Thread: television picture tube

Can somebody tell me i have a scrap tv here and i want to take it apart problem is that it has a sticker on the ray tube saying caution high vacuum picture tube is dangerous to handle refer servicing to qualified servicing personnel. there is also an x ray warning but that is just for when it is in use. it has been sitting outside for years and im wondering if it would be safe to take it apart now?

Seriously ill put up pictures of the tv if you want i love taking things apart

By "take it apart" do you mean break the tube? If so, there is the danger of flying glass, and possibly some toxic substances.
Cathode ray tube - Wikipedia, the free encyclopedia

Nah the tube will be evacuated so there should be no toxic chemicals. just the glass so.

Ps pictures will take a computer i will paste them up when i am near one

Anybody here understand logic gates?

What is the crimson wire in the cathode ray tube called?

The ouchie wire

It's the anode high voltage connection and carries 10,000 to 30,000 volts in operation.

If the tube has not operated in a long time, any residual voltage should have bled off. If not, you'll find out the hard way.

The primary hazard is the risk of implosion as you break the vacuum within the tube. We usually did it waith a baseball bat, wearing proper eye protection from as far away as possible, knocking off the electron gun assembly.

Originally Posted by fiveworlds

Seriously ill put up pictures of the tv if you want i love taking things apart

The danger of injury due to flying glass is quite real for the larger tube sizes of the type you mention. It is easy to break the vacuum without exposing yourself to danger, though. There is a glass nipple at the base of the tube, where the connector mounts to the tube. There is a keyed plastic cylinder in the center of the base; the glass nipple is inside it. Take a pair of diagonal cutters and break off the seal. It will hiss ominously for tens of seconds as air fills the tube. When it stops hissing, you're done.

The fat red wire that connects to the bell of the crt with a suction cup affair is called the anode wire. "Ouchie wire" is indeed a good name for it. If you're unsure of when it was last powered up, you will want to discharge it. Take a screwdriver, use a wire to connect it to the metal band that surrounds the crt's bell, and then shove the screwdriver between the suction cup and the crt until it makes contact with the anode connection. Hold it there for a good solid 10 seconds or more. That will discharge it enough to prevent an unpleasant shock.

Thanks for the help i have most of it taken apart now havent smashed the glass yet though maybe tomorrow

Im going to try and make a diagrammatical representation of the circuit in order to help me understand it which may take a while

Another question i have realised how much i enjoy doing this and i was wondering if it is possible to take technologies apart and learn how they work professionally. I think the process is called reverse engineering but there is nowhere in ireland that teaches it.

on the back of the tube right at the end is a glass round bit, tap it off and air will enter the tube making it safe for disposal.

Originally Posted by fiveworlds

Anybody here understand logic gates?

They are about the only thing I do understand. What did you want to know?

logic gates are like this,

2 inputs, if both are high the output is high, thats an "and gate"
2 inputs, if either is high, thats an "or gate"

high means high(+v), low means grounded(0v), its not an open circuit like a mechanical switch.

Edit: Sorry bit more: http://en.wikipedia.org/wiki/Exclusive_or

Thanks its okay, one thing though what exactly is shot noise? Oh and it turns out im going to be busy studying computers is python a good place to start or c++ ps i was looking at trying to learn machine code supposedly it is different for each cpu but there is a toolkit to help people circumvent this my only problem is that it is only available to people with a sundrive@harvard.edu account anybody know another way?

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http://www.thescienceforum.com/electrical-electronics/29431-television-picture-tube-new-post.html

Here is the message that has just been posted:
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I used to work for a TV repair company and was amazed how heavy the 32 inch TV's were, about 3 times the weight of a person so it felt.
I learned to handle them easily could rest it on my fingertips no problem.
So recently I checked online for there weight, there only 13 stone.
Pick one up and they feel MUCH heaver.
Is there something strange going on? Like a vacuum makes an object feel much heaver than what it says on a weighing scale?
Give it a try, weigh your tube, then find some bricks same weight on the scale. Compare by picking them up then the tube.
Interested in your opinion.
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Dont know why post was deleted if you want i could weigh a working version of the tv with the non-working version of the tv and see if there is a difference between the two if you want. It will take a few months though as i am currently in my college flat and not at home. I think the soonest i can possibly do this is christmas. But you are right the tubes are exceptionally heavy.

Originally Posted by fiveworlds

But you are right the tubes are exceptionally heavy.

Of course they're heavy. They have to be in order to support all that vacuum. Remember, atmospheric pressure is about 15 lbs/sq in. Multiply that by the surface area of a CRT. You get a big number. The glass thus has to be very thick, and thus very heavy, or it would fracture.

I think is kinda obvious tk but thanks anyways