- 72 -5. Lamp ControlLamp Driving CircuitLamps on and off are carried out by signal "BALAST1_SW" and "BALAST2_SW". IC801 sends IC4802EXPANDER> the lamp on/off signal through the parallel bus. IC4802 outputs the lamp drive signals from pins 34and 35 and sends to the Lamp Ballast Unit via the IC5825 as the name of "BALAST1_SW" and "BAL-AST2_SW".The signals "LAMP1_TXD", "LAMP1_RXD","LAMP2_TXD" and "LAMP2_RXD" are sent to Balast1 and Balast2 viaIC4751. IC801 communicates Ballast1 and Balast2 with these signals to control the each lamp.When an abnormality occurs at the lamp or ballast, the error signals "LAMP1_RX_EX" and "LAMP2_RX_EX" outputfrom the ballast unit is sent to pins 167 and 168 of IC801 through IC4751. Then IC801 sendsdriving signals "BALAST1_SW" and "BALAST2_SW" to ballast unit to stop operating of the ballast unit which has afailure.Power Supply CircuitSignals "BALAST1_S" and "BALAST2_SW" are applied to POWER 1(AC) unit and POWER 2(AC) unit as the signal"LAMP1_SW" and "LAMP2_SW" respectively. These signals drive the output power of lamp ballast. Signal "PFC_SW"output from pin 36 of IC4802 is applied to power control circuit of POWER 1(AC)/POWER 2(AC)through the IC5825. The power control signal "POWER_SW_CPU" output from pin 211 of IC801 is appliedto power switching circuit of POWER (DC) unit through the IC5825.Lamp Cover Switch (SW902/SW905), Thermal Switch(SW914)When the Lamp Cover is not fixed securely, the switches SW902/SW904 do not turn on. Thesignal "LAMP_COVER" passing through the SW902/SW904 is applied to pin 2 of IC9870. The signal "MS_THERMO" output from the thermal switch for the mechanical-shutter is applied on pin 1 of IC9870. Wheneither the input signal "LAMP_COVER" or "MS_THERMO" becomes "High", the output signal "LAMP_STOP" on pin4 becomes "High", and the cuts off Q9802. As the result, the power supply for the lamp ballast unit is cut off and thelamp ballast unit stops operating.Bottom Cover Switch (SW904), Thermal Switch (SW911/SW912)The signal "SHUTDOWN1" becomes "High" and stops lamp ballast unit operation if the below cases happen.- The bottom cover cabinet is not fixed securely. (SW904 turns off)- The temperature of Lamp1 or Lamp2 exceeds a certain value. (SW911 or SW912 turns of)[NO POWER]Point of RepairWhen am abnormality occurs on the Lamp1, Lamp2, Ballast1 or Ballast2, projector cannot turn on due to operate theprotection circuit. Also if Lamp Cover or Bottom Cover is not fixed securely, projector cannot turn on due to operatethe protection circuit.LAMPREPLACE1WARMINGTEMPWARNINGFILTER LAMP READY SHUTTER LAMPREPLACE2Failure Parts[SIgnals]❂ ● ❂ SW902 or SW905 is opening[LAMPCOVER: High]❂ ● ● Lamp1 failuer[LAMP1_RXD: High]● ● ❂ Lamp2 failuer[LAMP2_RXD: High]● ● ❂ SW914[MS_THERMO: High]SW904, SW911, SW912[SHUTDOWN1: High]● ...... LED lightning❂ ...... LED blinkingLED Indication in the Lamp FailureChassis Description & Troubleshooting
