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convert 65" to 92" rptv  

post #1 of 6
4/15/02 at 10:56pm
Thread Starter 
I am curious if anyone has tried using an existing rptv and doing a built in with a larger rp screen size?

I currently have a 65" Toshiba and I am considering purchasing a new screen of 92" and doing a built-in application with the new screen.

I can't see any reason this would not work. I can build a rack for the mirror and other hardware and then just refocus the guns to the new screen size and distance from the mirror.. The set is in very good shape but I want a bigger picture for a dedicated room.

Can anyone tell me why this wouldn't work?

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post #2 of 6
4/16/02 at 9:57am
You'll lose brightness (inverse square law) but you can probably compensate for that somehow.

Biggest thing: The lenses are probably limited in throw distance/ focus range, selected for your screen size (same chassis used in different screen size models often have completely different lenses.)

SO you might have to figure out what new lenses to use.
post #3 of 6
4/16/02 at 7:17pm
Thread Starter 
Thanks Mike for the Information. I hadn't considered the need for new lenses. I assumed the current ones would work going from 65" to 92".

Do you know of a way to determine if the lenses are fixed for a 65" screen?
I have the service manual for the set.

I will also try an contact Toshiba and see what they think.
post #4 of 6
4/18/02 at 3:44am
Just consider the manual focus adjustment. Move it to its max/min travel limits and you probably don't have more than a few inches of variation available for changes in the focal plane location (the screen).
post #5 of 6
4/18/02 at 8:52am
The lenses are also angled so that they converge on a 65" screen. When you go to a 92" screen and the associated longer throw distance the lenses won't be all aimed at the screen. Front Projectors allow the angle of the red and blue guns to be adjusted for the screen size, RPTVs don't.

You would also have to redo geometry and convergence from scratch, not to mention mechanical focus and Scheimpflug (another tricky thing since it's not generally adjustable on RPTVs). The lenses may not focus onto a 92" screen.

You're probably better off getting a projector.

KJP
post #6 of 6
4/19/02 at 2:53am
Thread Starter 
I think you guys are right, I'll just go with front projection and leave the RPTV in the living room. Thanks for the help.
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