User`s manual

Sierra Video Systems
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damage. Second, it protects the bus in the system from a failure on an individual 504035
module.
U6 is a 4 line to 16 line decoder. Its output determines which bus on the 504035 is being
addressed by the central controller. The strobe input (J1-6S) is centered timing wise in
the data time that appears on the other logic lines to the 504035.
Power Supply
Low voltage AC enters the 504035 on J3 pins 27 and 28. If dual supplies are used, low
voltage AC from the second supply enters the 504035 on J3 pins 25 and 26. The low
voltage AC is rectified (D1 through D8) and filtered (C1 and C2) to unregulated DC. U10
provides +5VDC for the logic circuits and switching array. U11 provides -5VDC for the
switching array. U12 is a 78M15 and provides +15VDC to the analog circuits. U13 is a
79M15 and provides -15VDC to the analog circuits.