discharging CRT monitor

E

Everfalling

Gawd
Joined
Jul 12, 2005
Messages
676
does anyone have a good site with a visual walkthrough of how to discharge a CRT monitor, and any information about taking one apart? ii'm planning on making one of those CRT > fish tank mods but i dont wanna, you know, DIE. i've read you can just take a wire with two alligator clips on the end, and attach one to the chassis (or ground lugnut or w/e) and the other to a screwdriver (while wearing gloves and everything) and discharge that way. is this safe? will it get all the charge out? also, how is it that the charge goes away completely if the charge just goes to the chassis? do you plug in the monitor for it to be completely grounded?

also, what would happen if you just dunked it in water? i mean, i dont need the actual tube or anything, just the case, so i dont mind if the boards inside get fried. just donno if the damn thing will explode on me or anything.
 
I would try to stay away from all mods that might involve death by electrocution and/or shrapnel.
 
Yank the plug while it is on. Highly unlikely for that to NOT discharge it.

And don't dunk the thing in water, that's just retarded.

Also, do not attempt to cut into the tube whatsoever. You must find another tank or glass shell or something. I am not sure if you want to use the existing tube but I am just making sure.l
 
Whatsisname said:
Yank the plug while it is on. Highly unlikely for that to NOT discharge it.

And don't dunk the thing in water, that's just retarded.

Also, do not attempt to cut into the tube whatsoever. You must find another tank or glass shell or something. I am not sure if you want to use the existing tube but I am just making sure.l
Click to expand...

yeah sure? yank it when it's still on? havn't heard that technique before

and yeah i didn't think the dunking in water method would be a very good idea anyways :p

and after all this, where do i put the parts? i dont think i'll be needing the tube at all. is there a way to find places that recycle computer parts?
 
all you need to buy is a crt discharge tool

cliky

just ground the sucker, look for the cap, poke it, pop it off

done
 
piako said:
all you need to buy is a crt discharge tool

cliky

just ground the sucker, look for the cap, poke it, pop it off

done
Click to expand...

wouldn't a wire with alligator clips on the end and a screw driver pretty much do the same thing?

and is that all i need to do? all the charge ust goes away into the chassis? i dont gotta worry about it anymore unless i let it sit there for a while longer?
 
Everfalling said:
wouldn't a wire with alligator clips on the end and a screw driver pretty much do the same thing?

and is that all i need to do? all the charge ust goes away into the chassis? i dont gotta worry about it anymore unless i let it sit there for a while longer?
Click to expand...

once you buy one you'll have it for ever. or you could borrow a friends. don't think a screwdriver would work.

my old boss at compusa said he saw someone discharge a crt once and it threw him across the room. true story
 
I ripped two or three CRT's apart when I was around 10 or 11. I have no idea how I didn't kill myself.
 
Shroomie said:
I ripped two or three CRT's apart when I was around 10 or 11. I have no idea how I didn't kill myself.
Click to expand...
I kicked through a 21" Trinitron that wasn't displaying picture with my Steel Toe Caterpillars... that was fun, didn't hurt myself either.
 
I've taken apart 2 CRTs without shocking myself. Just be sure to properly... dispose... of the tube. I kinda... left mine... behind a supermarket...

You didn't hear that.

Luckily it was raining...

I hope it discharged itself


Just kidding. Anyways, if the afro thing does not work, you can always throw the whole damn thing into a lake. That way, it will short and ground everything so that there is really no risk whatsoever. Also, if there was a charge, hearing a big zap would be rewarding :D
 
where would i go to buy that apple crt discharge tool? i've been to every electronics store near me and even a few hard ware stores and no one had it.
 
The best way to do it IMO, is to stick your fingers under the rubber cap. That way you'll know for SURE when it's discharged!

I like smashing CRT tubes after I take monitors apart... there are lots of nice magnets and electron accelerating parts in there :).
 
that...doesn't really help me. :/

could you tell me how, and what with you discharge them?

also, isn't smashing them dangerous considering the amount of vaccume in the tubes?
 
recycle it if you can, but if you can't put the tube in a cardboard box, cover it in a burlap sack or something, and smack it with a shovel, throw it in with some other trash then take it to the dump.
 
Tutelary said:
I would try to stay away from all mods that might involve death by electrocution and/or shrapnel.
Click to expand...


Are you kidding me? Those are the best ones!
 
disposing of the tube isn't a big worry, i'm sure somepalce will take it. it's the 1.21 giggawatt charge the tube keeps when off. will unplugging it when it's powerd on really discharge it? or do i need to do some more probe poking? also, where do i attach the probe? just to the metal chassis inside? i saw one picture taking about a ground bolt or something. how does the charge ground iitself f it doesn't go into the ground?
 
Even if it doesnt lose its charge its not really that big of a charge sure it hurts like hell but it is usually not enough to kill a grown person just knock ya on your ass. It just depends the really old CRTs are much more dangerous than the new ones as most of the new ones mostly discharge themselves while the old ones do not. I know from experience it doesnt always kill ya because often arcade machines are not properly grounded on screens that are way up in the air so if you try to reach up and clean it and touch metal like your cheek while the game is on all you get is one hell of a shock and get to see the monitor flash off for a couple of seconds.

If you kill yourself its not my fault nor do i condone taking apart a CRT monitor.
 
donno about that. from everything i've heard, the charge stored in a crt tube is enough to kill you. I'd still rather not touch it even if it's only half charged...
 
.

High voltage: CRTs operate at very high voltages. These voltages can persist long (several days) after the device containing the CRT has been switched off and unplugged. Residual charges of hundreds of volts can also remain in large capacitors in the power supply circuits of the device containing the CRT; these charges may persist for weeks. (Modern circuits contain bleeder resistors to ensure the high-voltage supply is discharged to safe levels within a couple of minutes at most.)

Those working inside CRT-containing equipment should know how and be able to safely discharge these hazards. In particular, the large rubber connector which looks like a suction cup is responsible for supplying accelerating voltage to the bell of the CRT. Under the suction cup is the ultor which couples the accelerating voltage to the inside of the tube. Inside the glass bell is a coating of metallic paint, while the outside of the bell is coated with a conductive graphite coating called Aquadag; between the ultor's connection to the flyback transformer and the Aquadag, there is therefore a capacitance capable of maintaining the full accelerating voltage for weeks. While this accelerating voltage is high (typically from 7kV to 50kV depending on screen size, monochrome or color, direct view or projection), both the capacitance and flyback current are small (on the order of picofarads and nanoamperes respectively), so shocks from the accelerating voltage are typically embarrassing and painful but usually harmless. On the other hand, the voltages and available currents used in the deflection and power supply circuits can result in instantaneous death.

Implosion: All CRTs and other vacuum tubes operate under negative pressure so that air and gas molecules will not interfere with electron streams. CRTs have large viewing areas and proportionally larger bells required to accommodate the deflection of the electron beams to the rear of the screen. As a result, these highly evacuated glass bulbs have a large surface area, with each and every square inch exposed to atmospheric pressure.

As an example, consider a 17-inch (16-inch viewable) CRT at a mean sea-level atmospheric pressure of 14.7 pounds per square inch. Measuring the visible portion of the CRT and rounding up to the nearest inch (accounting for invisible portions of the face), a Viewsonic model E771 monitor has a screen of 13x10 inches, or 130 square inches. At 14.7 PSI exterior pressure and a near-perfect internal vacuum, the face of this monitor is supporting over 1,900 pounds of air mass on its face alone. The entire CRT is conservatively supporting three times that - or nearly 6,000 pounds, the weight of three typical automobiles - across its entire surface. The larger the CRT, the more surface area, the more total exterior air pressure load.

Therefore, CRTs (outside of finished end-user products) present a hazard to those without proper training and appropriate precautions. While a great deal of research has gone into implosion protective designs for CRTs, all CRTs present an implosion risk. Even CRTs in finished products present a hazard if handled uncautiously. Early television receivers even included a "safety glass" to protect viewers from flying glass due to spontaneous structural failures of the CRT; with modern (early 1960s onward) banded and bonded-face CRTs, the safety glass has become redundant. Safety goggles, leather gloves, and heavy sweaters are considered indispensable safety equipment amongst experienced technicians and preservationists of early television equipment.

Pretty much what that is telling you is that thte voltage on the actual monitor section it fairly harmless due to its low amperage however if you screw with the power supply you can seriously electrocute yourself. CRTs use a high voltage with very low amperages in for the actuall display part. The bad part of the CRT is the power supply as the current on that hasnt been stepped down to safe levels. Also almost any modern CRT has a niftly little gadget called a bleeder resistor to get rid of the nasty voltage pretty quick. If I was doing something as stupid as opening a CRT monitor I would power it down normally unplug it and let it sit overnight then go about discharging anything I could before trying to mess with it to much. Also The power supply is probably the most dangerous part.
 
are you able to handle the power supply without immediatly killing yourself? meaning, with the tube, the bad part is under the rubber cup. what are the places to avoid touching on the power supply? is it like regular computer supplies where it's covered with a metal shield or what?

also, i know it's a risky operation, but do you have to keep calling the process of dismanteling a crt monitor stupid (yeah i know you only said stupid once, but still, you're pretty negative about it)? I'm trying to take every precaution with this so it's not like i'm hacking away at it with a hammer while standing in a pool of water.
 
Hey I did not say that I did not do stupid things but taking apart a perfectly good monitor and plaything with High voltage does not exactly fall under the smart catagory. I have done things just as stupid if not stupider than that. I would say avoid touching any capaciters you see with a bare hand and you can pretty safely discharge any capaciters you see with a screwdriver with a rubber handle just do not get scared at any really big sparks. All you do is put the screwdriver across the two ends of the capaciter. I would wear eye protection when you do this just as a safety precaution. I would wear an oven mit while i do that and stand on a plastic mat just to be sure though so you are not grounded. See when I do stupid things I make sure to take as much precautions as possible. As for other safety tips STAY AWAY FROM ANY COILED WIRES. This is very important as thats probably the deflection or focusing coils and those If they hold a charge still can kill you. I repeat COILED WIRES = BAD. What part of the monitor are you trying to scavenge anyway; the tube or the plastic casing? The power supply probably wont be covered but you should see some heat sinks just like you would inside a normal power supply. It will most likely be at the very back of the case. Also before you try to unscrew anything discharge it by grounding it perferably with a well insulated wire making sure to connect ground last. then take a voltmeter and hook positive part of voltmeter to screw and negitive end to a negitive end of battery and check and see if you have voltage on the screw. If you get no voltage or amperage you should be safe to unscrew it. Be sure not to hold the voltmeter in your hand when you hook it up. This is probably all going way overboard on the safety side though. At the least I wouldnt unscrew anything withought making sure the screw did not hold a charge.
 
i just want the plastic casing. liek isaid in the beginning, i wanna make a fish tank out of this. i dont have a voltimeter, just wire and a screw driver unless i can get one of those apple tools (which no one has given me a link for where to buy one yet).

i'm wondering. how good or bad of anidea would it be to take a wire, put it into the ground port of a wall socket, and touch that to the part under the rubber cup with a screw driver? wouldn't that sufficiently ground it and discharge it?

also, as perfectly good as it is, it's a 20 inch behemoth that must weight like 50 pounts or something. i already have two lcd screens so i dont need another monitor, let alone a hulking CRT that takes up probably as much power as those two LCD's.
 
First off never ever stick anything in the socket you can ground so many safer and easier ways. if you have any metal pipes those will be well ground just run a wire to one of them. I usually dont play with to many things with high enough voltage that I would have to worry about deadly shock usually just god damn that hurts levels of shock.
 
If you just want the case, screw all this shit about grounding and just chuck the piece of shit in a lake. Be sure to stand back though...

Then, wait a few seconds and go dig it out.

Most CRTs have anti-implosion protection, so you probably will be fine. But just in case, throw it gently :D


I don't even see why there is any sort of an argument here. You could even just leave the damn thing out in the rain and clean it off afterwards, you will probably be fine. Call me an idiot, but I have taken apart a few CRTs with no problem. I think a previous poster suggested unplugging it while it is on to lose all the charge, try that and just be careful not to touch anything that could ground to you, or wear thick rubber gloves. As long as you take the proper precautions, you will be fine...
 
well reguardless if it's needed or not considering i'm not gonna use the tube, i'd still like to know where to get said discharging tool just incase.
 
why pay money for something you can do for free. Yank the plug while its on and be careful while you remove the tube and shit, it really isn't all that difficult.
 
i've never seen yanking the cord as amny sort of safe way of actually discharging the tube. how do i know this is very effective? at least with the probe thing i know the charge is going away.
 
Okay, let me make this simple for you:

THROW THE DAMN THING IN A LAKE.

All the charge will discharge into the lake, which is obviously grounded. Therefore, you know it is fully effective. All charge will be gone.

I would not reccommend standing in the lake when you throw the monitor in though...
 
I say go to a craft store, get a long aluminum metal rod, attach a wire to it with a gator clip on one side and then clamp the gator clip to something metal. put a thick layer of say...cloth, rubber and electrical tape around the metal poll to use as a handle, and just start poking shit with it. Anything that looks like electricity could pass through it, just touch it. That should deffinatly discharge it...and it will probably only cost like 5 bucks.
 
I notice nobody mentioned one of the better pieces of advice for messing with a CRT:

Work with one hand, PUT YOUR OTHER HAND IN YOUR POCKET. This will ensure that you don't blast electricity across your heart if you do take a shock. It will be tempting to take your other hand out and work with it, but don't.
 
I would rather the shock be to my heart than my nuts. Plus its still going to go through your heart. it goes from your upper body down through your feet which are usually the closest thing to being grounded.
 
Tutelary said:
I would try to stay away from all mods that might involve death by electrocution and/or shrapnel.
Click to expand...

like this technique?

kill4killin said:
...get a long aluminum metal rod, attach a wire to it with a gator clip on one side and then clamp the gator clip to something metal. ... and just start poking shit with it. Anything that looks like electricity could pass through it, just touch it...
Click to expand...


LMAO
 
Maethor said:
I would rather the shock be to my heart than my nuts.
Click to expand...


I LOL'd at work. People were looking at me wierd. Holy batman this sentence alone made me LOL for like 5 minutes.
 
1) your nuts don't do you much good when you're dead
2) when discharging a monitors capacitance, "ground" is meaningless.

Maethor said:
I would rather the shock be to my heart than my nuts. Plus its still going to go through your heart. it goes from your upper body down through your feet which are usually the closest thing to being grounded.
Click to expand...
 
I'd be willing to bet that that apple monitor tool is just a probe and a wire with a relatively high wattage resistor between them.
 
JUST LET THE MONITOR SET FOR A WHILE!!!!!

after a few days it is not going to give off any more then a small buzz...

i seen a guy hit a kill switch to a tiller with a hand instead of a stick. he flew back about 4 feet and was knocked out for 10 minutes but it DIDN"T DIE!!!

think you guys are a bit paranoid about electricity. respect it yes. but at least understand it before you hype up fears about it.


edit: it is not the volts that hurt it is the amps that will kill you.
 
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