Intelligent AXM-1500, Maintenance Manual, Page: 13 / 29

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Description:
1) Power source: Rechargeable Battery 6V/4Ah or AC adaptor(9V,
500mA)
2) How Battery is charged completely?
The charging voltage is regulated by Q1 (C1061) and ZD1 (8.2V) for
about 7 volts.
The
charging current will go down automatically when voltage reached.
Q2 (C945) and R1 (1.2R, 1/2W) provide Over-Current protection.
3) +5V power drives digital circuit system.
U6 (AIC 1722-5.0) is a 5volts Voltage Regulator.
4) +5V power drives analog circuit system.
U4 (NS2950A) is a 5volts Voltage Regulator.
4) Auto-off:
If the scale is set with 4_oFF or even under LO-BAT situation,
after fixed time interval, CPU will release a low potential signal
to draw down Q2, then Q1 cuts off, the scale will be shut down
immediately.
5) Low Power Detection:
The Q6(A733) is designed to detect the power level. When battery
power
is less than 5.5V, the collector pole will become high potential,
then CPU will instruct LCD display to show LO-BAT symbol.
4.2.1.2 Input voltage: 5.5V or higher
Check and recharge battery if voltage is less than 5.5V.
4.2.1.3 System voltage (Vcc): 5V +/- 10%
Check that the system voltage is within 5V +/- 10%
a) less than 4.5V, the CPU may not work properly.
b) more than 6V, ghost will appear on LCD.
4.2.2 Platform Stopper Checking
The platform device shall not touch anything around itself during
operation. Check that the platform is not contacted with the upper
(no load) and/or lower (with load) stopper.
4.2.3 LCD Display Checking
4.2.3.1 Check that it is soldered and connected properly between LCD
and driver IC (PCF8576), driver IC (PCF8576) and CPU.