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 Post subject: Re: Tech-Master NIB TV Kit #5516
PostPosted: Jan Fri 06, 2017 6:06 am 
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Joined: Jan Sun 18, 2015 5:01 am
Posts: 796
Location: Waxahachie Texas
Tom Schulz wrote:
I noticed in your last photo of the screen that you have some black showing at the edges of the screen. CRT TV sets are designed to over scan, at least a little. The idea is that a momentary dip in line voltage should not cause any black to show at the edges. Perhaps you are trying to reduce the width too much. Just how much too wide is the picture? If you have other CRT TVs, how does it compare with the other sets?


Tom,
The over scan is several inches on each side.

Hmmm, I haven't checked the other 2 TV's that I have that are working. I'll check them tomorrow.

I'm thinking of trying to round up another CRT, perhaps a 17" one. We'll see.

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 Post subject: Re: Tech-Master NIB TV Kit #5516
PostPosted: Jan Fri 06, 2017 6:09 am 
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Location: Waxahachie Texas
Audioman wrote:
I think that reducing the screen grid voltage on the horizontal output tube is the way I would go. It will reduce the current through the tube and flyback and I would not use the sleve. same results smaller width and unfortunately the hv wil go down too but as I stated lower current is a good thing lower temperature on components and no metal under the yoke for it to arc to and ruin the yoke.



I did try increasing that resistor. I'll keep that in mind as the way to go. Reduction of current would be a good thing.

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 Post subject: Re: Tech-Master NIB TV Kit #5516
PostPosted: Jan Fri 27, 2017 5:19 am 
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Joined: Jan Sun 18, 2015 5:01 am
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Location: Waxahachie Texas
When watching TV, I have to have the "Contrast" 99% all the way up. I'm considering adding or taking away some resistance in the contrast circuit. Here is the schematic and the contrast when watching TV the resistance is almost all the way down and the wiper is moved closer to the tube.

I'm thinking of reducing the R53A from 1K to something like 680 ohms. Would this put the contrast control more off all the way? If not, what could be done.

BTW, the schematic shows the pot value as 2K, but the kit came with a 5K pot.


Attachments:
100_5746a.JPG
100_5746a.JPG [ 114.9 KiB | Viewed 599 times ]

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 Post subject: Re: Tech-Master NIB TV Kit #5516
PostPosted: Feb Tue 07, 2017 5:31 pm 
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Joined: Jan Sun 18, 2015 5:01 am
Posts: 796
Location: Waxahachie Texas
Just wanted to let you guys know that I borrowed a 17" CRT but instead of a 70 degree the borrowed one is 90 degrees.

When I tried it, sure enough the picture was well within the CRT screen. After some adjusting and such I got the picture close to the outer edges of the screen. Of course this is without the sleeve. The 90 degree CRT didn't quite work well enough, so back in went the 70 degree CRT with the sleeve.

Looks like I have a 80 degree yoke!

It's all adjusted and playing well now. Life is good.

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 Post subject: Re: Tech-Master NIB TV Kit #5516
PostPosted: Feb Wed 15, 2017 12:19 am 
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Joined: Jun Thu 25, 2015 3:21 am
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glad you got it working


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 Post subject: Re: Tech-Master NIB TV Kit #5516
PostPosted: Feb Wed 15, 2017 2:09 am 
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Joined: Jan Sun 18, 2015 5:01 am
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Location: Waxahachie Texas
Thanks Thomas

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