I understand the reasoning behind putting a safety glass in old TVs.

I'm wondering whether anyone has seen or heard of a case in which a CRT imploded during normal operation.

Trying to think of a scenario in which this occurs. Maybe a Bad Thing happens while you're watching Bonanza, causing a chassis fire, and then the CRT pops . . . ? Or would the CRT just pooch out backward, leaving the front intact?

Was the glass there to protect against a significant danger? Or merely an extra precaution against the occasional ape who bashed the TV while trundling it around the house?

Phil "just curious" Nelson

Somebody who is very very diligent, patient and lucky would probably be able find an AK post from about 18 mos. ago which was a scan of a 1955 article about the spontaneous implosion of the CRT in a very recent-model RCA table set.

I'm sure somebody remembers the picture of the set sitting in a corner of some poor woman's apartment with glass shards all about and noticable mangling to the chassis--plainly visible through the empty CRT surround.

The safety glass was blown out by the force IIRC, so how effective it really could be is debatable.

But that is, of course an isolated--if not unique--incident.

...

Back in the day, my brother and I tossed an old TV into a lonely dumpster. It didn't implode. So I tell my brother that TVs had to be built to take the rigors of shipping.... :D

I wouldn't want to be near an older CRT without safety glass...

I did read about one person being killed by a CRT imploding. What happened was that family members were fighting. In doing this, they were throwing a small TV set around and at each other. One of the participants went to pick it up and it imploded, sending glass into her neck.

When I was young, a local person who sold TVs was killed in his shop. I had always thought that this was also due to a CRT imploding. However, I later found out that this person was using a lathe and something flew off of it and killed him. Not related to TVs at all.

I too am VERY cautious when working with tubes w/o integral implosion protection. Think about it...even in the 1940's, well before the heyday of injury lawyers, manufacturer's were plastering "caution" notices on both the tubes themselves and on the insides of TV cabinets, warning about the possibility of serious injury when removing or replacing even a small 10 or 12 inch CRT, let along a 21 inch or larger. The service manuals of these sets even went so far as to highly recommend eye protection and arm protection.

When you consider how many things of that era were also truly "dangerous", yet carried no warnings (ie big ole' GE fans with brass blades and little to no guarding), there was obviously some well-founded basis for the concerns, even outboard of strict legal liability.

I couldn't find the thread, but here's the article I posted:
http://i11.photobucket.com/albums/a196/jpdylon/100_3506.jpg

Not just TVs that pop, every now and then you hear about a car window spontaniously breaking, especially in the heat. If the car's relatively new, most manufacturers will chip in to pay, even if it's out of warranty..

Any kind of manufactured glass product like this has the potential for a manufacturing defect to suddenly spring up. Any time glass is worked, there are stresses involved. And glass is really more of a very, extremely, slow moving liquid anyway. It can change a bit in shape over time - and if it was stressed or defective in some way, I could see how it would crack. Car windows, being tempered, are laminated with plastic and somesuch - and a tiny crack or break can spread very quickly. Especially something like a windsheild that is glued in all around, and if the metal of the car deforms somehow, or is putting pressure on it, the crack would expand as well. Picture tubes are full of vacuum (or is that not full of it... :) ). Lots of pressure is trying to crush the tube from the outside. One little crack in the right spot and *FOOMP!*.

Modern tubes have the "integral implosion protection" which is just a tensioned rimband around the outside, to crush the tube in on itself if it breaks. Old tubes, without this, lived behind glass, just in case.

One thing I've wondered - is on the 21FJP22, with the bonded safety glass, what happens if it implodes and the glass has been de-glued due to cataracts and taped back on? It should provide protection, but will it stop glass from flying everywhere?

But, all that aside, these things really have a one in a million chance of spontaneously imploding if they're not abused/kicked/dropped.

But still. The set came with a very durable glass in front of it, and I think that leaving it there is a good idea - but I wouldn't lie awake at night if it were missing. Any spontaneously occurring crack is most likely to happen at the weakest area of the tube AFAIK. That would be the neck or stem. And such failure would be just a hiss as the vacuum escaped. Nothing spectacular.

I've never had a tube implode unexpectedly. I've had some tubes unexpectedly NOT implode though - modern tubes at least are very tough. When throwing away some dud modern tubes, even chucking it into a dumpster won't always break it (the face and sides are very thick).

-Ian

...

I have radios built in the 1940s where if a knob is removed or you touch one of the screws holding the chassis in , you could be touching 120VAC (if it was plugged in). Even some of the early Hoffman TVs that I have have a live chassis where safety depends on paper type insulation. Would not fly today at all.

I also have a 1963 Ford Falcon-no fan shield on this model (as well as a solid steel steering column). One of my mother's brothers was killed by a car with no fan shield-the fan flew apart as he was working on it and hit him in the head.

In general, safety is a much higher priority in things built today.

They won't be any worse than a 21FBP22 with separate safety glass.

Logically that glue would also help keep at least some glass from flying. If the glue is new it could even make a huge difference.

I suspect the non-laminated safety glass would not stop any glass from flying. I think the non-laminated safety glass is simply to help anything hitting the CRT directly.

[QUOTE=peverett;

I also have a 1963 Ford Falcon-no fan shield on this model (as well as a solid steel steering column). One of my mother's brothers was killed by a car with no fan shield-the fan flew apart as he was working on it and hit him in the head.

In general, safety is a much higher priority in things built today.[/QUOTE]



Where have I read about the Falcon's safety issues in here? Seems like some brash and sassy writer claimed the Falcon is extremely unsafe only to be punished for doing so.

Logically that glue would also help keep at least some glass from flying. If the glue is new it could even make a huge difference.

That's just the thing - when a tube with cataracts gets repaired, the safety glass doesn't get glued back onto the tube. It's impossible to get it glued on and have it be perfectly clear. Typically the glass just gets taped around the edge of the tube with packaging tape.

I actually don't think it would be any more or less safe this way. In a way, it may even prevent glass from flying out - instead of an imploding tube simply breaking the faceplate along with the face of the tube (because they're glued together), it would have to hit the safety glass hard enough to break it _and_ blow through it to cause harm.

But, that's really all just speculation. I have no real clue which is safer. As others have pointed out, safety wasn't a prime concern back then. And yet we're all still alive...

-Ian

definately safer... no question about it.

How much safer? I think alot safer in many situations. So if it's just 1% safer is it worth the trouble to get it re-laminated? I guess it depends on how much you value any extra amount of extra safety.

I am 100% certain there is a product available to re-laminate. I will eventually figure out what that is whether I get help from those who know here or not.

Somebody here definately knows what product is available and where to get it.

Wow, that implosion photo is scary.

The safety glass blew out, too, as David noted. But who knows -- had it not been there, perhaps the lady would have been injured more seriously. The safety glass might have slowed down the CRT shards, broken them into smaller pieces, etc.

You have to wonder what happened right before the implosion. A frying sound, followed by a loud pop. I wonder if an electrolytic capacitor blew up. If a can electrolytic blew its top, or took off like a little rocket, I could imagine that cracking the neck of a CRT.

I have never had a radio start on fire, but I have had a couple of electrolytics that popped with an impressive firecracker noise.

In my irresponsible teen years, we used to take our .22 rifles to the town dump, shooting at rats and every glass item in sight. We wrecked plenty of old radios and appliances, but we never managed to blow up a TV. Thank God there is no videotape of me on those excursions, shooting up old console radios that I would now gladly rescue and restore.

Phil Nelson

Back in the mid 70's we had a B&W TV that we were tossing. Probably something we'd restore today, but back then just an old POS... Cheap wood cabinet with fake wood grain plastic "paper" over it. Anyway, the town wanted us to let the vacuum out of the CRTs, to safe it for the trash men. A few other CRTs were easy, just break off the little glass seal in the middle of the tube pins in back. But one CRT, 21 incher or so, had a bakelite tube plug covering over the seal, and thus inaccessable. So I decided to put the TV at the curb, without the chassis and back, and standing about 30 feet away, toss rocks to try to bust the neck off. I missed the neck, but scored a hit right in the big part of the tube. KABLAMM! Glass flying all over the place, and it turned out to be wise to stand as far away as I did...

An about-1964 23" B&W console made a nice Melluva Hess when I unloaded a clipfull of 115 grain 9MikeMike from my Uzi at it....But I have shot .22s at rectangular color sets, if you aim at the corners, sometimes they just spiderweb the tube...

Never purposely imploded a crt older than mid 70s. By then they mostly all had implosion prevention built-in.

What does 'integral implosion protection' actually mean?

What does 'integral implosion protection' actually mean?

All they did was to put a tensioned metal rimband around the face of the picture tube. This band is sometimes combined with mounting ears in later tubes. It's purpose is to hold the edges of the face tight, so that if the tube does implode, it's more likely to crush in on itself, rather than spraying glass all about.

-Ian

Several years ago, I was carrying a 23" color tube to the van to haul off. The thing slipped out of my hand and I hauled butt as it was falling. It hit the concrete on the corner and KA-BOOM! My mother heard the noise and came running out of the house to make sure I was OK. We spent 30 minutes sweeping up tiny pieces of glass from the driveway.

Several years ago, I was carrying a 23" color tube to the van to haul off. The thing slipped out of my hand and I hauled butt as it was falling. It hit the concrete on the corner and KA-BOOM! My mother heard the noise and came running out of the house to make sure I was OK. We spent 30 minutes sweeping up tiny pieces of glass from the driveway.


You must be one of the quickest serviceman imagineable.

You must be one of the quickest serviceman imagineable.

Well, I was a little younger and moved a little faster back then. I was lucky that I didn't meet up with flying glass. I will say that tube didn't make quite the bang that a 21" non-implosion protected tube did when I threw it away.

I also had a friend that had a "near miss" when a tube imploded. He had an early '80's Sylvania console that used the inline tri-pot tube. That tube had mounting ears on it and no metal degaussing shield. He tried to replace that tube with one of the Zenith tubes of the era that had no mounting ears and used a degaussing shield. He fabricated some sort of metal band to hold the Zenith tube in the Sylvania case. When he sat the TV in it's normal, upright position - BOOM! I guess the band that he fabricated put too much pressure on the tube. He was not hurt; but, he had a mess to clean up.

That's valuable info!

Thank goodness nobody was hurt.