Found an RCA CTC5
 

Hi All, Within the past few weeks our family has relocated to Canada. In the Toronto Craigslist I found what turned out to be an RCA CTC5 colour TV. I duly purchased it and carted it home. (I specifically use the Canadian spelling of "colour" here for it appears this set was made for the Canadian market.)

From the back cover, the receiver was manufactured in Camden. But note the 25Hz power. A separate enormous power transformer was mounted on a subsidiary chassis beneath the main chassis. There is no power transformer on the main chassis. Note that the subsidiary chassis has 80mfd Canadian manufactured capacitors.

RCA Victor had a Montreal plant which manufactured US designed receivers with minor variations. I have an RCA 8T243 receiver made in Montreal which has different IF transformers and a 25Hz power transformer.

Colour broadcasting in Canada began in September 1966. Hence any receivers sold in Toronto prior to 1966 received colour programming from the US networks affiliates in Buffalo New York. WBEN TV (now WIVB) purchased RCA TK41 cameras in 1954 and WGR TV later became the NBC affiliate carrying the NBC colour programming. So a colour set in Canada as early as a CTC5P would be quite rare.

The interior of the cabinet has a whitewash paint sloppily applied. It looks as if the white wash may have been done in the factory. I would suggest that the set came to Canada by way of the Montreal RCA Victor company, where it was modified and interior whitewashed. I shall research this.

Anyhow, the set has been stored well. The cabinet is in good shape and the marks are mainly acculmulated dirt. The set seems to have had an easy life: all the receiving tubes are factory RCA and the 21AXP22 tests strong without any rejuvination or even waking up.

This will be a fun project once we have settled!

Really nice find there. Is the electrical service still operating at 25Hz in Canada?

Wow what a great find. It is a perfect new house warming present to yourself lol!
Beautiful Whitby, that was always one of my favorites without doors. The Wingate is my favorite with doors. I can't wait to see a picture on it, I bet it don't take much either.

Yes I was lucky to find this. It only goes to show that these sets are still lurking about and one never knows when they will pop up.

Toronto power was 25 Hz for many years. Being close to Niagara Falls, AC power reached Toronto in the 1890's. It was 25Hz from the 1890's until the 1950's. The swich to 60 Hz occurred i thought in about 1952-53 but I expect there were still 25 Hz spots in Southern Ontario Canada in the late '50's.

Incidently, the last 25Hz alternator at Niagara, the William Rankine plant closed just a few years ago.

Here is a link to the history of 25 Hz power:

http://www.ieee.org/organizations/pe...eshistory.html

You lucky Dawg !

That 25Hz 120VAC power transformer in theory would be happy at 240V at 60Hz. Except that all the secondaries would produce twice their rated voltages (like 12.6V instead of 6.3V). However, the high voltage secondary may get overvoltaged, if it's rated say 500V centertapped, it would produce 1000V centertapped, but the insulation might not take it. Of course the rest of the set won't like it either. :nono:

All of North America is now 60hz(with a few exceptions I'm sure). Probably best to look for a transformer that is rated at 117V 60Hz. Someone here with a junk chassis may have one. Probably wont be a direct fit size wise but can be made to work easily. Congrats on the 5. pretty rare there!

Green with envy here!

The CTC5 25Hz power transformer will run perfectly well on 60 Hz. In fact it will probably run as cool as a cucumber. It doesn't need replacing as long as it checks OK.

I have an Admiral 7 inch 19A11 set that was built in Canada with a HUGE!!! 25 Hz power transformer and it runs very cool on 60 Hz here in PA.

Cliff

That's what I was thinking. You can always go up in frequency, but you need the larger core size to pass 25Hz and stay cool. No need to change the primary voltage, that is always primary to secondary turns ratio dependent.

Seems to me I recall another Canadian modified CTC-5 posted here on VK, or AK at the time, some years ago. Not sure why they would whitewash the inside of the cabinet? Of course Canadians could also pick up the Detroit area early color broadcasts from Windsor, Ont. Would be interesting to see if U.S. color sets were advertised by RCA or dealers in these Canadian border cities in the 50's & early 60's.

-Steve D.

thats something i never hurd of, all of the utility service in canada was operating on 25 hz in the early yrs , learn something new everday. i want one of those cool sets someday.

That is a NICE find! Especially with the like-new CRT.

Is the "black box" in the location of a power transformer on the chassis empty?

Colour, indeed! I would hurry up and unpack so that I could start playing with that wonderful TV.

Phil Nelson

Correctomente bro. The set should be virtually 'plug and play' (after the usual pre-powerup procedures, cap replacements etc.). The big tranny will be very happy on 60 cycle. :guitar:

And its a DELUXE, with the 7-tube color stages. Nice treasure there!

Very curious! It appears that the original US Factory power transformer is on the main chassis. So just exactly how does this 25hz transformer chassis interface with the main chassis. Is the original 60hz transformer just sitting there disconnected? or is the 25hz chassis interconnected in some way as a step up to supply the primary of the 60hz trans on the chassis.

I don't understand why they would leave the original 60hz trans on the chassis.

cancel post. bad info.

Bravo!:banana: Another early RCA Colour set saved! And the fact its got a strong CRT is even better. If Miniman hasn't seen this thread yet, when he does I'm sure he will be grinning from ear to ear! What an awesome find! Congrats! :D

Wow. Excellent find. You wonder how many more are yet to be discovered. Maybe I'd better to move to Canada, it seems there has been a lot good stuff found up there this summer.

I'm going to guess that's just an empty can acting as a hole plug on the main chassis.

The spot where the US transformer sat does appear to be just an empty can. I haven't taken the set apart yet but the can is held in place by the unique Canadian Robertson head screws. The rest of the chassis has Philips, slot or hex head screws but the dummy can has the Robertson head screws.

I have a number of other early Canadian manufactured sets from the '30's onwards with massive 25Hz transformers. They now run a cool life on 60Hz with no problem. But I am curious for a set this late (1956-7) with a 25Hz power transformer implies that there were still pockets of 25Hz regions as late as then.

The set seems to have spent all of its life in an older section of Toronto which was perhaps late to switch to 60Hz. I suppose the only difference with this CTC5 is that an already heavy TV set is that much heavier (by about 10 to 15 pounds).

Nice.

It's a nice scroe, a la AK. lol

Glad that you got it. I really like the results on the CRT tester ;)

25hz right into the 50s ! what were they thinking ?
Could have been worse: Canada could have adopted PAL :eek:

Surprizingly, the town of Roosevelt, AZ was on 25 cycle from the adjacent Roosevelt Dam hydro plant until 1974.
Some kinda interesting notes on the Salt River Project's upgrade to their antiquated hydro system..
https://www.srpnet.com/gallery/trd/1971.aspx

You have to consider that Toronto was one of the first electrified cities in the world. 25Hz was the first alternating current frequency. Once you establish a standard, it is always difficult to later change.

The availability of Niagara hydroelectric energy was very early (before 1900). Niagara power was transported via perhaps the world's first long distance high voltage corridor to Toronto. It was an enormous undertaking to make the switch to 60Hz in the '50's. I am surprised that 25Hz lasted into the color tv era!

In Toronto, the street railway system was fully electrified by 1893. I recall reading that the last horse drawn street railway car retired in that year. Eaton's Department Store building on Queen Street in Toronto, built in 1892-1893, was also fully wired for electrical lighting.

And also consider that the Rogers Radio company in Toronto was the first to sell fully 25Hz AC powered radio receivers in 1925: this was two years before RCA sold their first AC powered sets.

In hindsight 25Hz was a poor choice. But when you are an early adopter you must pay the price.

I got around to pulling the chassis on this set today. It is pretty well preserved with no tar on the HV components.

I looked at the power transformer(s) on the main chassis and second chassis. The main chassis mounted box is indeed a transformer and not an empty box. This being a 25Hz set, it appears as if the outboard transformer augments the main chassis transformer. I'll trace out the power supply circuit to see what modifications the Montreal factory did. Perhaps the Toronto Reference Library has the notes for the Canadian version of the CTC5-P?

The "Series 700 Notes" posted on the earlytelevision.org website suggests that to service the set, extension cables be employed between the removed chassis and the CRT. I am sure this has been discuused before in this forum: does anyone here know of the thread?

The cables look as if they should be easy to fabricate except for the convergence socket and plug. Does anyone have an extender to loan? Or alternatively, does anyone have the socket and plug to spare from a scrapped CTC5 chassis?

Cheers, Terry

Try to find an early Admiral scrapped chassis from a model 30A14CC1 or similar with the separate power supply chassis. The cable that connects the power supply chassis to the main chassis on that set uses the same plug and the socket. The one on the chassis can be removed to use as the female end. This is a very common B&W set and there are probably a number of parts chassis around. Else you will need to find a CTC5 parts chassis and a CTC5 convergence yoke to obtain both the socket and the plug to make up the needed cable.

Thanks Bob.

In the meantime until I find the appropriate connectore I shall extend the CRT and yoke leads and just leave the convergence coils attached to the chassis and off the CRT until I have confirmed a sensible picture.

I had a chance to work on the CTC5 today. I am methodically going through the chassis. I traced the 25Hz power supply and this is what I found.

The main chassis transformer was exchanged for a filament transformer only. The box on the chassis is indeed a transformer with 3 secondary windings: two for the 6.3v strings and 5v for the rectifiers. Note the Montreal factory substituted the unique Canadian Robertson head screws to hold the main chassis transformer.

The auxillary chassis has a whopping 20 pound transformer for the B supply only. The auxillary chassis also has a big filter choke and a pair of 80mfd 450v electrolytics which parallel with the 80mfd filters on the main chassis.

The 25Hz transformer will run cool at 60Hz and the extra filtering should make the B supply really clean.

There is evidence of the history of the set's manufacture. The date codes on the main chassis run from the 20th week of 1956 through to the 39th (the latest I could find on a component). The auxillary chassis electrolytics are dated December 1956 so the set's delivery was probably early 1957.

I was amused by the somewhat sloppy modification in one regard: some of the added connections were not soldered! The wire that attached to the rear socket for the primary of the B supply transformer was not soldered as was the B transformer lead that attached to the 5U4 rectifier plates. The connection to the 5U4 actually is burnt from arcing. I suspect the previous owner must have found the set unreliable hence it appears it was not used much. All of the receiving tubes, including the 6CB5 Horizontal Output and the 5U4 rectifiers appear original.

That chassis cleaned up nice. Looks like a nice project.

Some progress has been made with this set. I was lucky because this color TV receiver was not stressed or hammered during its life. Apart from a capacitor change on the vertical sweep board in 1965 (assumed from the 1964 capacitor date code and the 1965 repair tag on the HV cage) it looks as if it hasn't been touched. Oh yes, it had the contrast control mod. and from the look of it with same type paper capacitor, it was done at the same time.

I am currently reforming the electrolytics. It appears as if this set had not been powered for many years because the electrolytics were almost a dead short. By slowly reforming the dielectric, it is important to limit the current to about 5ma. Each capacitor took about 15 minutes to come up and at full rated voltage the current is about 0.1 mA. Because this is a Toronto set for 25Hz, two additional 80mfd capacitors were added to reduce the ripple. These are Canadian made Mallory electrolytics and they are taking much longer to reform. If the current does not drop below 1mA, I will be inclined to replace these.

Paper dielectric capacitor leak current and I will replace all paper capacitors which are in high impedance circuits and/or have above 20VDC across them. The larger 0.47ufd in the convergence circuit I will likely leave unless I have problems with convergence.

There was an interesting RCA modification made to the later CTC5N chassis: this involved changing the source of the plate voltage to the bandpass amp. and the plate supply to the color difference amplifiers. This was to prevent grey scale changes between color and B&W programs (color burst on vs off from the broadcaster). My set has the 10kohm dropper resistor which replaced a 6.8kohm unit. The 10kohm 10watt resistor dissipates about 8.5 watts! In the closed container chroma circuit, the heat melt the wax on the paper capacitors and burnt the insulation of wires running about half and inch away from the resistor. I plan to mount a 10k 20watt resistor outside the chroma can near the rectifiers.

I have attached the drawing of the chroma chassis highlighting the modifications RCA made on the later chassis. I have also attached the Radio College of Canada note of the Toronto 25Hz power conversion modification.

Lastly, I was curious to find that the static convergence is governed by the the DC obtained from the 6CB5 Horizontal Output cathode current. It would seem that investigating using a separate outboard DC supply would be more suitable. Would this element of the design possibly account for the frequent reports I have read about the drifting CTC5 convergence?

The Canadian Mallory electrolytics (80 ufd @ 450V) eventually reformed okay. Leakage current for each eventually dropped to 0.1mA at 450v after an hour for each. These capacitors were initially reluctant to come back: at first, when only 20VDC was applied, the leakage current was already 5mA and the current initially didn't appear to drop significantly. However, as these capacitors woke up the currently dropped right down.

I am now confident all the electrolytics have reformed okay and are fine. I am grateful the previous owner did not power up the set.

I today removed the components from the neck of the 21AXP22A for cleaning and examination. After reading the previous posts about disintegrating yoke covers, I was expecting the worst. Somehow the yoke on my set survived. I simply removed the yoke, cleaned off the dust and wiped it over with a damp cloth and found no problem with it. Curious why this one has survived and others I have seen are totally shot.

The cold in the Great White North preserved it, ehh ?!? (grin)

I suspect moisture has a lot to do with it. Better make a cast of that thing and get it reproduced before it falls apart!

Interesting, the one on my Wingate is ok too. It was produced in 1956, while my CTC4 was made in '55. The 4's cover has turned to dust. Both sets were from their original homes in a similar climate. I wonder if there was a change in material somewhere in production?

I have nearly replaced all the paper capacitors. I have gathered from an earlier thread that there are paper capacitors masquerading as mica look-alikes which should be changed.

I examined some of the paper capacitors for leakage and they are all bad! What is worse is when they are heated: I tried applying a little heat at the leakage increased at an alarming rate. Maybe I could use them as a temperature sensor in a thermometer.:thumbsdn: Boy, RCA must have really skimped on quality to keep the cost down!!!

I checked the electrolytics again and they have remained good apart from the additional Canadian Mallory 80mfd units for the 25Hz modification. These capacitors have become very leaky again and have lost the dielectric reforming I did a few weeks back. They will have to go... time to repack.

Going through the chassis (it is a CTC5 Deluxe) I have found an RCA factory modification which I feel was poorly executed. Mine is a "P" chassis and the later factory runs had the modification to improve grey scale between color (burst on) and black and white (burst off) programming. The plate supply for the first chroma bandpass amplifier was originally attached to the +300 vdc line through a 6.8kohm resistor dropping resistor. The modification moved the supply to the +385vdc line dropped through a 10kohm resistor. The modification meant that the power dissapation for the dropping resistor increased substantially (to 8.5 watts). This left charred insulation and components near the resistor. Because the chroma unit is enclosed, the ventilation is poor which made a bad situation worse. All the wax capacitors showed evidence of melting!

I decided to split the resistance: I installed a terminal strip near the rectifier ventilation and installed a 6.8k 10 watt resistor there. This was in series with a 3.3kohm 5 watt resistor mounted in the chroma chassis exactly where the 10kohm resistor was. The 3.3kohm resistor will dissipate now just over two watts.

Note the photo of the charred remains of the old terminal strip. I had already replaced the charred wiring. The original terminal strip was a miniature unit and I went to the trouble of modifying a larger terminal strip to fit. (I would not expect to make money on a CTC-5 anyhow:no:).

My set otherwise looks lightly used. I would be curious to hear from others who have the earlier versus the later deluxe chassis and this issue. There must be others with this problem...

which look alike paper mica are there, I did not change any thing but the tube paper caps on mine?