Fire-Lite Alarms MS-4012 Instruction Manual page 25

Charger Test, Older Models (Older Model MS-4012/4024s only)
For MS-4012/4024s that do not provide non-resettable power, the battery charging circuit can be checked and
if neccessary, calibrated under the following procedure. Remove the batteries and place a 1k, 1-watt resistor
across the charger ouput pins [plug P2: pin 1 - (+), pin 3 (-) ]. Using a voltmeter, measure the DC voltage across
the 1K resistor. If the voltage measured is not 13.2 - 13.3 (4012) or 27.5 - 27.7 VDC (4024), perform the
following calibration procedure:
Step 1
Step 2
Step 3
Step 4
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Note: This procedure may result in destruction of the batteries if used on
CMS-4012/4024s and newer MS-4012/4024s that provide non-resettable power!
Adjust R5 until the voltage across the 1K resistor is 30 VDC (MS-4024) or 15 VDC (MS-4012).
Adjust R108 until the the Battery Trouble LED just turns on (threshold point).
Adjust R5 until the voltage across the resistor is 27.6 VDC (MS-4024) or 13.2 VDC (MS-4012).
Remove the meter and resistor and reconnect the batteries to Plug P2.
If this adjustment fails to bring the charger voltage to within the specified range,
or fails to extinquish the battery trouble indication, (and the transformer and
batteries are known to be good), have the panel repaired or replaced.
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15586 Rev E 5/14/93 P/N 15586:E
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