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#558140 - Sun Oct 17 2010 09:08 AM Shut off LCD TV for one hour?
root17 Offline
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I've received conflicting advice on this. I have a Sanyo LCD HDTV (located in my living room), which I often watch before dinner (actually, recorded programs on a DVR). When I go to the kitchen to prepare and eat dinner (usually about an hour), I was in the habit of leaving it on but muted if I planned to come back after supper. A friend said that shortened the life expectancy, and that I should instead turn it off. What do you advise?
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#558215 - Sun Oct 17 2010 02:15 PM Re: Shut off LCD TV for one hour?
tellywellies Offline
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The screen's back-lights only last a certain number of hours but that is reckoned to be 60,000 hours. Other components could go wrong based on the length of time they have been used but time isn't a big failure factor in my opinion. Electronic components can last anything from a day to 20 years, their failure often being a random thing.

Nonetheless, I'd probably put the TV to stand-by for the time spent not watching it. I wouldn't be too zealous about it though. If I forgot to switch it off or put it on sand-by for that period of time, I wouldn't kick myself that much.

It could be argued that we shouldn't leave any electrical/electronic item running unattended but I think we all do it (computers for example). I reckon TVs and the like are pretty safe these days but there can always be the exception to the rule of course.
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#558255 - Sun Oct 17 2010 05:48 PM Re: Shut off LCD TV for one hour?
lesley153 Offline
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Alternatively it may be "Capacitor Plague" that accounts for the sudden death of some electric/electronic equipment.

Bad capacitors probably kill more machines more quickly than owners who leave them switched on. All you need to get them working again is a supply of replacement capacitors, and an amenable teenager who knows how to use a soldering iron.
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#558270 - Sun Oct 17 2010 09:44 PM Re: Shut off LCD TV for one hour?
mehaul Offline
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And the ambidextrous, four-handed monkey to open the case.
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#558327 - Mon Oct 18 2010 05:43 AM Re: Shut off LCD TV for one hour?
lesley153 Offline
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Yes if the ambidextrous, four-handed monkey ever manages to get the child-proof lid off the lavatory cleaner.
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#558343 - Mon Oct 18 2010 07:58 AM Re: Shut off LCD TV for one hour?
WesleyCrusher Offline

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Actually, while the life expectancy of a backlight is in the vicinity of 60,000 hours, it will lose brightness over time long before that. A 3-year-old monitor or TV used for 8 hours a day (still under 10,000 hours) can lose 1/4 to 1/2 of its brightness.

However, components also experience extra stress each time you switch on or off a device. As such, an hour of switch-off time is probably a toss-up with regards to the life expectancy of your TV. However, you should also consider that your TV is also using electricity in the order of 100 watts while showing a picture. That's 36 kilowatt hours per year or probably some ten dollars in electricity cost per annum, not counting the extra CO2 released.

I'd thus recommend switching off if you leave the room for longer than 15-20 minutes. Your TV will still last until the day you need to buy a 3D one and you'll reduce your electric bill and carbon footprint.

Wes
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#558463 - Mon Oct 18 2010 05:07 PM Re: Shut off LCD TV for one hour?
ladymacb29 Offline
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Originally Posted By: WesleyCrusher
Your TV will still last until the day you need to buy a 3D one


Wow - so my TV will last forever, since I'm never buying a 3D TV? wink
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#558530 - Tue Oct 19 2010 01:21 AM Re: Shut off LCD TV for one hour?
mehaul Offline
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A more important energy comsumption and electronic equipment life expectancy factor has to do with whether or not the equipment has remote sensing for control. Leaving a remote controlled piece plugged in to allow the sensor to merely turn on the equipment runs a continuous strain through the power supply. That constant current draw (though low) does generate heat, the enemy of circuit elements, especially IC's. So it is more important these days with low consumption, but instant or always on devices to attend to the manner of your "shut off".
When not in use nor expected to be in use for many hours, it is better to unplug the equipment altogether either by pulling the plug or having it plugged into a switchable wall outlet. Another option is a power surge protector that has an on/off switch. That way, you turn on the wall switch or surge circuit to energize the infrared remote cicuit and then sit back to enjoy.
A side issue with surge protectors is that on multiple outlet ones, everytime you turn one of its elements on or off, you create a surge on that side of the protector (TV, DVD player, VHS Player, Cable/ satellite boxes, all: shut one off you surge the rest of them on the same protector). It is better to have individual protectors for each device.

(I have written about fifty stress analysis and life expectency documents for high and low power microwave devices and hardware. Mil-Handbook-217, with its tables of component stress versus mean time to failure, was my bible (in the work manual meaning of the term)).


Edited by mehaul (Tue Oct 19 2010 01:33 AM)
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#558536 - Tue Oct 19 2010 02:51 AM Re: Shut off LCD TV for one hour?
tellywellies Offline
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That's true mehaul - I won't leave items on stand-by (waiting for a remote control command) for very long. If out for the day or longer, they get the mains disconnected. I also use a remote control power switch for some items that that would otherwise be left on stand-by.

I do have a couple of exceptions to that though. Two of my LCD TVs are left on stand-by nearly all of the time (unless going away) ..but then one of them uses only 0.75 of a watt in stand-by and the other uses 1 watt. I think other domestic equipment can do equally well these days. Years ago, an item could use many watts while on stand-by but things have improved I think.

You're right about stand-by though. On a worldwide scale, there's an awful lot of megawatts used by items being left on stand-by, or just fully powered up and not being actively used. Think of all the computers constantly running. I've read about those who never turn their home computer off.


Edited by tellywellies (Tue Oct 19 2010 02:52 AM)
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#558544 - Tue Oct 19 2010 04:10 AM Re: Shut off LCD TV for one hour?
WesleyCrusher Offline

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Originally Posted By: ladymacb29
Wow - so my TV will last forever, since I'm never buying a 3D TV? wink


When this 3D stuff really takes off in a few years and sets not requiring glasses become the norm, you'll soon have a major problem using your old 2D one for anything since no one ever said the new signals would be compatible with old receivers and I could not imagine why the industry would want anyone to keep their old devices when they can force you to buy shiny, expensive new ones just at the time your current shiny, new, digital HD set has seen the age the industry would prefer to see it replaced at (which, for a TV set, is around 5 years).

If the industry had a way to change the physical properties of sound, they'd do it, just to make sure you won't use the same set of loudspeakers for more than a decade smile. So I'm sure they will find a way to make you embrace 3D weathermen and casting shows just so they can have 3D ads jump at you in larger than life size.
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#558545 - Tue Oct 19 2010 04:23 AM Re: Shut off LCD TV for one hour?
mehaul Offline
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Those Watts, no matter how small or seemingly insignificant, are culprits. They represent heat generation. Those stand-bys wattages are feeding a dummy load (usually the LED stand-by indicator lamp) until a ray of infra-red causes a switching. The heat builds up in those dummy loads to very high temperatures. elevating the thermal stress on the circuitry even without running anything. A component is rated at standard temperature and pressure that means about 70F. turning things on should start from that stress point. But if you've raised the temperature in the power supply to 130F without even using it, the temp, and therefore the stress, rises up from that temperature to determine mean time to failure.

It's interesting to see the article posted here linking to a BBC report of a girl who burned her legs from having a lap top and its internal DC power supply sitting on her legs for a few hours. Try this test (or for legal reasons, don't try it) After your TV has been on for a while. Shut it off and unplug it from the power line. Now feel around the case to locate the hot spot where the power supply is located (it should be in back near where the power cord enters the unit). The warm spot indicates where the power supply is located. Now plug the set back in and leave it "off" for a few hours. Then go back and see if you can feel the heat the infrared circuit draws by being on while the TV is off. It should be about the same spot as before or a little toward where your sensor window and standby indicator LED are.
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#558618 - Tue Oct 19 2010 09:37 AM Re: Shut off LCD TV for one hour?
tellywellies Offline
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Hello WesleyCrusher smile
Quote:
When this 3D stuff really takes off in a few years and sets not requiring glasses become the norm, you'll soon have a major problem using your old 2D one for anything since no one ever said the new signals would be compatible with old receivers.

As with the changes that are occurring in UK now (analogue to digital) a complete changeover to the latest TV standard is likely to be a fairly slow process. When the old standard is dying out, there will likely be a box that converts any new format to something will enable the old TV to still give sound and vision, just as there is now with the switchover from analogue to digital. I feel that old TVs probably won't become redundant before they break down and need to be replaced because of that.

The slowest changeover in UK must be the one from 405 to 625 line transmissions. 625 was being transmitted by all TV stations by 1969 (earliest was BBC2 in 1964) but it was still possible to use a 404 line TV until 1984-5. Dual-standard TV's were the norm for all of those years. Many of those were still in use on 625 only for a while after that. I don't think a change from one standard to another would ever be that slow again but today's TVs probably won't become useless within any short space of time should a new transmission standard become the norm.

Hello mehaul smile
Quote:
But if you've raised the temperature in the power supply to 130F without even using it, the temp, and therefore the stress, rises up from that temperature to determine mean time to failure.

I don't think that is necessarily the case. The 1 watt and 0.75 watt figures my TVs use in stand-by are those not only stated in the manual but also the figures measured by my trusty power meter at the mains socket. So this really is all that is taken by the primary circuit while in waiting for a remote control command. There is no LED alight, although there has to be a remote control sensor powered up. I think this sort of current usage isn't likely to raise the temperature of components very much. Indeed, there are no hotspots at the back of the TVs or any discernible warmth from the ventilation slots. Electronic components can run pretty hot and still be reliable although the cooler the better does apply. Even if there are stand-by components running at 130ºF, I feel this wouldn't be a life-shortening temperature or factor.


Edited by tellywellies (Tue Oct 19 2010 09:40 AM)
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#558702 - Tue Oct 19 2010 04:33 PM Re: Shut off LCD TV for one hour?
ladymacb29 Offline
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Originally Posted By: tellywellies
I've read about those who never turn their home computer off.


At work, we're told not to turn off our computers at the end of the day 'in case' the tech support people need to push some updates to the computers.

I've always thought that's a wasteful thing - just do the updates when you come in the morning...
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#558747 - Tue Oct 19 2010 09:33 PM Re: Shut off LCD TV for one hour?
mehaul Offline
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Rather than ... Can we agree that when not being watched, unplugging is better than leaving TVs plugged in and the IR ckt on? Since most people don't put surge protectors on the TV, it is even more important to separate from line fluctuations with your power supply in the 'on' condition. What good does it serve your TV power supply to be strained by your refrigerator cycling on, or your AC or Heater blowers (notoriously noisy things to be in line with)? The Coffee grinder? Or that noisy electric shaver sending that noise power through the filter capacitors of the power supply when the TV isn't even being watched? Once the filter caps are cooked, the ac noise passes right on through the rectifier diodes and voltage divider to your IC's. Unplugging also gets you bending over for exercise to reach the plug/outlet.
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#558764 - Wed Oct 20 2010 12:25 AM Re: Shut off LCD TV for one hour?
tellywellies Offline
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True that the mains has interference/spikes on it but I can't say I've ever had any problems with domestic electronics items caused by this. Certainly, a power supply's voltage output to the working components of any domestic electronics item will be very clean and stable (regulated). I think designers of power supplies are aware of conditions that may occur in the mains supply and design power supply circuits to cope. They perhaps didn't succeed at this to start with but it seems to me that, these days, power supplies are pretty reliable. All aspects of domestic electronics items are more reliable than they used to be years ago.

I never had internal mains filter capacitors go wrong but It's been a while since I was involved with domestic electronics repairs. If you say that modern filter components can fail, then I'll have to accept that. Also, I'd have to say that not all electronics items on stand-by will only use a watt of electricity. I consider this factor before I buy a TV but not everyone will.

I think we're in broad agreement anyway mehaul. It's best to turn equipment off if not in use but I'd qualify that with a time factor. I think it's OK to leave any item in stand-by if it's only for an for an hour or so. Circuits are made for it. Stand-by is OK While cooking dinner but when going to bed, turn the TV off at the mains ..apart from my 1 watt or less televisions that I've had for a number of trouble-free years now. smile
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#558772 - Wed Oct 20 2010 01:12 AM Re: Shut off LCD TV for one hour?
WesleyCrusher Offline

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Originally Posted By: tellywellies

As with the changes that are occurring in UK now (analogue to digital) a complete changeover to the latest TV standard is likely to be a fairly slow process. When the old standard is dying out, there will likely be a box that converts any new format to something will enable the old TV to still give sound and vision, just as there is now with the switchover from analogue to digital. I feel that old TVs probably won't become redundant before they break down and need to be replaced because of that.


You're right about the digital transition of course, but the slowness of that change (and the willingness of the industry to support it with set-top boxes) is mainly due to the fact that it conflicts with the (botched :)) changeover to HD. When the digital conversion was brought up, some 10-20% of households had already purchased HD sets and more were on the verge of considering it. With a generation change already in swing and acceptance rather reluctant, the industry did not want to add deterrents and rather merged in the digital transition as unobtrusively as possible.

With 3D likely coming at full strength in about 5 years, I am pretty sure they'll want to make a fast switch. It looks like by that time, there will be a good content base for it as well (unlike for HD) including top-level upconverted content such as the Star Wars and Lord of the Rings series, so the consumer interest in sets will be much higher than for the HD change. The main acceptance barrier for 3D right now is that you need the somewhat uncomfortable glasses, once the current prototype technology for putting the beam separation right into the screen is market ready, I see things going very fast.

(BTW, I am from the industry myself - on the technology provision for broadcasters side, but I can't help seeing the trends on the major annual trade shows.)

Wes
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#558776 - Wed Oct 20 2010 01:45 AM Re: Shut off LCD TV for one hour?
tellywellies Offline
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The thing that comes to mind is that there was a real feeling a while ago that older televisions would become redundant when we all went digital. That misconception was even voiced in the press and many people genuinely believed it. Well, we knew it wouldn't be the case. A Freeview (or other) box was all that would be needed.

So now 3D is being spoken of. I suppose we'll all have to see how it pans out but personally, I wouldn't be at all surprised if that 3D signal can be picked up by a box and made compatible with 2D TVs.

As with the digital switch-over, the majority of people might go for 3D long before any permanent change to the signal format has been made. However, there will always be a good number of people who just want to watch a spot of TV and are not interested in the latest innovations. I'm reasonably sure there'll be a handy box to cater for them.
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#558806 - Wed Oct 20 2010 06:19 AM Re: Shut off LCD TV for one hour?
sue943 Offline
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Quote:
The slowest changeover in UK must be the one from 405 to 625 line transmissions. 625 was being transmitted by all TV stations by 1969 (earliest was BBC2 in 1964) but it was still possible to use a 404 line TV until 1984-5. Dual-standard TV's were the norm for all of those years. Many of those were still in use on 625 only for a while after that.


In the Channel Islands we were amongst the last to switchover to 625 and to get colour television which came even later. We bought a secondhand dual standard black and white television set to tide us over the interim period as our old home couldn't pick up 625 without costly aerial replacement. We bought a colour set for our new home though.

Quote:
The thing that comes to mind is that there was a real feeling a while ago that older televisions would become redundant when we all went digital. That misconception was even voiced in the press and many people genuinely believed it. Well, we knew it wouldn't be the case. A Freeview (or other) box was all that would be needed.


My bedroom television set is over 20 years old and has no SKART socket but as it has hardly been used I was reluctant to replace the set. The Switchover Help people literally fitted the missing part yesterday afternoon, it is a UHF Modulator which is connected to the TV set and sits beside the FreeSat box on top of the television. I can now pick up all the digital signals.
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#559185 - Thu Oct 21 2010 11:20 AM Re: Shut off LCD TV for one hour?
tellywellies Offline
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Modulator? I thought that was someone who helped look after forums. smile
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#559356 - Fri Oct 22 2010 03:45 AM Re: Shut off LCD TV for one hour?
sue943 Offline
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smile Well at least it is all working ok.
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#559434 - Fri Oct 22 2010 10:01 AM Re: Shut off LCD TV for one hour?
tellywellies Offline
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That's good Sue. I hope your old(er smile ) TV will continue to give good service. If it does decide to go west because of old age (heaven forbid), I notice some of the smaller screen TVs suitable for bedrooms are a good price now.
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