Tait T850 II Series - Page 89

M850-00 T855 Fault Finding B5.15
Copyright TEL 31/09/98
Y
N
Y
Y
Y
Y
N
Y
Y
Y
C
Noisy synth; poor
selectivity &/or
poor residual FM.
Correct DC V
present on Q1 VCO?
Chan
g
e trimmer;
still noisy?
Chan
g
e Q1;
still noisy?
Chan
g
e TCXO;
still noisy?
Chan
g
e varactors;
still noisy?
Replace VCO
assembly.
Synthesiser OK.
N
N
N
N
Check inductors,
biasin
g
resistors
& Q1.
Replace if faulty.
Go to B.
Loop filter &
components around
op. amp. (IC750) OK?
N
VCO phase locked?
3-16V present on
control line?