Nokia 6255 Rf Description And Troubleshooting

Also see for 6255: User guide User guide User guide User guide Disassembly manual

Contents

Nokia 6255 Rf Description And Troubleshooting Manual pdf 2 page image

6255/6255i/6256/6256i (RM-19)RF Description and Troubleshooting Nokia Customer CarePage 2 ©2005 Nokia Corporation Company Confidential Issue 2 05/2005Contents PageIntroduction ..................................................................................................................................................... 5Mobile Terminal Components ..................................................................................................................... 6Main PWB ......................................................................................................................................................6UI (Secondary) PWB ....................................................................................................................................8Preliminary RF Troubleshooting............................................................................................................... 10Mobile Terminal Cannot Make a Call ..................................................................................................10Tx Power Low ..............................................................................................................................................10Transmitter RF Troubleshooting .............................................................................................................. 11Transmitter Block Diagram .....................................................................................................................12Transmitter Schematics ...........................................................................................................................13Transmitter Troubleshooting Setup ......................................................................................................15AMPS Tx Setup ....................................................................................................................................... 15Cell Tx Setup ........................................................................................................................................... 18PCS Setup................................................................................................................................................. 20Transmitter RF Troubleshooting Procedures ......................................................................................22Failed Test: Tx PA Detector ................................................................................................................. 23Tx Output Spectrum.............................................................................................................................. 24Tx DC Test Points - Bottom Side ....................................................................................................... 25Tx DC and RF Test Points - Top Side................................................................................................. 26Tx RF Test Points - Bottom Side ........................................................................................................ 28RF Power Supply DC Test Points - Bottom Side............................................................................ 29Receiver RF Troubleshooting .................................................................................................................... 31Receiver Block Diagram ...........................................................................................................................32Receiver Schematics .................................................................................................................................33RF AGC Status ............................................................................................................................................35Turning on the Rx Path ............................................................................................................................36Switching the Rx Gain States ................................................................................................................38Checking AMPS from RF to IQ ........................................................................................................... 38Checking Cell Receiver from RF to IQ.............................................................................................. 39Checking PCS Receiver from RF to IQ.............................................................................................. 41Receiver Diagnostic Signal Tracing ......................................................................................................42Receiver DC Test Points........................................................................................................................ 43Receiver RF Test Points ........................................................................................................................ 44Receiver IF Test Points.......................................................................................................................... 45Receiver Logic Input Voltages ................................................................................................................46N7160 Receiver Overview .......................................................................................................................47Synthesizer Troubleshooting .................................................................................................................... 49Synthesizer Block Diagram .....................................................................................................................50Synthesizer Schematics ...........................................................................................................................51Synthesizer Troubleshooting Setup ......................................................................................................52Incorrect PLL Frequencies.................................................................................................................... 52VCTCXO Troubleshooting .........................................................................................................................53VCTCXO Manual Tuning ....................................................................................................................... 54AFC Voltage Troubleshooting .................................................................................................................55UHF Synthesizer .........................................................................................................................................56UHF Synthesizer Test Points ............................................................................................................... 57Rx VHF LO (N7100) Schematic ..............................................................................................................58