Japanese Color TV set without a tricolor tube
 

Hi folks! In the mid 1960s, in Japan a cheaper color television set was available which contains three b/w crt's and a mirror system instead of a tricolor shadowmask tube. Who is able to give more informations about it? Did such a tv set survive until today and is it possible to display a picture of it in working condition?

I've seen one, or one using the same system, on a site but I can't remember where.

And we thought projection sets were particular about where the viewer sat. This set would have one hell of a small 'sweet spot'. Like watching tv thru a tunnel...

That looks like a Mitsubishi logo on the front of the set under the picture tube.

- Pete

Sorry, I was wrong with the date. This color tv set was bought by Walter Bruch in 1955 at the airport of Tokyo. It is working with NTSC. Here is a look inside it. The drawings on the metal plate show the b/w screens. Above the vertical crt's there are two colored mirrors which reflect the picture to the front screen. The third horizontal crt at the top of the left side has a color filter too. It is a Mitsubishi tv set. Do there exist any sets like this today?

I still can't figure out why they went this route-looks like 3 CRTs, the mirrors/filters, additional circuitry, would have made it almost as expensive as sticking in a color CRT-even in 1955. And rotsa ruck aligning all that monkey-motion up & getting a decent picture...Still wouldn't mind having one for the historical/novelty value. -Sandy G

More questions than answers?
 

Eyeball Observations:


The line cord and its plug (foreign-style to us on this side of the pond) provide a sense of overall size.

Three CRT’s, their magnetics, and the optics occupy three-quarters of the internal volume of the case.


Fact:

Even a ‘reduced tube’ CTC4 of 1955 had two dozen tubes.


Question:

Is this little guy also transistorized? four years before the Safari?

Was there a second electronics package that held the tube circuits?


?

On the ETF page
http://www.earlytelevision.org/color_prototypes.html
there is a triniscope prototype (RCA Triniscope #2, 1950) which looks very similar to that Mitsubishi tv set. Did somebody saw such a triniscope set ever working? They were developed in the early 1950s as an alternative to the very expensive tricolor kinescopes.

No, the tricolor kinescope was developed soon after as there was no alternative. The earlier, massive trinescope was totally impractical on so many levels.

1955?
 

Just looking at the cabinet, logos, knobs ect. This set looks to be of a later design then 1955.
I also recall a previous post of this or a similar set some time back, but can't recall where.

-Steve D.

Mitsubishi showed a trinescope at the NY World's Fair, in the Japan pavilion. Even as a starving student, Iwas fascinated enough to spend two slides worth of film on it. There was also a demonstration of the dichroic mirrors, which I took a picture of, but now I don't know if that was in the Japan pavilion or maybe in the Hall of Science, which had some exhibits on color.

One advantage the trinescope had was that it was BRIGHT, and with that tunnel, you could watch it in daylight.

Look in my gallery for all 3 pix

Does anyone else see the resemblance of the "nudie" photo to the typical home computer?

Anthony

That set must be mid 1960s, not 50s. I would think the CRTs are maybe 5"? And I expect it IS transistorized.

I think you are correct. The pictures were taken from the book "PAL - Das Farbfernsehen" by Walter Bruch and Heide Riedel, p. 32. On page 33 was written:

"In der Zeit, als es noch keine Dreifarben-Bildroehre gab, also in der ganzen Entwicklungszeit fuer NTSC, musste man solche Empfaenger benutzen. Und auch dann noch, als die ersten Dreifarbenbildroehren noch knapp und teuer waren, verkaufte man solche Farbempfaenger fuer NTSC. Ein derartiges Geraet hat der Verfasser 1955 in Tokyo am Flugplatz gekauft."

Translation:

"In the time when no tricolor kinescopes exist, i.e. in the entire time of development of the NTSC system, one had to use such trinescope color receivers. And later in the time where the tricolor crts were rare and expensive, such trinescope color sets for NTSC were sold. One of these trinescope sets the author (i.e. Walter Buch) has bought in 1955 in Tokyo at the airport."

I think the time has to be 1965. "1955" had to be a type writer error. And 1965 lies within the range of time were Walter Bruch travelled all around the world to demonstrate his PAL color system.

Fascinating. I find the old World's Fairs very interesting. So many new things to see...if we could all go back for a day.

I think this particular set was discussed here on AK a couple years back. Not quite sure what to use in the search field to locate the thread.

If you want ot go back to the New York 64-65 fair, here are some links:

an absolutely huge site covering New York 64-65:
http://www.nywf64.com/

including my writeup and pix of the RCA exhibit
http://www.nywf64.com/rca01.shtml

a discussion forum covering mainly New York (64-65 and 1939), plus other fairs, with some of the most expert people on the subject:
http://www.peacethroughunderstanding.org/

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Hmm if you look at their 1st catalog for this set there, it shows the b/w monitor, then the 3 color filters stacked on top of it, with the 2 lcd shutters layered between the filters. I don't get how this works - the filters are all stacked so the light has to go thru ALL of them? How the heck do you just get red, or just blue? (with a wheel, it only has to go thru one color at a time). How do the shutters work, obviously they can't shut light off completely, or just the first shutter would result in no picture. Are the shutters divided into pixels, or is it just a solid pane shutter that goes from clear to black? Can anybody explain how this thing works? thanks...Frenchy

I remember seeing this set before as well. There was discussion on this, or a similar set, back in 2001 on the ARF site. The photos are gone now though. http://antiqueradios.com/forums/Forum6/HTML/000068.html

Have seen many of the 3 LCD projectors (by Sharp) that use an LCD light valve for each color and prisms to combine the RGB to one beam. The light valve is dark untill a pixel or pixels are excited then it goes clear to let light thru. They use an arc lamp as the light source.

I suspect the 3 color filters are not plain red,green blue, but are polarized somehow - one LCD then switches transmissions between red and cyan, and the other between blue and yellow.
Red+yellow --> red
cyan+yellow--> green
cyan+blue--> blue
red+blue - not useful - black or nearly so

---

But how can you get only cyan+yellow, if red is inline with the other two filters? Dito on the other combinations. Their graphic shows all three filters stacked on top one another in front of the crt face.

You are correct that if there are stacked filter sheets that always look red, green, and blue, then no light can be transmitted! So, obviously, the drawing and explanation must be confused and misleading. You can find an example of the kind of LCD shutters I described here:
http://www.colorlink.com/tecpage/tecpage.html

different possible arrangements:
http://www.colorlink.com/tecpage/pdf...olorswitch.pdf

complementary color version I described:
http://www.colorlink.com/tecpage/pdf...0colorquad.pdf

more:
http://www.colorlink.com/tecpage/pdfs/pw97.pdf

what I described:
http://www.colorlink.com/tecpage/pdfs/pw96.pdf

The last tech paper in your list has a graphic that looks similar to theirs, two shutters sandwiched between color layers.... sort of.

I'm the one who posted about this set a few years back here and on antiqueradios.com. I still have it and it is in working condition, but is missing the knobs, the two woodgrain escutcheons, and the red Mitsubishi light-up logo below the channel selector knob. The picture shown at the top of the thread is a smaller version of the set I have; I guess the "viewing window" was widened a bit soone could view the set slightly off axis. This set uses series-string vacuum tubes; the chassis sits vertically on the right-hand side. The three CRTs have red, green, and blue phosphors; no color filters are used. Like someone just said, it produces a bright picture, and I'll add to that a Technicolor-like vividness to the color. The downside is the small (5-6") picture; but Mitsubishi provided a plastic Fresnel lens to mount in front of the window as a magnifier. The set appears to have been made in 1964 since many parts in the set have a 1964 date code. I doubt these were ever sold in the US in great number as the tricolor CRTs had already existed for years, and the trinescope, at least to me, appears to be a bit Rube Goldberg-ish in comparison.

Mitsubishi trinescope flyer
 

I just picked up the flyer handed out at the NYWF for the Mitsu trinescope.

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Dang! Interesting set, but it does - in a way look like a furnace.

Certainly a strange mutt...
 

No color killer?
21-MHz IF!
pulse-width AFC.

I want one.

Trinescope, could you post photos of the set? Wayne, thanks for posting the flyer for the set. Would I ever love to find one of those!

Hey Trinescope, if you are coming to the ETF convention, you should bring it along, I know we would all love to see it.

Thanks all!

That's a really neat set.

David

I'll see if I can get a few pictures of the set up later on this evening.

Here are a few pictures of the set in question. I was just fooling around with video from my computer fed into an RF modulator for the screen shots.

Super! What adjustments are there for convergence/registration? Electrical? Mechanical? Both?

It looks like viewing a Philco Safari 2" set. Small tube(s) buried deep and looking large when viewed up close. Gotta have one.

Dave A

A very cool set but it looks like a microwave sitting on a window air conditioner.

- Pete

Convergence is both electrical and mechanical. The blue CRT is the reference; there are individual height, width, centering, and linearity adjustments for red and green. Also, there are magnets on the red and green CRTs for fine adjusting on the sides and corners. The set does display a bright picture like the brochure says, but is really finicky with convergence. Convergence changes with viewing angle to some degree. The circuits drift quite a bit, especially the tuner, but that might be due to age (this set has only had a few capacitors replaced in the vertical section so far).

VERY cool link to the RCA Triniscope!