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● Description of Power supply circuit
When the projector is standby mode, IC301(Main CPU) is not working and IC4801(Sub CPU) is only working for saving ener-
gy.
When the projector is connected to outlet with AC power cord and the Mains SW is switched to ON, SS3.3V line is supplied
to to standby circuit, including IC4801. IC4801 is waiting for the POWER ON/STAND-BY key input or remote control signal.
When the projector is turned on, "STANDBY_SW" signal (Power ON:H) is sent to the ECO POWER board, and then the
switching power supply circuit starts operation. "POWER_ON_SW" signal (Lamp ON:H) from pin 25 of IC301 is also sent to
the POWER board, and then the lamp power supply circuit starts operation.
The "1.8V_SW", "3.3V_SW", "15V_SW" and "FAN_SW" signals are also sent to the power supply circuits.
Power failure protection of secondary power circuit
The projector provides a protection circuit to prevent the secondary failure when the power failure, fans failure or tempera-
ture failure occurs on the projector. The power failure detection lines are connected to the main power supplies. When a
failure occurs, IC301 receives the power failure detection signals "POWER_FAIL" through the power failure detection lines
and "POWER_ON_SW" signal (Lamp OFF:L) is supplied to the POWER board to stop the power supply operation, and the
lamp operation is stopped with "LAMP_SW" signal (Lamp OFF:H).
Chassis Block Diagrams
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