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Repairing LCD projector

Discussion in 'Electronic Repair' started by Mike, Mar 6, 2004.

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  1. Mike

    Mike Guest

    I probably wont get an answere to this one either,

    but.

    I am repairing a sharp XG-E850U movie/computer LCD projector.

    The ballast crapped out.

    I am working on the ballast, and when the unit powers up, you can hear the
    SMPS inside the ballast start up, or the high freq pulse.

    But, the ballast will NOT pulse the bulb, and the open circuit volage on the
    bulb is 0v. it will pulse to 2v and back to 0 when you first turn on the
    projo.

    The heatsink, when left on for a minute, will get too hot to touch.

    IC1702, which has an odd number of 10T45 is the culprit of overheating the
    heatsink, and the thermal relay will kick in, and shut down the ballast.

    IC1702 drives the bulb's transformer. and I need a cross to the 10T45 IC.
    Its probably a mosfet in a packege, but I need either a cross, or a pinout
    of the IC.

    The number on the board is K837IDE

    The bulb is good, because it was tested in a friends projector.

    Any Ideas? The 300+vdc source is on the ballast.

    I removed the IC, and the ballast is pulsing, and lighting the arc. But the
    IC is needed to put the bulb into run mode i guess.
     
  2. David

    David Guest

    Any reason you are posting three times over a couple of hours? One posting
    is quite enough.

    Your choice is to buy the service manual for the unit from Sharp and
    troubleshoot the ballast assembly. oops, forgot, Sharp quit including the
    ballast assembly schematic on some of these, the repair part is to replace
    the entire ballast with one that has been rebuilt by Sharp for around $250.
    On others the schematic was available, but some of the custom Sharp parts
    were never made available as individual parts.
     
  3. Mike

    Mike Guest

    my mail server has screwed up, so i posted over at google, and it didnt show
    at first.
     
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