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#16
11-02-2014, 09:42 AM
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Re. the low focus CRT, I have never seen one produce good focus, period. No matter which of the 3 taps was used, they always had soft focus. Just the nature of the beast.
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#17
11-06-2014, 10:01 PM
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Well, you guys were right about the focus. :p
I checked out those focus taps today and it does not even matter if the plug is plugged into a hole in the block, the focus does not change at all... Also, on my set the red seems a orange, and the yellow is a bit green. Is there any way to adjust thins? I think it has something to do with the gray scale being out of adjustment. According to the Sams I am to turn each screen controls clockwise until I see a faint line on the screen with there service switch on, and the color turned off I also turned the CRT bias switch all the way to the left unless I was not able to get a line. My question on this is when it says turn until a line is just hardly visible how intense does it mean? Am I looking for a ghost or a distinct sharp line? Eventually I would like to learn how to adjust the convergence and purity correctly...
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Lebe dein leben für dich selbst **Searching for any all tube or hybrid or color portable sets would consider some early solid state color too**
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#18
11-07-2014, 04:41 AM
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This set does have a service switch, its over by the focus thing.... It's the
one with only 2 positions.... As for the colors.... The Yellow, that is a little green.... It's suppose to be green.. Only new flat screen Sharp tv's have a dedicated yellow.... Not sure how that's going.... For purity adjustments, First turn color off... you are best to leave the service switch set to normal, full screen. Then with the brightness set somewhat mid point, move the VHF tuner to a point between stations. You will have to pick a mid-cam position, not easy to keep that will give you a blank-white screen, no snow.... I don't remember who, maybe RCA, but their service switch was 3 position and one of the positions was a full white screen with no snow.... Doing it with that line is just stupid.... they were smokin something when the decided the line was the way to go- Then turn down the green, and blue screen adjustments. Set the 2 drive adjustments somewhere mid-point. (or just don't touch them yet.) You should have a red screen.... There are purity rings on the yoke easily visible near the screw clamp. Move one around and see if the red improves. If it does not easily improve, you may have to move the yoke forward or back, but try not to do that... I'm not sure if they have only a red ring, or other colors on that set, so remember where each is, and don't go nuts turning everything, just move one a 1/4 turn then put it back if it don't change a lot..... I guess a few of my brain cells for purity on that set are going.... going.... If you get a good solid red, then do the same with green, and blue.... Then re-check. If you have the Sam's refer to the procedure they have for purity as this set is off my memory, and it's been more than 20 years. Once you get pure single color from each gun done one at a time, you can bring up the red till you see it, then green, then blue, and compare it to a nice well lit piece of white paper, when you get it right, then you have basic purity and gray scale set up.... Convergence is next, for this set I would use the tic-tac-toe board, don't bother with the dots, and just do a overall with the convergence magnets on the tube... I'm pretty sure the convergence board is not marked, you will need to refer to the sams for the pots and coils.... .
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Yes you can call me "Squirrel boy" Last edited by Username1; 11-07-2014 at 05:01 AM.
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#19
11-07-2014, 08:26 AM
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Quote:
never helps, cant see a difference. When brand new they look a lot better but in a few years they loose it. A clean & balance usually helps a lot BUT there is risk & it dont last long as a rule. I would go with the squirrel & do a set-up on it & use it for learning. Also keep in mind it will never look "good" in strong lighting. One other thing to look at is the IF & video amp tubes. They can test OK but still rob you of the detail & contrast, this looks a bit washed out to me on top of the other issues. 73 Zeno 
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#21
11-07-2014, 09:30 AM
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I disagree with username1's instructions on how to set the grayscale. The problem with simply setting the drives at a nominal midpoint and adjusting the screen controls for a good looking blank white raster is that it is possible to have the lowlights off quite a bit when you are done. Use the barely visible line in service mode to get the lowlights neutral, then adjust the drive controls to get good whites on a blank white screen or a regular picture. There can be some interaction, so return to the service position and faint line to recheck the screen controls. This should get you a neutral gray from shadows to highlights.
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#23
11-07-2014, 10:30 AM
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I was kinda hoping that if he just didn't mess with the drive's yet that he
might just get away with not touching them..... I have found that after a screen setup, the drives look better when adjusted watching a show in B&W, as in just turn the color off.... If they need to be done, starting at a mid point just gives him a range up or down... Good starting point for someone who has possibly not done this before.... Anyway, there was a good point made, this is a good set to do some learning on since doing all those alignments could be a good learning experience.... That's what I did with my Toshiba.... I did get a nice picture, good color, just not sharp like a small screen should have gotten.... old-tv-nut: If you got insight in the type of setup with his purity rings you might wanna pipe in on that too, I just don't recall fully what he might have there.... If you got the Sam's follow it.... No brightner.... Can't see hv lead, it's blocked by the conv. board. They have a good clip and full cover. Anyway joseph this will be a good set to learn on, it is well made, has lots of adjustments, almost each stage has a single tube, there are transistor stages, I think as mentioned IF stages are I think transistorized, as is with the first color and osc, I'm pretty sure the demod's and finals are tube....? .
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Yes you can call me "Squirrel boy" Last edited by Username1; 11-07-2014 at 11:12 AM.
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#24
11-07-2014, 11:10 AM
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Thete is no brightner on it, if you ate talking about the cap on the tube it was removed when the set was powered up on a variac. I need to post since pictures of the set now. I might pay a picture of the color bars when i get hone from school. ..
Also, I did not mess with the drives at all yet. Just the screen controls, the bias switch, and the service switch. That's everything I have touched. Tonight, i am going to check out the purity and see if that needs work, then i will do the gray scale adjustments and go from there.
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Lebe dein leben für dich selbst **Searching for any all tube or hybrid or color portable sets would consider some early solid state color too** Last edited by josephdaniel; 11-07-2014 at 11:33 AM.
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#25
11-07-2014, 12:59 PM
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On the service switch collapse to line, and tweak screens procedure I go for a viewing brightness level in a VERY dimly lit room. I turn up the red first then add enough green to get a yellow line then enough blue to get white. If the blacks look tinted afterwards I dial down the prominent color or dial up the missing color. If the whites look tinted after tweak the drives.
The more ya do it the better of a feel ya get. And some sets color demods make a slight tint of some type improve apparent color accuracy.
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Tom C. Zenith: The quality stays in EVEN after the name falls off! What I want. --> http://www.videokarma.org/showpost.p...62&postcount=4
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#26
11-07-2014, 06:00 PM
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So i just tested the CRT and it tested pretty good, or so I think so. Here are the results Green 750,Blue 825, Red 900 all of this on a scale from 0-1000
I checked the purity and it wasnt too bad so I will leave it alone for now. The static cinvergence is WAY WAY off. When i put the grid pattern on i could see tge red shiftedto the right a LOT, the blue was shifted up a little bit too. I will work on that tonight. I think that is part of the reason the picture seemed so horrible last night.
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Lebe dein leben für dich selbst **Searching for any all tube or hybrid or color portable sets would consider some early solid state color too**
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#27
11-07-2014, 09:00 PM
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Hi Mr. Daniel,
I usually do this--I set customer color control to zero. Then, tint control to halfway. Contrast at zero, and brightness at half. Evaluate what the issue is--is there too much red or green in the dark parts of the pic? or are the whites tinted? Use drive controls to set shading of high-contrast components, after making shit sure that the background levels are set so that a low brightness scene has zero amount of color bias..it should be blackish grey after you're done...and the whites shall be white as possible after touching up the drives. Convergence is next.
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#28
11-07-2014, 10:44 PM
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I got the color setup batter, I also figured out the purity and convergence. I could not get the screen to converge towards the top of the screen, but I assume that has something to do with the dynamic convergence...
I still have one major problem. The brightness is extraordinarily weak despite the fact that the CRT tests pretty good... At halfway up on the brightness control I get no picture. I have to turn it almost all the way up. I was also having problems with the picture washing out. Any ideas on what this could be? On the plus side, I am not getting pretty good color, I got the purity and static convergence done. The set has been running now about 6 hours now with no drift or anything so it seems to be pretty stable for the time being... The focus problems I was having are now mostly gone since I setup the static convergence. Before I did the convergence if a white title came on the screen it would be so blurry I couldn't read it at all, and there would a ghost if you will on different sides for different colors... When I put on a crosshatch pattern it became even more pronounced...
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Lebe dein leben für dich selbst **Searching for any all tube or hybrid or color portable sets would consider some early solid state color too** Last edited by josephdaniel; 11-07-2014 at 10:54 PM.
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#29
11-08-2014, 08:44 AM
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You can cheat the brightness with the bias switch BUT you
may be just covering a dog turd with leaves. I would measure the CRT voltages at abt 2/3 bright & cont. then compare with sams. The set does lack snap in the video & you are getting your setup lines so may be a video amp prob. I am missing this manual so if you can post the CRT end it would help us. When you get to the convergance remember to go back & forth to the center every few steps. Ignore the sides when doing the center. & it will never be perfect ! You want it not noticable at normal distance & an active pix. 73 Zeno
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#30
11-08-2014, 11:15 AM
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The bias switch is already all the way over, I will post the sams tonight and check the CRT voltage this evening.
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Lebe dein leben für dich selbst **Searching for any all tube or hybrid or color portable sets would consider some early solid state color too**
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