| Author |
Message |
jantje112
Joined: 17 Jul 2006
Posts: 328
|
|
| Back to top |
|
 |
draganm
Joined: 08 Mar 2006
Posts: 8990
Location: Colorado
|
| Posted: Wed Apr 02, 2008 6:15 pm Post subject: |
|
|
WOW,WOW,WOW !  I've seen burnt tubes before but those are like little Charcoal Brickets. Isn't CRT amazing though, can you imagine how many hours that sucker ran to burn the tubes like that. 
|
|
| Back to top |
|
|
jask
Joined: 17 Mar 2006
Posts: 10187
Location: kamloops BC
|
| Posted: Wed Apr 02, 2008 6:19 pm Post subject: |
|
|
|
I don't think those are burnt, that is part of the lens system.
|
|
| Back to top |
|
|
kal
Forum Administrator
Joined: 06 Mar 2006
Posts: 18114
Location: Ottawa, Canada
TV/Projector: JVC DLA-NZ7
|
|
| Back to top |
|
|
ecrabb
Forum Moderator
Joined: 13 Mar 2006
Posts: 15909
Location: Utah
TV/Projector: JVC RS40, Epson 5010
|
| Posted: Wed Apr 02, 2008 6:47 pm Post subject: |
|
|
Those rectangles are the back sides of reflectors... If you're familiar with telescopes, it's basically a Cassegrain design, which works like this (but in reverse).
SC
|
|
| Back to top |
|
|
zGman
Joined: 22 May 2006
Posts: 599
|
| Posted: Wed Apr 02, 2008 7:03 pm Post subject: Novabeam |
|
|
Greetings,
Actually, the rectangles you see thru the lenses (with the little strip
leading off to the side) are the back side of the phosphor, which
is deposited on the front of the tube as usual, but on an opaque
aluminum substrate. The electron beam fires thru a hole in the
curved mirror, and the light from the phosphor goes back toward
the curved mirror (which is flashed with aluminum) and then once
reflected, back through the front of the tube, which (I think) is also
curved. Its been a while since I looked at one.
In the drawing from ecrabb - substitute the phosphor for the secondary
mirror, and imagine the electron beam on axis from where the
eyepiece would be, and the image light output then heads out
through the barrel, but then thru another lens for projection.
The interesting thing is that it works with so little phosphor area.
The way the optics are designed, there is only one throw distance
for which the system is in focus.
Cheers,
Galen
Last edited by zGman on Wed Apr 02, 2008 7:14 pm; edited 1 time in total
|
|
| Back to top |
|
|
Brooklyn
Joined: 17 Sep 2007
Posts: 494
Location: Morgan Hill, CA
|
| Posted: Wed Apr 02, 2008 7:03 pm Post subject: |
|
|
|
Well it is unique at least.
|
|
| Back to top |
|
|
Tim in Phoenix
Joined: 21 Oct 2006
Posts: 4409
Location: Phoenix
|
| Posted: Wed Apr 02, 2008 7:14 pm Post subject: |
|
|
Guys!
We sold several hundred Novabeams around Michigan; built on a Magnavox chassis. They were among the first to employ magnetic focussing. The Novabeam threw a pretty nice image on a 79" diagonal hi gain curved screen, and was easy to troubleshoot with a box of spare modules.
.
|
|
| Back to top |
|
|
ecrabb
Forum Moderator
Joined: 13 Mar 2006
Posts: 15909
Location: Utah
TV/Projector: JVC RS40, Epson 5010
|
| Posted: Wed Apr 02, 2008 7:16 pm Post subject: |
|
|
Duh. Galen's right. The little tabs are the phosphor targets, and mirrors are at the back facing the screen.
SC
|
|
| Back to top |
|
|
jantje112
Joined: 17 Jul 2006
Posts: 328
|
| Posted: Thu Apr 03, 2008 7:37 am Post subject: |
|
|
Well, learned something again!
The machine is probably older then I am.
|
|
| Back to top |
|
|
|
|
