Rx Vhf - Nokia NKC-1X Series Troubleshooting Instructions

CCS Technical Documentation

RX VHF

The RX VHF signal is used to generate receiver Intermediate frequency. RX VHF has one
fixed frequency 271.08 MHz. Operating frequency is locked in Phase locked Loop.
RX VHF PLL output signal is integrated in TACO. There are only four external components,
VCO coil L730 and loop filter components C740, C741 and R741. Fault finding chart for
RX VHF VCO
3
C h e c k lo o p ifilte r
c o m p o n e n ts :
Replace TACO
C 7 2 0 , R 7 2 1 , C 7 2 1 , R 7 2 2 ,
C 7 2 2 , R 7 3 3 , C 7 3 3
c h e c k a ls o R 7 2 4
Issue 1 02/03
Figure 16: Fault tree:
4
C h a n g e
S A F A R I
O K
N o
1
O K
S T A R T H E R E
freguency
Is o s c illa to r lo c k e d
2
3 .N o
to 2 7 1 .0 8 M H z
1
2 .N o
O K
C h e c k re s o n a to r
c o m p o n e n ts :
V 7 2 5 , C 7 2 4 , C 7 2 5 ,
L730, C740, C741, R741
L 7 3 0 a n d D C b lo c k C 7 2 6
Nokia Corporation
Troubleshooting Instructions
RX VHF
Y e s
2
NKC-1X
O K !
Page 31