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  #1  
Old 06-03-2018, 05:22 PM
Electronic M's Avatar
Electronic M Electronic M is offline
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Smile CTC-5A acquired!...It wants to live.

First off a hardy thanks to Dave for giving me a very good deal/trade on this set.




Originally I only wanted the 21AXP22 from this set, but since Dave was okay with selling the whole set and I like the compact table model cabinet I ended up going for the whole thing.

My plan this morning was to variac it for a laugh (it has an 80's-90's antenna balun on it so I figure it was worth a try), then mercilessly remove the CRT and swap it into my MUCH rarer Motorola 21CT2B (which is more deserving of a 21AXP)...However, it is so close to working properly, that I've decided to delay the swap till I change some capacitors (hopefully that will be done later tonight)...I think it deserves a chance to show a relatively perfect pic at least once on its original CRT before I swap the tube over to the Moto.

The variac got me a raster (20KV HV right off the bat), then video with no synch, then playing with the internal slug and reducing blue screen got me a synched color picture albeit kind of a poor one. This is the oldest color set I've seen give me this good of a reaction to a variac power up in as found condition. I'm surprised and very happy that it has surpassed my expectations.



The original tuning knob was cracked, and I thought I had a replacement. It turns out I had 2, but neither is the exact same color as the original, but they are close enough to not bother anyone. It is interesting that RCA had so many shades of dark brown.


Oh, ya no with a chassis noomber like CTC-5A I'm surprised they didn't make it a Canada only chassis, Eh? Badum tiss.
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Old 06-03-2018, 06:35 PM
mbates14 mbates14 is offline
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ooooo. Pretty. Only color set I have is my zenith roundy and its in rough rough shape.

Hopefully it comes good! the Flyback is good so thats a plus.
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Old 06-03-2018, 07:28 PM
EdKozk2 EdKozk2 is offline
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Hi Tom,
Glad to see the crt works so well. Don't forget to save all the left over parts after you remove the crt. Never know when you or someone could use them later.
Ed
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Old 06-03-2018, 08:14 PM
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Once I swap the CRT I plan to follow the great instructions in your thread Ed and convert it to a all glass CRT... I'll do my best to make it reversible, and of course keep all the spare mounting hardware with it for the future. You never know when even the most arcaine part will suddenly become needed(though in my experience it is usually within a month of getting rid of it ).
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Old 06-04-2018, 12:53 AM
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Changed all the papers on the H and V boards, all the papers under chassis and all but 3 sections of can lytic. It had 2 extra cans zip tied under chassis that I had to re-replace on principle. I also did the vertical lytic, and every can with an obviously dead section. I made sure to change the lytics right off the rectifier too since the power trans has leaked a very noticeable quantity of wax...Much more and I'd have expected it to be bad if I had started the recap before doing the variac power up.

Vert fills the screen and is linear now. Neither of the syncs are as stable as they should be (no change there), monochrome video is weak and color is prone to noise, but it is behaving better overall...I figure once I go over the remaining boards it will be happier.
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Last edited by Electronic M; 06-04-2018 at 12:59 AM.
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Old 06-04-2018, 07:05 PM
EdKozk2 EdKozk2 is offline
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Tom,
The power transformer on my CTC5f gets quite hot after about an hour and a half of usage. At the ETF Wayne , old tv nut told me because the transformer is potted it tends to run hotter. I've been operating my set with a voltage regulated isolation transformer.
Ed
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Old 06-04-2018, 07:21 PM
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I finished the recap earlier, and now am sort of satisfied with the picture.


Seems like the alignment is goofy. On rabbit ears and my TX it does not get enough signal to produce sufficient contrast, and chroma is very noisy, it only seems to get sound on the ragged edge of the picture finetuning, and AGC does not seem to do anything. Feeding it directly with a VCR gives plenty of contrast and less chroma noise also optimum chroma, luminance and sound get close enough to have all fairly decent to optimum simultaneously (also the AGC has an effect). Can't totally ditch the chroma noise though (thinking about it maybe the garage fluorescents are interfering).

I think it is about time to harvest the 21AXP22.

Quote:
Originally Posted by EdKozk2 View Post
Tom,
The power transformer on my CTC5f gets quite hot after about an hour and a half of usage. At the ETF Wayne , old tv nut told me because the transformer is potted it tends to run hotter. I've been operating my set with a voltage regulated isolation transformer.
Ed
Good to know. I need to keep an eye out for more of them. I've got 4 but 5 of the 4 are needed by sets (it would be more if I did serious watching on more of my collection).
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Old 06-04-2018, 10:04 PM
EdKozk2 EdKozk2 is offline
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Tom,
Those screen shots look good. The crt I'm using came out of a dumpster set. I can see the difference a good green gun makes. The sound on these set leaves a lot to be desired. The whiter the screen the more buzz. There is a buzz control on the I.F board, it helps a little. The AGC control on my set is able to overload the signal.
Ed
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  #9  
Old 08-03-2018, 12:29 PM
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Well, I finally got tired of it sitting dismantled in the garage taking up 3X the space it should, and got round to installing a glass CRT.

Looking at EDs modification closer I decided to try a different approach since I did not want to cut a hole in the original 21AXP22 plastic shroud.

I've had a spare 21FJP22 bracket kicking around since buying a CRT from Miniman82 (nick) ~6 years ago... Initially I thought I'd rob the back plate drill some holes in it and get really long bolts to reach it, but that seemed like it would not work well with the existant bolt locations in the cabinet or the chassis mounting considerations. The strap with 4 brackets riveted to it seemed like a better choice...I noticed there were holes in the strap that suggested alternate rivet points for two of the brackets. Those points looked right so I drilled out the rivets of two of the brackets and moved them. They were close but not right so two of the brackets are not riveted to the first band. The first band effectively does nothing other than helping keep the two unriveted brackets snug against the plastic rim of the mask.
The 4 brackets themselves had to be modified a bit too...Specifically the top brackets had to have a pinch of and the bottom brackets had to have a good portion of the outer corners of the bolt flange ground off so they would not hit the top of the cabinet or interfere with the chassis. There was also a hook on the inside of the brackets designed to grab the face of the CRT that had to be bent in so that the brackets could get close enough to the rim for the bolt holes to line up with the bolts.

IMG_20180801_154527235 by Tom Carlson, on Flickr

I then realized the first strap wraps around the plastic rim of the mask holding the 4 brackets against it but does not do anything to snug the brackets against the CRT...At that point there was a small gap between the rubber on the brackets and the bell of the CRT. This gap was big enough for the tube to be quite loose in its mounts yet not able to come out of those mounts...I fixed that by adding a second strap (which I had to shorten by cutting and bolting back together) around the rear groove of the brackets...This allowed me to tighten the brackets so the rubber on the brackets touches and holds the CRT securely, provides better side support of the CRT and serves to prevent the brackets beading outward and releasing the CRT. I took a discarded piece of round outer insulation sheath from a discarded section of power tool cord and placed it over the edge of the second strap where it touched the CRT side for cushion. Bringing me to my final solution which holds the CRT quite securely and accommodates the chassis (note bottom brackets not ground in that pic as I did not notice they needed it yet when I took that pic).
IMG_20180801_162321910 by Tom Carlson, on Flickr

The yoke seems to grip the neck firm enough on its own that unless I need to drive the set somewhere (or pick it up and shake it violently) it should stay in place fine with no clamps or brackets.
It seems happier with a strong signal.
IMG_20180801_215453170 by Tom Carlson, on Flickr


I briefly considered adding the rear plate of the 21FJP mounting assembly hoping to add automatic degauss to a CTC-5 , but soon realized it would only make it harder to get the chassis in....Which already required two adapters be made to lay two signal tubes on their sides.
IMG_20180801_162515678 by Tom Carlson, on Flickr

My hat is off to the mechanical designers of RCA on this model...It blows my mind that they found a way to fit a 21AXP22 and all its purity hardware etc. into such a compact package in such a clever way...
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  #10  
Old 08-03-2018, 02:29 PM
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I can explain some of the issues such as the sound, this "5A" is the "special", not the "5N" "deluxe" and sound circuits were one difference and color demodulators was the other.

It looks great regardless, this is the Aldrich model I believe. My grandparents had one until 1971, without the UHF.
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Last edited by DavGoodlin; 08-03-2018 at 02:33 PM.
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Old 08-03-2018, 02:29 PM
WISCOJIM WISCOJIM is offline
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Quote:
Originally Posted by Electronic M View Post
Well, I finally got tired of it sitting dismantled in the garage taking up 3X the space it should, and got round to installing a glass CRT.
And just when I stumble upon a hoard of 21AXPs.

.
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  #12  
Old 08-03-2018, 04:11 PM
Electronic M's Avatar
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Quote:
Originally Posted by WISCOJIM View Post
And just when I stumble upon a hoard of 21AXPs.

.
If you're not joking please Email me...I could use a couple of decent AXPs. I purposely made this and the FJP conversion on my CTC-4 easy to completely reverse.

Otherwise, good humorous irony.
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Old 08-03-2018, 04:44 PM
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init4fun init4fun is offline
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I'll be interested to see the right angle adapters you make for the two small signal tubes . The glass bell is that much bigger than the metal cone ?
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  #14  
Old 08-03-2018, 05:08 PM
Electronic M's Avatar
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Originally Posted by init4fun View Post
I'll be interested to see the right angle adapters you make for the two small signal tubes . The glass bell is that much bigger than the metal cone ?
One of the other recent CTC-5 threads had a better method/tutorial on making the right angle adapters than what I did. They used 2 wafer sockets and stuck the right gauge wire through one socket (to make a 9-pin base) bent it cleanly and wired it to another socket.
I did not have either the wafer sockets or the right gauge of wire on hand so my adapters are VERY UGLY...Picture the bottom of a dud 9-pin tube carefully hacked off with a bench grinder and a 9 pin PCB type socket joined with a mess of sloppily bent and soldered wires that look as though Picasso and Salvador Dali teamed up to do the interconnect work. I was going for fast, free and functional.

The problem with the glass CRT here is the mounts. One signal tube hits the second strap in the middle the other hits the strap under the bracket...If the strap was gone I could probably install both tubes normally...Though the one under the bracket would have to be removed any time the chassis was being removed or installed since it would live in the hollow of the bracket.

The glass CRT is deeper between the face and the bell than the AXP. The bell of a glass CRT also takes up more room than a metal CRT, but both are the same length socket to screen so the bell and difference in mounting methods are the only two issues to contend with.
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Last edited by Electronic M; 08-03-2018 at 05:13 PM.
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  #15  
Old 08-03-2018, 06:23 PM
EdKozk2 EdKozk2 is offline
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Looks Great Tom .
Ed
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