Nokia RH-17 Series Troubleshooting - Rf page 47

CCS Technical Documentation
VCTCXO G501 TP30
at 19.2 MHz
CLK19M2_R TP29
CLK19M2_B TP32
CLK19M2_UPP TP31
AMPS Mode
PDM
Setting
-1024
-512
0
+512
+1023
Issue 1 04/2003
Table 6: VCTCXO Troubleshooting
AFC_Volt
PDM
[0]=2.2V
[-1024]=1.4
[+1023]=3.1
19.2 MHz at
amplitude of
-24.0 dBm
19.2 MHz at
amplitude of
-24.0 dBm
19.2 MHz at
amplitude of
-21.0 dBm
Table 7: AFC PDM (Local Mode) AMPS
AFC Frequency Output
Voltage @ G501 using
Oscilloscope
1370 mV 19.19 MHz
1780 mV 19.21 MHz
2.2 V 19.23 MHz
2.65 V 19.23 MHz
3.1 V 19.23 MHz
Nokia Corporation
Troubleshooting — RF
Check supply voltage VR3 at G501 is at
2.7 Vdc, verify C520, R512 and C505.
Control voltage AFC should be ~ 1.27
Vdc, check R511, R510, C503 make sure
VR1A is present at 4.75 Vdc.
Check AFC PDM control in local mode
using Table 7 as a reference.
Check C513
Check C512
Check Buffer Amplifier V500 for correct
dc bias voltages via VR3.
Emitter = 0.38 Vdc
Base = 1.04 Vdc
Collector = 1.75 Vdc
Check components V500, C502, R520,
R521, R522, R517, R518, C523, C525
and C524.
Frequency Output
@ G501 using
Spectrum Analyzer
19.199515 MHz
19.199735 MHz
19.199965 MHz
19.200000 MHz
19.200220 MHz
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RH-17
Page 47