[simpits-tech] My projector fix project

[Marv De Beque]

The size of the LCD doesn't buy you anything by increasing the panel
dimensions.  However, it will require different optics since the size and
focal points change.  It also complicates the light source.

The bulb, ideally, should be a point light source.  This is the reason bulbs
cost so much and their life is so short (high filament temperatures).

It might be possible to take a diffuse light source and reflect it into a
point source, but I don't have the optical experience to know that.

In the end, it may be easier and cheaper to buy a new bulb (if that is why
your projector failed) and you will have reset the clock on the life of the
projector.

Marv


On 7/29/03 2:54 PM, "Sean Galbraith" <sean.g@paradise.net.nz> wrote:

> As some will know my projector took it' s own life in a rather grand manner
> some time ago, and I have been working on a cheap fix.
> 
> I have investigated alternatives to the seriously expensive original
> replacement bulbs, but have ended up at a bit of a brick wall;  The
> projector uses a metal halide bulb, which uses a ballast and transformer
> setup which is very sensitive to the type of bulb being attached.  From
> research I've done it appears that if the replacement bulb is more than
> about 1% different in spec then it will blow either the ballast or
> transformer.  Not good.
> 
> I have however stumbled over (which is a fair indication of my research
> skills...) two possible solutions.  One easy, one much harder, but do-able
> and with some very positive benefits.
> 
> 1, Many projectors have a way for technicians to isolate the signal
> generator from the lamp parts of the unit.  Used for service/repair
> work.  The down side is you will most likely need a tech/repair manual for
> the projector to find out how to do this.  Tech manual for my projector is
> not available, so I have asked around and got some tips..... results to
> follow, assuming I don't blow myself to tiny little bits :)
> 
> 2, If I can't get No1 to work then it's off to the department of drastic
> measures!
> I have been looking at some of the DIY projector projects on the net...and
> thought to my_sick_self "I can do better than that.."  Most of the DIYs use
> little tiny LCD's lit with consumer lighting units....
> So I, using the Tim "The Toolman" approach thought.....more power :)
> A projector consists of 3 main parts;  Light source, Image generator and lens.
> - Lens I got, remember the dead projector?
> - Light source... I spec some pretty good lights in stuff I design at work
> so that's no problem.
> - Image generator, forget 4" LCD's.... What about a 15" LCD..which are
> getting cheaper by the hour?
> I figure, rip the back of the LCD, shine honking big light through, focus
> with lenses...easy huh?
> This solution will be much *MUCH* bigger than a commercial projector setup,
> but has two definite advantages;  Bulbs will last thousands of hours,
> rather than hundreds (oh and they are cheap) and a modern LCD has much
> better resolution and colour depth than my existing projector.
> 
> This weekend I plan on test flying the P-3 sim setup and then delving into
> the innards of the projector and see what happens...wish me luck!
> 
> Sean.
> 
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