Abell A720T, Руководство по обслуживанию

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A720T (VHF) Service Manual V1.0
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5.7 CPU Control System
U300 micro processor clock running on 12.228MHz.
Low voltage warning of battery
：
The battery voltage is monitored by U300 microprocessor. When it is below the low voltage of warning, the warning
tone will alarm.
On standby status:

When battery voltage is lower than preset warning value, system enter into low voltage warning status, radio
will give a “Beep” sound at preset intervals
On transmitting status:

When battery voltage is lower than preset warning value, press PTT key, the indicator LED will keep showing
flash red, radio is on transmitting status; When you release PTT key, radio will give a “Beep” sound at preset
intervals.

When battery voltage is lower than preset warning value but still withing the required transmitting voltage, red
long bright, you can press PTT key to transmit, radio will give a “Beep” sound at preset intervals.

If voltage lower than required transmitting voltage, when release PTT key, radio will give a “Beep” sound at
preset intervals. When you press PTT key again, red keeping flashing, radio will give a “Beep” sound and stop
transmitting; The transmitting will recover again till voltage higher than required transmitting voltage, red flash
and “Beep” sound will disappear.

When battery voltage lower than standard, red keep flashing, if you press PTT key, radio will give “Beep”
sound at preset intervals.

Radio will power off when battery voltage lower than power voltage. You need to charge the battery till higher
than power voltage to power on again.

When battery voltage higher than high voltage protection circuit, transmitting will be stopped, radio will give
“Beep” sound. Radio can only be allow to transmit till voltage turn normal.
R E S E T
E E P R OM
1 2 .2 8 8MH z
X 3 0 0
X OU T
X IN
S D A
S C L
W P
2 4 C 51 2
U 3 1 8
S -8 0 1 2 2A N MC
U 3 1 7
R E S E T
S T M3 2 F1 0 3 V B T 6
U 3 0 0
P T T
MON I
P T T
MON I
1
2