Article about Chromatron Tube

[Einar72]

Amen to that. Not likely to change in my lifetime...

[etype2]

The truth of the matter is American company's lacked the foresite to see the future. They only looked at short term profits, unwilling to invest in long term projects. If American companies would listen to their engineers we would be in a different place, instead they rule by committee. I have seen it happen time and time again in my 67 years on this planet.

Sorry that the Japanese Chromatron I brought up stirred up bad feelings.

[NewVista]

Originally Posted by etype2

The truth of the matter is American company's lacked the foresite to see the future.

Well not General Electric (doing much better than Sony today)..
GE wisely exited television just as Sony was ramping up..

Americans (knowing it won't work) sell Chromatron to Sony
Sony burn through billions then ditch it for a modified shadowmask nothing like a Chromatron.

Sony boss brags in book about Japanese superiority
just before Japan slides into a 25 year recession

[rca2000]

One of the BIGGEST blunders in tv history, was RCA giving up the rights to the lcd. They could have produced a workable B/W pocket tv by the late '60's and a COLOR tv a few years later. They would have owned the tv business by now, , bigger than Sony ever was... lock, stock and barrel!! instead...they pi**ed it all away..and they are a "nobody " now.

That pix with that engineer holding that little B/W LCD monitor with a GOOD test pattern on its screen in 1966 or so just hurts me to see.....

[NewVista]

http://www.visions4.net/journal/time-line/
It is amazing to see an actual Chromatron picture, and yes it shows unique qualities.
Trust the Japanese to bring it to actual production no matter what the loss.

[technicolor]

Originally Posted by old_tv_nut

Radio-TV Experimenter December 1964 / January 1965 -
Seven-page article on the Lawrence Chromatron color tube.

http://www.bretl.com/tvarticles/rtve1264/rtve1264.pdf

Reminder: a large assortment of TV-related articles are posted at:
http://www.bretl.com/tvarticles/tvarticles.htm

awesome links, thanks.

[egrand]

Here's a 1969 Popular Science article about LCD's and work to make LCD TV's: http://books.google.com/books?id=wSo...d%20tv&f=false

And a 1970 PS article on LED's: http://books.google.com/books?id=-AA...0diode&f=false

According to the 1969 article RCA could create a high resolution still image, but was totally unable to make a moving picture.

As I understand it, what finally made LCD tv a reality was the built in computers that can process the huge amount of information needed to create a moving image. Electronics of 40+ years ago were unable to process a signal and turn on and off all those tiny dots quickly enough.

[etype2]

Originally Posted by old_tv_nut

Radio-TV Experimenter December 1964 / January 1965 -
Seven-page article on the Lawrence Chromatron color tube.

http://www.bretl.com/tvarticles/rtve1264/rtve1264.pdf

Reminder: a large assortment of TV-related articles are posted at:
http://www.bretl.com/tvarticles/tvarticles.htm

Are we defending RCA or are we discussing the Chromatron, the subject of this thread?

[NewVista]

How many Sony Chromatrons estimated today?
How Much are they known to change hands for?

[etype2]

Originally Posted by NewVista

How many Sony Chromatrons estimated today?
How Much are they known to change hands for?

The Sony KV 7010U Chromatron was marketed July, 1968 and replaced by the Sony KV 7010UA Trinitron approximately, October, 1968. Based on that and 3 known serial numbers and chassis numbers of the the two versions, best guess speculation, possibly one thousand or less Sony KV 7010U Chromatron's were produced. I could be way off though, just best guess speculation as to what we know now.

Anybody's guess as to how many survived today and the value, it's whatever the collector is willing to pay. I can say for me personally, very rare and would pay appropriately.

[dtvmcdonald]

Let me get this right: the Chromatron they sold in the US, 7010U,
was a three gun tube, inline guns, with ? (one or three) ? lenses
(Trinitron has one, PortaColor has three) and TWO HV voltages, one
to the screen and one to the wire grid resulting in a focusing effect
between grid and screen. There was no AC applied to the grid.

Is that correct reading? What about the (19 inch???) Chromatron
said to have been sold in Japan???

I'm mixed up.

[etype2]

Originally Posted by dtvmcdonald

Let me get this right: the Chromatron they sold in the US, 7010U,
was a three gun tube, inline guns, with ? (one or three) ? lenses
(Trinitron has one, PortaColor has three) and TWO HV voltages, one
to the screen and one to the wire grid resulting in a focusing effect
between grid and screen. There was no AC applied to the grid.

Is that correct reading? What about the (19 inch???) Chromatron
said to have been sold in Japan???

I'm mixed up.

Hope this helps.

1. Sony put into pilot production a 17 inch one gun Chromatron in Japan only, it was not mass produced.

Because of the many problems with the one gun 17 inch they decided to,

2. Introduce a 19 inch Chromatron, but it used three guns, which departed from the original design of a one gun. This is the set that was mass produced in Japan only in 1965 and 1966, 13 to 18 thousand units.

They still had problems, extremely difficult to manufacture, time consuming, technical problems, they pulled the plug on the Chromatron but they did not give up. This led to the development of the Trinitron. For Sony, it had one gun, three inline beams, one lens and the Aperture grill was similar to the Chromatron, meaning it had the vertical stripes and passed much more light like the Chromatron. They did not want to copy the American system. Essentially the Trinitron was born from the Chromatron.

Now the interesting part, before Sony marketed the 7 inch KV 7010UA TRINITRON, one gun, three inline beams, one lens, in the U.S.,

3. They actually marketed the 7 inch, KV 7010U CHROMATRON one gun, three beam, one lens CRT with a color selection system like the Chromatron. A hybrid Chromatron.

4. Approximately three months later in October 1968, the KV 7010U CHROMATRON was replaced by the KV 7010UA TRINITRON.

Why did Sony introduce the KV 7010U Chromatron only to be replaced so soon by the KV 7010UA Trinitron?

Only speculation on my part, it was known that Sony had a few production mules of the 7 inch Chromatron, the development was finished by Spring, 1967. Sony showed the 7 inch prototype at a press conference in Summer, 1967 in New York and said it would be introduced the following year. I believe that share holder pressure, dealer pressure to get Sony's first color television on the market, (they were behind their competitors) caused them to release the KV 7010U Chromatron because the Trinitron was not yet ready. Possibly they wanted bragging rights as well to say they actually marked a Chromatron in the States. All the while they were working hard to get the Trintron to market. Sony's chief CEO pushed the engineers 24/7 to meet the production deadline.


Adding this: I don't have the expertise to tell you how the Sony KV 7010U Chromatron works. I do know that it has two HV supplies, three connections to the CRT bell, electronic purity adjustment and a color selection grid consisting of fine wires which focus the three beams. Perhaps others here can explain it further.

[dtvmcdonald]

Originally Posted by etype2

Hope this helps.


Adding this: I don't have the expertise to tell you how the Sony KV 7010U Chromatron works. I do know that it has two HV supplies, three connections to the CRT bell, electronic purity adjustment and a color selection grid consisting of fine wires which focus the three beams. Perhaps others here can explain it further.

What you wrote is what I more or less thought. It now boils down to
one question: is there RF on two of the three HV leads? If
so, it TRULY IS a chromatron, not just a larval Trinitron. If there
is no RF on any of the three leads, I would call it a larval Trinitron.

This question could be answered by a schematic or a scope with
its probe merely held a half inch or so from the CRT HV wires.

I believe the owner has a schematic ... it would be wonderful if
he could scan and post it! (the 7010U, not the 7010UA).

Doug McDonald

[etype2]

Originally Posted by dtvmcdonald

What you wrote is what I more or less thought. It now boils down to
one question: is there RF on two of the three HV leads? If
so, it TRULY IS a chromatron, not just a larval Trinitron. If there
is no RF on any of the three leads, I would call it a larval Trinitron.

This question could be answered by a schematic or a scope with
its probe merely held a half inch or so from the CRT HV wires.

I believe the owner has a schematic ... it would be wonderful if
he could scan and post it! (the 7010U, not the 7010UA).

Doug McDonald

I am the owner and unfortunately the service manual or schematic could not be found for the KV 7010U. I have searched extensively for them.

The service technician who worked on it said this:

“I suspect they are applying a DC voltage to the wire mesh and only using
it to focus the electron beams onto the correct phosphor stripes."

"The purity control on your set is probably varying the bias on the wire mesh.”

There is a label attached to the CRT bell identifying it as "Sony Chromatron Licensed under Patents of Paramount Picture Corporation"

The CRT tested very weak on all three beams (.1) and yet the KV 7010U still produces a very bright image due to the absence of a shadow mask or Aperture grill. I have screen shots. The promise of the Chromatron was to overcome the dim brightness of early RCA color, and no need to adjust for convergence, only one beam. The Sony KV 7010U shows very bright images, surprisenly bright for such low emissions.


Adding this: We compared the KV 7010U to the KV 7010UA. The KV 7010U has two HV instead of one, three connections of HV to the CRT instead of two, an electronic purity control instead of the standard control, the fine wire selection grill instead of the Aperature grill and the CRT bell is shaped diferently. Most of the circuit boards look the same.

[etype2]

Originally Posted by dtvmcdonald

What you wrote is what I more or less thought. It now boils down to
one question: is there RF

This question could be answered by a schematic or a scope with
its probe merely held a half inch or so from the CRT HV wires.

Doug McDonald

I went back to revisit a long list of emails exchanges with the service technician that repaired my KV 7010U. He said thinking about it later, he should have measured for RF radiation, but did not. He said DC voltage is applied to the color selection grid and creates an "electronic lens" which focus's the electron beams to the correct color stripe without need for convergence. That is why there is two HV supplies. It's called "post acceleration and focus effect"

I don't much about repairing sets and would not want to touch anything for fear of screwing things up.