T830 Series II Base Station Equipment 136-174MHz Service Manual

C5.14 T836/837 Fault Finding M830-00
C
Noisy synth;
poor residual FM.
VCO phase locked?
5-13V present on
control line?
Y
N
Go to B.
Correct DC V
present on Q1 VCO?
Y
N
Check inductors,
biasing resistors
& Q1.
Loop filter &
components around
op. amp. (IC750) OK?
Y
N
Replace if faulty.
Isolate audio
modulation on VCO;
still noisy?
Y
N
Trace audio fault.
Change trimmer;
still noisy?
Y
N
Change Q1;
still noisy?
N
Y
Change TCXO;
still noisy?
N
Y
Change varactors;
still noisy?
N
Y
Replace VCO
assembly.
Y
Synthesiser OK.
30/04/98 Copyright TEL