Nokia 6680 RM-36, Service Manual

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Appendix A: RF Troubleshooting Nokia Customer Care
Company Confidential
Copyright © 2005 Nokia. All rights reserved
A-3
4.1.2 Does WCDMA TX transmit enough RF-power and power levels otherwise ok? ..........................83
4.1.3 WCDMA transmitter frequency correct?...................................................................................................93
4.2 Does the phone give realistic RSSI-values? .....................................................................................................98
4.2.1 Is Hinku ASIC (N7500) receiving RF-power correctly from the WCDMA-antenna connector? .98
4.2.2 Hinku WCDMA LNA output ok?....................................................................................................................99
4.2.3 WCDMA SAW Z7501 in place and working correctly? ..........................................................................99
4.2.4 Are RX-IQ signal waveforms and levels correct?...................................................................................99
4.2.5 Does RAP3G ASIC get ok VREFCM-signal from Hinku (N7500)? Signal level ok?........................ 107
4.2.6 RAP3G faulty?................................................................................................................................................ 108
4.3 WCDMA modulation spectrum and ACLR ok? ............................................................................................... 108
4.3.1 Does N7504 give correct voltage level (Vcc11) to the WCDMA PA (N7503)? ............................. 108
4.3.2 Does WCDMA PA (N7503) get correct bias currents Icont11 and Icont12?................................ 110
4.3.3 Are TX-IQ signals ok? .................................................................................................................................. 111
4.3.4 Is TX VCO signal level in the T7503 output high enough? .............................................................. 112
4.3.5 Replace Vinku (N7501) or WCDMA PA (N7503) or both ................................................................... 112
5. Does the phone have a reliable connection to the network (GSM)?............................................................. 113
5.1 GSM receiver Bit Error Rate (BER) ok? ............................................................................................................. 113
5.1.1 Does the phone give realistic RSSI-values? ......................................................................................... 113
5.1.2 Hinku (N7500) or RAP3G (D2800) faulty?............................................................................................. 113
5.2 GSM transmitter power levels and transmit frequency ok?.................................................................... 113
5.3 GSM Transmitter phase error ok? .................................................................................................................... 113
5.4 GSM (GMSK) modulation spectrum ok? .......................................................................................................... 113
5.5 TX power vs. time ok? ......................................................................................................................................... 113
6. Does the phone have a reliable connection to the network (WCDMA)? ...................................................... 113
6.1 WCDMA receiver Bit Error Rate (BER) ok?....................................................................................................... 114
6.1.1 Does the phone give realistic RSSI-values? ......................................................................................... 114
6.1.2 Hinku (N7500) or RAP3G (D2800) faulty?............................................................................................. 114
6.2 WCDMA TX power and transmit frequency ok?........................................................................................... 114
6.3 WCDMA Transmitter error vector magnitude ok?....................................................................................... 114
6.3.1 Is capacitor C7579 in WCDMA PA (N7503) bias line in place? ........................................................ 115
6.3.2 Are capacitors in Vinku REG1 and REG2 lines in place?.................................................................... 115
6.3.3 Are capacitors in WCDMA PA power supply lines in place?............................................................. 115
6.3.4 Are TX-IQ signals ok? .................................................................................................................................. 115
6.3.5 Is TX VCO signal level in the T7503 output high enough? .............................................................. 115
6.3.6 VCTCXO frequency and output level correct? ...................................................................................... 116
6.4 WCDMA modulation spectrum and ACLR ok? ............................................................................................... 116
6.5 Troubleshooting pictures................................................................................................................................... 117
6.5.1 VCTCXO Output (DC Offset 1.24 V)............................................................................................................ 117
6.5.2 TXC in GSM mode (DC Offset 0 V) ............................................................................................................. 117
6.5.3 TX VC in GSM mode (DC Offset 1.8 V) ...................................................................................................... 118
6.5.4 Icont_21/Icont_22 (DC Offset 1.2 V)........................................................................................................ 118
6.5.5 Icont_31/Icont_32 (DC Offset 1.2 V)........................................................................................................ 119
6.5.6 GSM RX IQ (DC Offset 0.4 V)........................................................................................................................ 120
6.5.7 RX VC in GSM mode (DC Offset 1.5 V)...................................................................................................... 121
6.5.8 TX Modulation spectrum (GSM) ............................................................................................................... 122
6.5.9 RFBUS............................................................................................................................................................... 123