Are flat panel TVs dangerous to open, like old CRTs?

[Patrologia]

So, we have come into possession of a large flatscreen TV, that doesn't work very well. My son is gung ho to open it up and see if he can fix some contact or other that he thinks might be the problem (he's been watching youtube videos). Before I let him do that, I want to check about how dangerous it might be. He's pretty responsible, and if this is on the level of taking apart and putting back together a computer, there's no problem. If it were on the level of an old CRT television where you really do need to know what you're doing to be sure you don't hurt yourself, I probably wouldn't let him do it. I'm guessing that it is somewhere in between--can you tell me where in that range it falls?

My expectation is that the TV ends up at the dump in either case, but if he can get an educational experience out of the deal without unreasonable risk, I'm up for that. (To be clear, I haven't taken apart an old CRT before, but I mess around with old radios, so I'm not entirely wet behind the ears.)

Thanks,
Mike

[Eric H]

Other than possibly high voltage capacitors holding a charge (and that seems unlikely) I can't think of any dangers, if it's unplugged.
I guess you could cut yourself on the sharp edges of the stamped out sheet metal.

[Electronic M]

CRT sets aren't particularly dangerous to open either as long as they are unplugged. The CRT can implode if struck with significant force but that's about the worst that can happen. A lot of people hear that there is high voltage on a CRT but it is low charge/low current high voltage...the charge stored in the high voltage system of powered off TV is approximately the same as that you get from shuffling your feet on carpet and touching a doorknob (the static shock case sometimes has higher voltage). I've been bit by CRT HV countless times and am still here to tell about it. Most sets since solid state electronics came along don't store CRT HV charge for more than 1 minute after power off...there are ways of safely discharging the older sets too.

The thing you never want your kid working on is microwave ovens. The power transformers in them are high current (it's current that kills) and high voltage and are alternating current which is harder to let go of and disrupts muscle control including the heart...the tubes in some microwaves are filled with poisonous gas too.

[Jeffhs]

Originally Posted by Patrologia

So, we have come into possession of a large flatscreen TV, that doesn't work very well. My son is gung ho to open it up and see if he can fix some contact or other that he thinks might be the problem (he's been watching youtube videos). Before I let him do that, I want to check about how dangerous it might be. He's pretty responsible, and if this is on the level of taking apart and putting back together a computer, there's no problem. If it were on the level of an old CRT television where you really do need to know what you're doing to be sure you don't hurt yourself, I probably wouldn't let him do it. I'm guessing that it is somewhere in between--can you tell me where in that range it falls?

My expectation is that the TV ends up at the dump in either case, but if he can get an educational experience out of the deal without unreasonable risk, I'm up for that. (To be clear, I haven't taken apart an old CRT before, but I mess around with old radios, so I'm not entirely wet behind the ears.)

Thanks,
Mike

If your son can get the TV working, why send it to the dump? If the set he is working on is a flat screen, the chances of restoring it to working condition are not as good as with an older CRT set (in fact, the way all flat screens are made, if anything goes wrong with them after the warranty expires, the next step is usually to throw them away and to get a new one). However, if he will be working on an old CRT TV, the chances of restoring the set could be good, depending on exactly what's wrong with it. Some parts of older televisions, such as picture tubes, could be difficult to find in this age of flat screens, but if the tube is good and the problem can be remedied by changing chassis tubes or chassis components, I would say go for it.

If the problem with the flat screen is just a bad contact, say between the display and the main board, it could be an easy fix as well, but without seeing the set I have no way of knowing exactly what is going on with it. As I mentioned, however, as inexpensive as flat screens have become these days, it often is not worth trying to fix them if they go bad; the cost to have a set repaired is often more than the set sold for when it was new.

In any case, good luck. I hope your son can get the TV working again as it once did, but if not, at least he will have gained some experience by having worked on it.

[Jeffhs]

Originally Posted by Electronic M

The thing you never want your kid working on is microwave ovens. The power transformers in them are high current (it's current that kills) and high voltage and are alternating current which is harder to let go of and disrupts muscle control including the heart...the tubes in some microwaves are filled with poisonous gas too.

Don't forget the danger of the radiation from any microwave oven's magnetron, and do not, under any circumstances, bypass the door switches, even for testing. Microwave energy is very dangerous if handled indiscriminately, so unless you know exactly what you are doing, you can get into very serious trouble by trying to troubleshoot or repair a microwave oven. Microwave ovens, like flat screen TVs, are so inexpensive these days that it is hardly worth trying to repair them when they go bad, once they are out of the manufacturer's warranty period; this is the way all electronics, home appliances and just about everything else are made now (there are a few exceptions, such as automobiles). As well, do not under any conditions whatsoever operate a microwave oven empty or put anything made of metal into the oven; this will destroy the magnetron and may cause a fire.

[JohnCT]

No more or no less dangerous than any other AC operated device really. But nothing inside that will suddenly explode if prodded, but do take the same care when dealing with flat tvs as you would any other.

John

[MadMan]

Originally Posted by Patrologia

My expectation is that the TV ends up at the dump in either case, but if he can get an educational experience out of the deal without unreasonable risk, I'm up for that.

Good outlook. Large capacitors can hold a charge for a good while and give you a nasty zap. In general, that's more of a nuisance than a danger. The fluorescent lights that illuminate the screen (assuming it's an LCD) run on high voltage, but again that's not particularly dangerous, just zappy. If the device is plugged in, however, everything will naturally be live and those capacitors especially can really hurt, and actually burn, I learned that one the hard way. Nothing a little basic caution won't prevent.

In short: no unreasonable risk. Besides, a little electric shock here and there will make your son a man.

Additionally, I haven't worked on too many flatscreens, but here's a couple things I've noticed, tips for your kid. The fluorescent backlights can burn out, sometimes leaving an otherwise working tv, but with a black display, sometimes making the power supply freak out and turn itself off. Power supplies can be damaged by surges in which case the set will likely do nothing, those can be obvious to fix sometimes, having burn marks and such.