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TDC Projector Heat filter problems


  • From: P3D <Alan.Hancock@xxxxxx>
  • Subject: TDC Projector Heat filter problems
  • Date: Tue, 22 Oct 96 18:55:10 GMT

    Have seen a post recently about TDC projector heat filters that are
    fogged over, and that has prompted me to also request some help on the
    same subject.

    It is possible to polish off the white fog that appears on these filters
    using metal polish or fine jewelers rouge powder mixed with water.
    Unfortunately if the filter has had a lot of exposure to heat then the
    surface can become fogged, cratered and ridged to an extent that the
    filter needs replacing, which I am sure is now the case with many of
    these old projectors.

    I have being trying to locate some direct replacement heat filters for
    my TDC 716 Stereo Projector for some time now. The size of the filters
    in my unit are 60mm diameter x 3mm thick and fit in a carrier with two
    recesses that are designed to take filters of that size, with a metal
    clip to hold the filter in.

    It is possible to get modern superior scientific quality KG1 or KG3 type
    heat shield filters made in this size but this would normally be a
    custom made size in the UK, and would cost in excess of US $150.00 a
    pair. It is not possible to cut down a larger sized standard square or
    circular filter because they are made to size then tempered, this helps
    the glass to withstand up to 300C. Trying to cut such glass when
    tempered would shatter it.

    Does any one know of a source of this type of filter? I have tried all
    the usual 3D supply catalogues and projector companies. The only
    possibly viable suggestion I have had is from Bob Aldridge, to use 54mm
    square RBT projector heat filters which should be available as spares. I
    have not yet measured the light path width going through the filters,
    but it should fit within a 54mm square. The heat filters are mounted
    between the condenser elements to maximise beam width to spread out heat
    dissipation over as large an area of the filter as possible. It should
    be fairly easy to make up a different filter carrier to take RBT
    filters, assuming they are suitable to dissipate the required amount of
    heat.

    If anyone has any information about possible sources of supply of
    suitable heat filters or further information about their own heat filter
    arrangements for TDC projectors, I would be pleased to receive any
    information or ideas you may have.


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