User Guide

NSM–5
Service Software Instructions
PAMS Technical Documentation
Page 88
Issue 1 02/2002
 Nokia Corporation
PCN (nominal)EGSM (nominal)Gain step values
6 92 83
7 102 93
8 112 103
Troubleshooting
If the calibration does not succeed the software normally reports ”Unable
to read data from phone” or ”Failed to set high reference” or ”Failed to set
low reference”.
In this case check first the basic functionality of the receiver chain: RF
generator frequency set as in the calibration and level for example to the
high reference value.
Then go to the RSSI reading menu (under RF controls). If the reading is
very low there is something broken in the receiver and must be found by
measuring voltages and signal levels at different places (information of
these can be found elsewhere in this manual).
If the RSSI reading seems to be within 5 - 10 dB the same as the RF in-
put level check that the VCTCXO frequency is close enough the wanted
frequency. This is most easiest done by measuring VCO frequency in
GSM middle channel 60 (VCO frequency is be 3788 MHz). If the devi-
ation is bigger than about +/–50 kHz it is probable that the VCTCXO is not
operating correctly.
If both of these (RSSI reading and the frequency) seem to be correct and
calibration still fails the most probable reason is that there must be some
missing gain step in Hagar or then the problem must be in Coppa.