Nokia RM-57 Service Manual page 220

Appendix A: RF Troubleshooting
1. Using these instructions .................................................................................................................................................. 4
2. RF Self tests.......................................................................................................................................................................... 5
2.1 RF-BB interface (ST_CDSP_RF_BB_IF_TEST)........................................................................................................... 7
2.2 Supply test for Hinku and Vinku (ST_CDSP_RF_SUPPLY_TEST)........................................................................ 9
2.3 TX IQ self test (ST_CDSP_TX_IQ_TEST) ..................................................................................................................13
2.4 TXC Data test (ST_TXC_DATA_TEST) ......................................................................................................................14
2.5 RX PLL phase lock self test (ST_CDSP_RX_PLL_PHASE_LOCK_TEST)...............................................................15
2.6 TX PLL phase lock self test (ST_CDSP_TX_PLL_PHASE_LOCK_TEST) ...............................................................16
2.7 RX IQ loop back self test (ST_CDSP_RX_IQ_LOOP_BACK_TEST).......................................................................17
2.8 GSM transmitter self test (ST_CDSP_GSM_TX_POWER_TEST) .........................................................................18
2.9 Error Code Interpretation Examples ..................................................................................................................19
2.9.1 Example 1 .........................................................................................................................................................19
2.9.2 Example 2 .........................................................................................................................................................19
2.9.3 Example 3 .........................................................................................................................................................19
3. Does the phone register to the network and make a call (GSM)? ....................................................................21
3.1 GSM transmitter power levels and transmit frequency ok?.......................................................................21
3.1.1 Does GSM TX transmit RF-power at all? ...................................................................................................22
3.1.2 Does GSM TX transmit enough RF-power and power levels otherwise ok?.................................33
3.1.3 GSM transmitter frequency correct? .........................................................................................................42
3.2 Does the phone give realistic RSSI-values? .....................................................................................................46
3.2.1 Is Hinku (N7500) ASIC receiving RF-power correctly from the GSM-antenna connector?........47
3.2.2 Are RX-IQ signal waveforms and levels correct?...................................................................................49
3.2.3 Is RAP3G ASIC getting ok VREFCM-signal from Hinku (N7500)? Signal level ok?.........................60
3.2.4 RAP3G faulty?...................................................................................................................................................62
3.3 GSM Transmitter phase error ok? .......................................................................................................................62
3.3.1 Are capacitors in Vinku REG1 and REG2 lines in place?.......................................................................62
3.3.2 Are capacitors in GSM PA power supply line in place? ........................................................................62
3.3.3 Are TX-IQ signals ok? .....................................................................................................................................63
3.3.4 Is TX VCO signal level in the T7503 output high enough? .................................................................63
3.3.5 VCTCXO frequency and output level correct? .........................................................................................63
3.4 GSM (GMSK) modulation spectrum ok? .............................................................................................................64
3.4.1 Are components in GSM power control loop in place and working ok? .......................................65
3.4.2 Does GSM PA (N7502) get correct bias currents? Is the level of bias currents ok?.....................66
3.4.3 Are TX-IQ signals ok? .....................................................................................................................................66
3.4.4 Is TX VCO signal level in the T7503 output high enough? .................................................................67
3.4.5 Replace Vinku (N7501) or GSM PA (N7502) or both.............................................................................67
3.5 TX power vs. time ok? ............................................................................................................................................68
3.5.1 Is the TXC-signal coming to Vinku ASIC (N7501) OK? ..........................................................................68
3.5.2 Does GSM PA (N7502) get correct bias currents? Is the level of bias currents ok?.....................69
3.5.3 Does GSM PA (N7502) get correct DET_SW_G -voltage from Vinku ASIC (N7501)?......................70
3.5.4 Are components in GSM power control loop in place and working ok? .......................................70
4. Does the phone have a reliable connection to the network (GSM)?................................................................71
4.1 GSM receiver Bit Error Rate (BER) ok? ................................................................................................................71
4.1.1 Does the phone give realistic RSSI-values? ............................................................................................71
4.1.2 Hinku (N7500) or RAP3G (D2800) faulty?................................................................................................71
4.2 GSM transmitter power levels and transmit frequency ok?.......................................................................71
4.3 GSM Transmitter phase error ok? .......................................................................................................................71
4.4 GSM (GMSK) modulation spectrum ok? .............................................................................................................71
A-2
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