Orban 424A - 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