RCA TK-42/43 Cameras

[TVBeeGee]

How many of you had experience with the RCA TK-42/43 color camera? Were they a constant maintenance hog, or did yours perform well? Was component and thermal drift a problem, or did you suffer from "tweaker drift" (adjusting too often) as RCA warned about in their setup instructions. If you had more than one TK-42/43, were your cameras difficult to keep matched? Just curious.

I never worked with the TK-42/43, but saw many of them in operation when touring various TV stations in my youth. Plumbicons seemed to make them quickly obsolete. Before long, it seemed the TK-42/43 cameras were history, often replaced by the TK-44 or Norelco's PC-70/72.

(My first experience with color broadcast cameras was with a set of three brand new Norelco PC-72's at WOUB-TV in 1973.)

If you worked with the TK-42/43, what did you think of them?

[Dave A]

I spent my early tv years behind a TK-43 (the modified version with outboard zoom and focus) in 1969 and became proficient and pushing that beast around. The studio never had an operator that would dolly the thing live for a shot. You just had to learn leverage and momentum. And a cable puller helped.

Ours need about 1/2 hour warmup on a chart before use. Not much tweeking and ours stayed close. The big problem was the three 1" vidicon color tubes. They just added a color smear to the big orthicon. Not much better than VHS reproduction. No wonder NBC never bought any and waited for Plumbicons.

We actually dumped one over one night. The electric pedestal wheels jammed while moving it between shows and it went over and landed on the steering ring. It was a cam head to keep the CG low and not bolted on. It flipped off and hit on a corner bending the upper frame. It was a church show and the church gathered in a prayer circle to pray for it while I had to figure out how to continue with a BW camera. RCA bent it back for more years of service. Me on the left in the studio photo.

[TVBeeGee]

Thanks for the great info, Dave A. I hope others will step up to talk about their experience with the TK-42.

As I mentioned, I never worked with the TK-42, but saw many of them when visiting various TV stations in my youth.

I've included three pictures.

The first is from a 1967 RCA Broadcast News showing one of two brand new TK-42 cameras in KDKA-TV's Studio B in Pittsburgh. At age 13, I was given a wonderful electronic tour of these cameras by an engineer who I believe was named Larry Kepner, or something very close to that last name. Terrific guy. Ironically, ten years later and fresh out of college, I would begin working as an engineer at KDKA-TV!

The second and third pictures show a TK-42 I saw in 1968 while visiting WCHS-TV in Charleston, WV. They're doing Romper Room in the second picture and The Sleepy Jeffers Show in the third. The Jeffers show was kind of a country music competitor to the Today show. It featured music, news and other segments.

In those days, WCHS-TV only had one TK-42 (plus one TK-27 color film island). They did all their shows with just the one studio camera! They got really quite good at it. They used clever slide bumpers as quick transitions between segments.

For example, just as Jeffers and his band were ending a song, the director would dissolve to a cute "news next" type of slide. As soon as the TK-42 tally light went out, the TK-42 would whip around to the news set in the blink of an eye. By the time the last note rung out as Jeffers introduced the newscaster, they were ready to dissolve to the news set. It was smooth and quick enough that the average viewer was never aware that only one camera was doing double duty.

[Electronic M]

Is that the back of a Setchel Carlson color monitor in the 3rd picture?

[TVBeeGee]

Yes, I think so, Electronic M. Sadly, it was too long ago and I was too young then to remember the brand of the monitor now from memory, but I had a look at my higher resolution version of the photo. Although fuzzy, two blurry words can be seen on the same line, printed in white on the rear apron, that have the size and shape of the Setchell Carlson brand. I think you got it right.

What I do remember is that it looked pretty bad. It was on a roll around cart and was moved almost constantly, without degaussing, and was also adjusted by the floor crew to allow the talent to see the image in the glare of the studio lighting. It was only there to let them have some idea about what type of shot was on the air. I do remember that the saturation was set extremely high, to the point where the CRT was being overdriven and smearing. But the monitors in the control room looked quite good. Those were probably Conrac and adjusted only by the engineers.

At age thirteen, I found it quite fascinating that WCHS-TV had only one color camera, one color film island, and two color quadruplex VTRs. (One VTR was either an RCA TR-22, or TR-70, while the other was a TR-60, I think.) I had recently visited several other stations that had 2-3 times that much equipment. So, I was really surprised that WCHS-TV was able to do as much as they were doing with only a bare minimum of color gear. Their maintenance engineers must have been under enormous pressure. They had to fall back to their old B&W equipment if anything at all died.

I also remember a whole rack of sync generator. They still had a vacuum tube sync gen (RCA?) that was apparently new enough to output a color subcarrier reference. I was impressed that they kept a frequency counter on it to monitor the subcarrier reference. It was the first freq counter I ever saw. It displayed the 3.579545 mHz carrier frequency on Nixie tubes. The engineer explained that the FCC required them to keep the frequency within five cycles of the ideal. I think it was two cycles high when we looked at it. That degree of accuracy blew me away at age 13. I never forgot it. I walked away thinking, "This broadcast stuff is amazing. I guess that's why it's so expensive."

[Mi40793]

I have experience operating and maintaining TK42, TK27, and PC70. My opinion: For all the griping and rock-throwing, TK42’s, and TK27’s, delivered from 1965 worked, were very reliable overall, and had a stable color encoder. These first generation solid state cameras were in service many years.

TK42’s were noisy in color channels compared to later cameras due to the light split to the IO. Hard to even see the registration chart in the blue channel of the 42 for the noise. But produced good B&W with the 4.5 in IO. Yes, NBC rejected 42’s, kept running TK41’s in studios, and installed many PC-70’s on all their field trucks, except Burbank.

PC70 was very rugged, took abuse, stable circuit design. Three tube cameras had more light on color channels so that helped with chroma noise. Tradeoff for any 3 tube design was monochrome resolution due to any registration errors, relatively minor problem. PC70s used an image enhancer to improve apparent resolution, overall very acceptable pictures, and sold many cameras.

RCA caught up with the TK-44A. RCA had tried to make a small IO, the TK-44 ‘Isocon’, but production failed, so TK44A used plumbicons and RCA licensed the technology. Simplicity of a vidicon with sensitivity of an IO. Plumbs were good but not perfect, Amperex later years had trouble making good tubes. RCA and EEV did ok. A tough business. Solid state sensors were the breakthrough, pioneered for broadcast cameras. by RCA.

TK27 film camera was also reliable, as it used the same modules as the TK42. At one station I maintained five 27’s. RCA sold a lot of these starting 1965. Reliable, stable, not as good as later film cameras but many in network and local operation after 12-15 years. To accommodate film density variation TK27 used an auto-target voltage sensitivity method. Problem was tracking all vidicons together was virtually impossible, plus a characteristic ‘blooming’ on large scene brightness changes as target voltage changed. Solution was to lock the target voltages and use a variable density light wheel operating on the video level. Adding an image enhancer to the mono channel also improved the TK27 a lot.

Further, both the 42’s and 27’s originally had fixed gamma, RCA expected tube selection and neutral density filters at each vidicon to match gamma, very difficult. Later versions of TK27 and 42 video modules added gamma controls so you could adjust gray scale tracking on color channels.

[Electronic M]

Originally Posted by TVBeeGee

Yes, I think so, Electronic M. Sadly, it was too long ago and I was too young then to remember the brand of the monitor now from memory, but I had a look at my higher resolution version of the photo. Although fuzzy, two blurry words can be seen on the same line, printed in white on the rear apron, that have the size and shape of the Setchell Carlson brand. I think you got it right.

What I do remember is that it looked pretty bad. It was on a roll around cart and was moved almost constantly, without degaussing, and was also adjusted by the floor crew to allow the talent to see the image in the glare of the studio lighting. It was only there to let them have some idea about what type of shot was on the air. I do remember that the saturation was set extremely high, to the point where the CRT was being overdriven and smearing. But the monitors in the control room looked quite good. Those were probably Conrac and adjusted only by the engineers.

At age thirteen, I found it quite fascinating that WCHS-TV had only one color camera, one color film island, and two color quadruplex VTRs. (One VTR was either an RCA TR-22, or TR-70, while the other was a TR-60, I think.) I had recently visited several other stations that had 2-3 times that much equipment. So, I was really surprised that WCHS-TV was able to do as much as they were doing with only a bare minimum of color gear. Their maintenance engineers must have been under enormous pressure. They had to fall back to their old B&W equipment if anything at all died.

I also remember a whole rack of sync generator. They still had a vacuum tube sync gen (RCA?) that was apparently new enough to output a color subcarrier reference. I was impressed that they kept a frequency counter on it to monitor the subcarrier reference. It was the first freq counter I ever saw. It displayed the 3.579545 mHz carrier frequency on Nixie tubes. The engineer explained that the FCC required them to keep the frequency within five cycles of the ideal. I think it was two cycles high when we looked at it. That degree of accuracy blew me away at age 13. I never forgot it. I walked away thinking, "This broadcast stuff is amazing. I guess that's why it's so expensive."

I think I have that model sans the back cover. They sold it under their own name and rebadged under other names. http://videokarma.org/showthread.php...etchel+Carlson

They can perform VERY nicely when adjusted properly. One interesting Quirk of these SC sets and monitors is that despite having degaussing it is not automatic. It's driven off the boost line and needs to be manually opperated with a pushbutton.

[TVBeeGee]

Ah, thanks for your reply, Mi40793. Your details really take me back to that era.

I have a good friend and mentor who experimented with replacing the 1" vidicons in a trio of monochrome industrial cameras with a trio of 1" retired Plumbicons I gave him. The downside was that the spectral response of the Plumbicons was not broad enough to create a proper monochrome image for all colors (due to color optimized target of each tube), but the improvement in sensitivity and noise was absolutely spectacular.

As for telecine, I remember that the RCA TK-27 used a much larger vidicon in the luminance channel than the 1" tubes it used in its color channels. I recall the luminance channel looking pretty sharp and quiet by comparison, helped also by telecine providing lots of light.

One of the advantages of the four tube approach was that image enhancement of the luma channel included the edges of reds and blues. This was generally not true in three tube cameras, as the enhancement was usually derived solely from the green channel in order to avoid the registration errors you mentioned.

For example, I remember PC-70's looking very blurry on red and blue artwork. However, they sure were workhorses, easy to maintain and built like tanks...except the planetary control on the CCU iris knob...which so often seemed to get broken in the field. Remember those? We sure replaced a lot of those. They didn't have to get bumped very hard to get screwed up.

[Mi40793]

Yes, a 1.5 inch vidicon in the mono channel on a 27. The 27/42 vidicons were magnetic deflection and electrostatic focus, so not quite as sharp focus as magnetic focus. I added enhancers to the mono channel, offset vertical centering one line to compensate for delay. TK27B had enhancer standard equipped. Beston built retrofit light servos.
TK27 color filters were poor. I knew a guy at ABC NY who had an optics company build new color filters for their 27’s. NBC not do that. NBC had a TK26 and TK27 at Englewood Cliffs Nj where they ran prime time 35mm, avoiding NYC film tax. First run of ‘Patton’ on NBC network was run on the TK26.
Yes, registration errors at edges of raster weren’t helped by enhancers on 3 tube cameras. Some cameras better than others. Philips yokes used on PC70 and TK44 were pretty well matched. We sometimes swapped yokes to try to match better. Late 1970’s RCA lost expertise in vidicons due to retirements, and I had to reject some tubes, bad alignment, focus.

[TVBeeGee]

Yes! I remember orange looking original filters in the red channels. I think some engineers may have found that this allowed the red channel to respond too much to colors between red and green. Perhaps this might have been an RCA attempt to keep skin tone from tending toward green, but as I recall it may have reduced the ratio of the red channel output to pure reds, causing a loss of saturation on pure reds. In other words, red gain might have been set lower on a chip chart with the orange filters due to that channel seeing a broader spectrum from white light, causing output during pure reds to be proportionally lower. Just a guess.

Matching vidicons to achieve proper grey tracking must have been very difficult and time consuming. The addition of gamma controls must have been quite a welcomed change! Ditto with trying to get things to track during varying target voltages.

I knew ABC ran film out of NJ to avoid NYC film tax, but never knew NBC did the same trick. Interesting.

[Mi40793]

I was able to upgrade three tk27’s by swapping modules with gamma controls from a TK43 that been donated to a Univ. and then junked.
The NYC 35mm projection tax was figured on the number in the audience, so CBS may have used NJ for film also, don’t know.

[TVBeeGee]

It pains me to think about a TK-43 being junked. Such a piece of video history!

[Mi40793]

It was actually modules from three junked TK43’s. Amazing how much SD gear has been dumpstered, from personal experience. Even today, storage is expensive.

[kf4rca]

But did you ever see a TK26 film camera. It was different than a TK27. Missed out on the TK28 but we had a TK29. At about that time telecine was becoming a big thing in our market.
The TR22 was the first solid state tape machine.
Much of that obsolete equipment was donated to the local colleges and universities. BUT, that later fell out of favor when they wanted our station to install and maintain them. Consequently I saw a Chyron 4100 go into the dumpster. Really broke my heart since I had been to the school on it.
The problem with the early solid state equipment was the pinboard construction. The grounds (square pads) would loosen up and cause problems. And then there was all those carbon resistors. Metal film resistors had not come along yet.

[Mi40793]

Never maintained a TK26 but I know they were used for a long time. NBC NY ran prime time 35mm movies on a TK26 into the late 1970’s. I think the 26 color separation was preferred over the 27.