16
MDS 4790/9790 Series I/O Guide
MDS 05-3438A01, Rev. F
Invisible place holder
Figure 11. Battery Backup Switch Location
(Front Panel Removed)
Low-Voltage Disconnect Feature
The Low-Voltage Disconnect Assembly contains a low-voltage discon-
nect circuit. This circuit prevents damage caused when the backup bat-
tery drops below 10.65 volts, such as during an extended AC power
outage.
When the back-up battery voltage drops to 10.65 Volts (± 0.2 V), the
low-voltage disconnect circuit automatically disconnects the battery
from the radio. This stops operation of the radio and protects the battery
from potential damage. When AC power returns, the battery is
automat-
ically
connected to the power supply for re-charging, and the radio
resumes normal operation.
Battery Reset Switch (SW1/LVD PCB)
Normally, the operation of the Low-Voltage Disconnect Assembly is
fully-automatic. The only exception is when replacing a discharged bat-
tery with a charged battery
when AC power is not present
. In this case,
it is necessary to press the
BATTERY RESET SWITCH
SW1
on the
OFF
ON
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