Nokia RH-13 Series Troubleshooting Manual page 52

RH-13
Troubleshooting
kHz +/- 3 kHz, you may try to change AFC value (-1024...1023) and see does it
have effect to the frequency. Frequency should be tuned to target value with the
AFC value of +/- 100.
• If the signal amplitude and frequency in all testpoints is correct and signal
amplitude changes when the LNA, MIX2 and BB gains are changed, RX chain is
OK.
• If the signal amplitude in all testpoints is too low (< 1 Vp-p), you have to con-
tinue with RX front-end measurements.
1 Set signal generator frequency to 1960.06771 MHz and level to -60 dBm.
2 2) Set spectrum analyzer settings as following:
• Center frequency: 133.2 MHz, Span: 200 kHz
• RBW: 3 kHz, reference level: -20 dBm
3 Set phone receiver to continuous mode with full gain using Phoenix (see figure
33, RF controls, in step 3).
4 Connect spectrum analyzer probe to the output of GSM IF filter (at the one end
of R804) and record the level.
5 Connect spectrum analyzer probe to the input of GSM IF filter (at the one end of
R803) and record the level.
• If the IF signal levels are according to the picture below and local oscillators are
OK (see step 2 Local oscillator checking) but RX I/Q signal is not correct (see step
3 to check RX I/Q signal) the problem is probably due too malfunction of either
2nd mixer or AGC blocks inside Safari.
• If the IF signal level is correct at the filter input but not at the output side the fil-
ter shall be replaced with new one.
• If the IF signal level is not correct at the filter input side and the local oscillators
are functioning properly, inductors L814 and L815 should be checked, as well. If
they are OK and there is a signal at the input of 1st mixer, the problem is proba-
bly due to faulty 1st mixer inside Safari.
Page 52 ãNokia Corporation
CCS Technical Documentation
Issue 1 11/02