Sanyo PLC-EF31 Service Manual

Also see for PLC-EF31: Owner's manual Service manual

-30-ASS'Y POWERHot circuitAC-INPUTCPU IC801andI / OEXPANDERIC1831SUB POWERSystem ControlINTERLOCK SWFUSESW902F901DC outWARNINGTEMP.READYPOWER-ON/OFFIIC-SCL & SDAACDC outI / OEXPANDERPOWERCONTROL SWITCHINDICATORSFANON/OFFFANSFANSPOWER-FAILCONTROLLAMPREPLACELAMPAlwaysSwitched16V /9V /6.25V /-6V=== NOTE : Temperature monitor operation ========================The temperature monitor system is provided to prevents damage of optical components (the LCD panel and polarizationfilm etc.) inside a projector from overheat. Two protection systems are provided. Each system operation as follows :------ The temperature monitor -1: ------------------------------------------------------------------ To control the air-flow of the cooling fans.The CPU checks the temperature and atmospheric pressure inside a projector. It checks a temperature using temperaturesensor-IC5801 and it checks an atmospheric pressure using pressure sensor-IC886.CPU judges data from sensors and controls the air flow of the cooling fans so the temperature inside the projector is main-tained to normal temperature. To shut down the projector urgent.The CPU checks temperature of LCD panel periphery and inhalation air(IC5801). If each part temperature reaches toabnormal temperature, the CPU will turn off a projector, and will blink TEMPERATURE WARNING indicator at inter-vals of 0.6 seconds. Cooling fans operate until temperature returns to normal. Indicator will stop blink, if temperaturereturns to normal. Trace the cause of the abnormalities-temperature, and repair the projector.------ The temperature monitor -2 : ------------------------------------------------------------------ Temperature check of lamps.Temperature switches (SW 903~904) are arranged near the two lamps. Temperature switches will oper-ate, if temperature reaches 90~100 degrees. When temperature switches have operated, lamp ballast unitswill be shut down, then a projector will be turned off. Note;(1) If other protection equipments ( The function of fan operation check, The function of voltage check "Power-failure"and Temperature monitor 1 ) are rightly operating, the lamp does not become an unusual temperature. So, the tempera-ture monitor 2 rarely operates. However, when those protection equipments do not operate with fault, the temperaturemonitor 2 operates and the broken protection equipment is covered. If this temperature monitor 2 operates, it is thoughtfault of other protection equipments. Also trace the cause of fault of other protection equipments with the cause of anunusual temperature.(2) The CPU does not check operation of temperature switches. Therefore, when temperature switches have operatedand a projector has shut down, TEMPERATURE-WARNING indicator does not blink.TEMPERATURE ABNORMALITY -1TroubleshootingNOTE : CPU OPERATION CPU (IC801) performs an input check by the IIC-SDAsignal pin. When it has detected abnormal condition, CPU turns offthe projector compulsorily. Cooling fans operate untiltemperature returns to normal. Moreover, a projectorcannot be turned on during this period.*NOTE : TEMP. MONITOR LED OPERATION The red LED indicates temperature monitor operation as follows:LED off: Normal temperature.LED flashes in 0.6 second interval: Abnormality temperature.Doesn't the temperature warn-ing indicator (red) blink?The projector is turned off whenthe temperature around the LCDpanel reaches 46 - 48 degrees.And a temperature warning indi-cator blinks.Refer to page 32CHECK !CHECK !CHECK Fan