Orban 424A Operating Manual page 29

Ratio Output
Le\
infinity +
1 1
.OdBm
6:1
+8.8dBm
4:1
+8.0dBm
3:1
+7.6dBm
2:1
+8.2dBm
TABLE
D-l
RATIO
CONTROL
TEST
6)
ATTACK
TIME
control
and
threshold circuitry
test
a)
Without changing other control
settings, restore the
RATIO
control to
"infinity".
The
G/R
meter
should read "lOdB".
b)
Adjust the attack
time
control
to
the settings
shown
in
TABLE
D-2, and
verify that the
424A
output
level
approximately corresponds
to the values
shown
in
the Table, +ldB.
c)
Restore
the
ATTACK
TIME
control to "0",
and
adjust the
OUTPUT
TRIM
control
between "0"
and
"-I0".
Verify that
the
G/R
meter
stays
between
9
and
I
IdB
G/R
as
this
is
done.
When
you
are through, restore the
OUTPUT
TRIM
control
to "0".
Attack Time
"fast"
m2>*
"
4
"
"
6
"
"
8
"
"slow"
Output
Level
+
1
I
.OdBm
+7.6dBm
+5.
OdBm
+4.5dBm
+3.8dBm
+0.5dBm
TABLE
D-2
OUTPUT
LEVEL
VS
ATTACK
TIME TEST
7)
GATING
Circuitry Test
a)
Temporarily
suppress the oscillator output.
Turn
the
GATE
THRESHold
control
fully
counterclockwise, and
verify that the
GATED
lamp
is
OFF.
Then
rotate the control
clockwise,
and verify
that the
GATED
lamp
lights at
approximately "3". Turn the control counterclockwise, and
verify that the
GATED
lamp
goes out
at
approximately
"2".
b)
Restore
the oscillator output to the
level
required
to
produce lOdB gain
reduction. Then reduce
its
level
by
20dB. Starting
fully
counterclockwise,
rotate
the
GATE
THRESHold
control clockwise
until
the
GATED
lamp
lights.
Verify that
this
occurs
at
approximately
"5"
on the
dial.
c)
(424
A
only):
(Note: These
instructions
apply
when
you are
testing
Channel A.
When
you are testing Channel
B,
exchange
all
of
the
"Channel A" and
"Channel B" references
in this
paragraph.)
Without applying
signal to the input
of
Channel
B,
adjust the
Channel B
GATE
THRESHold
control
to
"5".
Place
the
Channel B
COMP/LIM
OP/DEFEAT
control
in
OP,
and verify
that
the Channel
B
GATED
lamp
lights.
Now
increase
the output of the
test oscillator
connected
to the
Channel
A
input
until
the Channel
A
GATED
lamp
goes out.
Switch the
COUPLED/INDEP
switch
to
COUPLED,
and
verify that the
Channel B
GATED
lamp
goes
out.
Restore
the switch
to
INDEP,
and verify that the
Channel
B
GATED
lamp comes on
again.
25