AVD-3120
VA-700
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Page 16 of 23
Revision 10
CONFIGURATION
The AVD-3120 requires no configuration or adjustment for normal applications.
Detector threshold:
The detector threshold is set by RV 1 and is factory adjusted to respond to a 6 dB loss in signal level referenced to a
1 volt p-p composite video signal at the input to the VA-700 VDA with the looping connector terminated by
75 Ohms.
Adjustment of RV 1 can change the threshold level by approximately
±
3 dB.
To adjust the threshold level:
1.
Apply a 1 volt p-p video signal to the VDA rear assembly with the VDA operated on the bench from a
14 - 0 - 14 Volts AC supply or on an extender board in the Eurocard frame. Ensure that the VDA input
is correctly terminated in 75
Ω
.
2.
Reduce the input level to the trip level by attenuating the input.
3.
Adjust RV 1 so that the LED status indicator on the front panel just changes state.
INSTALLATION
VA-700:
The following links should be in place:
LK 2 - LK 3,
LK 6 - LK 7.
Under normal circumstances no adjustments need to be made to the VDA in order to fit the AVD-3120 and the
performance of the VDA will not be affected by the inclusion of the AVD-3120.
AVD-3120:
If a second equaliser sub-module is fitted to the VA-700 as is the case with the VA-700T this may first be unplugged
from its socket, taking note of the correct alignment so as to facilitate replacement after the AVD-3120 is fitted.
This step is not essential, but will make insertion of the AVD-3120 easier.
Carefully position the sub board over the VA-700, tilting to place the LED indicator in line with the ”TRIM” hole in
the front panel. Ensure that all pins of PL 2 & PL 3 of the VA-700 slide neatly into the corresponding socket
positions of SK 2 & SK 3 of the AVD-3120.
Press down firmly and evenly on the AVD-3120 sub board ensuring that the cut-out in the top left hand corner just
clears the gain potentiometer on the VA-700 as the board slides into place.
Check alignment of the sync alarm LED with the hole provided in the front panel of the VA-700 and adjust LED
position slightly if required.
If second equaliser sub-board was removed from VA-700, re-insert it carefully ensuring that all pins are correctly
aligned with the socket.
Connect alarm wiring to remote connection on rear assembly using the three pin IDC socket provided.