Requesting cateract removal info

[Phil Nelson]

I would like to hear results of any solvent experiments, too. The heat method seems scary/dangerous, and I don't have a lot of Kevlar suits, space helmets, or other protective clothing lying around the place :-)

Dipping the whole thing in a kiddle pool filled with -- whatever -- for a few days sounds much more relaxing.

Phil Nelson

[fsjonsey]

I was thinking, what about using your standard basement stationary tub filled with hot water? I imagine that warm water would loosen the PVA much faster.

[radotvguy]

Be very careful on removing a safety glass . I had a crt implode on my bench and it was only inches away from me . Wear safety glasses, long sleave shirt and be careful!!!!!!!!!!!

[radio63]

Originally Posted by radotvguy

Be very careful on removing a safety glass . I had a crt implode on my bench and it was only inches away from me . Wear safety glasses, long sleave shirt and be careful!!!!!!!!!!!

This thread:

http://www.audiokarma.org/forums/sho...d.php?t=184752

goes hand in hand with this one and shows the dangers one can face while trying remove cateracts from a CRT.

Gilbert

[Tomcomm]

Charles wrote: "There must have been some kind of official tool for this purpose, and there were CRT re builders all over the place. I can think of a half dozen in the West Los Angeles area. Some of them were just one oven and lathe in the back of a regular TV repair shop (such as West Coast TV repair on Sepulveda Bl in Culver City). So we should all keep an eye for articles, and for any stuff like that on eBay."

Ah yes, West Coast Rebuilders, located near the Culver City Drivein. I knew them well. I got all my rebuilds from them including the 21FBP22 in my 21CT55. It was really dark in there. I recall they even had a dirt floor, although I might be mistaken, senior memory and all. But I'm positive they used a red hot piano wire connected to a car battery to remove all face-plates before rebuiding. At $45 a rebuild they couldn't waste time on some of the dainty procedures described above.......Tom

[radotvguy]

Originally Posted by radio63

This thread:

http://www.audiokarma.org/forums/sho...d.php?t=184752

goes hand in hand with this one and shows the dangers one can face while trying remove cateracts from a CRT.

Gilbert

I do remember this posting .

I myself do not attempt to remove safety glass unless its in the soaking in water(kiddie pool ) way . That seem to be the best and safe approach for me . After having a crt implode once , i have not wanted to attempt with a heat gun again . But as i have read others like Doug have had success

[jeyurkon]

I tried the method I suggested using two 8" watch glasses. It worked well, except that it's difficult to control the lowering of the watch glass. I would suggest instead that if the CRT can be supported face down, to raise the lens up to it using a lab jack.

I also made a mistake in my message to JB5pro. When I estimated the volume needed I did pi*d**2 instead of pi*r**2 for the area. I was a factor of 4 too high.

[El Predicta]

If you don't mind paying $80 each + shipping, there's a former employee of Video Display Co. (now relocated) that might help. He's in Dallas and did a couple that turned out good for me last winter.

Larry

[kx250rider]

Originally Posted by El Predicta

If you don't mind paying $80 each + shipping, there's a former employee of Video Display Co. (now relocated) that might help. He's in Dallas and did a couple that turned out good for me last winter.

Larry

Does he have an oven and facilities to rebuild tubes at home, or just the cataract repair? I'll be in Dallas in the next few weeks, and I might pay him a visit

Charles

[polaraman]

Video Display moved their Dallas CRT operations to Pennsylvania and is no longer servicing CRTs there. Charlie started a thread about it here on Ak. They were rebuilding 21 inch roundies for $150. Not anymore!

Is this person rebuilding CRTs or just servicing the faceplate?

polaraman

[El Predicta]

Just the faceplates.

Larry

[bgadow]

After work yesterday I checked things out-it had been 48 hours. There really was no visible change over the last day. The pva that was exposed had turned a fatty white but there was no sign of delamination. I decided it was time for some gentle coaxing. I grabbed a handful of popsicle sticks and broke them in half. I started inserting them in the corners. I found that the top of the crt had slightly thicker pva than the bottom and thus I could insert them better there. The pva in those areas had softened, it seemed. Upon insert there were some bubbles in the area of insertion. I layed it back down in the water for another couple hours.

When I returned I spent a few minutes prodding the top corners with additional sticks. One corner in particular was responsive. In short order I had the situation shown in the first picture, an area roughly the size of my hand that had popped loose. I was being gentle. I know the crt faceplate is very thick and that did not concern me. The worry is that I have heard from several others about safety glasses that broke. Anyway, the other corners were not as responsive. I layed the glass back down for a few more hours.

At 10pm I went out with my flashlight and checked again. (I knew I couldn't stand waiting all night) After another few minutes of gentle prodding fully 1/4 of the face had popped and the other top corner was starting to loosen. I added additional sticks all around and went inside for about another hour.

When I returned the entire top half-more like the top three fifths-was delaminated. With the crt layed down I prodded and tugged and was able to feel the glass let go. It just took some gentle tugging to break the last bond-it was loose but rubbery.

I took these photos this morning. I left them in the pool for today because I didn't have time to work on it and the additional time under water will make it easier to clean the glass. I plan on trying double sided tape on this one. This is a spare crt that I just had in storage. It's not real strong on the tester but acceptable. It next goes back in the attic.

Is water the magic bullet? It's not perfect but, yes, it does work. I suspect eventually the pva would let loose entirely on its own without any prodding but what I did was gentle-not even as harsh as when I did one with a heat gun. If you have someplace where it can sit out of the weather you could leave it for quite a long time. The crt will float, sinking just enough to keep the faceplate underwater. The biggest advantage over a harsh solvent is that when you are done you can just drain it, and of course there are not the hazards involved with flammability. It may be that things could be added to the water to expedite the process-maybe lots of dish detergent? One issue with a solvent is that I doubt the vinyl of a pool like this would hold up to it. Finding a metal or poly container large enough might not be easy.

Between now and fall I am going to be working on a set with a crt that has the "gray" cataracts. I will try it in the pool-I suspect it will be quicker to respond if anything. I will report the results at that time.

[fsjonsey]

Originally Posted by bgadow

After work yesterday I checked things out-it had been 48 hours. There really was no visible change over the last day. The pva that was exposed had turned a fatty white but there was no sign of delamination. I decided it was time for some gentle coaxing. I grabbed a handful of popsicle sticks and broke them in half. I started inserting them in the corners. I found that the top of the crt had slightly thicker pva than the bottom and thus I could insert them better there. The pva in those areas had softened, it seemed. Upon insert there were some bubbles in the area of insertion. I layed it back down in the water for another couple hours.

When I returned I spent a few minutes prodding the top corners with additional sticks. One corner in particular was responsive. In short order I had the situation shown in the first picture, an area roughly the size of my hand that had popped loose. I was being gentle. I know the crt faceplate is very thick and that did not concern me. The worry is that I have heard from several others about safety glasses that broke. Anyway, the other corners were not as responsive. I layed the glass back down for a few more hours.

At 10pm I went out with my flashlight and checked again. (I knew I couldn't stand waiting all night) After another few minutes of gentle prodding fully 1/4 of the face had popped and the other top corner was starting to loosen. I added additional sticks all around and went inside for about another hour.

When I returned the entire top half-more like the top three fifths-was delaminated. With the crt layed down I prodded and tugged and was able to feel the glass let go. It just took some gentle tugging to break the last bond-it was loose but rubbery.

I took these photos this morning. I left them in the pool for today because I didn't have time to work on it and the additional time under water will make it easier to clean the glass. I plan on trying double sided tape on this one. This is a spare crt that I just had in storage. It's not real strong on the tester but acceptable. It next goes back in the attic.

Is water the magic bullet? It's not perfect but, yes, it does work. I suspect eventually the pva would let loose entirely on its own without any prodding but what I did was gentle-not even as harsh as when I did one with a heat gun. If you have someplace where it can sit out of the weather you could leave it for quite a long time. The crt will float, sinking just enough to keep the faceplate underwater. The biggest advantage over a harsh solvent is that when you are done you can just drain it, and of course there are not the hazards involved with flammability. It may be that things could be added to the water to expedite the process-maybe lots of dish detergent? One issue with a solvent is that I doubt the vinyl of a pool like this would hold up to it. Finding a metal or poly container large enough might not be easy.

Between now and fall I am going to be working on a set with a crt that has the "gray" cataracts. I will try it in the pool-I suspect it will be quicker to respond if anything. I will report the results at that time.

Thats great news! I have the exact same tube that I've been wanting to do since I got the TV. It has the yellow cataracts pretty bad around the top edges. This Zenith is my first tube color set, and its in one of the most hideous colonial cabinets I've ever seen, plastic woodwork and all. Beggers cant be choosers i guess? I've been thinking about having someone build a custom cabinet for it, seeing that the tube tests strong on all guns, and the chassis is in good original condition. Time to go to walmart for a baby pool, and maybe an aquarium heater to keep the water warm.

[captainmoody]

Great idea Bryan! Wow! That worked so well, I am now going to try it on one of my tubes. I always stayed away from the green pva problem ones due to the difficulty. Thanks to you, it looks like we have another way to keep them going!

[bgadow]

Yes, Captain, I figured I was just stuck with green halos because I really didn't want to try the hotwire trick. I'll add a couple observations: the real progress came when water started getting under the glass. Once one corner opened up I think the water was able to seep down. The pva is tenacious. It took some time to remove it all from the glass-with some of it I ended up taking a brillo pad to get it clean. One of the things that happens here is that the pva absorbs water. Even after a couple days underwater the crt face looked just like it did when I started. But by the time the safety glass came off the adhesive was white in color. I piled up the stuff and once it dried it was again yellowish/clear. It has a foul smell. I would warn anyone who tries this to take your time, don't force things. And keep your hand away from that ultor connection while you're moving that crt around!

I've posted a pic of the finished product.