1.5mm CRT front?

** 5" CRT = what ??

A 5" diagonal colour TV picture tube ??

A 5" old fashioned round scope tube ??

A modern, 8 x 10 cm rectangular scope tube ?

** Try and see what it takes to break it.

........ Phil

"Chris Jones"

** Huh ???

All vacuum tubes "suck" - Chris.

** Let the dumb troll answer my Qs first.

....... Phil

Due to the refractive index of the glass, it may be thicker than it appears.

Do you mean safe in that it prevents flying glass from hitting a person, or safe in that it protects you from x-rays?

Chris

The glass front on older tv's was dual purpose. One was to protect from flying glass due to picture tube implosion. The other was to protect from x-rays on the early color tv's that ran about 25kv on the picture tube anode.

Luhan

True, but I have seen an older TV (all valves inside) that had a plastic sheet between the user and the tube. I am not sure if this was to protect the user because the glass of the tube was thinner than on more modern tubes, or if it was just there to improve the contrast of the picture in the presence of room lighting. (The plastic was tinted dark.)

I have not seen any imploded TVs myself and I have no idea whether the more modern ones offer much protection against glass being projected forwards through the screen.

Chris

While its true that vacuum tubes do implode, the pieces continue moving and can fly quite a distance. I have picked up pieces over 20 feet from the face of a CRT that had the neck snapped off, propelling the electron gun through the faceplate, causing it to shatter and fly out the front of the cabinet. this was a monochrome set built a couple years prior to the bonded safety glass. Someone had replaced the CRT with a different type and left the safety glass out because the new tube was slightly thicker and it wouldn't fit. Then they over tightened the bolts which put a lot of stress on the glass bell. A month later it exploded while no one was home. The customer wouldn't tell us wo did the modification, but we were sure that they had replaced the CRT themselves.

I have hit the face of the '70s era color CRTs with a bonded safety glass faceplate with an ax to break them up. Some took several blows before they cracked enough to let air into the bell.

--
Service to my country? Been there, Done that, and I\'ve got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida

"Chris Jones"

** Huh ?

The front glass was there to protect the ** B&W TUBE** from accidental damage by the user.

** That is obvious.

........ Phil

Hi Chris. Its a 5" B&W tv tube. I dont think there would be any x-ray problem, its going to be relatively low EHT, but im/ex -plosion is another matter. As you say its hard to be accurate about the thickness, I've just compared it with a drinking glass viewed in the same way, and can now revise the estimate to 2mm. A 2mm mildly curved glass vacuum envelope doesnt strike me as exactly robust. In fact I think the old

1950s tubes would be stronger, they were about the same thickness but with more curvature. And they definitely needed a toughened glass front for safety.

OK I opened it up, and the tube has no rimband. I get the feeling this is well below the safety standards normal 50 years ago. And being a mini portable, is much more prone to breakage than a full size tv. Its Chinese.

NT