I worked for a monitor manufacturer for 13 years we used those CRT's with and without the bonded face plate and it was added by the manufacturer to give the etched anti glare surface. It did give extra protection but the bare CRT met all implosion requirements.
Is it correct that older CRTs (maybe pre-1980's) do not meet implosion requirements without the bonded face plate, whereas more modern CRTs meet those requirements regardless? I thought part of the reason for the bonding was to create a barrier between the face plate and the tube. The face plate looks like it serves as both containment and a cosmetic barrier.
I used to take old tellys to bits when I was a kid.... and my dad used to dispose of the tubes by deliberately imploding them over our dustbin... and I don't think anyone can comprehend the sheer violence of a CRT implosion until they experience it. Pieces of glass were thrown out of the "detonation" sometimes to a distance of 30 meters!
Yes they can be very dangerous. I spent 7 hours today making this video to try to help people and yet there is still a baby that gives the video a thumbs down without commenting why. Without people like you that have an honest interest in electronics it would be pointless.
@@JerryWalker001 Don't worry about the thumbs down Jerry, you have one of the best channels about retro electronics and it seems that your knowledge is endless. Keep up the good work.
It is easy to get a CRT not to implode, you just break the evacuation pip on the thin end of the neck, this way the vacuum is safely removed. Then the glass can be broken quite safely without the risk of implosion.
I've read anecdotal info that the 'jelly' adhesive layer is part of the safety mechanism itself; however, what you said in regards to that layer helping absorb shock so it doesn't transfer from the face plate to the tube itself, makes sense. Still, I do wonder if part of the reason for the 'jelly's' thickness is to do the reverse and protect the glass face plate from the tube itself: if the tube implodes, that shock and the resulting flying shards of glass would first have to get through the 'jelly' before hitting the face plate. Since the face plate is still glass itself and can shatter, I'm led to believe that removing the 'jelly' layer does reduce to an extent the protection. I heard of someone replacing the 'jelly' with a curved sheet of Lexan, but that sounds quite difficult to create. Also, Lexan could yellow or cloud with age. If someone still has CRT manufacturing equipment and can reproduce the final step of injecting the area between the tube and face plate with fresh 'jelly,' that would be great.
Yes the internet is full of anecdotal 'advice'. A few mm of soft 'jelly' will make little difference. If in doubt then do as I have and try breaking a few old CRT's to see what really happens. In some designs which used the same base tube there was no jelly and the face plate was fitted to the machine itself rather than the tube. Also try braking the face plates if you want to see where the strength is. The main advantage of the layer when it is clear is that it reduces diffraction of the images which you get with an air gap. Having said that you can leave the tube untouched if you do not mind being unable to see the image.
@@JerryWalker001 Interesting to know that some designs involve a face plate not adhered to the tube itself. Which models are those? The CRT I am dealing with is from the early 1990's and is a computer monitor; it has a very tiny cataract that looks like an air bubble, much like you'd see behind a poorly applied window tint. I don't even know whether or not the tube's assembly employs 'jelly' - all I know is that the tube is a Trinitron. I am still debating when it comes to fixing it. To begin with, it might be extra difficult to lift the face plate (if there is one) given the damage to the presumed 'jelly' layer is limited to that one spot.
I worked for a monitor manufacturer for 13 years we used those CRT's with and without the bonded face plate and it was added by the manufacturer to give the etched anti glare surface. It did give extra protection but the bare CRT met all implosion requirements.
Is it correct that older CRTs (maybe pre-1980's) do not meet implosion requirements without the bonded face plate, whereas more modern CRTs meet those requirements regardless? I thought part of the reason for the bonding was to create a barrier between the face plate and the tube. The face plate looks like it serves as both containment and a cosmetic barrier.
I have repaired a lot but I have never seen this before. thank you for explaining.
I used to take old tellys to bits when I was a kid.... and my dad used to dispose of the tubes by deliberately imploding them over our dustbin... and I don't think anyone can comprehend the sheer violence of a CRT implosion until they experience it. Pieces of glass were thrown out of the "detonation" sometimes to a distance of 30 meters!
Yes they can be very dangerous. I spent 7 hours today making this video to try to help people and yet there is still a baby that gives the video a thumbs down without commenting why. Without people like you that have an honest interest in electronics it would be pointless.
@@JerryWalker001 Don't worry about the thumbs down Jerry, you have one of the best channels about retro electronics and it seems that your knowledge is endless. Keep up the good work.
@@marshalljmp800 I totally agree! His videos are a wealth of knowledge and we are so fortunate that he shares it with us!
It is easy to get a CRT not to implode, you just break the evacuation pip on the thin end of the neck, this way the vacuum is safely removed. Then the glass can be broken quite safely without the risk of implosion.
Very interesting - thanks so much for taking the time and trouble to explain your work so clearly - fantastic video! I'm really enjoying your channel.
Many thanks for the feedback
I've read anecdotal info that the 'jelly' adhesive layer is part of the safety mechanism itself; however, what you said in regards to that layer helping absorb shock so it doesn't transfer from the face plate to the tube itself, makes sense. Still, I do wonder if part of the reason for the 'jelly's' thickness is to do the reverse and protect the glass face plate from the tube itself: if the tube implodes, that shock and the resulting flying shards of glass would first have to get through the 'jelly' before hitting the face plate. Since the face plate is still glass itself and can shatter, I'm led to believe that removing the 'jelly' layer does reduce to an extent the protection. I heard of someone replacing the 'jelly' with a curved sheet of Lexan, but that sounds quite difficult to create. Also, Lexan could yellow or cloud with age. If someone still has CRT manufacturing equipment and can reproduce the final step of injecting the area between the tube and face plate with fresh 'jelly,' that would be great.
Yes the internet is full of anecdotal 'advice'. A few mm of soft 'jelly' will make little difference. If in doubt then do as I have and try breaking a few old CRT's to see what really happens. In some designs which used the same base tube there was no jelly and the face plate was fitted to the machine itself rather than the tube. Also try braking the face plates if you want to see where the strength is. The main advantage of the layer when it is clear is that it reduces diffraction of the images which you get with an air gap. Having said that you can leave the tube untouched if you do not mind being unable to see the image.
@@JerryWalker001 Interesting to know that some designs involve a face plate not adhered to the tube itself. Which models are those? The CRT I am dealing with is from the early 1990's and is a computer monitor; it has a very tiny cataract that looks like an air bubble, much like you'd see behind a poorly applied window tint. I don't even know whether or not the tube's assembly employs 'jelly' - all I know is that the tube is a Trinitron. I am still debating when it comes to fixing it. To begin with, it might be extra difficult to lift the face plate (if there is one) given the damage to the presumed 'jelly' layer is limited to that one spot.
Very nice result 👍👍
Where do you get the black double stick foam? Do you recall what the thickness was for the ADM3A?
I got it on ebay. The thickness varies with different tubes but for the one in the video it was 5mm .