Orban 424A Operating Manual page 28

Fig.
D-l:
IOOHZ
DISTORTION RESIDUAL,
LIN
RELEASE
c)
Restore
the
oscillator
output.
Switch
the
RELEASE SHAPE
switch
to
EXP,
and
verify that the distortion decreases, and
that the distortion residual looks
like Fig.
D-2. Suppress the
oscillator
output, and verify that the time required
for
the
G/R meter
to
move from 20dB
to
lOdB
G/R
is
2.0seconds,
+0.5seconds.
Fig.
D-2:
IOOHZ
DISTORTION RESIDUAL, EXP RELEASE
NOTE
The shape
of the
distortion
residual
provides a good
indication of
whether
the timing
module and other
circuitry within the control
loop are
operating properly.
If
the distortion residual
which you
observe
is
significantly different than the
Figures
(particularly
if
accompanied
by audible
problems with sound
quality),
we
recommend
returning
the
424A
for
factory service, as
it is
usually impractical
to
diagnose and
repair subtle control circuitry problems
in
the
field.
5)
COMPRESSION RATIO
control test
a)
Set the
424A
ATTACK
TIME
control
to
"0"
(FAST), and the
RATIO
control
to "infinity". Set
the oscillator
frequency
to
IkHz, and
its
output
to
produce
lOdB
G/R.
Adjust the
OUTPUT
TRIM
control
as
necessary to
produce
+
II.OdBm
at the
424A output. (The
OUTPUT
TRIM
control should be within
2dB
of "0" after
you have done
this.)
b)
Set
the
RATIO
control at
each
of the
panel
markings
in
TABLE
D-l, and
verify
that the
424A
output
level
is
close
to
the values indicated, +ldB.
24