#1
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Color 21" Cataract removal
Using the combined wisdom here I'm going to remove the safety glass from an RCA round color tube. Being this is not the sticky agent, I will use the clothespin method. I was able to remove some of the material from the edges to make room for the "shims" Hand applied only till snug with equal pressure all around. The CRT is face up in the south Florida sun and I will check it every half hour or so and look for the "fingers" and attempt to keep an equal pressure.
This is out of a CTC-16 of another VK member |
#2
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Great pics!
Out of curiosity, what happens to the safety glass when you fully detach it? One for the bin or does it clean up? I've never seen that on an Australian set, but any things possible. Not sure if plastics had improved by the time we had TV or not.
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Four Predictas down, now to score a Continental. |
#3
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Success!
Went to check on it and noticed no change so I checked the tension on the cloths pins and found a couple that were loose. I heared a noise when walking away and went back to look and noticed a wave of fingers slowly moving accross the face of the tube and got a shot of it. By the time I got to a better angle for a second photo there was another noise and some of the clips fell out. The glass lifted right off intact. woo hoo.
Cleanup time. The hardest thing was not messin with it to hurry it along. I'm not sure what the surface temp was at the time but I was not able to keep my hand on the face while checking the wedge tension. |
#4
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The old glass
Hi Down Under. The saftey glass, is glass, in this case and will cleanup well like the face of the CRT. With the filler material gone it will not provide full protection as designed but is certainly better than nothing. Don't believe I've ever seen plastic bonded to a CRT face for safty other than a few small size CRT's in tiny battery sets.
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#5
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once you can see the fingers form you are on the way, they accelerate as there is less and less stuck to unstuck surface. The key as you can see is not to hurry it up, that's when glass breaks. I would also recommend you allow the tube to cool slowly, maybe put it out of direct sunlight. I dont think it would be a good idea to take the hot tube directly into a aircondioned house and esp not to wipe it down with any liquids until its at ambient temp. |
Audiokarma |
#6
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Next steps
Yup, I thought of that also. It's cooling slowly in my garage for now. The safety was cool so I cleaned it up. I feel like the dog that caught the car, now what.
The tinted glass is slightly frosted on each side and if I hold it up to another CRT and look from the other side resolution is slightly degraded. Is there any handy solution to this challenge or do we just decide that it's better than having the cataract and be grateful? There comes a moment that we must realize we can't always get water out of a rock. |
#7
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They did make non frosted clear ones but it would not look correct. Just install the one you have to make it look authentic. It may degrade "some" of the resolution but will still have a fantastic picture. It will look better than having PVA in there since(when new) that is not perfectly clear either. Put some thin black weather stripping around the edge of the CRT and use packing tape to hold it down and seal it up like the original. Some use double sided tape and/or clear RTV silicone. The way I do it takes WAY less time and is much easier and has no issues and mistakes can be fixed easily.
__________________
"It's a mad mad mad mad world" !! http://www.youtube.com/user/mwstaton64?feature=mhee |
#8
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I don't think you will really notice the frosting that shows up now that the PVA (or what ever it was) is gone. I just replaced by putting some one sided sticky foam tape (about 1/4" thick and about 3/8" wide) around the perimeter of the crt, then set the lens on top, and used some packing tape to seal it all the way around, careful to not let it hang over too much on the sides, the top and bottom is not a problem due to the mask.
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#9
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Looks great Dave.. Now that this is done, I'm still looking for a brightener for this tube..
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#10
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One method to brighten it up would be leave the smoked safety glass off. Once the bonding agent has been removed it offers little to no 'safety' anymore.
I take it the emissions is low to the point you cant get a line on one of the colors with the bias at max and the screen all the way up? Once it has gotten to that point its life is very short, maybe a few hundred hours max. A brighter will help but accelerate the demise. |
Audiokarma |
#11
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The blue is a bit weak and effects the grey scale when bright is adjusted or what ever image is going on, on the screen.. When we tested the tube, the emissions when much higher when filament voltage was increased.. All we need is a brightener and the project is done..
This is the same set in this thread I started months ago. http://videokarma.org/showthread.php?t=254422 Last edited by tvcollector; 07-28-2012 at 03:57 PM. |
#12
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Looking good even with the frosted glass. Focus is good. Emission is low for blue, the other guns check decently but emission ballance between the 3 are very wide indeed. If I boost the fillament to just under 7 volts on the tester, it makes a world of difference. Once I get a booster I will evaluate and possibly even lower the voltage to this level for an acceptable picture and maximum life. As we all know due to manufacturing inconsistencies of the day CRT life can be a coin toss. I've seen CRTs last several months with a brightner as well as several years. With the exeption of present day running time the variables were set into play 45 years ago and it is what it is and is out of our control. Gray scale tracking and blue emission will get a shot in the arm and I suspect this CRT has some decent run time left.
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#13
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Learn something every day - I didn't know the frosted ones were frosted on both sides. The effect of the inner frosting might be reduced when the PVA is intact, but if it looks OK now, run with it!
Thanks for posting this! |
#14
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seems like you could use the autoformer out of a later model color brighener. It would not be plug and play but would prob work ok (you would need to wire it in with the filament leads). It would prob run hot as I assume the older CRT's had a higher filament current than the later ones, but that may work anyway as it would mean the voltage drop would cause the boost to be less, closer to what you are looking for anyway. If you dont leave it on for long periods I would think the overloaded autoformer would not be a danger. I have a GE roundie that needs such a boost that I may try this out on.
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