change UEM Check V151 V152 R161 C164 L158 Check the components of XMIC HEADINT and MICB2 lines Check bottom connector Check SGND voltage from bottom conn...

Page 21: ...okia Corporation Page 21 Phone clock on display does not function properly Figure 10 Fault tree sleep clock Sleep mode not working Measure sleep clock from J404 Check C203 C204 Change B200 Change UPP D400 Fail Measure sleep clock from B200 Change UEM D200 Fail Ok Ok Ok ...

Page 22: ...hts do not work Figure 11 Fault tree Display Keyboard lights Display Keyboard lights are not working Check R300 Display and R301 Keyboard Replace resistor s Check LEDs V300 V303 V310 V311 Display and V304 V309 Keyboard Replace LED s Use Display Test in Phoenix to set lights ON OFF FAIL OK FAIL OK Replace UEM FAIL ...

Page 23: ...n Check PWB and elastomer connector Run LCD test in Phoenix BB Self Tests ST_LCD_TEST Proceed to phone doesn t power up troubleshooting Replace display module Clean PWB and replace elastomer if needed Check capacitors C302 C304 FAIL OK FAIL FAIL OK FAIL Replace capacitors s FAIL Replace elastomer OK OK Replace display module FAIL Use Display Test in Phoenix to check if display works OK In any phas...

Page 24: ...ix to set vibra parameters frequency duty cycle If it doesn t effect to the magnitude of vibration change vibra Keyboard does not work Check that there is no dirt between the dome sheet and the PWB and also check that Z300 is properly soldered and the cornner mark is located in the right place If the key board still doesn t operate normally try to use Keyboard test in Phoenix to see if the pressed...

Page 25: ...R module VCC pin6 should be 2 78V Change UEM D200 Check R350 R351 C351 and V350 Replace faulty component s Use ST_IR_LOOP_TEST in BB Self Tests in Phoenix FAIL OK FAIL OK Use ST_IR_IF_TEST in BB Self Tests in Phoenix OK Phone OK Measure Tx Data from IR module pin3 2 78V 9 6 115 2kbps FAIL Measure Rx Data from IR module pin4 OK Change IR module OK Change UEM FAIL OK UPP or UEM is faulty FAIL ...

Page 26: ...ance is specified for critical signals voltages Before changing single ASICS or components please check the following things 1 The soldering and alignment marks of the ASICS 2 Supply voltages and control signals are OK The PA module is static discharge sensitive So ESD protection must be used when dealing with PA IC ground straps and ESD soldering irons The PA is also moisture sen sitive component...

Page 27: ...oubleshooting instructions are included Please note that before changing ASICs or filters all solderings and missing components must be checked visually After any possible component changes phone must be re tuned using Phoenix autotune procedure Signal levels are not shown in the flowcharts below because of the figures apply with specific measurement probes It is useful to compare the results agai...

Page 28: ... 1900 LNA 850 Band filter Band filter 1st mixer 1st mixer GSM ch filter TDMA ch filter AGC AGC 2nd mixer 2nd mixer Buffer Buffer BB filter BB filter AGC AGC Q I Q I Receiver Block Diagram SAFARI GTE UHF LO VHF LO 1930 1990 MHz 869 894 MHz 133 2 MHz BW200 kHz 134 04 MHz BW30 kHz 2063 2124 MHz 1003 1029MHz VCO 2 133 2 MHz VCO 2 AGC 1 31 dB 5 steps AGC 6 36 dB 7 steps TDMA AGC 6 30 dB 5 steps GSM AGC...

Page 29: ...e bottom connector to audio Analyzer AMPS RX is OK SINAD 12 dB SINAD 12 dB Apply signal to ext antenna connector f 881 4091125MHz ch 380 unmodulate level 50dBm Check signal level at diplexer Z908 input Replace external antenna connector X900 Not OK OK Check signal level at duplex filter Z906 input Replace diplexer Z908 Not OK OK Check signal level at LNA_a input coil pad L802 If coil L802 is ok re...

Page 30: ...d filter Z801 Not OK OK Check signal level at IF filter Z803 input 134 04 MHz R801 Not OK OK Start synthesizer Troubleshooting UHF VCO OK Not OK Check signal level at IF filter Z803 output 134 04 MHz R802 Not OK OK Replace IF filter Z803 Check signal level at RX I Q J808 J809 J818 J819 Not OK OK Start synthesizer Troubleshooting RX VF HF Check UEM and startbaseband troubleshooting Measure VR4 from...

Page 31: ...de set audio test mode See picture below Step 2 Local oscillator checking Carrying out this step VCO signal of 1st and 2nd mixers can be checked 2nd mixer RX VHF VCO frequency is constant 268 08 MHz but for the 1st mixer UHF VCO frequency depends on the channel The UHF VCO frequencies for the 1st mixer are Channel 991 2006 16 MHz Channel 380 2030 88 MHz Channel 799 2056 02 MHz 1 Set signal generat...

Page 32: ...18 and record RX VHF VCO signal level and frequency Signal level should be around 25 dBm and frequency 268 08 MHz 6 Set spectrum analyzer settings as following Center frequency 2030 88 MHz Span 200 kHz RBW 3 kHz reference level 10 dBm 7 Connect spectrum analyzer probe to VCO output pad and record UHF VCO signal level and frequency Signal level should be around 5 dBm and frequency 2030 88 MHz 8 Rep...

Page 33: ... looking at the RX I Q voltage during signal level change 7 Measure and record the frequency and peak to peak voltage of RX I Q signal from each test points Voltage should be around 100 mVp p and frequency 6 5 kHz 3 kHz TDMA800 Since there is same physical signal path for both analog AMPS and digital mode TDMA in lower band there is no need for additional troubleshooting in digital mode If digital...

Page 34: ... MHz ch 1000 unmodulated level 50 dBm Check signal level at RX I Q J808 J809 J818 J819 OK T DMA 1900 RX is OK Not OK Check signal level at diplexer Z908 input Replace external antenna connector X 900 Not OK OK Check signal level at duplex filter Z962 input Replace diplexer Z908 Not OK OK Check signal level atL NA V 804 input Replace duplex filter Z962 Not OK OK ...

Page 35: ...annel The UHF VCO frequencies for the 1st mixer are Channel 2 2064 12 MHz Channel 1000 2094 06 MHz Channel 1998 2124 00 MHz 1 Set signal generator frequency to 1960 0230375 MHz and level to 80 dBm 2 Set phone to TDMA mode and select RF Test UI in Phoenix Maintenance Testing Check signal level at RX band filter Z802 input Check components around lna and measure supply voltages Not OK OK Check signa...

Page 36: ... probe on the inductor L818 and record RX VHF VCO signal level and frequency Signal level should be around 25 dBm and frequency 268 08 MHz 6 Set spectrum analyzer settings as following Center frequency 2094 06 MHz Span 200 kHz RBW 3 kHz reference level 10 dBm 7 Connect spectrum analyzer probe to testpoint J813 and record UHF VCO signal level and frequency Signal level should be around 5 dBm and fr...

Page 37: ...ate level 83dBm Check signal level at RX I Q J808 J809 J818 J819 STEP 3 OK GSM1900 RX is OK Not OK According STEP 4 Check signal level at diplexer Z908 input Replace external antenna connector X900 Not OK OK Check signal level at duplex filter Z962 input Replace diplexer Z908 Not OK OK Check signal level atLNA V804 input Replace duplex filter Z962 Not OK OK ...

Page 38: ...aintenance GSM RSSI Meas 3 Set Band to GSM1900 and Rx Tx channel to 661 Check signal level at RX band filter Z802 input Check components aroundlna and measure supply voltages Not OK OK Check signal level at mix1_B input L810 Replace RX band filter Z802 Not OK OK Check signal level at IF filter Z804 input 133 2 MHz R803 Not OK OK Check signal level at IF filter Z804 output 133 2 MHz R804 Not OK OK ...

Page 39: ...tep 2 Local oscillator checking Carrying out this step VCO signal of 1st and 2nd mixers can be checked 2nd mixer RX VHF VCO frequency is constant 266 4 MHz but for the 1st mixer UHF VCO frequency depends on the channel The UHF VCO frequencies for the 1st mixer are Channel 512 2063 4 MHz Channel 661 2093 2 MHz Channel 810 2123 0 MHz 1 Set phone receiver to continuous mode using Phoenix 2 Set spectr...

Page 40: ...alyzer settings as following Center frequency 266 4 MHz Span 200 kHz RBW 3 kHz reference level 0 dBm 3 Connect spectrum analyzer probe on the inductor L818 and record RX VHF VCO signal level and frequency The result should be like in the picture below 4 Set Rx Tx channel to 661 using Phoenix 5 Set spectrum analyzer settings as following Center frequency 2093 2 MHz Span 200 kHz ...

Page 41: ...trum analyzer probe to testpoint J813 and record UHF VCO signal level and frequency The result should be like in the picture below 7 Repeat measurement for channels 512 and 810 Step 3 RX chain checking 1 Set signal generator frequency to 1960 06771 MHz and level to 83 dBm 2 Set phone receiver to continuous mode with full gain using Phoenix ...

Page 42: ...small the fault is probably due to Safari ASIC If the signal amplitude is correct but its frequency is something else than 67 71 kHz 3 kHz you may try to change AFC value 1024 1023 and see does it have effect to the frequency Frequency should be tuned to target value with the AFC value of 100 If the signal amplitude and frequency in all testpoints is correct and signal amplitude changes when the L...

Page 43: ...e step 2 Local oscillator checking but RX I Q signal is not correct see step 3 to check RX I Q signal the problem is probably due too malfunction of either 2nd mixer or AGC blocks inside Safari Please note that these levels are measured with active probe If the IF signal level is correct at the filter input but not at the output side the filter shall be replaced with new one If the IF signal level...

Page 44: ...0 and power level 2 Select random data for digital mode of operation After any component change tune the phone with Phoenix auto tune SW GSM1900 Start Phoenix software and select GSM RF Control PL0 Ch661 and TX data type random Path of the transmitted signal AMPS DAMPS UEM TX I Q DA converters I Q modulator and Digital gain step amplifier SAFARI Dual TX IF BPF Up converter mixer C904 driver BPF PA...

Page 45: ... and Power level 2 Connect RF cable to Ext RF connector and connect cable to Spectrum analyzer input and measure RF level Please notice insertion loss of the cable and attenuations 213 2 MHz 214 08 MHz DIV 2 800MHz 1900MHz D E T VHF VCO 178 2 MHz 179 04 MHz UHF PLL 2G 2 2063 4 2124 MHz HB 1003 08 1028 01 MHz LB 1900MHz 800MHz VHF PLL 356 4 MHz 358 08 MHz 426 4 MHz 428 16 MHz 800 D I P 1900 I Q Saf...

Page 46: ...NPM 2NX Troubleshooting CCS Technical Documentation Page 46 ãNokia Corporation Issue 1 07 02 ...

Page 47: ... L980 and TX VHF 358 08 MHz N811 Start synth troubleshooting Check supply voltages VR2 VBATTRF VR5 IPA1 BANDSEL TX_ENABLE TX_GAIN_CONTROL NOK OK Check UEM and UPP Baseband NOK OK Check UEM Baseband Check TXi q signals Test points J810 J811 OK Check TX IF power 179 04 MHz C931 C932 Input 17 dBm 3 6 dB Check TX RF 836 49 MHz output power U C output RF 5 dBm 6dB NOK Change SAFARI N801 NOK OK OK NOK 1...

Page 48: ...ommon RF modulator and thus it is important that DAMPS mode have no faults Check TX SAW input and output power IL 3 dB OK Is Itot 850 1000 mA Check PA output power and gain Output power 28 dBm Gain 30 dB Change PA N901 Check PWRDET N900 insertion loss IL 0 3 dB NOK OK Change PWRDET N900 NOK OK Change Z906 or Z908 or RF connector Check duplexer Z906 diplexer Z908 and RF connector X900 Dupl IL 2 2 d...

Page 49: ...CCS Technical Documentation Troubleshooting NPM 2NX Issue 1 07 02 ãNokia Corporation Page 49 TDMA1900 GSM1900 ...

Page 50: ...A2 BANDSEL TX_ENABLE TX_GAIN_CONTROL NOK OK Check UEM and UPP Baseband NOK OK Change SAFARI N801 or Z901 Check TX IF input power TDMA 214 08 GSM 213 2 MHz C931 C932 IF 12 dBm 6 6 dB OK Check TX RF TDMA 1879 98 GSM 1880 MHz U C output power Z961 input TDMA 4 dBm 6dB GSM 8 dBm 6dB Check Z961 input and output power IL 3dB NOK 1 Check Z960 input and output power IL 3dB 2 Change U C N902 NOK OK OK NOK ...

Page 51: ... similar for both bands except both bands have Is Itot TDMA 350 500 GSM 200 300 mA Check PA output power and gain Gain 30 dB Pout TDMA 29 dBm GSM 32 dBm Change PA N901 Check PWRDET N900 insertion loss IL 0 3 dB Change PWRDET N900 Check duplexer Z962 diplexer Z908 and RF connector X900 insertion loss Dupl IL 2 2 dB Dipl 0 35 dB RF conn 0 1 dB Change Z962 or Z908 or RF connector Start Power control ...

Page 52: ...0D Pout TXPWRDET Pout TXPWRDET Pout TXPWRDET PL dBm dac mV dBm dac mV dBm dac mV 2 25 7 440 27 3 27 3 503 3 23 3 320 23 3 23 3 304 4 19 3 190 19 3 19 3 182 5 15 3 110 15 3 15 3 105 6 11 1 60 11 1 11 1 57 7 7 0 33 7 0 7 0 30 8 3 0 18 3 0 15 9 1 0 8 1 0 6 10 5 0 3 5 0 2 Is DAC value vs TXPWRDET mV OK Check UEM BaseBand Is TXPWRDET vs output power OK See chart below Check VR2 and PATEMP Check C921 C9...

Page 53: ...ges at power levels PL0 PL15 Note DAC VALUES MAY VARY ABOUT 20 Note TXPWRDET is difference between TX on burst and off burst 850 1900 Pout TXPWRDET Pout TXPWRDET U_value PL dBm dac mV dBm dac mV 0 29 5 660 1 28 556 2 26 436 3 24 343 4 22 364 5 20 203 6 18 158 7 16 118 8 14 91 9 12 66 10 10 50 11 8 35 12 6 27 13 4 18 14 2 13 15 0 9 ...

Page 54: ...quency range for 2GHz UHF VCO is 2006 16 2124 MHz The output frequency range for the lower band is from 2006 16 to 2056 02 MHz In TDMA upper band the out put frequency range from the UHF VCO is from 2064 12 MHz to 2124 MHz and GSM 2063 40 2123 MHz BB PLL frequencies are in TDMA 77 76 MHz and in GSM 78 MHz It is practical way to check out synthesizer status by measuring control voltage of the VCO f...

Page 55: ...cy is locked in Phase locked Loop RX VHF VCO output signal is fed to SAFARI Inside the SAFARI signal is divided for Phase detector and RX parts Before I Q modulator frequency is divided by 2 Fault finding chart for RX VHF VCO Measure oscillator frequency over L818 coil Don t connect probe to pads AMPS CH383 RX VHF frequency 268 08 MHz GSM1900 CH661 TX VHF frequency 266 4 MHz START HERE Is VCTCXO o...

Page 56: ...RF clock to base band It has two fixed frequencies 77 76 MHz in 1 START HERE Is oscillator locked to TDMA 268 08 or GSM 266 4 MHz OK Yes 2 Check resonator components V801 C845 C871 L818 and DC block C821 3 Check loopifilter components C848 R808 C847 R807 C846 R820 C870 check also R826 2 No OK 3 No OK 4 Change SAFARI No OK ...

Page 57: ...hart for BB PLL Measure oscillator frequency over L829 coil Don t connect probe to pads TDMA BB PLL frequency 77 76 MHz Freq Phase comparator Charge Pump Divider 324 or 325 Divider 4 or 6 Loop Filter Varactor Resonator Active part BB VCO Divider 65 or 80 VCTCXO 19 2 MHz RF IC RFCLK to BB GSM 13 MHz TDMA 19 44 MHz Data Data are related to vctcxo frequency and mode selections ...

Page 58: ...DMA 428 16 MHz and GSM 426 4 MHz for upper band Operating frequency is locked in Phase locked Loop and frequency is divided by two before modulator Fault finding chart for TX VHF VCO AMPS CH383 TX VHF frequency 358 08 MHz TDMA1900 CH1000 TX VHF frequency 428 16 MHz 1 START HERE Is oscillator locked to TDMA 77 76 or GSM 78 MHz OK Yes 2 Check resonator components V805 C871 L829 and C893 3 Check loop...

Page 59: ...4 MHz In upper band TDMA1900 GSM1900 2 GHz synthesizer frequency is fed straight to mixers In lower band case AMPS TDMA800 2 GHZ UHF VCO frequency signal is first divided by 2 inside SAFARI and then that divided signal is fed to mixers The output fre quency of the VCO depends on the DC control voltage which is controlled by PLL circuit inside SAFARI 1 START HERE Is oscillator locked to 358 08 426 ...

Page 60: ... frequency locked 2006 16 2124 MHz Is EVM OK 1 Check loopfilter components Yes No OK Change SAFARI N801 No Check VCO operatig voltage 2 78 V 1 No OK YES Check resistor R811 No OK OK Low band Is divided signal OK low band Yes No Check loopfilter components and balun T801 C863 C862 C861 C860 R806 R815 R814 R813 2 No OK 4 No Change VCO G802 3 No OK ...

Page 61: ...ing TDMA RF tunings TDMA RX tunings AFC tuning Purpose of the tuning is to correct phone frequency error If AFC tuning fails it might be due to Problems with lower band signal path synthesizer etc If AFC DAC tuning value or step size is too low or high it might be due to faulty VCTCXO component UEM UPP RX LP and AMP2 filter tunings ...

Page 62: ... than 2 further analysis is needed Result 32752 means that the signal doesn t go through RX chain at all or it has a lot of attenuation If it fails there can be following problems Rx chain is totally deaf or some gain is missing start receiver troubleshooting LB RX AGC tuning LB TDMA minimum gain around 2 dB measured when lna is switched off LB LNA gain step measured when lna is switched on Result...

Page 63: ...Safari Too low output power TX power levels and crossband TxPwr Purpose of this tuning is to tune all power levels PL2 PL10 TX crossband Low band Purpose to tune ch991 and ch799 equals to mid ch383 channel power Upper band Purpose to tune ch2 and ch1998 equals to mid ch1000 channel power Crossband tuning is done only with PL2 If tuning fails there can be following problems Broken component PA Safa...

Page 64: ...rs tunings This is done using Safari internal loop No external signal is needed If it fails there can be following problems Safari problem GSM AFC tuning Purpose of the tuning is to correct phone frequency error If AFC tuníng fails it might be due to Problems with upper band signal path synthesizer etc VCTCXO component can be broken UEM UPP ...

Page 65: ... lna is switched on Result is gain difference between lna on and off around 20 dB If it fails there can be following problems Rx chain is totally deaf or some gain is missing start receiver troubleshooting RX temperature calibration NTC resistor calibration in ambient temperature If NTC temperature fails it might be due to Faulty NTC resistor or pull up resistor faulty UEM wrong ambient temperatur...

Page 66: ...litude 45 to 55 dBc and Phase 50 to 60 dBc If tuning fails there can be following problems UEM or Safari Too low output power TX Power levels Purpose of this tuning is tune all power levels PL0 PL15 If tuning fails there can be following problems Broken components PA Safari up converter some filters Missing components TX crossband Purpose to tune ch512 and ch810 equals to mid ch661 channel power T...

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