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-   -   RCA CTC 24 Vertical Output (http://www.videokarma.org/showthread.php?t=275192)

RCAmark1 08-08-2022 05:44 PM

RCA CTC 24 Vertical Output
 
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I’ve just purchased a 1966 RCA Mark I, New Vista, CTC 24, Caulfield HH-856, TV and Stereo console in very nice shape. I haven’t got in to it too deep yet, but at first inspection it powers up and the turntable works, the stereo works and the TV powers up. But the TV picture looks like the vertical picture is collapsed (if I’m using the right terminology). The picture tube is only showing a thin white line in the center of the screen. Not sure where too look first for the problem?

I have a schematic for the CTC 24 and I see on the PW200 the vertical OSC and output.
Not sure if this was a common problem or not and that it might just be tubes or caps.
I haven’t open up the back yet and found the PW200 for a visual inspection to see if there is anything burnt .

Any help to point the right place to look or knowledge of this issue would be greatly appreciated.

Electronic M 08-08-2022 06:08 PM

First off turn the brightness down to the MINIMUM necessary to see the line. If you run it for more than a few seconds with that bright line you can burn the phosphor and be stuck with a permanent dark line across the middle of the screen when you get your vertical deflection working.

Vertical deflection failure (what has happened to your set) happens when a component fails in the vertical stage or you loose B+ to the vertical circuit. A quick-ish way to troubleshoot it is to run the set and measure the voltages on the pins of the vertical tube and compare them to the schematic.

The parts typically fail in the order most common to least: the 2-3 electrolytic capacitors (distinguished by being polarized) in the vertical, the vertical tube it's self, the rest of the vertical caps, circuit board ground solder joints(as well as tube socket solder joints and the sockets), resistors, the vertical transformer and or yoke. If there's no B+ the issue would be in the power supply instead of the vertical stage.

It's not possible to tell you which exact part has failed with the information you have provided so far... measurements and testing are needed to narrow the issue down.

Do you have the schematic/service manual for the set from Sam's or RCA?

Let me know if you need clarification.

old_coot88 08-08-2022 06:15 PM

Try working the Service switch for a few cycles.

dieseljeep 08-08-2022 08:18 PM

Quote:

Originally Posted by RCAmark1 (Post 3243672)
I’ve just purchased a 1966 RCA Mark I, New Vista, CTC 24, Caulfield HH-856, TV and Stereo console in very nice shape. I haven’t got in to it too deep yet, but at first inspection it powers up and the turntable works, the stereo works and the TV powers up. But the TV picture looks like the vertical picture is collapsed (if I’m using the right terminology). The picture tube is only showing a thin white line in the center of the screen. Not sure where too look first for the problem?

I have a schematic for the CTC 24 and I see on the PW200 the vertical OSC and output.
Not sure if this was a common problem or not and that it might just be tubes or caps.
I haven’t open up the back yet and found the PW200 for a visual inspection to see if there is anything burnt .

Any help to point the right place to look or knowledge of this issue would be greatly appreciated.

Are you sure about the chassis number? The CTC24 was the cheapie chassis used in the entry level models! Two stage IF and 6GH8's galore.
That set looks like a CTC28, a better model!

damen 08-08-2022 08:49 PM

The HH-856 uses the CTC-21 chassis. The vertical circuit is very similar to the CTC-24, but the part location numbers may be different.

dieseljeep 08-31-2022 10:10 AM

Quote:

Originally Posted by damen (Post 3243685)
The HH-856 uses the CTC-21 chassis. The vertical circuit is very similar to the CTC-24, but the part location numbers may be different.

I forgot about the CTC21 chassis! I have one! A very impressive set.
It is in excellent condition and under contract with RCA Service Company until the end. The rebuilt CRT is labeled RCA Service Company, so it must've been under contract.
It's obvious that the set was a well loved by the original owner! :thmbsp:


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