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LCD overhead projector Mistubishi no light

Discussion in 'Electronic Repair' started by Roy and Rosa, Sep 14, 2005.

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  1. Roy and Rosa

    Roy and Rosa Guest

    I was given this projector because they said the bulb was too expensive to
    replace.
    Its a Mitsubishi LVP X70UX.

    When turned on the lamp does not come on at all. Not even a strike.
    The power LED comes on red 1 second after main switch is turned on.
    Then all fans start to turn.
    At 3 seconds the lamp LED comes on yellow and the temp led starts flashing
    red.
    At the same time the fans shut down and the power led flashes red to green
    every other second.
    The temp led continues to flash once a sec for 4 secs then waits 1 sec and
    repeats.
    Lamp timer was reset. no change.

    I get 393 vdc to lamp powersupply
    door switches check good.
    Are the temp sensors some kind of thermistor or just a switch?
    The fan sensor reads 9 k ohms (measured while disconnected) with 2.9 vdc
    across it when on.
    Internal sensor 9 k ohms " " "
    " 4.6 volts across it.
    Lamp sensor 86 k ohms " " "
    " 4.7 " " " ".
    lamps sensor looks like it is epoxied into a ring lug.
    Should these be open or closed ? or are they actual temp readings?

    OR is it just really a bad lamp??
    Thanks Ropy
     
  2. Roy and Rosa

    Roy and Rosa Guest

    Lamp and ballast are ok. I was able to determine which wire was the signal
    to start the lamp ballast. I jumped across the transister side of the opto
    isolator after turning on the main switch and the lamp arced and came on.
    Since fans still shut down I turned it off quickly.
    When I jump the return signal to tell main board that the lamp is on does
    not help. System still shuts down.
    I am not getting the start signal to ballast from main board. Appears to
    be
    a board problem.
    Unless someone can help me with the temp sensor voltages, this projector is
    junk.
    Thanks Roy
     
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