Shure Four Channel Automatic Microphone SCM410 - Manual (Page 15)

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CHANGING THE LIMITER THRESHOLD
To change the limiter threshold from the preset value of +16 dBu,
modify the circuitry according to the following table.
CHANGING HOLD TIME
To change the hold time from the preset value of 0.4 seconds, modify
the circuitry according to the following table.
LOCAL AUX OPERATION
This modification removes the auxilliary audio from the SCM410 out-
puts. Auxilliary audio originates from the aux inputs of the Shure SCM810,
SCM800, and AMS8100 mixers when linked to the SCM410.
Procedure:
1. Remove resistor R9187.
MUTE IN PRECEDENCE TO OVERRIDE IN PRECEDENCE
When both MUTE IN and OVERRIDE IN logic are grounded, the Over-
ride mode will take precedence (as supplied, the MUTE IN takes prece-
dence over OVERRIDE IN).
Procedure:
1. Short jumper X1005.
2. Remove resistor R1087.
DEAD ZONE ON MUTE IN DEFEAT
As supplied, MUTE IN is intended for use as a momentary cough but-
ton or privacy function (mute when necessary). However, if the MUTE IN
is intended to be used so that the talker must unmute microphones to en-
able speech pickup (unmute when needed), this modification is needed.
This removes the muted channel from the MaxBus which eliminates
“dead zones.” A dead zone is an area in which a microphone picks up a
talker through a muted microphone and other microphones do not acti-
vate for that talker.
Procedure:
1. Short jumper X1002.
CHANGING MUTE IN TO INHIBIT
As supplied, a channel will mute when its MUTE IN terminal is ground-
ed. The mute function for each channel can be modified so that a logic
“low” at the MUTE IN terminal prevents that channel from gating on if it is
off, but allows it to remain on if it is already on. Use this modification to
enable Filibuster Mode.
IMPORTANT: To prevent high-frequency oscillation, never connect
the GATE OUT to the MUTE IN of the same channel unless the
“Inhibit” modification has been made.
Procedure:
1. Short jumper X1007.
CHANGE LIMITER THRESHOLD
Limiter
Threshold (dBu)
Limiter
DIP switch
X9003 R9149 R9142
0 On -- Remove 20k
+4 On Short -- --
+8 Off Short -- --
+12 On -- Remove 110k
+16
(default)
Οn -- -- --
+20 On -- Remove 300k
+24 On -- Remove 400k
CHANGE HOLD TIME
Hold Time
(seconds)
X9000 R9073 R9079
0.3 -- -- 2M
0.4 (default) -- -- --
1.0 Short -- --
1.5 Short 470k --