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The Set: Pete Deksnis's Site about the CT-100

Restoring a Vintage Color Television Set

THE SET

08-27-2005

TIDBITS
The 4th and 5th Years
June 2003 to August 2005

Still have time?
Skim or peruse this catch-all page
devoted to anything related to vintage color TV.



Let's start off Tidbits IV with a little reminiscing of my own...

Back in the early '60s I would occasionally photograph an eventful happenstance on color television, but more often than not, I'd record common and (for then) quite ordinary television snippets. All, of course, on film: both 35-mm still and 8-mm movie.

Somewhere I have a color movie clip of a live color broadcast from the 1964 World's Fair, another color clip of the first transatlantic satellite color video broadcast (Oct. 10, 1964), and later in the decade, the first moon landing.

This is my only picture of the NBC peacock, and it's not a very good one, but it is a fairly accurate portrayal of the peacock's hue distortion. I still recall being ticked at the time because the color was "off." It was taken in the spring of 1964 under fringe area conditions, which should account for the color anomaly.

Unlike today where NTSC color broadcasters stabilize hue with the use of atomic clocks and color sets are full of microprocessors, one had to bolt to the receiver at the beginning of a color broadcast in time to use the peacock image -- AFTER it completed its fluttering animation -- to adjust the hue control for the best yellow... the left and right bars and that center blob of yellow.

The reasoning was presumably sound. Yellow consists of full green and full red. So if you saw a strong yellow, the red and green were also relatively accurate. --Pete



You may have already seen this six-pack of
brand-new shiny under-vacuum 15GP22s
in Lancaster PA where they were made
as early as the fourth week of 1954.


But, how did RCA package this, the first practical application of a new invention, for safe shipment to dealers, repairmen, and commercial installations? The geek in me often wondered...

There were six main components involved. The carton itself, four cardboard inserts, and a horsehair-like block of shock-absorbing material on which the 15GP22 faceplate rested.

Recently, I photographed a well preserved and complete tricolor CRT packaging system that survived its last commercial shipping event in April 1957. (Today, however, this is NOT a good way to ship a 15GP22. At least one 15G was destroyed by a major shipper in recent years using just original packaging. It's a good start, but this carton itself must be packaged.)
[click here] .


Unedited Email
[Old editors simply CANNOT not edit.
But these are very close to what came off the modem.]
To: dexnis60@yahoo.com
From: Kirk Stankiewicz
Subject: A Merrill changes hands
Date: Sun, 14 Sep 2003 22:09:17 EDT

Two weeks ago I purchased (In a private sale) a CT 100 from a collector and friend. This Merrill is in good condition, all parts accounted for.

The 15GP22 is gassy, but not at 14.7 PSI yet. The filament stayed lit for a week on my 467, but when I attempt to raise the G2 voltage on the tester, the neck glows pink. The getter flashes are part silver/part white. This tube would be a good rebuild candidate.

This set was rescued from the East Hartford RCA Service Co. Branch in 1974. I am a Former RCA Service Tech, but was in High School in 1974. There are several RCA Repair tags on the chassis, the customer's name was "Gettell" and lived in Farmington, CT. Kevin G. Picked up the set on from RCA on the day it was to be discarded. It stayed with him until 8/23/03.

It should be added to the list of non-operational sets, until a 15G comes
along :-)


CBS
FIELD SEQUENTIAL
COLOR

(1)
As you know, the ETF has reproduced the 1951 CBS COLOR signal using modern components; they display a color bar pattern on a restored 1951 monitor. Two collectors who have vintage CBS COLOR receivers are restoring their super-rare sets to operational status. Included in this miniscule number is one of the two known original CBS-Columbia model 12CC2 sets.

(2)
I have exchanged email with Alexis Ward, who reminisced recently about Patty Painter, her mother; as a young model, Patty served as the photogenic subject for CBS COLOR demonstrations. Here she is in a picture from a 1950 magazine showing a CBS color test. Below the picture, find a color video clip identified by Alexis as a 1946 image of her mother.
CBS field sequential COLOR clip [wmv]
CBS field sequential COLOR pix 2004

"The person pictured is my mother, Patty Painter. That is the first color TV demonstration for the FCC in 1946. She was 19 at the time."

"I am trying to remember anything she told me about the day... I believe there was a big discussion about the choices of scarves to show off the color aspect of the broadcast."

"She had a silver kaleidoscope that was handed out to the participants as a memento."

The destination of the broadcast was a hotel about 40 miles away from the studio. I don't know if you already know any of this so if this is redundant, please forgive me."

"I know there was a show on A&E on September 9th of this year [2003] about CBS and they had some info about the event and interviewed the head honcho at the FCC.... The gentleman is still alive and residing in FL I think, in his 90s. My mother and father were friends of Peter Goldmark's.... She was a fairly famous model who had worked for the top women's fashion magazines and ads. She emceed the Saturday movies on CBS and traveled around the country demonstrating color TV. She was chosen from a large group of hopefuls for this opportunity. She basically had a variety show as she showed all sorts of animals and other very colorful things.

The head honcho was the person who spoke to [my mother] while she was doing the broadcast."

I would love a copy of the videotape; it would be wonderful since I have recently lost her. Alexis Ward, November 2003
-


Our friend and long-time contributor to this and other vintage television sites has published a webpage of his own. Thanks Steve for your dedication, experience, and passion for vintage color television.
Steve's Vintage Color TV collection
-

A WEIGHTY TOPIC

Shipping a CT-100 safely and efficiently can be a challenge. One of the most often asked questions associated with transporting a Merrill is just how much does one weigh in pounds.

Bare cabinet with speaker and mu-metal shield: 60
+ CRT add 26
+ Magnetics add 10.5
Cabinet, CRT, and magnetics subtotal: 96.5

Chassis CTC2: 67.5

Cabinet, CRT, magnetics, CTC2 total: 164 pounds

During the gala celebration week
commemorating the 50th anniversary of the
first CT-100 production run, the 25th
operational and the 4th RIP were added to the
Living CT-100 list.
Here's a quote from an article in the
Cleveland Plain Dealer
with relevant details and challenges concerning
our attempt to rebuild the 15GP22 tricolor kinescope.

...collectors and restorers are experimenting with a way to repair the old picture tubes. Unlike modern-day picture tubes that are all one piece of glass, the CT-100's picture tube is made of two pieces of glass -- the rounded screen and the 24-inch-deep, ice-cream-cone shaped rear portion. Those two pieces of glass were fused by a metal strip and adhesive.

When the picture tubes were manufactured, air was removed at room temperature by a vacuum machine. The picture tube then was heated in a 700-degree oven designed to excite the remaining air molecules so that as many as possible could be pulled out with the vacuum machine.

With time, the adhesive fails and air leaks through the seam. Restorers are experimenting with a new adhesive that has potential to keep air out for a long time, but the adhesive degrades at 500 degrees. Putting it in a 700-degree oven would not work.

"Right now, we don't know why 700 degrees is the magic number," McVoy said. "Was that the perfect temperature to remove all the air, or will something less than 500 degrees be enough?

"If it works, then we could have lots of tubes," he said. "I have four tubes and six sets that could use them." In addition to the RCA CT-100 and Model 5 prototype, several other brands of TVs of that era used the 15-inch color picture tube.

No matter whether the fleet of CT-100s can be restored to working order, the first production models remain a touchstone for collectors.

"It is a coveted item," said Deksnis, whose CT-100 worked the last time he turned it on in 1965 or 1966. "There are so few of them and it is a special milestone. This anniversary is special to those of us who have CT-100s, but our interest won't wane -- not with all the challenges to keep them running."


1953's
Model 5
>the Rose Bowl set<
B570 cabinet as stored in two New Jersey homes 1978 through 2004.
UPDATE
Four Model 5 sets survive. The first is in California and may be an engineering unit that predates the Model 5’s modest run of a couple hundred. The second Model 5 (B583) was acquired in late 2003 by the Early Television Foundation near Columbus, Ohio and is restored to full operation. The third Model 5, serial number B668 and discovered in New Jersey in 2000, is now in Connecticut. At the Early Television Convention in April 2004, B570 was acquired by a collector from Florida.

Corporate Concoction
or
Colorful Coincidence?
March. 25, 1953: CBS bows out of the conflict over color TV standards.
...one year later...
March 25, 1954: RCA begins a run of CT-100 compatible color TV sets.
You decide...


Unedited Email
[Old editors simply CANNOT not edit.
But these are very close to what came off the modem.]
From: "Dan Burns"
To: Subject: Re: RCA CT 100
Date: Sun, 9 May 2004 16:16:36 +0000

I saw Mary Martin's "Peter Pan" on an RCA CT-100 in 1955. I was nine years old. I had to have one! I washed windows for Main street businesses in our dusty little Oklahoma town until I had saved up $400 ... and bought my set. (It must have been about 1959 or '60).

When I was still in high school, about 1966, I sold my CT-100 in a newspaper want ad for next to nothing to make room for a honky-tonk piano I bought at an auction. I don't remember who bought the TV. Of course I regret it mightily.

Do you suppose there are any more of them sitting around in warehouses? I hear there were 5000 manufactured, but far fewer sold. My career took my down the humanities path rather than the engineering path, but I still maintain my boyhood enthusiasm for all things technological.

I heard a tale from an antique dealer in rural Oklahoma of a CT-100 junked in a field under a tree. I hope it is not mine.


Scott Marshall found this 30-year-old Tidbit
in the pages of Radio-Electronics...

Click here to see 15GP22 in 1974 article

Then, check out some nostalgic rambling on my part...

In June 1974, Larry Steckler had the printer's proof of his July 1974 issue of R-E plopped on his desk. It was on an upper floor of the building at 222 Park Avenue South in Manhattan. It had this 3-month-old article on the 20th anniversary of Color Television. Now, a newstand magazine back then was put on the rack dated a month early to extend its shelf life, which means Steckler, Bob Scott, et al., sent the mechanicals to the printer about three months before in March... which is when, a week or two earlier, he would have received a press release from the RCA publicity department in the RCA building at 30 Rock on which the article was based.

Just across the street from R-E's offices, I was managing/technical editor of a group of vertical technical consumer magazines at 229 Park Avenue South.

I don't remember seeing the RCA press release from then, for I'm certain something would have appeared in our flagship magazine "Elementary Electronics." I lived in Oakhurst, NJ then where my CT-100 sat in a back room -- the same room where in 1975 I shot the pictures of my 2-in. home built TV.

Today of course that same CT-100 enjoys a privileged location in the living room.

By chance, spoke to Scott Marshall last night (14 May '04) at the Sarnoff Library in Princeton about the press release, but still can't figure out why or how I missed an opportunity to publish color TV's twentieth anniversary event back in 1974... must be getting old!
--Pete


From the 2004 Early Television Convention...
CT-100
Caretaker-attendees converge for a
photo op with the Museum's
operating CT-100.
Thanks again Phil Dudley
for conceptualizing and
photographing the event.
[click here]


From the 2004 Early Television Convention...


From the first day of the convention, this never-before seen experience.

It's 1951 CBS field-sequential color, side-by-side on a
Gray Research monitor (left) and a 1949
CBS experimental RX-43 receiver.

A CBS field-sequential color system has no 'hue' control or 'color' control. It's not a factor to a viewer because the color filter material in the camera and receiver are fixed and specified according to the CBS standard.

So why is the color different, as seen on these two side-by-side sets?

Simple enough, the color filters are different on each set at this time due to the cost of suitable Wratten filters.

Darryl Hock’s transcoder was programmed to adjust the intensity of given primary colors on the first day to favor the CBS RX-43 set. On the second day, the transcoder was reprogrammed to favor the Gray Research monitor. Screen photos seen elsewhere on this site were taken on the second day from the monitor (link below).

The filter problem is being considered and a reasonable-cost solution was recently proposed by John Folsom.

CBS field sequential COLOR pix 2004

End of TIDBITS Year 4
Begin TIDBITS Year 5

I for one am absolutely fascinated with the CTC5 audio circuit. Here, in a 'reduced cost' chassis (and it’s the narrow-band R-Y / B-Y chroma demodulation chassis at that) RCA designed, and somebody approved, a dc-coupled audio amplifier. Most everything else about the audio section was the same... contact bias on the voltage amplifier, the multi-function 6T8 saved a 6AL5 dual-diode used in the CT-100, the 6AQ5 single-ended audio power output stage didn't change till years later, so why the added expense of dc coupling?
One chassis series.
One puzzle.



A subtle reminder about the 6BD4.
[click here]

Also, most CTC2 schematics are incorrect at the H-V regulator. They improperly show the 6BD4 cathode as pins 1 and 8, which would be correct only for a 6BK4. Only pin 1 is connected to the cathode in a 6BD4.

Remember, as shown in link, a CTC2 uses pin 8 as a tie point, which negates the use of a 6BK4 in a CT-100. If you have a 6BK4, ring out pins 1, 3, 4, 6, and 8. You'll see they are common. Do the same with a 6BD4; pins 3, 4, 6, and 8 will be open.



The following information is based in part on email from Dave Corbett and posts by Old_TV_Nut on AudioKarma. Thanks Dave and Wayne.
Then and Now
Vintage and Modern CRT Phosphor
Every CT-100 was shipped with a 15GP22 picture tube that used non-rare-earth phosphors capable of reproducing 1953 NTSC wide-gamut colorimetry specifications. It was probably the only consumer CRT that did.

[There is speculation that an RCA 21AXP22 can reproduce 1953 NTSC color specs. Perhaps the CBS 19VP22 has full 1953 color capabilities also, but it is universally accepted that the 15GP22 is the wide-gamut 1953 NTSC color standard.]

A major difference between modern CRT-based sets and the "true green" of a vintage 15-inch 15GP22 is the Willemite P1 phosphor, which matches the 1953 standard, but is rather inefficient. For this reason, the CT-100 color rendition is "standard" but rather dim.

Later, with the introduction of Sulfide green (more yellowish) and then Rare-earth red, the pictures got much brighter. Blue migrated over the years from the original NTSC blue to something more toward violet.

However, you don’t get more brightness without an ‘unintended consequence.’ A shift to more yellowish-green and orangey-red in modern CRT’s render them unable to reproduce the 1953 color standard. These color shifts are partially corrected by altering the matrix circuit, which defines how each electron gun is driven by the chroma signal.

Unfortunately, due in part to the gamma, or non-linearity, of the CRT, there is a limit to the amount of matrix-circuit correction possible, and so a modern receiver is not accurate over the full range of 1953 colors.

Living with 1953 Living Color
click here


CLICK Serial-Numbers Date-Codes HERE


For me, ATSC HD today is every bit as much of a jaw dropper as the first time I saw color TV in 1957.

I believe HDTV parallels the early days of NTSC color in this way— the technology behind the picture is amazing and awe inspiring. The same six megahertz of NTSC bandwidth that found space for chroma information in 1953 now contains an ATSC 1080i, 16x9 video signal with five discrete full-bandwidth audio channels plus a subwoofer channel. In the first NTSC color sets, the bandwidth of their video amplifiers is about 3-MHz, and the picture looks good. In an ATSC HD set, the video-amplifier bandwidth is about ten times as much as the 3 MHz of a CT-100.

There are a lot of variables, and television manufacturer’s shuffle designs to fit marketing strategy. But when you view high-definition video generated with the best HD cameras on a CRT with a dot pitch fine enough to reproduce what the system can deliver, for me it’s worth looking at even though the content doesn’t always measure up to the technology.


As for the behind-the-scenes developers of analog color television: These are some of the companies who contributed to the 1953 NTSC color television standard.

• American Telephone and Telegraph Corporation
• Farnsworth Television and Radio Corporation
• General Electric Company
• Hazeltine Research, Inc.
• N. V. Phillips’ Gloeilanpamfabricken
• Philco Corporation
• Westinghouse Electric Corporation

It’s a list that was compiled by RCA and appears on a label inside the cabinet of every CT-100 made.

Here’s a link to a page on this site discussing the Hazeltine and Philco contributions to NTSC color television
click here .

(Created 8-17-2003; Patty Painter picture added 4-23-2006)

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