Table Of Contents - Nokia 2255 Manual

Rm-97, rf description and troubleshooting

Hide thumbs Also See for 2255:

User manual (54 pages)

Baseband description and troubleshooting (44 pages)

Disassembly/assembly (14 pages)

Table Of Contents

Table of Contents

2255 (RM-97)

RF Description and Troubleshooting

Contents

Mobile Terminal Components ..................................................................................................................... 4

Preliminary RF Troubleshooting.................................................................................................................. 5

Mobile Terminal Cannot Make a Call .................................................................................................... 5

Tx Power Low ................................................................................................................................................ 5

Transmitter Block Diagram ....................................................................................................................... 6

Transmitter Schematics ............................................................................................................................. 7

Transmitter Troubleshooting .................................................................................................................... 9

CELL Tx Setup............................................................................................................................................. 9

Failed Test: Tx PA Detector ................................................................................................................. 11

Tx RF Test Points ........................................................................................................................................13

Tx AGC Tuning ............................................................................................................................................16

Receiver Troubleshooting ........................................................................................................................17

Receiver Schematics .................................................................................................................................18

Turning on the Rx Path ........................................................................................................................ 20

Switching the Rx Gain, IF, and IP States ............................................................................................21

Receiver Troubleshooting ........................................................................................................................22

Receiver RF Troubleshooting Test Points ............................................................................................24

Receiver IF Troubleshooting Test Points .............................................................................................26

Cell Receiver Check from RF to IQ ........................................................................................................28

Receiver Diagnostic using Signal Tracing and Call Box.............................................................. 29

Rx Front-End IC (N7150) DC Troubleshooting ..................................................................................30

Synthesizer Troubleshooting ..................................................................................................................31

Synthesizer Block Diagram ................................................................................................................. 31

Synthesizer Schematic .............................................................................................................................32

Synthesizer Troubleshooting Setup ......................................................................................................33

19.2 MHZ VCTCXO Reference Clock .....................................................................................................35

VCTCXO Manual Tuning ....................................................................................................................... 36

UHF Synthesizer Test Points ...................................................................................................................40

UHF Synthesizer Schematic ....................................................................................................................41

Incorrect UHF Frequency ..................................................................................................................... 42

Rx VHF ..........................................................................................................................................................43

Rx VHF Schematic .....................................................................................................................................44

Incorrect Rx VHF Frequency ............................................................................................................... 45

Tx VHF ...........................................................................................................................................................46

Tx VHF Schematic ......................................................................................................................................47

Incorrect Tx VHF Frequency ................................................................................................................ 48

FM Radio Troubleshooting ......................................................................................................................49

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Company Confidential

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ISSUE 1 10/2005