Beginning restoration of my CTC-5 Whitby. What do I need?

[JoeyPinball]

I'm really sick of seeing my Whitby sitting in storage. I think it's time I got it up and going. I just want to make sure I'm prepared and I'll have everything I may need beforehand.
Here's what I have:
Large workbench with lots of lighting.
Weller soldering iron with digital temperature control.
A Simpson 265 (well, the Bell System equivalent)
A Hickok 533a tube tester with CA-4 adapter for newer tubes
A Tektronix 535 oscilloscope with dual trace plugin
A Sensors CRT tester (I don't remember which model)
A 5 amp Auto transformer and isolation transformer.
Lots of brand new capacitors and resistors, along with dozens of New Old stock tube sockets.
One of those magic devices from China which tests capacitors, resistors, diodes and pretty much everything else.
The Sam's photo fact diagrams converted to vector and printed in very large format.

Can anyone suggest anything else that I should have on hand before starting what I know is a gigantic undertaking?

Thank you in advance!

[Electronic M]

I'd use the CRT tester before proceeding. 21AXP22s aren't easy to find and are expensive. 21FBP22s are comparably easier to find, but take a non-trivial amount of parts and work to adapt to a CTC-5.

Once you know the CRT is okay here are a few other things worth having for a repair:
HV meter capable of measuring 30KV.
Test pattern generator or DVD capable of putting out a crosshatch pattern, and color bars.
B&K 1077 analyst (if there's sweep or signal chain issues using one to do signal injection troubleshooting can save you hours of fumbeling around trying to troubleshoot something tricky...Most analysts need a recap too so it's a good warm up project).

Two things I highly recommend doing on a CTC-5: installing CTC-7 HV control pot circuit and installing CTC-7 contrast/brightness circuit.
If you compare the CTC-5 and CTC-7 Sam's schematics (earlytelevision.org has both under color TV -> technical information) the only difference between the CTC-5 and CTC-7 HV reg circuit is the 7 replaces a fixed resistor from the 5 with a potentiometer and a smaller fixed resistor. Having an HV adjustment makes life better.
I haven't tried the contrast/brightness mod yet (wanted to see the original circuit work for a while first), but RCA recommended it as a cure for various complaints and a performance upgrade. Supposedly it uses the same control pots as factory and just changed the wiring and possibly some fixed value parts.

If you have owned and watched other roundy chassis before, but NOT a CTC-5 reduced expectations are also a good thing to have....The CTC-5 was the Muntz(it was so Muntz like that Muntz actually bought CTC-5 Chassis from RCA to rebadge as their first color set)/Portacolor (both had a lack of DC restorationin the video going on) of RCAs roundy fleet. RCA cost reduced and simplified that chassis so far that they were the worst performing RCA roundy color. This coming from a guy that has owned and restored every RCA color roundy except the CTC-7,11 and 12 (well my 15s are clones/rebadged, but reasonable representation none the less). Even the CTC-20 which was a rectangular CTC-19 back engineered to use up the old stocks of roundy CRTs and cabinet hardware and was a 6GH8 eating machine was a better working set, when working, than the CTC-5.

[Penthode]

Originally Posted by Electronic M

Two things I highly recommend doing on a CTC-5: installing CTC-7 HV control pot circuit and installing CTC-7 contrast/brightness circuit.

I restored a CTC5 Whitby a decade ago. One issue was low high voltage. It would minimally make about 21kV. The shunt regulator drew next to no current.

I discussed this on the forum and it seems a common problem. I could not find anything amiss in the horizontal seep circuit. To help boost the HV to get it to the point the 6BK4 would do its job, I substituted for the HV rectifier a solid state plug in replacement.They regularly pop up on eBay.

I had problems with maintaining vertical sweep linearity and ended up replacing all the capacitors and many of tyhe resistors in the vertical sweep circuit.

[DavGoodlin]

Originally Posted by Penthode

I restored a CTC5 Whitby a decade ago. One issue was low high voltage. It would minimally make about 21kV. The shunt regulator drew next to no current.

I discussed this on the forum and it seems a common problem. I could not find anything amiss in the horizontal seep circuit. To help boost the HV to get it to the point the 6BK4 would do its job, I substituted for the HV rectifier a solid state plug in replacement.They regularly pop up on eBay.

I had problems with maintaining vertical sweep linearity and ended up replacing all the capacitors and many of tyhe resistors in the vertical sweep circuit.

I also have a Whitby and have not yet moved it and started any evaluation.

I do recommend also placing a 12 meg resistor from 6BK4 cathode to CRT cathode supply, plus a 1 K resistor in series with cathode to measure regulator current using a voltmeter. (1 volt drop across 1,000 ohms = 1 ma.) This was done with CTC15 and later models to improve HV regulation. I performed this on two CTC11 with improvement (noticeable during scene changes) to maintain brightness and focus.

[Penthode]

I think the problem most of us have found is trying to get adequate high voltage. Once O managed to squeak it up, the shunt regulator took over. The absolute voltage is not as important as keeping it constant and my CTC5 regulator keeps it constant at 21kV.

[old_tv_nut]

The Whitby is the DeLuxe chassis, and should have better performance than the Super chassis.

Regarding substituting a 21FBP22, the modifications are all mechanical mounting issues and no electrical mods are needed. It is quite possible to remove and save the 21AXP22 mounting hardware and save it for a future time when a good 21AX becomes available, while adding some home-made mounts for the glass tube. There were also mounting adapter kits sold by RCA, but these are rarer than the CTC-5's themselves.

You might find some of this long thread helpful, which is about my work on my Westcott (Super chassis):
http://videokarma.org/showthread.php...I%27ve+blessed

The CTC-7 contrast control change is definitely worth it, as the original CTC-5 circuit tends to run the brightness up and down along with any contrast adjustment. On the other hand, on my set, the contrast is always set at max anyway to get sufficient drive.

[Jeffhs]

I just looked at some of the pictures of the CTC5; I must say, it looks like it must have been great TV in its day.

I was wondering, though, about the CRT in the CTC5. I see it is a 21-inch round tube. Until now, I didn't know round CRTs were made any larger than 19 inches. Was the CTC5 one of the only (or perhaps the only) early color TVs to use a 21" tube?

One thing which is worth noting is the 21" round CRT used in this TV (21AXP22) is very difficult to find these days (as I am sure has been noted at least once), so it is very important to be extremely careful with the original tube. If the original is damaged in any way, the rest of the TV will be useless, as I don't think the 21AXP22 is available anymore, except maybe in a junker. Even at that, the size of such a CRT, and that the 21AXP22 is so difficult to find, demands the tube be handled very carefully so as to avoid any (and I mean any) damage to it.

The only solution if the tube is damaged, of course, is to replace it with a similar tube (if such even exists; there may not be any substitutes available for the 21AXP22); the problem with that approach is the substitute will destroy the authenticity of the TV, so if anyone decides to replace a 21AXP22 with any other CRT, please, don't mention anything to anyone about the substitution; there are people who would be very annoyed if they ever heard any other CRT than a 21AXP22 was used in an RCA CTC5 color TV. Some collectors are very fussy about these things, sometimes to ridiculous extremes.


BTW, the Early Television Foundation is fortunate to have a CTC5 in its collection of rare old color televisions, as I am sure this model is very difficult (if not impossible) to find. The only RCA "Super" TV I ever saw in my life was a 1950s set, with a round CRT, in a mahogany cabinet; it belonged to relatives of mine, now deceased, who lived in a rural area of northern Ohio.

[old_tv_nut]

CBS produced 19 inch outside diameter round color tubes, used in Westinghouse and Motorola sets as well. Motorola later went to 21 inch O.D. tubes from RCA.

RCA never produced 19 inch tubes. Both the metal shell 21AXP22 and the later all glass round tubes were 21 inch O.D.

The 21AX is subject to leakage problems. The one I originally had in my CTC-5 had a leak at a very small ding in the weld between the two metal pieces that join the face assembly to the bell, as verified by the first tests with the helium leak detector at ETF.
So, yes, if yours is good, be careful with it. If it is good, there is probably no reason to remove and handle it.

"Don't tell anyone if you replace the 21AX with all-glass" is stupid nonsense. Of course you would reveal this. Why would you care what someone else thinks about your decision to get a working set? It is a well known workaround to get a working set, and not revealing it in order to make a sale would be fraud.

Regarding rarity, the Super chassis is least rare for that year. There are quite a few parts sets still in existence (unfortunately, most with burned out DC convergence pots). Your DeLuxe is rarer and more desirable.

[Electronic M]

Some collectors are suspicious of the 21AXP22 going to air on them to the point of preferring one converted to an all glass tube (every all glass roundy color is compatible with the 21AXP).

The conversion doesn't bother me (I did one and reversed it later when I found a usable 21AXP) as long as the person did it in a way that is easily reversible (what I did). IMO hacking things up so the conversion is hard to reverse hurts value.

[old_tv_nut]

Originally Posted by Electronic M

Some collectors are suspicious of the 21AXP22 going to air on them to the point of preferring one converted to an all glass tube (every all glass roundy color is compatible with the 21AXP).

The conversion doesn't bother me (I did one and reversed it later when I found a usable 21AXP) as long as the person did it in a way that is easily reversible (what I did). IMO hacking things up so the conversion is hard to reverse hurts value.

Exactly.

[reeferman]

You will also need;
Patience.
Sense of humor.
No set completion date.
Knowing when to walk away to fight/enjoy another day.
Remember, you have an OLD TV.
You will not achieve perfection, especially in convergence.
It has the capacity to deliver a beautiful picture.

[Tom9589]

I had a high school friend whose dad bought a $399 Muntz color TV. It was awful. Even with an outside antenna in a metropolitan area, reception was dismal. IIRC, the cabinet didn't even have a printed woodgrain pattern - it was just a dull gray.

There evidently was an intermittent contact in the tuner. The owner used the "slap-on-the-side-of-the-TV" method so many times that it had a hole in the side of the cabinet.

I worked on a number of Muntz B&W TVs, but never a color model. I consider myself lucky.

[JoeyPinball]

Before I even start, I want to get my hands on a second 21axp22, mainly to have in case of unexpected gravity.

[Penthode]

Originally Posted by JoeyPinball

Before I even start, I want to get my hands on a second 21axp22, mainly to have in case of unexpected gravity.

Have you tested the one you have first?

[old_tv_nut]

Originally Posted by JoeyPinball

Before I even start, I want to get my hands on a second 21axp22, mainly to have in case of unexpected gravity.

I suggest you put that on the list of things to search for continuously into the future, as you are more likely to complete the restoration first.