That's a Puma that thinks its a dog. He needs professional help. Tom

That's a Puma that thinks its a dog. He needs professional help. Tom

The cat may have a serious identity crisis.

https://live.staticflickr.com/4813/46655178671_40e4184104_z_d.jpg

:D

jr

Now that we all have this photo sharing down pat, could we have an updated photo of the HV cage from post #226? I really would like to see the CTC-20 flyback in operation.

I operate as an early color TV Performance Enhancer rather then an early color TV restorer. This fact was clearly demonstrated by my "trashing" of the 21CT55’s floor model cabinet to make it a table model so it can rest on my bench top. No big deal?

I constantly seek to demonstrate the potential of the RCA 21CT55 basic electronic design by pushing circuit implementation to the max without the constraints of convention.

Operation of the 21CT55 as a video only monitor allows all the performance advantages of modern digital baseband video to be displayed without the constraints of over the air video RF bandwidth limitation. RCA's 21CT55's inherent low level chroma demodulation and CRT drivers have been used as control room direct video camera monitors so they must be good. My great volume of resulting modified 21CT55 screen shots compared to top of the line crt tvs and crt monitors should be apparent.

All of this TV Performance Enhancement terminated March 21, 2010 at 3:30 when the
original 55 year old 21CT55 fly back transformer primary shorted out. It had been running unintended for about 10 minutes and cooked. Horizontal circuit current had been running approximately 200 ma but was fused at 1 amp by mistake. Disaster, these transformers were non obtainable! I was dead in the water.

After much agony and research I decided to substitute the horizontal circuitry from a RCA CTC-20, the last of the 21FB22 roundys. Horizontal transformers and circuit components were still available. Sounds simple but the interface circuitry was radically different between the 1955 CTC2 and CTC-20 series, 14 series later of evolution later!

Notebook and photo records indicate that after many circuit evolutions and hardware hacks later I got my first stable full screen photos on the original 21FB22A CRT on October 28,2010 after seven months of part time effort. So have there been other successful attempts of 21CT55 horizontal transformer replacement? Anyone?

What amazes me is the refusal of some members to accept this reality. This was dramatically demonstrated by the “pile on” of a few members to scold me for not following the dictates of a few super restoration members. These included elimination of paper caps, restuffing of electrolytics , never exceeding the original specified max RCA ratings etc. Sorry, these limitations do not apply to my personal 21CT55 performance enhancement charter. I can live with their rejection.

Complaints of my posting of “hundreds of screen shots” during my “Photo Bucket’s $400 ransom extortion” attempt jnvestigation was justifiable to prove my photos were recoverable using previously recorded texts........

http://i677.photobucket.com/albums/vv134/tomcomm/55%20RCA%2021CT55%20scrn-shots/220-2070_IMG.jpg

Nobody is obligated to view my Tomcomm stuff, right? No one got hurt, eh? So what’s the problem here?

I am truly grateful to those members who finally got me connected to FLICKR. It’s a great posting sight. I promise to use it with constraint………Tomcomm

Agreed.

Well after my "21CT55 Restorer" vs "21CT55 Enhancer" manifesto has been likened to my 1957 Austin Healey V8 engine Enhancement history, let me revisit some ancient history:

Where I'm Coming From Feb 2003

I don't know how long you Modified Healey guys have been hot rodding. I suspect that most of you have been messing with cars continuously since you were a kid.

Well, I’ve always been an electronic geek. I didn't even have a driver’s license or owned a crescent wrench until 1953, when at 18, I got a job as an electronic technician at RCA, West Los Angeles, and was forced to get and repair a car, a '41 Plymouth, yuk, But then I was hooked! In '54 with a friend's big help, I installed an original 303/348ci '49 Olds Rocket in my second car, a '49 Plymouth fast back business coupe ( I'm a slow learner) With a '37 La Salle 3 spd top loader this was the hot street sleeper, even against the hot '32 Ford 4x4s, '55, '56, '57 Chevys and Buick Centurys.

In early 1957 I bought my third car, a ‘54 Austin Healey 100 4. I liked the car, but after the Olds Plymouth it was a zero performer. Three months later at 22, I pulled the monstrous Olds/La Salle combo out of the Plymouth and jammed it into the cute little British roadster. It was an act of brutal incest, I admit.

I did this 6 month conversion entirely by myself in a garage I rented with four SB Chevy guys who were sure I was crazy to do such a stupid thing as putting an obsolete 8yr old 700+# engine and 20yr old obsolete 3 spd in a new 3yr old 2100# British roadster. Of course I would have preferred a 500# SBC with the latest 4 spd but none of these guys or anyone else would sell me one reasonably, they wanted them for themselves.

It weighed 2486# curb, had a 48% front vs 52% rear weight distribution and was really quick off the line. One of the Chevy guys was Bones Balough of NHRA fame. We went to all the local So Calif drag strips where we cleaned up,

We were active in drag racing from late 1957 to early 1960 in modified sports, turning 112mph in 12.5sec best. The modified Corvettes were our only competition but couldn't beat Bones off the line due to my 30% engine setback. Then we beat a Buick V8 Doretti modified sports and he protested my engine setback. The NHRA forced us into the altered competition roaster class that had enormous engine setbacks; huge slicks that ran in the 11's at 130mph.

This put me out of drags and the car became a daily driver until 1964 when I installed the 394ci/ 418ci '59 Olds and also did the Cobraized nose. I took it to the drags only once with the "new" engine but couldn't launch it with the street tires so I turned 13.2 at 118mph. Although I could beat the SB Cobras, the new BBs had come out and were getting faster. I realized I couldn't beat the modern 427ci/ 4 spd with my ancient 418 engine/ 3 spd so I simply retired the car in 1967, consigning it alongside the garage where it deteriorated into a decrepit rust bucket. I was now totally out of the modified sportscar scene while pursuing a career in electronics and raising a family.

In 1999 at 65, I completely retired and pulled the 45yr old heap from its 32yr grave and started a "1964 Period" restoration. With the V8 engine and body alterations (Healey people call it an abominable desecration) I decided to restore it to its 1964 configuration, complete with 43yr old engine and 63yr old trany. I would retain the original '54 Healey wire wheels and 70 series tires all around. I also decided that in no way would I flare the fenders for big tires. Any enhancements to the engine would be limited to items that were available before 1965. I realized that these restrictions would make it extremely difficult to compete with the faster Modified Healey members but I would give it the good shot.

And so it is today. I would respect the car as a piece of early Healey history and just make it run well. At my advanced age, I can't start another life consuming, advanced car project.

https://live.staticflickr.com/7823/47530316981_b897f9fc30_b.jpg (https://flic.kr/p/2fq6iiP)217-1793_IMG (https://flic.kr/p/2fq6iiP) by Tom Schnerk (https://www.flickr.com/photos/tomcomm/), on Flickr

https://live.staticflickr.com/65535/46895948185_7a0e31871d_b.jpg (https://flic.kr/p/2es2ZyM)HV-cage-rebuilt (https://flic.kr/p/2es2ZyM) by Tom Schnerk (https://www.flickr.com/photos/tomcomm/), on Flickr

:sigh:https://live.staticflickr.com/65535/47806002552_72a58726dc_b.jpg (https://flic.kr/p/2fQsg2j)b!00000119 (https://flic.kr/p/2fQsg2j) by Tom Schnerk (https://www.flickr.com/photos/tomcomm/), on Flickr

This is first pix of my 21CT55 using a repaired CTC20 FBT. Note that the VTVM shows full scale reading on 30 range with 1000 divider at the crt anode or 30,000 volt range. The VOM shows 200 on the 500ma range or 200ma current at the HV .5amp fuze which is the same as measured at the horz output cathode. This indicates the CTC20 FBT circuit is more efficient than the original 21CT55!
This pix was taken 1/2/2016, over 5 years after the original FBT failure.

Presently the 21CT55 is inoperative since the repaired CTC20 FBT failed due to arcing of the repaired silicone covering. Not to worry, I've got an extra CTC 20 FBT in it's original RCA box. All I got to do is make wire to wire switchover from old to new FBT, what could be simpler, eh??


https://live.staticflickr.com/65535/47806002552_72a58726dc_b.jpg (https://flic.kr/p/2fQsg2j)b!00000119 (https://flic.kr/p/2fQsg2j) by Tom Schnerk (https://www.flickr.com/photos/tomcomm/), on Flickr

With your second CTC-20 flyback, make sure NOT to run it above 25KV. 25KV is what it was designed to run at, and RCA tended to run their flybacks at the top end of what they could survive...Pushing it beyond that is asking for failure.

Tom, why did you apply silicone to the first CTC20 FBT?

The HV rectifier plate socket on the transformer top was open circuited. Should have measured around 600 ohms to the horizontal driver plate. Since the FBT was obviously never soldered in I elected to attempt a repair rather than send
it back to Mouser. This entailed removing the plastic coil covering and resoldering the very fine "horse hair" wire from the coil ending to the rectifier socket. It then measured 630 ohms which was about right. I decided to recover the coil with Permatex Ultra Blue instrument grade silicone sealer to protect the very fine coil wire. This fix worked fine for all of my "Performance Enhancement" experiments for the last 8 years as well documented in this VideoKarma thread.

Point of interest: What does an unmodified 21CT55's CRT anode voltage run with cutoff screen and the HV regulator pulled, with 130V AC Line input? Anyone?

Seems this worse case scenario must have been envisioned by RCA engineers before they got it released to production. What sort of catastrophic failure of non-tube replaceable parts would they tolerate? The CRT and FBT for sure are major items of concern and must be specified with at least 10% safety factor.

My 21FBP22A CRT is spec'd at 27000 volts max. My 21FBP22A CRT is set to run at 30000 volts with 120v AC or 11 percent over max spec for demonstrable maximum picture quality. I accept this risk vs performance tradeoff.

Most makers assumed that a set would not be running for a long time in failure mode...just because you can run an engine for a couple of minutes with no oil or coolant in it without it burning up doesn't mean it won't if driven in that state for a prolonged period.

You've already seen the original and 1 replacement burn up. Shouldn't that tell you to dial it back a bit? Even 3-4KV (lets say a tech had a HV probe that was 1-2KV off and set it for 26-27KV) less than you've been running it at will have only very minor effect on brightness, sweep and general image quality and will be at least reasonably close to factory specifications. Even before the X-ray alarmists many makers in their service literature stressed proper HV adjustment. New flybacks don't grow on trees; why not cherish what may be the last one you can find?

https://i677.photobucket.com/albums/vv134/tomcomm/Restore3.jpg (https://s677.photobucket.com/user/tomcomm/media/Restore3.jpg.html)

https://i677.photobucket.com/albums/vv134/tomcomm/Restore3.jpg (https://s677.photobucket.com/user/tomcomm/media/Restore3.jpg.html)

I'm getting warnings on bandwidth limits. I dont use PB anymore and wont let me login. Lol

https://live.staticflickr.com/2659/4276717899_3109d71974_b.jpg (https://flic.kr/p/7vViev)Copy of 39 (https://flic.kr/p/7vViev) by Tom Schnerk (https://www.flickr.com/photos/tomcomm/), on Flickr

http://i677.photobucket.com/albums/vv134/tomcomm/55%20RCA%2021CT55%20scrn-shots/CopyofP3050208_1_.jpg

Picture is not working.

http://www.videokarma.org/attachment.php?attachmentid=199671&stc=1&d=1572901043

.

Picture is not working.

http://www.videokarma.org/attachment.php?attachmentid=199671&stc=1&d=1572901043

.

On my smartphone I don't get the bluring and water mark*. They either don't do that with smartphones or they only water mark photos going to IP address associated with current and former customers of Photobucket.

* Noticed this effect with photos in old threads I posted....the computer I posted them with gets the water mark and others don't...some other members photos get watermarked on my upload PC too.

If I had time and motivation I'd make my own photo hosting server, delete every picture on my Photobucket and Flickr so they could not make any money off it and be done with the whole mess.

http://i677.photobucket.com/albums/vv134/tomcomm/55%20RCA%2021CT55%20scrn-shots/CopyofP3050208_1_.jpg

http://i677.photobucket.com/albums/vv134/tomcomm/55%20RCA%2021CT55%20scrn-shots/CopyofP3050208_1_.jpg

Mine Is Blured

blurred

Blurred and watermarked.

Photobucket.... What a disgrace...

killed 2 unobtanium flybacks.... What a disgrace...

Fixed that for you.:thmbsp:

I don't get your post. What are you trying to say? "Fixed that for you."

Something about me destroying two flyback transformers? Get A Life!

My 21CT55 blew its original FBT March 21, 2010 due to old age. That's one.

I replaced it with a new RCA CT20 from Mouser which didn't work. Seems it
had no connection to it's CRT HV socket! I fixed it and recoated the entire HV
FBT in silicone. It worked great until the coating failed and arched over to
the HV cage last March. I had other things to do so the 21CT55 just sits there!

I offer no apologies. Tom

I don't get your post. What are you trying to say? "Fixed that for you." Something about me destroying two flyback transformers? Get A Life!

My beef with you is that your ham fisted attempts to 'improve' and hack parts into a historically important chassis are decreasing a finite supply of irreplaceable parts which only seems to end in disaster every time. I've already made my feelings known before this thread was 'cleaned up' by mods in the past, but it seems nothing has changed. You might as well be melting down 15GP22's to turn them into Trinitrons, they objectively have better picture quality so let's get rid of those pesky old CRT's right?

My 21CT55 blew its original FBT March 21, 2010 due to old age. That's one.

Revisionist history!

You melted them down by running them outside their design specifications in an ill fated attempt to make some unverifiable 'improvement' in picture quality. Apparently your definition of quality is no picture at all... You were told, and continue to be told by very knowledgeable people that what you are doing is not only wrong but dangerous, yet you persist. I can only hope I don't come here reading about your obituary one day.

I'm petitioning this thread to be closed, by allowing it to continue this body is condoning your actions. I won't.

This thread started over 7 years ago and has received over 237 replies.
My 21CT55 is inoperative, awaiting repair of it's CT20 FBT horsehair ultra hv
wire, as reported. I'm presently working on my classic car hobby. Checkout
VideoKarma "Things With Motors", "Olds V8 Healey". I'm not easily intimidated.

http://pic20.picturetrail.com/VOL1792/11235128/19914223/322121650.jpg

Point of interest: What does an unmodified 21CT55's CRT anode voltage run with cutoff screen and the HV regulator pulled, with 130V AC Line input? Anyone?

Seems this worse case scenario must have been envisioned by RCA engineers before they got it released to production. What sort of catastrophic failure of non-tube replaceable parts would they tolerate? The CRT and FBT for sure are
major items of concern and must be specified with at least 10% safety factor.

My 21FBP22A CRT is spec'd at 27000 volts max. My 21FBP22A CRT is set to run at 30000 volts with 120v AC or 11 percent over max spec for demonstrable maximum picture quality. I accept this risk vs performance tradeoff.

The absolute maximum spec is just that - the maximum that a device can be subjected to - no safety factor here. The nominal 25KV spec that RCA specified for this TV should have some safety margin associated and 10% is not a bad estimate.

30KV is 20% over the nominal operating voltage of 25KV. Considering the date of manufacture of this TV, there were not many provisions for shielding the repairman or viewer from x-Rays. Consider the safety provisions of later years such as higher lead content of the tube envelopes and even lead shielded HV rectifiers and these are for TVs operating at 25KV.

If you continue to work on this TV or watch it in close proximity running at 30 KV, you may end up like Homer Simpson in post #5 of this stream:

http://www.videokarma.org/showthread.php?t=272531

No emotion here, just common sense.

Pretty sure I ran mine without the HV reg for a few seconds....it arced to the HV cage when the HV came up and I shut it down as quickly as I could...

I suppose I could run that test for 5 sec After HV comes up from cold and it would probably not hurt for that brief of a run, but more than that is a risk I'd never take.

Nominal line voltage when these were new was 117V, and much above 120V was rare...the engineers that made this would have advised contacting your utility or adding a stepdown transformer to reduce line voltage if you had 130V at your outlets in 1954....heck this set draws enough current that copper losses in household wiring drop the voltage at the outlet a bit when one of these is running so you would have to have an even more implausibly high line voltage with nothing major plugged in to have 130V with it on.
Also engineers assumed in absolute worst case scenarios for the support life of the set (10-20 years after production) if you blew the fly a new one could be ordered.... that time is passed so we should be running these for longevity rather than the bleeding edge of what the design is capable of.

These sets performed excellent when perfectly adjusted to stock specifications. Going beyond stock in a manner that increases the risk of destroying unobtainable parts on a set that is highly desirable and of which only 40 examples are known is not going to be met with encouragement (and acceptance may be a stretch) from a community dedicated to preservation no matter how hard you try to justify it...

Increasing the HV only really does 3 things: 1.) Increase the brightness, 2.) Reduce width and height of deflection a bit, 3.) Change optimal focus and gun bias setting points. 1 should not be necessary since you are using a brighter later production all glass tube. The other 2 are not necessary either and can be achieved with minor adjustment to the deflection circuits and such.

With some effort you should be able to achieve an identical picture a tad less bright at the correct HV spec... rather than turning it up to 11 to try and somehow brute force better picture out of it, why not instead challenge yourself to dial it in to look right at 25-27KV and maybe reduce your room lighting so it seems just as bright?

Granted with the incorrect flyback and other random modifications maybe there is no sense trying to make it reliable anymore and you have introduced design changes that doom it to failure...If that is the case and you don't mind it dying irreparably by all means run it till it dies. Given you've held on to it this long one would imagine you'd want to see it still around after you check out, but what you do with it is your business.... rubbing what, to everyone else here, is dangerous mis-treatment of a rare piece of history in our faces when we have repeatedly explained this and tried to convince you not to, comes across as trolling at this point.

No emotion is present in this and no insult is meant just my appraisal of the situation.

Thanks for your considered and friendly replies regarding my 21CT55 modifications. I'll be 85 in March, much too old to apologize for the actions of my badass youth....... Nobody got hurt. Get a life, folks!!

http://pic20.picturetrail.com/VOL1792/11235128/19914223/413664583.jpg