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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, "POWER_ON SW" signal (Power ON:H) is sent to the UNIT_POWER, and then the switching
power supply circuit starts operation. "MAINON_SW" signal (Lamp ON:H) from pin 25 of IC301 is also sent to UNIT_POWER,
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 "MAINON_SW" signal (Lamp OFF:L) and "POWER_ON SW" signal (Power OFF:L) are supplied to the UNIT_POWER to
stop the power supply operation, and the lamp operation is stopped with "LAMP_SW" signal (Lamp OFF:H).
Power Supply Lines
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