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 Post subject: Re: 1949 Westinghouse H-223 Retrace Lines
PostPosted: Jun Sat 19, 2021 5:49 pm 
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Jackmach5 wrote:
Are you saying if I replace T4 with the primary of an audio output transformer, it might be a solution to the vertical problem? I know I’m probably simplifying it a lot but would this be a way to see if this current T4 choke may be the problem affecting the image? I didn’t realize the primary of an AOT was a choke.

The primary of a AOT will be a choke if nothing is connected to the secondary. Any coil of wire will be a choke of some sort. And with the secondary left unconnected the primary is just a coil of wire on a core. Now the core has to be suitable for the frequency in use. But the horizontal frequency is at the top end of what is normally considered to be the audio range. (It is in range for young people and not for older people).
Anyway this should be an interesting experiment to try. Don't remove the current choke, just haywire in a AOT and see what happens.

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 Post subject: Re: 1949 Westinghouse H-223 Retrace Lines
PostPosted: Jun Sat 19, 2021 6:44 pm 
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Ahh okay I will definitely try this when I’m back in town on Monday and post results. Thank you so much.


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 Post subject: Re: 1949 Westinghouse H-223 Retrace Lines
PostPosted: Jun Sun 20, 2021 12:16 am 
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It would be worth a try anyway. Especially if you have a transformer.
But audio output transformers come in different inductances and resistances.
It could be that what is in there now is a modified AOT.

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 Post subject: Re: 1949 Westinghouse H-223 Retrace Lines
PostPosted: Jun Sun 20, 2021 1:21 am 
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Jackmach5 wrote:
I tried turning T3 from all the way one way to the other and this was the result of each end of the coil. Vertical overlap scan is still there but not quite. Definitely excessive horizontal scan. T4 looks like it originally had an adjustable coil to it which doesn’t exist on this replacement. I’m so close to this restoration, I’d hate for it to end here. Anyone have a suggestion about a replacement T4 choke? Or a way to make it adjustable? I’m at a loss.


On this question, if you had some spare laminations from another transformer, These come in E and I shapes, you could tape a number of the I's together to get a block about say 1/4 to 1/2" wide, and hold across the exposed ends of the E shaped laminations in your existing T4 choke. This would drastically increase the choke's inductance.

But, I am suspicious that your replacement choke there is perfectly fine.

The reason is that if its inductance was too low, the problem would show up likely on the R side of the scanning raster, (if you had a test signal visible would show as compressed linearity) and without the test signal, the raster would tend to brighten up a little on the right , as the beam would spend more time there, and it is not doing that, so I think that replacement T4 is probably fine.

Looking at your raster images, the two photos show both fold around of the left side of the raster and the vertical bar, caused by the output valves coming abruptly into conduction, in a condition where either the grid drive to them is too high (excessive horizontal drive) or, when the damped current is too low a value to suppress resonances (hence the beam tracking over itself in the vertical white bar area, due to under-damped oscillation in the H yoke coils current).

So both of the problems you are seeing in the raster, are consistent with insufficient damped current on the left hand 1/3 to 1/2 of the H scan. So the first thing to check is the damper rectifier 6W4, and the components in its anode circuit where the damped current is returned.

Also it is important to determine if the H scan osc is running at about the correct frequency around 15.7kHz.


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 Post subject: Re: 1949 Westinghouse H-223 Retrace Lines
PostPosted: Jun Sun 20, 2021 5:03 pm 
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Location: Dallas, TX
A video of the CRT image was posted and it seems that the horizontal was locked in sync. However the video on the screen is very faint and the scene looked to be of dancing, so that wasn't the best choice for a test signal. Next time maybe he can turn the room lights down. There could have been a double image.

The SAMS info only indicated the resistance of T4 as 490 ohms, the replacement measured a bit higher.
SAMS doesn't give a Westinghouse part number, which is odd.
The Rider info indicates the part number is V-6455-1. Both schematics indicate T4 has a solid core, not air.

The OP stated he replaced the electrolytic and paper caps as well as resistors over 1 Meg that had drifted.
Maybe this means he didn't measure resistors below 1 Meg.
He did say he had ordered new horizontal output tube although they originals tested good for shorts and emission. I suppose one or both of them could have a problem not detected.
I noticed the damper tube has a dedicated filament transformer, maybe there is something odd about it.
There is a small capacitor in the yoke, could this cause the problem if it was open?
This is certainly a puzzler.

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 Post subject: Re: 1949 Westinghouse H-223 Retrace Lines
PostPosted: Jun Sun 20, 2021 10:37 pm 
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Got home and realized the resistor metal strip that is bolted to the chassis is shorted. Also, R98 which is supposed to be a 1500ohm resistor is testing at 8500ohms. So I ordered replacements and hopefully this will fix the issues. The damper is connected directly to that resistor strip so surely that will give me some good news when replacements come in.


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 Post subject: Re: 1949 Westinghouse H-223 Retrace Lines
PostPosted: Jun Mon 21, 2021 1:01 am 
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Jackmach5 wrote:
Got home and realized the resistor metal strip that is bolted to the chassis is shorted. Also, R98 which is supposed to be a 1500ohm resistor is testing at 8500ohms. So I ordered replacements and hopefully this will fix the issues. The damper is connected directly to that resistor strip so surely that will give me some good news when replacements come in.


I can see a green wire wound resistor in the area labelled as 8500 Ohms.

But definitely it is very important that the damper rectifier has good emission, that the resistor and capacitor in its anode circuit are the correct values and in good condition. Or there will be insufficient damped current and poor energy recovery. Under these circumstances it can produce the scanning raster defects you are seeing because it requires more H drive to get full width, producing the the vertical line, and commonly raster fold over on the left.

One thing it helps to remember; if the R side of the raster is inadequate or defective, likely the issue relates to the H output tube, its power supply & surrounding components. If it is the left side of the raster defective, likely its to do with the damper diode or its surrounding components. If both sides are defective or inadequate width, possibly the power supply internal impedance is too high (electrolytics defective) or voltage too low. And in rarer cases, defective transformers & yokes.

Not related to your vintage set, one interesting thing that has been reported with vintage computer VDU's, is that the rubber spacers or wedges that often space the yoke from the CRT bulb, break down & chemically attack the yoke windings, destroying the enamel and causing shorts. A video was posted a while back, that was filming the CRT face, right at the moment when the H yoke coils shorted out a section of the windings, a freakish event to have actually captured on video. If I can find the link, I will post it.

Here is the video,one of the H yoke's coils near totally shorted just near the end of the video, prior to that there were some small erratic disturbances:

https://photos.google.com/share/AF1QipM ... N1MGJwQTNB

or this link might work better:

https://photos.google.com/share/AF1QipM ... N1MGJwQTNB


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 Post subject: Re: 1949 Westinghouse H-223 Retrace Lines
PostPosted: Jun Mon 21, 2021 2:16 am 
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Acornvalve,

I see that other resistor measured at 8500ohms. I had to do a double take because i have basically two 5W resistors at 8500ohms. I don’t know why this resistor tests so high. Can these types of resistors drift that far? I ask because it looks like the original. I’ve heard there can always been problems with this old “sand” type resistors.

I’m very excited that the resistors tested out of spec and had those shorted resistors because I know I’m not at a dead end just yet. New resistors should be here Wednesday.

I also have two different damper tubes that test well with emissions. Both show the same vertical effect so I know it’s not the damper tube itself. Also wow, I didn’t know this effect on different sides of the screen were caused by two different things. I’m learning more and more with each reply. I’m so grateful you all have helped me through this. I can’t wait to show the restored result with everyone.

Also pretty crazy those spacers break down cause I’ve come across many of them and they all seem fine. Usually I’ve seen them made out of tough foam. Maybe I haven’t opened up an old enough computer monitor.


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 Post subject: Re: 1949 Westinghouse H-223 Retrace Lines
PostPosted: Jun Thu 24, 2021 12:50 am 
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Joined: Feb Thu 18, 2021 3:09 pm
Posts: 63
Big update. Replaced the resistor strip which consisted of two 10 watt resistors and I replaced two other 5 watt resistors, R97, R98. The video I posted is the result. Good looking image except for the macrovision lines. I’ve read how to add in another section in the circuit to remove the retrace lines but I think I’m happy with this image for now. The photo attached is from after I put everything back together. Lot blurrier so I think some wires are touching so I need to check that out.
What do you all think of the image? Is this the most I can expect out of a set like this?


Attachments:

[ Play Quicktime file ] trim.8EBEF9A4-285F-40AB-8F7C-DC9C1AFB09E0.MOV [ 3.15 MiB | Viewed 419 times ]
8EAF9C9F-E2AC-4B52-A004-01E4E5204D9C.jpeg
8EAF9C9F-E2AC-4B52-A004-01E4E5204D9C.jpeg [ 732.18 KiB | Viewed 419 times ]
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 Post subject: Re: 1949 Westinghouse H-223 Retrace Lines
PostPosted: Jun Thu 24, 2021 1:35 am 
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So with my signal generator, image looks pretty solid. When I hook up a VCR, image is very low contrast, blurry, and showing double from fiddling with the horizontal hold. See both images to compare


Attachments:
DDE591FC-3666-447C-8A19-F40D852C33BD.jpeg
DDE591FC-3666-447C-8A19-F40D852C33BD.jpeg [ 736.54 KiB | Viewed 414 times ]
2FA8BB54-27D1-44B5-8279-AF3026E755BF.jpeg
2FA8BB54-27D1-44B5-8279-AF3026E755BF.jpeg [ 634.28 KiB | Viewed 414 times ]
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 Post subject: Re: 1949 Westinghouse H-223 Retrace Lines
PostPosted: Jun Thu 24, 2021 3:41 am 
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Location: Dallas, TX
Some odd distortion on the screen is evident in the picture using the test pattern. Does the image vary when using the test pattern?
There could be some instability in the sync circuit.
Early TV were watched in a dimly lit room. The screen would not be nearly as bright as modern tubes.
You might at least turn the lights down a bit when you photograph it.

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 Post subject: Re: 1949 Westinghouse H-223 Retrace Lines
PostPosted: Jun Thu 24, 2021 8:46 am 
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Notimetolooz wrote:
Some odd distortion on the screen is evident in the picture using the test pattern. Does the image vary when using the test pattern?
There could be some instability in the sync circuit.
Early TV were watched in a dimly lit room. The screen would not be nearly as bright as modern tubes.
You might at least turn the lights down a bit when you photograph it.


The vertical lines on the test pattern slowly move in a wavelike pattern. Horizontal is pretty locked. The image actually can get very bright, I can’t turn it up because of the retrace lines becoming way too visible.


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 Post subject: Re: 1949 Westinghouse H-223 Retrace Lines
PostPosted: Jun Thu 24, 2021 11:03 am 
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It should have a LOT more contrast than that.

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 Post subject: Re: 1949 Westinghouse H-223 Retrace Lines
PostPosted: Jun Thu 24, 2021 1:55 pm 
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irob2345 wrote:
It should have a LOT more contrast than that.


I agree. I’m gonna pull it back out and mess around with the coils.


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 Post subject: Re: 1949 Westinghouse H-223 Retrace Lines
PostPosted: Jun Thu 24, 2021 3:56 pm 
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To some degree the horizontal sync circuit determines when a line starts (compared to the image signal).
Some hum in the sync circuit can vary that timing by changing the trigger point. The slow change you may see is the result of a slight difference between the 60Hz power line signal and the sweep frequency (the modern vertical frequency is actually about 59.94Hz).

I think you have the width adjusted too large. The picture should just fill the vertical space in the mask in the cabinet. Remember the image is rectangular and wider than it is tall, it doesn't really fill a round screen.
Sometimes the sweep on sets can just be able to cover the distance without distorting. It sort of looks like there might be some foldover at the top of the screen.

Too bad there is no scope images in the service info. You could check whether the video signal at the CRT is large enough. You should check the DC voltages on the CRT socket anyway. I was hoping that replacing the multi-resistors would help more with the brightness-contrast since it looks like it would effect the bias on the CRT. The new video amp tube could have helped with that also.

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 Post subject: Re: 1949 Westinghouse H-223 Retrace Lines
PostPosted: Jun Thu 24, 2021 4:34 pm 
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I'm going to look into the resistance of the brightness pot because wiggling it back and forth changes the brightness which isn't good. I'm going to mess around with it more when I get home from work. I'll bring the image in more. I wonder if any of the peaking coils may be bad. They look fine and don't look like those cement looking tear drops you see in RCA sets.

I'm going to check the voltages on the CRT. Strange the contrast isn't better. There are adjustable video IF coils. Wonder if that should make a difference in the picture.


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 Post subject: Re: 1949 Westinghouse H-223 Retrace Lines
PostPosted: Jun Thu 24, 2021 6:32 pm 
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Don't adjust the coils in the IF. You can quickly really mess things up and fixing that requires specialized test equipment. Take a look at the alignment instructions in the Sams to see what is involved.

You can adjust the fine tuning knob on the tuner to get better sharpness. If it seems that you could get a better picture if only the fine tuning had more range, you can adjust the oscillator adjustment in the tuner to shift the range of the fine tuning. The alignment instructions will show you where that is.

What happens when you adjust the contrast control?

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 Post subject: Re: 1949 Westinghouse H-223 Retrace Lines
PostPosted: Jun Thu 24, 2021 9:07 pm 
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I hooked up a DVD player rather than a VCR since I believe I was getting that macro vision interference. The picture is now pretty steady and looks good for me. I messed with the audio coils and it came in a bit louder which is nice. I’m happy with this image so far.


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[ Play Quicktime file ] trim.215DBBAD-6458-4AEF-A4B5-FA9F5E695105.MOV [ 3.27 MiB | Viewed 356 times ]
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 Post subject: Re: 1949 Westinghouse H-223 Retrace Lines
PostPosted: Jun Thu 24, 2021 10:58 pm 
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Did you ever replace the shorted 6AH6 video amp tube?


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 Post subject: Re: 1949 Westinghouse H-223 Retrace Lines
PostPosted: Jun Fri 25, 2021 12:34 am 
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bandersen wrote:
Did you ever replace the shorted 6AH6 video amp tube?


Yes! I replaced it as I replaced the shorted resistor strip


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