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How to check a Speaker Circuit resistance
To avoid a speaker circuit mismatch fault it is a good idea to check the speaker circuit resistance.
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Before checking the speaker circuit resistance always ensure the Mains Powered DAU is powered
down with mains supply switched OFF and battery supply disconnected.
Then using a suitable multimeter measure the speaker circuit resistance. Ensure the measured resistance reflect the number of
End-of-line (EOL) resistors connected on a speaker circuit. If there are differences then ensure the error is corrected. Note the
number of EOL resistors fitted to each speaker circuit, this information is required for entry into the Commissioning tool later.
W
10k
End-of-line
(EOL) resistor
W
10k
End-of-line
(EOL) resistor
W
10k
End-of-line
(EOL) resistor
Number of
Measured
EOL used
Resistance
W
1
10K
W
2
5K
3
W
3.3K
4
W
2.5K
This example shows the use of 4 EOLs on a speaker circuit
having spurs and therefore the measured resistance will be 2.5K . W
On completion of measurement tests reconnect the terminal block to the Main Control Board (MCB).
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W
10k
End-of-line
(EOL) resistor
Spur circuit
Spur circuit
Spur circuit
2.5KW
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Mains Powered DAU
Disconnect the terminal block
S1+ S1-
from the Main Control Board (MCB)
S2+ S2-
PB10
SPEAKERS
MAIN CONTROL BOARD
Mains Powered DAU
PB11
9
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