Tx Vhf Vco - Nokia NPC-1 Series Troubleshooting Instructions

NPC-1
Troubleshooting Instructions
3
Check loopifilter
components:
C720, R721, C721, R722,
C722, R733, C733
check also R724

TX VHF VCO

The TX VHF VCO signal is used to generate transmitter Intermediate frequency. The fre-
quency of the TX VHF VCO is 361.08MHz. The operating frequency is locked in the Phase
locked Loop and the frequency is divided by two before modulator.
Fault finding chart for TX VHF VCO
AMPS, CH383 -> TX VHF frequency 361.08 MHz
Page 32
RX VHF VCO
Figure 16: Fault tree:
4
Change
SAFARI
OK
No
1
OK
START HERE
Is oscillator locked
3.No
to 271.08 MHz
2.No
OK
Check resonator
components:
V725, C724, C725,
L730 and DC block C726
ãNokia Corporation
PAMS Technical Documentation
Yes
2
OK!
Issue 1 10/01