NHM-8NX
Troubleshooting Instructions
PAMS Technical Documentation
Page 2
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Nokia Corporation
Issue 1 05/02
Table of Contents
Page No
Baseband Testpoints ....................................................................................................5
Fault Finding Charts ....................................................................................................5
Phone is dead ...............................................................................................................7
Flash programming does not work ..............................................................................8
Power does not stay on or phone is jammed ................................................................9
Display information: "Contact Service" ....................................................................10
Phone does not register onto the network, or the phone cannot make a call .............11
SIM related faults ......................................................................................................12
Insert SIM card fault ............................................................................................... 12
SIM-Card rejected ................................................................................................... 13
Audio related faults ....................................................................................................14
Charging failure .........................................................................................................16
General description of the RF circuits..................................................................... 18
Receiver................................................................................................................... 24
General Instructions for GSM900 RX Troubleshooting ......................................... 24
Fault Finding Chart for GSM900 Receiver............................................................. 26
General Instructions for GSM1800 RX Troubleshooting ....................................... 27
Fault Finding Chart for GSM1800 Receiver........................................................... 29
Measurement points in the receiver ........................................................................ 31
Measurement points for the transmitter .................................................................. 32
General instructions for GSM TX troubleshooting................................................. 33
Fault finding chart for GSM900 transmitter ........................................................... 34
PCN TransmitterGeneral instructions for PCN TX troubleshooting ...................... 37
General instructions for Synthesizer troubleshooting ............................................. 39
26 MHz Reference Oscillator ( VCXO )................................................................. 39
VCO ........................................................................................................................ 41
Fault finding chart for PLL Synthesizer.................................................................. 41
Measurement points for the PLL............................................................................. 42
Frequency lists......................................................................................................... 45
RX calibration ............................................................................................................47
RX channel select filter .............................................................................................49
RX Band Filter Response ..........................................................................................50
Tx Power tuning ........................................................................................................51
TX power tuning GSM............................................................................................ 52
TX power tuning PCN............................................................................................. 55
I/Q tuning ...................................................................................................................57
RF control ..................................................................................................................59