Nokia 2255 Manual

Also see for 2255: User guide User guide Antenna Description and Troubleshooting Baseband Description and Troubleshooting Disassembly/Assembly

Contents

2255 (RM-97)RF Description and Troubleshooting Nokia Customer CarePage 2 ©2005 Nokia Corporation Company Confidential ISSUE 1 10/2005Contents PageMobile Terminal Components ..................................................................................................................... 4Preliminary RF Troubleshooting.................................................................................................................. 5Mobile Terminal Cannot Make a Call ....................................................................................................5Tx Power Low ................................................................................................................................................5Transmitter Block Diagram .......................................................................................................................6Transmitter Schematics .............................................................................................................................7Transmitter Troubleshooting ....................................................................................................................9CELL Tx Setup............................................................................................................................................. 9Failed Test: Tx PA Detector ................................................................................................................. 11Tx RF Test Points ........................................................................................................................................13Tx AGC Tuning ............................................................................................................................................16Receiver Troubleshooting ........................................................................................................................17Receiver Schematics .................................................................................................................................18Turning on the Rx Path ........................................................................................................................ 20Switching the Rx Gain, IF, and IP States ............................................................................................21Receiver Troubleshooting ........................................................................................................................22Receiver RF Troubleshooting Test Points ............................................................................................24Receiver IF Troubleshooting Test Points .............................................................................................26Cell Receiver Check from RF to IQ ........................................................................................................28Receiver Diagnostic using Signal Tracing and Call Box.............................................................. 29Rx Front-End IC (N7150) DC Troubleshooting ..................................................................................30Synthesizer Troubleshooting ..................................................................................................................31Synthesizer Block Diagram ................................................................................................................. 31Synthesizer Schematic .............................................................................................................................32Synthesizer Troubleshooting Setup ......................................................................................................3319.2 MHZ VCTCXO Reference Clock .....................................................................................................35VCTCXO Manual Tuning ....................................................................................................................... 36UHF Synthesizer Test Points ...................................................................................................................40UHF Synthesizer Schematic ....................................................................................................................41Incorrect UHF Frequency ..................................................................................................................... 42Rx VHF ..........................................................................................................................................................43Rx VHF Schematic .....................................................................................................................................44Incorrect Rx VHF Frequency ............................................................................................................... 45Tx VHF ...........................................................................................................................................................46Tx VHF Schematic ......................................................................................................................................47Incorrect Tx VHF Frequency ................................................................................................................ 48FM Radio Troubleshooting ......................................................................................................................49