Restoring CT-100 #B1111566 - Videokarma.org TV - Video

ChrisW6ATV · #1 06-04-2011, 12:49 AM

Hello-

I bought RCA CT-100 number B1111566 in May 2011 from its former owner, who had owned it at least since 1989 and had had it restored and working about that time. I intend to restore it again as time and money allow, and I will post progress here. You can read the earlier details about the set in this topic:

http://www.videokarma.org/showthread.php?t=251001

I am going to make a numbered list of the items that need attention during the process, starting with the known issues I want to fix and adding others later as I find them, or as I solve bigger problems and let smaller ones get added. The description of the set when I got it was, the sound is working but it has no raster, and there is arcing in the HV cage. I plan to connect the chassis to my Sylvania CK3000 test jig for servicing.

Known initial issues:
1) Missing cabinet back.
2) HV cage cover missing (a replacement was installed but it has fewer ventilation holes than the original).
3) Four control panel knobs missing, replaced by other knobs.
4) Focus rectifier replaced by solid-state diode.

Other issues will be added to the list once I remove the chassis and evaluate it in the next few days. This is a joy to be able to work on this piece of American history. Despite 30 years in the video display repair industry, I feel like the teenage boy in the movie Sixteen Candles when he is in the driver's seat next to a cute girl, and his friend says "now, this is a ROLLS ROYCE..."

Sandy G · #2 06-04-2011, 06:41 AM

Ah HATE Yew....-Yosemite Sam, Esq.....(grin)

ChrisW6ATV · #3 06-08-2011, 08:32 PM

Yeah, I understand, Sandy. I hope you find one and have the budget for it at some point. This one just worked out after several years of hoping and trying in my case.

Dave A · #4 06-08-2011, 10:24 PM

Chris, PM me your address for a complimentary cage cover. Other parts from a junk chassis...no fly...are available if you...or anyone...need if they are still there. Spread the wealth. Dave A

Sandy G · #5 06-08-2011, 10:58 PM

Quote:

Originally Posted by ChrisW6ATV

Yeah, I understand, Sandy. I hope you find one and have the budget for it at some point. This one just worked out after several years of hoping and trying in my case.

You DO realise that I was just being my usual snarky, facetious self, don't you ? I would NEVER begrudge a fellow VK member on scoring such a valuable & desirable set. Way better for one of US to get it than some "Civilian" who'd turn it into a-SHUDDER-goldfish tank or some other horror. While I'd LOVE to be the keeper of a CT-100 someday, the fact is, I have neither the technical smarts to maintain one, nor the financial resources to ever seriously consider it in the 1st place. If I HAD one, I'd worry & fret myself to death that something terrible, dreadful, 'n' awful would SURELY happen to it...Yeah, I know, don't call you "Shirley"...(grin)

ChrisW6ATV · #6 06-09-2011, 12:00 AM

Yes, Sandy, I knew it was all in fun.

ChrisW6ATV · #7 06-09-2011, 12:01 AM

Quote:

Originally Posted by Dave A

Chris, PM me your address for a complimentary cage cover. Other parts from a junk chassis...no fly...are available if you...or anyone...need if they are still there. Spread the wealth. Dave A

Dave-

Thank you for the generous offer! I am sending you a message now.

ChrisW6ATV · #8 06-09-2011, 12:57 AM

I removed the CTC-2 chassis and checked it over. It appears that rather than a restoration, it was repaired in the 1980's but most of the original capacitors are still in place. Here is a picture:

Many parts have been replaced, but there are lots of old electrolytics and paper caps in there.

For you CT-100 experts out there, are these some of the peaking coils that go bad? One that is not visible in this picture has green corrosion on one of its leads. The picture above shows one white and three brown coils; I think I have read that maybe the brown ones will be OK? In any case, is there a good source for the needed coils?

The transformer wrapped in black tape is jammed between the other transformer and the back end of the tuner housing. I found out this is an added-on filament transformer. My tests of the CRT (in the original topic for this set) showed it has a heater-to-cathode short, so this part has to stay, but I hope I can find a better/more-secure way to mount it.

Overall, this is going to be a bigger project than I expected at first, but I have no hesitation about getting the job done. However, I have not previously done a full/major restoration of a chassis before, so I am going to pick another set of mine to do a "complete" job on first before taking on this top-of-the-chart one. That way, I will have a good amount of hands-on experience before jumping into the CTC-2. Likely, it will be an RCA 8TS-30 I bought a year or so ago. I will post updates here as I move forward.

miniman82 · #9 06-09-2011, 10:11 AM

Quote:

Originally Posted by ChrisW6ATV

is there a good source for the needed coils?

Shameless plug: http://videokarma.org/showthread.php?t=251288

Not sure if the coils are the same from the 2 to the 2B, if they are this would make super easy one stop shopping.

Steve K · #10 06-09-2011, 11:22 AM

Hi Chris:

It looks like a lot of those caps have already been replaced (other than the electrolytics). I would go and replace all the peaking coils and take Nick up on his offer. Some of the ones from the 55 may be different, I don't remember. I have restored 6 CT-100s, you'd think by now that I would have the parts memorized! It is a fun set to work on.

Steve

JCFitz · #11 06-09-2011, 12:14 PM

Quote:

Originally Posted by Sandy G

You DO realise that I was just being my usual snarky, facetious self, don't you ? I would NEVER begrudge a fellow VK member on scoring such a valuable & desirable set. Way better for one of US to get it than some "Civilian" who'd turn it into a-SHUDDER-goldfish tank or some other horror. While I'd LOVE to be the keeper of a CT-100 someday, the fact is, I have neither the technical smarts to maintain one, nor the financial resources to ever seriously consider it in the 1st place. If I HAD one, I'd worry & fret myself to death that something terrible, dreadful, 'n' awful would SURELY happen to it...Yeah, I know, don't call you "Shirley"...(grin)

You and I are in the same boat on the financial part. I have the tech smarts to restore one but I'm way too poor to even dream of CT100 ownership unless one fell in my lap for free and that ain't gonna happen.If only I had lived in a different time.

People that repair tvs for a living don't make the kind of money they did years ago.
They barely make more than the cashier down at Walmart or a burger flipper at Mcdonalds.

Phil Nelson · #12 06-09-2011, 01:45 PM

Quote:

Originally Posted by Steve K

Hi Chris:

It looks like a lot of those caps have already been replaced (other than the electrolytics).

If those mylar "maroon drop" caps were installed in the 1980s, I'd leave 'em alone for now. All original electrolytics must go, of course.

When I got my CT-100, I knew that the previous owner had recapped it. He passed away a couple of days after I picked up the TV, so that's about all I knew. It took some detective work to figure out what else had been done, and what work remained.

In the parts bins that I inherited from him, I noticed drawers and drawers of little inductors, which initially struck me as odd. I eventually figured out that he had replaced the peaking coils, as well as many resistors and even some cabling. Since he had never gotten the set into playable condition, none of this work had really been "battle tested." I spent loads of time nervously tracing connections and triple-checking for mistakes. All of his work was correct, and very neatly done, which was a great relief. Len deserves a lot of the credit for bringing this TV back to life.

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

ohohyodafarted · #13 06-09-2011, 02:47 PM

Chris,

The white peaking coils are the ones that usually are the bad ones. The brown ones are usually OK. You can easily tell if the coil is bad by lifting one lead and measuring the DC resistance which is on the Sams parts list.

Pete Deksnis · #14 06-09-2011, 10:29 PM

Quote:

Originally Posted by ohohyodafarted

Chris,

The white peaking coils are the ones that usually are the bad ones. The brown ones are usually OK.

Amen! That's a solid fact. Chris, you've received a number of suggestions so far. Let me add mine: I see only one white inductor on your chassis; it's a little distance from between the red and blue boards (they contain the circuitry for the matrix and R, B, and G amps). Check the continuity of that white inductor. If it's open replace it; if not, leave it. Replace it when it opens, if it opens.

My reason: I personally would rather have the original RCA part in the chassis with its factory-defined specifications. I can see the 6.7-uH coil in the Q filter was replaced sometime in the past in your chassis. On my site I had a page describing how the function of that stage deteriorated when the factory part was replaced with the NOS 1954-RCA-specified replacement part listed in SAMS.

Also, in my estimation, those three video boards have been restored; I would not repopulate them unless you found out-of-spec components.

Enjoy your CT-100.

Pete

ChrisW6ATV · #15 06-10-2011, 03:09 AM

I appreciate all of the help and suggestions from each of you-there is a great group of people here on VK!

I worked from the Sams schematic to my chassis and found 15 coils in the video and chroma circuits, matching Nick (miniman82)'s total. Of those, two are definitely bright white ones (L47 and L50; one of them is hidden under a large electrolytic between the green and blue video gain control shafts). Five others (L28, 42, 46, 51, and 54) have been replaced in ways that look less than ideal (series or parallel combinations, or mid-air joints). There have been plenty of resistors also replaced by combinations, and I would like to get those cleaned up ideally as well. Nick, I may get in contact with you about your coil set.