Main Board
USA MAV500/MKVI Service Manual
Replacing Battery
When the battery is changed, power will be maintained for a limited time by the
decoupling capacitors. A connector (J11) is provided to allow for external battery
backup during battery replacement.
10.4.9 Real Time Clock
The Main Board utilises the Dallas DS1302 Real Time Clock (RTC) and uses a
standard Dallas 3 wire interface. The real-time clock, meter RAM 0, and the battery-
backed security circuit on the I/O Driver Board are powered from the same battery.
10.4.10 Security
The system caters for two types of security inputs, optical and mechanical, with eight
of each. The sensor circuit is designed such that an external optional add-in security
module (on the Backplane Board) is able to share the sensors.
The add-in security module has the capability of monitoring both the optical and
mechanical inputs during normal operation and power off mode. The security system
also allows for the time stamping and logging of security events
Optical Security
The Main Board provides the necessary circuitry to interface eight IR LED
emitter/photo-transistor detector pairs. The optical security sensors are monitored by
the Main Board when the machine is powered.
Sensor sharing between the Main Board and the optional security module is
accomplished by the use of diodes.
The following emitters and detectors are used:
•
Emitter.
LD271A with a beam width of 50 and a frequency of 950 nm.
•
LED current: 15 mA
±
20%
•
Driving Source: +5 V DC logic supply
•
Current is on at reset.
•
Detector.
BPW77N with a beam acceptance of
±
10 and a peak sensitivity at 850
nm.
•
Output Signal: 10 K 5 % resistor pull up to +5 V DC.
•
Driving Source: +5 V DC logic supply.
10-16
28-00486-00
This document contains confidential information which is proprietary to ATI. It may not be disclosed to any unauthorized parties,
and it may not be copied. All rights reserved.
© Copyright (ATI) Aristocrat Technologies, Inc. 2002
