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CCS Technical Documentation
Fault finding chart for 19.2 MHz oscillator
2
Change
VCTCXO
RX VHF VCO
The RX VHF VCO signal is used to generate receiver Intermediate frequency. RX VHF VCO
has two fixed frequencies: TDMA 268.08 MHz, GSM 266.4 MHz. Operating frequency is
locked in Phase locked Loop.
RX VHF VCO output signal is fed to SAFARI. Inside the SAFARI signal is divided for Phase
detector and RX parts. Before I/Q-modulator frequency is divided by 2.
Fault finding chart for RX VHF VCO
Measure oscillator frequency over L818 coil. Don't connect probe to pads!
AMPS, CH383
GSM1900, CH661 -> TX VHF frequency 266.4 MHz
Issue 1 07/02
START HERE!
OK
Is VCTCXO
oscillating?
2.No
19.2MHz
1.No
OK
1
Check voltage
C867
2.78 V
No
OK
Check resistor
R816
-> RX VHF frequency 268.08 MHz
ãNokia Corporation
NPM-2NX
Troubleshooting
OK!
Page 55
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Troubleshooting
