The Set: Pete Deksnis's Site about the CT-100
Restoring a Vintage Color Television Set
A recent confluence of events that began five years ago culminated in the resurrection of one more dark CT-100 to operational status.
Here’s a timeline built from email (in italics) and
[The museum is now the American Museum of Radio and Electricity]
Pete, we have become the proud
owner of Jim Fries' CT-100 Set. In the event that you are able to get the
picture tube rebuilt we would certainly want to have this done. Jonathan
Hi Javier, First, thank you for taking the time to email me with information and photographs of the 15GP22.
Yes, I can confirm that it is in fact a 15GP22 from your close-up of the connector. There are two main clues: the connector has 20 pins and the hole in the center of the guide pin clearly shows the copper stem pinched off; this is where the manufacturing process connected the tube to a vacuum pump.
It is a delicate tube and is prone to a vacuum leak, which renders the tube useless as a functional device, good only for display.
May I suggest the following? Do not yet remove the tube; I can supply you with further instructions that will improve your chance of recovering the tube in tact.
There is a museum on the west coast with a partially operational TV set that the tube was made for. They are in need of good 15GP22 for their set and would be interested in purchasing your tube.
Thanks again for writing, and I hope to hear from you soon.
Thank you for responding so quickly. My wife and I are very excited that this tube may be able to further the preservation of history.
From what I can gather, the tube was purchased direct from RCA with the intent to make a custom wall TV, which was well within the capabilities of my wife's grandfather. For one reason or another this was not done. Still, he took it with him when he left that house, and against the wishes of his sons, put it in a corner of the attic, safely within its box, and there it stayed until the present day.
As you have suggested the box will not be opened any further than it has been and we eagerly await instructions from you to facilitate preservation. We are hopeful that its time in the attic has been a safe harbor, and that the vacuum seal has not broken, or leaked with the passage of time.
Hopefully the museum you
mentioned is located with in the
As to the 15GP22, it would be
best to determine how well it has survived the years. Fortunately, the
temperature extremes in
Below there is a link to a page on my website showing the internal parts of the original RCA factory carton for a 15GP22. Your carton should be similar.
There should also be an attached photo of a good, under vacuum, little-used 15GP22 with its neck vertical. It is vertical with its front face, called the faceplate, resting on the supporting surface. It is best to keep the tube in this attitude when it is out of its carton. But for now, it may not be necessary to remove the tube. The metallic area on the lower part of the tube in the photo is a mu-metal shield used when the 15GP22 is installed in a set and will not be present with your tube.
Some general information regarding handling a 15GP22: never pick up or support the tube by its neck — always pick up the tube by its faceplate. The tube weighs 26 pounds. I always use a folded blanket, a soft sofa cushion, or something similar such as a deep pile rug on which to place the 15GP22. If you remove the top two cardboard inserts, the neck should be visible and the 'getter flashes' should also be visible. These getter flashes are the three dark areas — blotches really — shown in the photo around the upper neck of the tube. What we hope for is that these getter flashes are either (1) black as in the photo or they can (2) display a silvery sheen (often with the black as a base from which the silvery appearance emanates).
These three areas inside the neck may also have a white halo around the black or silver blotches.
It can also be a chalky almost powdery white. This last condition is what we don't want to see, for it means the tube has lost its vacuum sometime over the last 50 years and is full of air.
There may also be a tag attached to the neck, or there may be (as in the photo) a serial number label taped or glued to the base (the 20-pin connector). I would appreciate knowing what information these possible tags contain; it is most usually the final factory-assigned serial number.
I do appreciate your interest in preserving this artifact from the early beginning days of color television and I look forward to hearing from you again. Please email with any question your may have or clarification I may offer.
Thanks for the great pictures;
it is clear that the 15GP22 has not ‘sprung a leak’ lo these many decades and
is very much under vacuum. Based upon the history of the tube you have provided
and the state of its vacuum, there is a very high probability that the tube
will perform correctly in a restored CT-100 color television set. Jonathan
Winter, curator of the
You should be aware that a functional 15GP22 is worth far more than it cost back in December 1954. If you wish the museum to have your tube for display and use in its CT-100, these are your options based upon my experience. Jonathan has funded the purchase of your 15GP22 for up to $2000. You may also wish to consider donating the tube to the museum. Or, you may wish to accept less: perhaps $500 or $1000. Either way, the museum will acknowledge you as the source of the tube. My reward in this process is the knowledge that one of the few remaining 15GP22 color picture tubes did not ended up in a landfill. I want you to know also that one used but still operational 15GP22 was bought for a little over $3000 eighteen months ago, but it did not reflect a typical selling price in my opinion. I am certain that arrangements can be made to pick up the tube if you decide that the museum should have the tube, as shipping a 15GP22 has in the past proven to be iffy. Perhaps it would be best for you to communicate directly with the museum at this point. I am certain Jonathan will contact you presently
Thank you so much for your help with this piece of history. After much discussion with my wife we have decided to sell it to the museum. It was my original intention to give it to them but have decided to sell it and use the proceeds to start an education fund for my two little ones.
I look forward to hearing from Jonathan.
Hi Pete, We have a working set... still a little problem with the convergence but the set works like a champ. I want to thank you so much for helping us find the tube. Happy New Year.