Got this interesting item yesterday:

http://antiqueradio.org/art/RCATM-10FrontPanel.jpg

http://antiqueradio.org/art/RCATM-10Rear.jpg

http://antiqueradio.org/art/RCATM-10SerialNumberPlate.jpg

It's a color studio monitor using a 15GP22 CRT. Its ID plate says MI-40206-A, but the ETF website says it's a model TM-10, so that's what I'll call it.

I was nervous about shipping this beast halfway across North America. It arrived in an 18-wheeler; the driver parked in the street and trundled it down our driveway with a pallet jack. I hovered beside him like a mosquito, grinning and waving my hands and babbling about how this RARE item has a G-L-A-S-S picture tube inside, and I had been a little worried about shipping it 2600 miles, blah blah blah. He probably couldn't wait to get away from the blabby kook.

Good news: The CRT is under vacuum and it tests strong on all three guns (Yay!). The rest looks unmolested and intact, apart from missing an HV cage cover.

It takes an ordinary video input, as you can see from the rear panel, so I should be able to make a picture with it, once restored.

http://antiqueradio.org/art/RCATM-10RearPanel.jpg

It's still bolted to a pallet in my garage, but this under-chassis photo from the previous owner shows an orderly, fairly spacious layout.

http://antiqueradio.org/art/RCATM-10UnderChassisPreliminary.jpg

It may be months before I can mess with this. I already have a winter's worth of projects underway or waiting in the queue. Fun to think about in the meantime, though.

Phil Nelson
Phil's Old Radios
http://antiqueradio.org/index.html

Oh my, what a find! :banana::banana::banana:

Love the looks of the getter flashes!

jr

Phil, that's a spectacular find. You're to be congratulated. I remember these monitors when they were new, right along with the TK-40 and 41 cameras that went with them. Good for you!

Me likey!! :yes: :yes:

Nice find Phil. I recall they were an RCA TM-10A model. Great it has a good CRT.

http://nrcdxas.org/articles/tm10a/

When I worked at KTLA-TV in the 70's, they finally cleaned out the tech equipment storage locker. 2 of these TM-10A's were up for grabs. All you had to do is stick your name on it and it was yours. I missed grabbing the unclaimed one by 10 seconds. Both of these had the full the metal cabinet on them. They were low use and out of service for probably 20 years. A few years later I did score a working CT-100 from the KTLA chief engineer's home for $100.

-Steve D.

Did I mention that Ah HATE Yew ?!? (grin) Seriously, EXCELLENT score !! Wonder how many of these Bad Boiz are still around ?

Thanks, Steve, for the pointer to that article. I suppose a schematic is too much to hope for, but any scraps of technical information about this monitor will be helpful.

Regards,

Phil Nelson

Great find, but I'm sure that will have zero WAF (Wife acceptance factor) at least in the living quarters.

What exactly is a "Tally" socket used for?

Wow that is blanking cool!

What exactly is a "Tally" socket used for?

The tally socket connects to the indicator lamps above the screen (lens is missing in the picture). The tally lights on different monitors/cameras were remotely controlled by the switcher in master control, to show which camera signal was being aired at any given time.

I knew a guy who bought the 21" version of this monitor (the TM-21) at a hamfest back in the '80s, but he stupidly gutted it for the transformers and other parts.:yikes:

The 21" version was HUGE, about the size of a washing machine, but heavier. All hinge-out modular chassis, fully regulated power supplies with a whole buttload of 6080 tubes. Used a 21AXP22, IIRC.

Great find, but I'm sure that will have zero WAF (Wife acceptance factor) at least in the living quarters.

What exactly is a "Tally" socket used for?

I believe the "tally" socket on this color monitor is much like the "tally" light on a broadcast camera that tells the performer which camera is on air. A red light is attached to the socket and when a camera is switched to line or is providing the on-air picture the tally light on that monitor lights up indicating to the director and others in the control room which monitor has the line or on-air picture being fed to it from the camera.
The tally light would switch on from monitor to monitor as the various cameras feeding a picture are "punched up" by the technical director or director. I hope this is clear.

-Steve D.

Dammit, did you get this from ufarad? He told me he wouldn't sell it!

Don't know a ufarad. A guy just emailed me out of the blue.

Phil Nelson

Lucky ()*&#@
lol

He probably got wind of that rotten B/W Philco I rescued from the E-waste recycler and thought, "Man, I bet I can sell that guy anything!"

:)

Phil Nelson

Don't know a ufarad. A guy just emailed me out of the blue.

Phil Nelson
I was going to post "How did you FIND this?". Congratulations on receiving and saving a rare piece of TV history, probably the second most significant find since the RCA prototype from Harry Poster.

Phil, you are going to have to update the name of your site to Phil's Old Radios & Televisions. :D

how satisfying would it be to sit and watch a movie or a dvd of a television show from the early colors days on this!i love this and it is in good hands now.

Sugoi!

I'd start playing the lottery if I were Phil......

"Its ID plate says MI-40206-A, but the ETF website says it's a model TM-10, so that's what I'll call it."

RCA professional gear often had a type number (TM-10 in this case) and always an MI number that appeared in the catalog book/price sheet for ordering. Even the crossover networks used for the public address/music speakers at the 1964-65 New York World's Fair were specified by MI-number, which allowed me to track them down to determine the circuit used.

Phil, nice to see you got it, unlike the sarcastic harpoons above! Just kidding and seriously, glad that you got this monitor and especially glad that the kinescope is good. How many can there be out there?

Yeah, despite all the frivolous noise I make when something like this is scored, I can't think of it going to a better home than Phil...Or any of several more of you guys here that have the technical smarts to truly do it justice...I most certainly DON'T.

Great score Phil! Look at all the lytics in that thing; certainly an impressive find. Please post pictures for us to follow on its progress! I look forward to seeing some stills of the picture it produces once you’ve got it dialed in. Bill

My very first TV station job had one of these monitors in prop storage. I could see it, I just couldn't get it out of there, or I would have owned it. Too much stuff between it and the doorway. I did wind up with a TP-6 RCA projector, though.

Congratulations on this find. These things are really scarce now, eh?

A nice overview of this monitor (and lots of early RCA color broadcast gear) available in a 1954 issue of RCA "Broadcast News" here:

http://www.americanradiohistory.com/Archive-RCA-Broadcast-News/RCA_Broadcast_News_77-01-1954.pdf

The site has many other issues available for download, as well....

Great reading from this. Thanks.

Alot of the broadcast equipment I got to see was from this era. Unfortunately, its all gone now. Hmmph. It only sat there in storage for 35+ years!

I hereby nominate you for the most significant historical find of the decade :banana: !!!

And as others said, I don't see any chalky crap in the tube, so maybe you got a military-spec version with a good seal!

Charles

The tubes that went into studio monitors were likely hand-selected from the best production tubes available. Is the tube in this monitor labeled as a standard 15GP22 or does it have a special number?

I hereby nominate you for the most significant historical find of the decade :banana: !!!


Ahem...

http://videokarma.org/showthread.php?t=251369

Just sayin'. :smoke:

http://users.inetware.com/androniq/template/smile/asd.gif

Very interesting set, what is that big circular plug near the RGB imput?

Thanks for the kind wishes. I promise to treat this thing right.

When I first heard about it, I contacted John Folsom, who advised that it's an interesting set and well worth getting.

The CRT is stamped 15GP22 (and PAR under that, whatever PAR means).

This will be a long term project, so don't expect exciting news any time soon. Today's big achievement was unbolting it from the pallet and grunting it onto a metal table where I can start to clean it up (photo below).

The previous owner also has a B/W monitor for sale, round CRT, model MI-36052. If anyone's interested, send me a PM and I'll get you his contact info.

Phil Nelson

http://antiqueradio.org/art/RCATM-10CleaningTable.jpg

Wowwwwwww...

Wowwwwwww...

My thoughts, exactly!

What a find and a half! You sure have landed a real rarity there by the sounds of it! Looking foward to the restoration story when you get to it..:yes: Congrats!:thmbsp:

The CRT is stamped 15GP22 (and PAR under that, whatever PAR means).


Unless somebody knows what PAR means, we could guess - here's mine:
Production Acceptance Run (?)

http://users.inetware.com/androniq/template/smile/asd.gif

Very interesting set, what is that big circular plug near the RGB imput?

If you're talking about the big plug near the red, green and blue-colored rings, I don't know what the plug is, but those colored things look like test probe points.

The largest connector, beneath the black and white test points, is the power input, a three-terminal Hubbell twist-lock plug.

The large round plug appears to be a twistlock AC power connector...

We know of a total of 6 of these that have survived.

Unless somebody knows what PAR means, we could guess - here's mine:
Production Acceptance Run (?)Interesting guess. Phil: is there a date code on the 15GP22? The earliest known by me is the fourth week of 1954. If this tube is earlier it could be quite a significant 15G.

Pete

All I can see is the CRT neck at this stage. Nothing else printed on the glass of the neck. On the base it says Made in U.S.A. 5-22.

I just noticed that someone wrote in pencil on the bottoms of two guns. One says 5/13, the other has an asterisk drawn on it.

Phil Nelson

http://antiqueradio.org/art/RCATM-10CRTBase.jpg

If that date code is correct, there are older 21AXP22's out there. The one in my 21-CT-55 has 4-52.

Some 15G's have production id numbers etched inside, but I've never seen pencil before. No contamination issues apparently.

Yes, it's a 'new' 15G. Not many around with 1955 date codes. As was speculated before, this may be either selected or, considering the inside dates, custom built for a TM-10.

Pete

So, the date code is something like year-week (5-22 being 1955, 22nd week)?

It didn't occur to me that the penciled numbers would also be a date code.

If I get some time later, I can look inside for etched codes.

Phil Nelson

P.S. New is good for me, from a customer standpoint. The last thing I want to buy is the first example (of anything) off the assembly line :)

So, the date code is something like year-week (5-22 being 1955, 22nd week)?

...:)

That would be my guess too...

And the gun was either assembled "rodded" or wired 9 weeks earlier (5-13).
jr

Don't really matter when it was made, its STILL Kewl as all H3ll, one of the best scores I've heard of since the "Prototype" set... This is almost as good as findin' a 1903 Ford Model "A"....Yes, they DID make Model "As" B4 1927...Henry couldn't bring himself to follow up Model T w/a Model "U" or "V", so he started over...

So, the date code is something like year-week (5-22 being 1955, 22nd week)?



That is so -- for RCA in the fifties. What ticks me off is when, in the next decade, RCA went to letter date codes for their 7- and 9-pin tubes.

As some of you know, I am slowly working on a 1956 Philco model 22D5102 color set with the TV-233 chassis. In the set, a Philco-branded, SYLVANIA-built 6AW8A date code -- for the 30th week of 1958 -- is "58 30", with the 58 stamped above the 30. However, a PHILCO-built 6M3 damper in the same set is stamped "249". I speculate based upon the history of the TV-123 in question that it stands for the 49th week of 1962.

Pete

Working at my usual snail's pace, I have gotten as far as easing the monitor onto its (protected!) face, so's to remove the CRT and get a peek at the nether bits. Looks pretty clean and unmolested underneath. I like that orderly layout.

After counting electrolytics (46) in the parts list, I decided to make a spreadsheet for ordering parts and keeping track of things that I replace.

Phil Nelson

http://antiqueradio.org/art/RCATM-10ChassisUnderOriginal.jpg

http://antiqueradio.org/art/RCATM-10ChassisFaceDown.jpg

I have an RCA TM-21 that was purchased from NBC in New York about 30 years ago. It was FULLY restored to PERFECT working order by Herman Reynolds III and Bill Cushman in 1987. The only problem with it is that the anti-glare glass that attaches to the picture tube has started to separate.

I have an RCA TM-21 that was purchased from NBC in New York about 30 years ago. It was FULLY restored to PERFECT working order by Herman Reynolds III and Bill Cushman in 1987. The only problem with it is that the anti-glare glass that attaches to the picture tube has started to separate.

What an awesome project! I am sure you will have fun with this one, Phil.

Does it have RGB inputs? If so, it should provide a superior picture if sourced from Y, Cb, Cr.

Wouldn't that be fun? I don't see any inputs like that, though. On the first page of this thread is a photo of the back panel, showing jacks labeled R, G, and B, but they are identified as test points in the manual. Likewise, there are test points for I and Q.

I told myself I couldn't start on this guy until I cleaned up some of the long-delayed and half-finished projects I've had sitting around for as long as 13 years. Only one more to go, and then I can get busy on this.

I have assembled a complete set of good tubes for it and I have a sackful of new caps ready to install.

Phil Nelson
Phil's Old Radios
http://antiqueradio.org/index.html

I have an RCA TM-21 that was purchased from NBC in New York about 30 years ago. It was FULLY restored to PERFECT working order by Herman Reynolds III and Bill Cushman in 1987. The only problem with it is that the anti-glare glass that attaches to the picture tube has started to separate.
Dan-

Welcome to Videokarma.

That sounds like a nice monitor. The picture tube (CRT) problem is commonly called a "cataract", and it can be fixed by a couple of different methods. One big discussion here on VK can be found by searching for the word "cateract" (notice the mis-spelling).

If you want to discuss your monitor more here on Videokarma, it would be best to start a new topic, and copy your notes above into that new topic.

How old is this monitor?
Gush, it "swallowed" "only" 450 Watts!!!

The consumer version (CT-100) was 475 watts...

I'm counting on that CT-100 to help me reduce my heating bill in the wintertime, once I get mine operational. It will be a decent source of electrical heat. :)

The consumer version (CT-100) was 475 watts...

I guess the remaining 25 watts was the tuner, IF strip and audio?

How old is this monitor?
Gush, it "swallowed" "only" 450 Watts!!!
The CT-100 and this monitor use the same 15GP22 CRT, which was quickly superseded by bigger tubes, so I assume they were contemporaneous -- 1954 or soon after. A monitor could have remained in service for years, of course.

You might think they could simply strip the tuner, IF, and audio from a CT-100 and say, "Hey, I've got a monitor," but it's a little more complicated than that. This monitor uses 31 tubes vs. 37 in the CT-100. After I restore it, I'll write an article including block diagrams & schematic so people can compare.

Phil Nelson
Phil's Old Radios
http://antiqueradio.org/index.html

The monitor probably uses different tubes, since some of the features of the CT-100 would not be needed. Does it have sound at all, or is this thing strictly video?

It's a video monitor.

http://antiqueradio.org/art/RCATM-10FullBlockDiagram.jpg

Phil

Update? Phil must be busy!:yes:

Working even more slowly than my usual snail's pace, I have begun replacing electrolytics & whatnot in the TM-10 monitor. In the service manual, someone penciled in a little modification to the power supply:

http://antiqueradio.org/art/RCA_TM-10_P-S_Mod.jpg

The mod would add two 7-ohm, 25-watt resistors in series with the selenium rectifiers, presumably to reduce surge on startup.

I'm debating whether to substitute something like CL-60 thermistors for the resistors. If you have an opinion on that, vote early and vote often.

I have begun an article about the restoration. Obviously, there will be much more to come.

http://antiqueradio.org/RCA_TM-10_15GP22_Monitor.htm

Regards,

Phil Nelson
Phil's Old Radios
http://antiqueradio.org/index.html

Any chance you can copy the mounts and ball bearings of those wand magnets? Not sure, but I seem to recall that the prototype needs a couple of those.

Making exact copies would take metalworking equipment that I don't own. Here are some photos that give an idea how they work.

http://antiqueradio.org/art/RCA_TM-10_Convergence01.jpg
http://antiqueradio.org/art/RCA_TM-10_Convergence02.jpg
http://antiqueradio.org/art/RCA_TM-10_Convergence04.jpg
http://antiqueradio.org/art/RCA_TM-10_Convergence03.jpg
http://antiqueradio.org/art/RCA_TM-10_Convergence05.jpg

The wands have a spherical part that allows movement within the mount, which is a simple clamp with beveled holes. At the ends, little swiveling clamps hold the cylindrical magnets.

If somebody held a gun to my head, I might try to fab something out of brass stock (assuming it wouldn't matter if the wands were non-ferrous). The spherical part could be a brass bead with a hole drilled through the center, soldered in place. The magnet clips on the end could be as simple as a piece of wire soldered to the wand and wrapped around the magnet. The magnets are practically weightless.

Eventually, I'll need to figure out how to replace the two missing magnets. Perhaps I'll try cutting bits from a frig magnet.

Phil Nelson
Phil's Old Radios
http://antiqueradio.org/index.html

I have begun an article about the restoration. Obviously, there will be much more to come.



Nice job on the start of your restoration article Phill! Looking forward to seeing more as time goes by. It's giving me a good idea of what I have to look forward to when I get to a point when I can start the restoration of the TM-10 I acquired a while back.

Thanks. Balloting is still open on whether to use a thermistor in place of a resistor in that little modification. Since I already have some CL-60s on hand, I'm leaning in that direction. Or, perhaps it doesn't really matter.

I'd normally just put something in and then monitor voltages when I bring the set up for the first time. The rectifiers are not in a convenient place, however. To remove the cage around them, you need to pull the CRT and yoke, which does not invite casual experimentation.

Phil Nelson

Phil-

Since you are likely to replace the selenium rectifiers with silicon diodes, wouldn't you kill two birds with one stone if you put in dropping resistors along with the diodes?

Your new restoration page for this monitor looks great.

Yes, good point. A dropping resistor should do.

Meanwhile, I'm trying to decipher what was done to this set. The choke L34 is missing. Nothing left but a rubber stamp on the chassis and two empty mounting holes.

The parts list describes it as "reactor: choke coil," giving a stock number of 78961 and no other specs.

The choke is connected between the junction of rectifier CR1 and capacitor C3 and its other lead goes to terminal 1 of R241, the screen purity control.

Perhaps someone intended to replace the choke, which had failed and caused other problems. The wires have been ripped from R241 and from R3, the purity control. Both of the 22-ohm resistors wired in parallel with those controls have broken in half. In this photo of R3, you can see that someone crimped a salvaged resistor around a couple of ripped-out wires, maybe as a reminder to "fix this someday."

http://antiqueradio.org/art/RCATM-10_R3_AsFound.jpg

I'll sort out the wiring eventually. Not so sure where to go for a replacement choke. I don't have bins of spare parts on hand, and the manual gives no spec for it, other than the stock number (78961).

Phil Nelson

Phil:

That same RCA part number is used in the CT-100 as a filter choke. L57 in Sams. .63ADC, 17.3 ohms, .6HY. The only sub Sams lists is Triad C-40X. Thordarson Catalog lists 26C81 as their sub.

I would love to have a unit like this. I remember the 21" round version of this set from RCA and Conrac and wanting one of them, too, knowing how well-built they were.

I look forward to seeing this set pass an image soon. I'm very glad that you saved it.

That same RCA part number is used in the CT-100 as a filter choke. L57 in Sams. .63ADC, 17.3 ohms, .6HY. The only sub Sams lists is Triad C-40X. Thordarson Catalog lists 26C81 as their sub.Thanks, I should have thought to look that up.

I contacted Moyer and they said that they have the Thordarson part. Yay!

Phil Nelson

FWIW, the Triad C-40X is still in production, and available from Newark:

http://www.newark.com/triad-magnetics/c40x/inductor-320mh-600ma-50-20/dp/03F765

Well, I'll be darned. It's available from Mouser and Allied, too, and all at about half the Moyer price.

Phil Nelson

:tears:Something made it get real HOT:tears::tears::tears:

Yah, and which was the chicken and which the egg?

Did those 22-ohm resistors fail and take out the choke? Or vice versa? Or, did a failure in some other part fry them all? So many unanswered questions in a chassis that's still 98% unrestored :)

Phil Nelson