Nokia NPM-2NX Troubleshooting Manual page 65

CCS Technical Documentation
GSM UB LNA GAIN AND RSSI OFFSET
• UB GSM reference gain (around 74 dB), measured when lna is switched off
• UB LNA gain step, measured when lna is switched on. Result is gain difference
between lna on and off (around 21 dB)
If it fails there can be following problems:
• Rx chain is totally deaf or some gain is missing, start receiver troubleshooting
GSM LB LNA GAIN AND RSSI OFFSET
• UB GSM reference gain (around 77 dB), measured when lna is switched off
• UB LNA gain step, measured when lna is switched on. Result is gain difference
between lna on and off (around 20 dB)
If it fails there can be following problems:
• Rx chain is totally deaf or some gain is missing, start receiver troubleshooting
RX temperature calibration
• NTC resistor calibration in ambient temperature
If NTC temperature fails it might be due to:
• Faulty NTC resistor or pull up resistor
• faulty UEM
• wrong ambient temperature (phone is too hot or cold)
GSM RX CROSS BAND CALIBRATION
• Purpose of the calibration is to compensate gain ripple due to rx-filters over the
band
• This is done in UB and LB
If it fails response over the band can be totally bad and there can be following problems:
• Please check that all components are ok and in place around rx-parts
• Please check that filters are ok
Issue 1 07/02 ãNokia Corporation
NPM-2NX
Troubleshooting
Page 65