re: Heat in the TDC116

[P3D Gabriel Jacob <jacob@xxxxxxxxxxxxxx>]

Jamie Drouin writes

>Besides six condenser lenses (three on each side), there are two pieces of
>flat glass.  Assuming these are the heat absorbers, they are positioned
>after two condensers from the bulbs, not immediately after the bulbs as
>had been described by someone earlier.  The polarizers are immediately
>behind the slide carrier, which is, I believe, where they're supposed to
>be.

It would make more sense to me that the HAG would be after the condensers
or between the condenser elements. My guess is that they wouldn't put a
HAG right after the lamp because not all the light would be capture if the
condensing lens was farther away or would have to be much larger diameter
to recuperate it. The condenser can handle the heat pretty well. This is
the way a lamp projector we use at work is arranged also (not for 3D :-(
thou). As long as the HAG's are before the slide it would be okay.

>I have just run a quick test, turning on the projector for 30
>seconds.  First, with an RBT mount with white towards the light, and after
>the said time the white was very warm.  Second, with an RBT mount with
>black towards the light, and it became very hot and had began to melt,
>with the window distorting and the surface turning gloss.

Yes my early experiments collaborate with your findings. ;-)

>Although there is an obvious difference between the temperature
>created by the two sides, the white side was still alot warmer than I had
>expected, and I believe this is not safe for the emulsion when I actually
>put a slide in.

Either way if it is very hot to the touch, I agree it wouldn't be safe
for the emulsion.
       
>Re-reading George's post about his TDC tests, I have concluded that
>I my TDC has one (or both) of the following problems:
>
>1.Improperly placed or weak heat-absorbing glass.
>2.Insufficient air produced by the fan.
>
>Question: should the air coming through the top vent be cool, warm, or
>hot?

Logic dictates warm. If it is too cool I'd be worried it isn't drawing the
heat, generated inside the projector. If it is too hot I'd be worried 
something is burning in there. ;-)

Regarding the RBT's being black to reduce reflections, I thought of that
aspect when I posted my original message but didn't give it much thought
because first the white area occupied by the mount is not substantial
and secondly it would be secondary weaker reflections being introduced.
In any case it is an easy way to reduce even these secondary reflections, 
so point well taken.

Gabriel



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