CTC 11 advice

[Travis]

Hi, I have been looking around this site for quite sometime and have never really said anything. I have been accumulating dead TV's with the thought that I am going to let loose and fix them all shortly.

I had decided that I want to start with my CTC 11. It's in the bedroom and color, so it should be fun to watch. It is clean. The only damage I can see in the antenna terminal is broken. T have checked the CRT and it tests very good. I did notice a hairline crack on the base and that it is starting to get loose. I am seeking some advice on how to proceed. I have checked the tubes and found seven of them to be weak or bad. I haven't powered it up at all. My variac is waiting by it, but I don't want to kill it. It looks like some of the caps have been replaced. Could I replace the bad tubes and try powering it up slowly?

I will post a pic of it soon though.

Thanks!

[Charlie]

Hi Travis... welcome to our group!

Before bringing up your set slow, take a quick look at your flyback transformer to see if you have any burn marks or lots of melted wax. Those RCA flybacks are not the greatest at times. If it looks okay, then you could proceed with the soft start.

Make sure to remove the horz output tube before bringing it up slow. Monitor the feel of your electrolytics to make sure none of them are getting hot as you bring up the juice. They should remain relatively cool... or slighty warm at the most. If you feel a can getting warm or hot... say by the time you get up to half power, you might need to replace the electrolytic before continuing further.

If all goes well, you should start to get some audio out of the speaker by the time you get to 80 volts... give or take. If you get any 60 cycle hum out of the speaker, you'll need to go change lytics.

After getting it up to full power and letting it run for a while, continue monitoring lytics and for any other sign of trouble. If all seems well, then you could power it down and put your HO tube back in to see what you get on the screen. Check that flyback again also after it has ran a little while.

If you have the time, it might be wise to yank the chassis first to take a quick look underneath so you can see if there were any apparent failures such as blown caps. If you see alot of those "black beauty" caps, it would be wise to get those swaped out for new caps. Old black beauties always seem to cause problems. While you have the chassis out, it would be good to spray some contact cleaner into the various controls.

My cTC11 had a shorted rectifier diode in it when I brought it up slow. Every time I got it up to 35 volts on the variac, it tripped the breaker. I'm glad the breaker actually worked... as many times they do not. If it turns out that you only get lit filaments and nothing else, the reset button may be tripped.

It will be a good assumption that some lytics will need changing, if not all of them. Although it might still power up pretty well.

Good luck!

[peverett]

A good starter test for shorted silicon recifiers is to ohm them out with an ohmmeter. If the short is gross, it will show up here prior to powering the set up.

I usually use the 20k ohm scale. There should be a reading with the positive/negative leads oriented one direction and an open when it they are oriented the other way.

In some cases, the electrolytics around the diodes may case erroneous readings, so disconnect one end to verify a short.

[Travis]

I put the new tubes in today and also looked at the flyback. It seemed to look ok, nothing burnt or melted. I am going to pull the chassis tomorrow. I tried to power it up and got nothing. I guess that means either the circuit breaker is shot on the power switch is. What size fuse would be adequate here? I looked at the schematic and it gave an RCA part number. I thought I could at least put a fuse in temporarily.


Thanks again

[Travis]

I found the amperage when I took the circuit breaker out. I took the chassis out today. Since I got nothing when I powere d it up, I am looking for this heater fuse. The schematic says it's a copper wire. There looks to be something of that sort on a barrier strip by the power transformer. Is that it? I am having trouble tracing the transformer wires. None of them are even close to the original colors :-)

[Chad Hauris]

Check to see if the 6BK4 and CRT are lit, they are on a different filament circuit than the other tubes.

A lot of the time, the power switch goes bad, especially if it is a push-pull type. Put the ohmmeter across the power cord plug prongs (unplugged from outlet) and see if you get continuity (a few ohms) when the power switch is turned on.

[Charlie]

Also, if you're getting NOTHING, does this set have automatic degaussing? If it does, it needs to be plugged in. If the degauss circuit is open, nothing will operate.

I have two 11's. Seems I recall a varistor under the chassis in the main line circuit (this was not for degaussing). The varistor itself had come apart, giving no juice to the set. Seems if I recall, it looked in the schematic that this varistor would simply give the tv a soft start when powering up. Since I didn't have a replacement, I just removed it and jumped the connection. All was fine after that.

[G.B.]

I have a mint 1962 RCA CTC 11 works like new. Travis , Hope you get yours gong soon. When you get it going You should have sound then Picture in 60 seconds. If longer may have weak High Voltage Tube.....

[frenchy]

Originally Posted by Charlie

I have two 11's. Seems I recall a varistor under the chassis in the main line circuit (this was not for degaussing). The varistor itself had come apart, giving no juice to the set. Seems if I recall, it looked in the schematic that this varistor would simply give the tv a soft start when powering up. Since I didn't have a replacement, I just removed it and jumped the connection. All was fine after that.

My 10 had that black varistor starting to bust up with about 1/3 of the disk missing and it was affecting the set, not getting enough juice. Then it finished popping apart and really killed the juice so I just soldered the leads together. So check the ohmage across it with the set unplugged and it should be like in the 100 ohm range.

[holmesuser01]

When I got my 10 in 1975, the varistor was the only reason that it wouldn't turn on. It is located on the parts side of the chassis under the top near the power transformer. It will probably have discolored the chassis metal above it. Mine has worked like a dream all these years with just a few tube replacements.

I recently purchased a CTC 11 on eBay (6217663879). The set is in pretty good condition with a strong CRT. The double on and off / color switch has a lot of play. It might need to be replaced. Also I needs schematic for the set. Based on the chassis and model number(213g225mv)the Sams book said that it is the 550-2. Assistance will be appreciated.

[Don Lindsly]

The globar type resistor in series with the power transformer primary provides a controlled warm up and, in conjunction with the varistor, provides the degaussing current. As the globar warms up, its resistance drops so the voltage applied to the varistor and degaussing coil drops slowly. That prevents the degaussing process from ending on a strong peak and disrupting the purity. They were often sold as a set when the TV was popular.

Don

[Chad Hauris]

I don't think the ctc-11 has degaussing but it does have that varistor for limiting the "turn on" surge current. I have a ctc-11 which worked when first tested but is dead now, and the varistor is probably the culprit.

[G.B.]

This is correct Chad my 1962 CTC-11 does not have degaussing so I do it with a degauss coil & don't move the set. I have a question about the Channel Selector Knob. Does it have a gold button in the center of it to match the other Knob's. I think mine fell of & in the center. I can see the tuner shaft in the middle.

[G.B.]

Nobody could tell me about the CTc 11 Knob ?