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  #346  
Old 01-30-2017, 10:23 PM
Kevin Kuehn's Avatar
Kevin Kuehn Kevin Kuehn is offline
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Keep in mind that maximum contrast on these old sets is a bit of an illusion that relies heavily on the ambient lighting in the viewing room. Of course the screen can never get darker than it is when it's off for a given ambient light level. So considering the relatively bright room lighting in your below picture, I'd say your set is putting out about the best contrast it's capable of. The modern set next to it likely has a darker screen filter, yet to me it looks more washed out than your Tech Master. Also remember that the contrast of the old program material was not all that consistent. Your set has a darn good picture with your DVD test pattern on it, so just be careful that you don't go chasing rainbows in an attempt to correct for a lousy picture that your OTA converter box may be responsible for.


Last edited by Kevin Kuehn; 01-30-2017 at 10:38 PM.
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  #347  
Old 01-30-2017, 11:32 PM
Crist Rigott Crist Rigott is offline
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Kevin,
Thanks for those thoughts. You are right about chasing rainbows!

What I eneded up doing is to eliminate R109, thus reducing the lowest value the pot can go to 93 ohms instead of 93 + 39 = 142 ohms. This gives me acceptable contrast when watching some of the older programs on MeTV. The contrast control is almost but not quite at its full stop. I live with it. What really helped was putting the 3.3K across the 5K pot to get the listed 2K. This gives me a little more dial to adjust the contrast.

Working on how to do the cabinet right now. I'm going back and forth on what I want to do. Once I settle on that then I can "lock" down the CRT mounting.

BTW, I've gone to a 17" CRT. I'm using a NOS rebuilt RCA 17LP4B. Thanks to El Predicta here on the forum. The reason is because I'm going to use the "sleeve" to control the width and when I do that, the HV goes down. So I thought the 17" CRT would handle the reduced HV better and thus give me better service for the life of the TV.
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  #348  
Old 02-07-2017, 10:30 AM
Crist Rigott Crist Rigott is offline
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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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  #349  
Old 02-07-2017, 11:08 AM
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Kevin Kuehn Kevin Kuehn is offline
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Interesting. It's hard to say exactly what the specs are for the yoke that was included with your kit. And I wouldn't put it past a kit manufacture of that period to use some oddball combination of surplus components.
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