EIA/RETMA codes

[Jon Kirwan]

Michael:

491 is not on the 1946 list which tops out at 477.

Hmm. So post-war, anyway. Boxed in between 1946 and 1957? Cripes.
Did I dismantle a 1950's slide show projector? Can't be. The large
aspheric lens was plastic. The other optics was glass and mounted in
nice, expensive metal tubes with baffles, though.

Thanks,
Jon

 

[Jon Kirwan]

Aspheric lens? That sounds like part of a TV projector
using a spherical mirror. Does that make any sense?

It uses lenses and projection and first surface mirrors to a ground
glass view screen. I bought it from Goodwill for a couple of dollars,
mostly for what I hoped to get back in lenses. My wife wanted the
mirrors for making magic illusion boxes. It was worth it.

Jon

 

[Tim Mullen]

On Tue, 19 May 2009 15:11:36 -0700, "Richard Knoppow"

It uses lenses and projection and first surface mirrors to a ground
glass view screen. I bought it from Goodwill for a couple of dollars,
mostly for what I hoped to get back in lenses. My wife wanted the
mirrors for making magic illusion boxes. It was worth it.

You didn't disassemble one of these, did you?

http://www.tvhistory.tv/1948-Scott-6T11-Proj.JPG

 

[Archimedes' Lever]

It uses lenses and projection and first surface mirrors to a ground
glass view screen. I bought it from Goodwill for a couple of dollars,
mostly for what I hoped to get back in lenses. My wife wanted the
mirrors for making magic illusion boxes. It was worth it.

Jon

Got mine at Goodwill, and used it for what is was made for. Microfiche
viewing. My Pioneer stereo had the schematic in microfiche.

What a waste of space. Those mirrors are nice, but you should never
attempt to "clean" them as you will scratch them for certain.

 

[Archimedes' Lever]

You didn't disassemble one of these, did you?

http://www.tvhistory.tv/1948-Scott-6T11-Proj.JPG

Scott made better speakers than TVs.

 

[Jon Kirwan]

You didn't disassemble one of these, did you?

http://www.tvhistory.tv/1948-Scott-6T11-Proj.JPG

No, the number of those remaining to the world hasn't changed due to
my recent activities. I probably would have scavenged it (savaged it,
some may say) had it been in sight, though!

Looks like a parts box to me.

Years ago I gave away (to a radio club in NYC) two 4'x4'x3' boxes
filled with vacuum tubes I've scavenged over my first 30 years of
life. These included VR-150's from a 1944 navy radar set (hmm, I
wonder if I still have the Selsyns from that in some box) and
everything up to one or two 4CX1000A's I'd picked up. It was a huge
haul for them, I suspect. Free, including shipping. I hope they used
them well.

Jon

 

[Jon Kirwan]

Got mine at Goodwill, and used it for what is was made for. Microfiche
viewing. My Pioneer stereo had the schematic in microfiche.

What a waste of space. Those mirrors are nice, but you should never
attempt to "clean" them as you will scratch them for certain.

I'll try and be careful. The only first surface mirrors I've had much
experience with are ones I made for telescopes, back when. I used
silver nitrate solution for that. The silver _was_ sensitive and I
had to replace it periodically (once a year or so.) Luckily, that
wasn't hard to do. Aluminum deposition is pretty solid, though, and
forms a protective layer pretty quickly from the air's oxygen. I
never made my own bell jar/vacuum system for depositing aluminum, but
the mirrors I handled seemed to hold up pretty well so long as I was
basically careful about it.

Jon

 

[Archimedes' Lever]

I'll try and be careful. The only first surface mirrors I've had much
experience with are ones I made for telescopes, back when. I used
silver nitrate solution for that. The silver _was_ sensitive and I
had to replace it periodically (once a year or so.) Luckily, that
wasn't hard to do. Aluminum deposition is pretty solid, though, and
forms a protective layer pretty quickly from the air's oxygen. I
never made my own bell jar/vacuum system for depositing aluminum, but
the mirrors I handled seemed to hold up pretty well so long as I was
basically careful about it.

Jon

The ideal optical surface is one that has never been "touched" or ever
needed cleaning which required other than mere liquid contact.

 

[Jon Kirwan]

The ideal optical surface is one that has never been "touched" or ever
needed cleaning which required other than mere liquid contact.

Well, I've no idea what they've been subjected to.

By the way, I didn't mean 'touch' as you write when I wrote 'handle'.
Surfaces for telescopes need cleaning. Dust collects without a sealed
environment (I never was able to afford that kind of thing.) The
three volume 'bible' set on making optics (Amateur Telescope Making)
recommended replacing the silvering every 6 months, something I
couldn't do that often. (So did Texereau's book.) But I did try and
replace the silvering once a year, or so. Aluminum surfaces were
considered 'good' for about 2-3 years, which I would have appreciated
while gladly accepting the slightly poorer reflection over wavelength
had I been able to consider it. But one does what one can afford to
do at the time.

Jon