What is harvest-worthy from an old CRT monitor?

Flaminpyro said:

Rember to short out the second anode on the CRT or you could get a real nasty shock that will make you

Click to expand...

that's an understatement. I one had a CRT supply nearly kill me when the back fell off and old HP monitor. I attempted to catch the fall of the monitor after it was knocked over and grabbed the HV lead without thinking. I couldn't let go and I felt my heart race (though I was going to die). There is quite a bit of current in the CRT supply. I'd say probably enough to kill.

Off circuit a CRT can produce 40-45Kvdc when HV has no load attached. DANGER!

Always be careful working on CRT screens. Usually the charge is not enough to actually kill you, but if you make a mistake you can be in for a serious jolt.

This applies to the power supply caps as much as it does to the tube charge.

As far as salvaging goes: There might be useful components in there, but usually the tv is broken for a reason, so at least something failed. Often this is the flyback transformer or its driver circuitry, but it CAN be anything.

Heatsinks and such will be fine, resistors or potmeters can be checked easily. Active components and caps i wouldn't salvage if i need them to be reliable in some other project.

I took apart an old disused CRT for the flyback, but I haven't used it yet. I just figure it's worth grabbing it as you won't see many of these monitors around in the future. It's like DVD burners, eventually they'll go the way of floppy drives (which have great little motors); get 'em while you can.

Flybacks would be a good thing to stockpile if you're into HV stuff. I'd consider buying some new ones now that they are still available though. The ones you pull from a tv set usually have a lot of hours on them, and if the set is broken they are often the cause.

I suppose neon sign transformers will be around for a while though, so there is hope for DIY HV projects still

Benm said:

Flybacks would be a good thing to stockpile if you're into HV stuff. I'd consider buying some new ones now that they are still available though. The ones you pull from a tv set usually have a lot of hours on them, and if the set is broken they are often the cause.

I suppose neon sign transformers will be around for a while though, so there is hope for DIY HV projects still

Click to expand...

Sad but true. Now they even have microwave ovens with no giant transformers. They use circuitry instead. NSTs have been upgraded from 60hz to high frequency ones too.

As for the CRT, The Flyback is always fun to play with. Theres usually decent capacitors on the boards, and the degaussing coil (if you can remove it good enough) sometimes is enough for a Tesla coil (small)

My 40 year old TV died and it wasnt due to the flyback

jbtm said:

Sad but true. Now they even have microwave ovens with no giant transformers. They use circuitry instead. NSTs have been upgraded from 60hz to high frequency ones too.

Click to expand...

Still a high voltage source, yes?

I have been taking apart CRT's for their flybacks and I have discovered that most computer monitors that turn on have good flybacks all you need to do is remove the wire from the side of the tube and use this 60-90kv hot lead to arc to any ground terminal in order to make 2-3" arcs however I suggest using a resistor in between these two in order to prevent ruining the power supply. If you wish to remove the tube and all useless junk I have found that most of the wires connected to the boards are useless except for the one going into the wall,the main one connected to the flyback itself(the hot lead) ,the on off switch ,and the 4 connected to the big ferrite core on the monitor tube itself which I've found is removable if you use a little care in breaking the glue and removing the hose clamps. Remember to unplug it when you're working on it,discharge the flyback after every time you turn it on(I use a glass or plastic rod with a wire on the end for this) , and only ever touch HV leads with one hand in order to minimise the chance of electric shocks passing through your heart.

If the monitor doesn't work it still has HV resistors,HV capacitors,copper,heat sinks,HV transistors,rectifier diodes,a switch,a 2 color led,a relay,magnets(well hidden),and many kinds of wire.
Btw CRT's DO in fact emit X rays however the radiation is limited by the thick lead glass that the CRT itself is made of. If someone wished to make one of these emit x rays they would attach the hot lead to the back and the ground where the hot lead was
they would also remove the electro magnets that spread the electron beam outwards
(this should make one really bright spot on the screen which can be moved with a magnet) after that one would grind the glass thinner in order to let more of the radiation through. However the only thing I can think of using this for would be a DIY X ray machine.

well very interesting first post kinda a necro post but at least you gave good info.
i never found a relay in mine ill have to look again.

CRT lol... does anyone actually have CRT this days ?
Do you also have that thing called VHS-players haha



Just joking...

It`s a pain in the ass that my old CRT cost 1500$ 5 years later you can buy a 42" plasma for less than 999$ !!

and soon laser tv for that very same price the world is a great place.
Remember the longer you wait to buy the technology the better it will be, but then you might find yourself waiting for an eternity.

kiyoukan said:

well very interesting first post kinda a necro post but at least you gave good info.
i never found a relay in mine ill have to look again.

Click to expand...

it's by the power cord looks like a 1" plastic box usually black