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 Post subject: 1966 RCA Color TV Transformer Meltdown: Can It Be Restored?
PostPosted: Jun Sat 06, 2009 3:37 am 
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Joined: Jun Fri 05, 2009 4:20 pm
Posts: 135
Location: Eastern PA
A lightly used 1966 RCA color console set, one of the first with a rectangular picture tube (21-inch, I think), was (unfortunately) stored in a damp garage. Some years ago, I tried to turn it on. Got a faint picture, then the set went dead and I smelled burning wax. The transformer had melted down, leaking into the wood console case and onto the floor.

Here's the question: If I provided the chassis number, could a replacement transformer be found? What are the chances that the rest of the chassis components and picture tube survived the transformer meltdown? Can this set be saved?

There is a non-electronic problem as well: the familiar "cataract" effect around the picture tube glass.

There is no practical need to restore this TV, just the pleasure of bringing back to life the set I watched as a teenager. The cabinet is in excellent shape, good enough to sell to a theatrical prop house.


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 Post subject:
PostPosted: Jun Sat 06, 2009 4:06 am 
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Location: MS
A chassis and model number would help. Someone on here may have the sams photofact and can provide you with the part number. RCA flybacks from this era were known to fail this way. When you change the flyback, it would be a good idea to monitor the horizontal output tube cathode current. If it's running high, you'll need to find the problem as this will burn up a flyback. Also, you need to check for horizontal drive at the control grid of the horizontal output tube. If horizontal drive is not present or insufficient, the horizontal output stage will draw excessive current and burn up the flyback.

another thing you probably want to do is replace all electrolytic caps. These can and will fail over time and can cause some serious problems.

Before you do anything, obtain a CRT tester to make sure that the CRT is good. No need to spend a lot of time on the chassis just to find out that the CRT is toast.


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 Post subject:
PostPosted: Jun Sat 06, 2009 5:45 am 
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Location: Eastern PA
Thanks for that. Chassis is CTC-24A. I think the CRT survived. The chassis looks good and there are no fried components visible from above. Everything looks like nothing ever happened. No char marks inside the tubes, except for two brownish-black flare marks from the large power beam tube that sits next to the flyback. The marks are symmetrical.

(As you can tell, I am not a tekkie.)

Do you know the ball park for a flyback from this era?

Also, is this model of any historical value as the immediate successor to the "roundies"? I realize it's no CTC-100, but it's an interesting console model than screams 1966-67.


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 Post subject:
PostPosted: Jun Sat 06, 2009 6:41 am 
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Joined: May Mon 11, 2009 12:19 am
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Location: LA
I just finished getting a 1966 ctc17 going I found on the curb. If you can find the flyback I would guess it to be around $50. As said you really need to check the current if you do replace it, a failed 20cent resistor can cause it to over heat and fail again.

I fixed this one for the same reason, we had one when I was a kid. It really works very well.

I had a thread going on a zenith with a similar issue you may want to read through. Some great help here.. http://antiqueradios.com/forums/viewtopic.php?t=109875


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 Post subject:
PostPosted: Jun Sat 06, 2009 6:54 am 
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Location: MS
I wanna say that the CTC17 was the first rectangular set. I'm not familiar with the CTC24 chassis; but, I do have a 23" color TV/stereo combo using the CTC25 chassis that is in need of much TLC. Before I found the CTC25, the oldest color RCA's that I'd worked on were the CTC38's and 39's of the late '60's-early '70's.

As far as the cost of a flyback for your set, I'd expect to pay anywhere from $25-$40. I think I paid $32 for the CTC25 flyback and $37 for a CTC38 flyback. These prices included shipping. Be aware that it may take quite some time to locate a flyback. It took me over a year to find a flyback for my CTC38 (which I have yet to install). Those '60's RCA color sets were rough on flybacks; therefore, much of the old stock is already used up. If you can, try to locate a Thordarson replacement. I've heard that these were actually better than the original RCA transformers.

Another common problem in these old RCA's was poor soldering. This is especially true of the tube sockets and ground connections where the PC boards attach to the chassis. And, don't forget about the ever popular 6GH8A tubes. RCA color sets were full of them and they are usually bad by now. These tubes are in the chroma circuit.

As far as any value for this set, it's hard to say. I wouldn't go to the trouble of restoring it unless you plan to keep it. There are collectors of '60's and '70's rectangular sets; but, location may be a problem. I will tell you that those older RCA's made a good picture when working right.


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 Post subject:
PostPosted: Jun Sat 06, 2009 6:55 am 
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Location: Eastern PA
Thanks. Will read your thread.

Set is missing the volume control knob. If I don't restore it to working condition, I might clean up the cabinet and use it as a curio. Do you know a source for knobs for '66-67 vintage RCA "New Vista" color TVs? Thanks.


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 Post subject:
PostPosted: Jun Sat 06, 2009 7:04 am 
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Location: MS
www.moyerelectronics.com has many NOS RCA and other brand parts. They may have the parts you need for this set. Otherwise, a wanted ad in the ARF classified section and ARC magazine may yield some results.

One thing I forgot to mention. When you get this set going, I'd add a fuse to the horizontal output tube cathode circuit. This way, if something goes wrong that causes the horizontal output tube cathode current to increase, the fuse will blow before burning up other things.

Oh, and we would like to see some pictures of this beauty, if possible.


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 Post subject:
PostPosted: Jun Sat 06, 2009 7:10 am 
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Location: Eastern PA
I'm such a Luddite... how do I get a picture from my computer onto this site?[/img]


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 Post subject:
PostPosted: Jun Sat 06, 2009 7:42 am 
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You have to have the picture hosted somewhere else on the internet (photobucket, ect.), then you link to it here by putting the url for it between the (img)(/img) thingies.


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 Post subject:
PostPosted: Jun Sat 06, 2009 7:51 am 
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I'll take some digital snaps and post them to my blog site if I can't post them directly. Thanks.

You know, with a 40-inch HDTV in the house, I'd probably never watch this old set even if it still worked. This is obviously about something deeper... "Rosebud..."


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 Post subject:
PostPosted: Jun Sat 06, 2009 9:39 pm 
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Joined: May Mon 11, 2009 12:19 am
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Im going to check the cathode current on my rca because the flyback is getting kinda hot. I will document it and post everything and pictures here in the next few days.


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 Post subject:
PostPosted: Jun Sun 07, 2009 2:09 am 
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Didn't some sets use a Belfuse (chemical fuse) in the cathode of the horizontal output? I'm tempted to say some Zenith sets...

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 Post subject:
PostPosted: Jun Sun 07, 2009 4:36 am 
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I'm sure the Zenith sets did; but, the large RCA's that I've worked on didn't. It's strange that the portable RCA series string color sets (like the CTC36, 53, etc.) had a fused HOT cathode.


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 Post subject:
PostPosted: Jun Sun 07, 2009 4:48 am 
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HuggyBear wrote:
Didn't some sets use a Belfuse (chemical fuse) in the cathode of the horizontal output? I'm tempted to say some Zenith sets...


No. That was in the lv power supply.
Bill Cahill

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 Post subject:
PostPosted: Jun Sun 07, 2009 1:05 pm 
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The CTC 17 was the first rectangular set...

That 24 is one of the first to use the seven 6GH8s, not one of RCAs better ideas...

Tom


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 Post subject:
PostPosted: Jun Sun 07, 2009 10:17 pm 
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Stupid non-tekkie question:

I have a vague memory of plugging in this set after the meltdown and seeing all the other tubes glowing but getting no pic, no sound. How stupid would it be to try that again?

Is that possible if the transformer is gone? Could that be an indication that something else melted down years ago and I am assuming it's the transformer? It's not worth it to me to get this set evaluated unless there's a good chance it can be restored without costing me an arm and leg. The chassis with tuner would be a real b*tch to remove from the cabinet, and the whole console weighs a ton...

I'm working on those pics. Also if anyone here can source me a volume knob, that would be great. I think all of the RCA big-tube color sets used this knob in '66-68. I am going to make a '50s-60s "room" with some old furniture. electronics and such and make use the cabinet as a curio... Nothing like living in the past, eh?


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 Post subject:
PostPosted: Jun Sun 07, 2009 10:36 pm 
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Location: LA
I think you should make a good attempt to fix it. I see so many old cabinets with the guts removed and they are basically useless.

Mine has a really good picture and its very usable. If I ran across it at a yard sale I would buy it right up.

If you send me the photos I can post them.


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 Post subject:
PostPosted: Jun Sun 07, 2009 11:06 pm 
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It's possible that the shorted transformer opened a resistor in the B+ circuit, killing the whole TV. It's also possible that the circuit breaker has tripped or is defective. The latter was the case with my CTC25. I will tell you that these old tube sets are usually more forgiving when something goes wrong. Let something go wrong with a modern TV and the whole thing might fry.

I'd still try to save this TV if possible. You'll likely either have to do the work yourself or find someone who enjoys working on vintage electronics do the work for you. Most present day TV shops won't touch anything with tubes. Heck, many of the current "techs" are not old enough to know what a vacuum tube is. One of our local shops will not even accept any kind of CRT TV for repair. If it's not LCD, DLP, or plasma; they will refuse to repair it. I think by the mid-late '80's, most shops around here stopped repairing tube sets.


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 Post subject:
PostPosted: Jun Mon 08, 2009 12:15 am 
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Location: Eastern PA
I went into a Radio Shack and asked if they still carried vacuum tubes in their catalog, and the kid said, "For a vacuum cleaner?" This is not a joke.

The tuners on these TVs were awful (no automatic fine tuning), and now, with the end of analog, the set's analog tuner only could be used with cable, and I understand that's going to end in a year or two, or as soon as the cable companies can get away with it.

Question is, if the tubes still glow, what does that mean in terms of the transformer? Because I think the last time I checked, everything was glowing but the CRT and no audio.

Being a videophile, it would be neat to have an example of how color TV used to look back in the day... I remember being impressed that this set's black and white was clean, with little to no green edge bleed indicating a convergence problem... Also, the detail on hair and such was impressive, if not the skin tones, which typically were off a bit.


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 Post subject:
PostPosted: Jun Mon 08, 2009 12:40 am 
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I'm getting a little confused by this thread. Probably because of my lack of knowledge about RCA models.

It sounds like you're asking whether the power transformer could have died and most of the responses seem to be about the flyback. Does this model have a power transformer or is it a hot chassis? If it has a power transformer, can you tell whether the wax came from it or the flyback?

Anxiously awaiting photos...

John


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