Broken LCD HDTV

My 5 months old LCD HDTV (a 19" Philips model with 1440x900 16:10 resolution and PC input, mostly used for computer stuff) broke down yesterday. It is
not completely dead. It dies within about 10 to 20 minutes of being powered on. By "dies" it no longer functions and the screen goes dark but the back light illumination appears to still be on. It won't turn off by remote or the buttons located on the top edge. I have to unplug the AC power.
I believe the problem is a thermal condition likely in the PSU.
This all started when I started watching WTOV-DT channel 9.3 weather radar. Someone online mentioned they saw the new channel so I checked it out. As some storms happened to be coming by the past few days, I left the TV on all night a couple times. Normally I have left it on with the PC, which would go into video power saver made shutting off most display functions. But with the radar it remained running constantly. I neglected to think about it. I was more concerned about the speed of getting it turned on if I wanted to watch in the middle of the night as that takes almost a minute for it to "boot up" from cold-off.
I did notice once that the air rising from the top side vents was particularly hot. I shut it off at that time. But later when I had it back on again, it eventually just up and died on its own, like the CPU had frozen.
I have allowed it to spend much time cooling down (hours in a cool room) and tried it again. The longest it will now run is about 20 minutes. When it actually dies (I finally watched it for long enough to see it do this) it does some kind of pixelation thing that is rather different than digital TV pixelation. It does this even for analog TV channels and PC input. It then blanks out and resets a couple times, coming back on. Finally it stays off.
It's unplugged for now and I won't use it in case such usage could cause more permanent damage.
I'm contemplating opening it up and trying to see if I can figure out what might be wrong inside. Maybe it has gotten too dusty inside and is not letting heat out fast enough and its a simple thermal trip. That pixelation on the screen does seem to me that the CPU or other digital circuitry is getting a low or incomplete voltage situation.
I've never opened up an LCD flat screen TV before. Are there any general suggestions on how to handle doing this to avoid damaging it in other ways?
Has anyone here ever opened up one of these before?
I'll only do this if I find it's not under warranty. I don't normally buy those extended warranty plans for something in this price range, and this event won't change that (I would for something in the $2000 price range). But maybe the factory warranty still covers it. I'll have to dig the box with all its paperwork out of the garage to see. Most things I buy don't break for years. This is the first thing to die that soon in at about 10 years (a 5GB HD died a month after I bought it long long ago).
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snipped-for-privacy@ipal.net wrote:

If it is only 5 months old, surely it is still very much under warranty? In the UK it would have 1 year's warranty as a minimum, from the supplier. Plus any additional warranty that the manufacturer might have provided.
It sounds like permanent thermal damage.
It may be that some thermal bonding material has become degraded and could be simply replaced - but that it a long shot.
You could opening it up and seeing if blowing in large quantities of cold air made a difference. Then localising the air flow to pin down which area, and finally which component, is causing the problem. It may be that a better heatsink, possibly with a fan, may do the job, even if the component itself is now less thermally efficient than it once was..
-- Sue
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| If it is only 5 months old, surely it is still very much under warranty? | In the UK it would have 1 year's warranty as a minimum, from the | supplier. Plus any additional warranty that the manufacturer might have | provided. | | It sounds like permanent thermal damage. | | It may be that some thermal bonding material has become degraded and | could be simply replaced - but that it a long shot. | | You could opening it up and seeing if blowing in large quantities of | cold air made a difference. Then localising the air flow to pin down | which area, and finally which component, is causing the problem. It may | be that a better heatsink, possibly with a fan, may do the job, even if | the component itself is now less thermally efficient than it once was..
It does appear to have a 1 year warranty. Now I need to find my receipt to prove purchase date. I have receipt piles in several places.
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wrote:

If you don't find the recipt check for the date code. Chances are it was MADE less than a year ago.
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| wrote: |> |> | If it is only 5 months old, surely it is still very much under |> warranty? |> | In the UK it would have 1 year's warranty as a minimum, from the |> | supplier. Plus any additional warranty that the manufacturer might |> have |> | provided. |> | |> | It sounds like permanent thermal damage. |> | |> | It may be that some thermal bonding material has become degraded |> and |> | could be simply replaced - but that it a long shot. |> | |> | You could opening it up and seeing if blowing in large quantities |> of |> | cold air made a difference. Then localising the air flow to pin |> down |> | which area, and finally which component, is causing the problem. |> It may |> | be that a better heatsink, possibly with a fan, may do the job, |> even if |> | the component itself is now less thermally efficient than it once |> was.. |> |> It does appear to have a 1 year warranty. Now I need to find my |> receipt |> to prove purchase date. I have receipt piles in several places. |> | | If you don't find the recipt check for the date code. Chances are it | was MADE less than a year ago.
Good point! I'll check for that.
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snipped-for-privacy@ipal.net wrote:

Cut rest.
This doesn't answer your question but there might be some guidance here: http://tinyurl.com/yuj27l Some hard core electronics users are here. It doesn't sound like any are EEs or fixers but maybe there is help there anyhow. There is a search feature near the top.
Dean
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Get shop to repair, replace or refund.
Lordy
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snipped-for-privacy@ipal.net wrote:

If you can't warranty exchange, try posting on sci.electronics.repair, that's where the techs hang out. I would get out the freeze spray and a hair dryer and start poking around. Wouldn't hurt to check all the power supply rails before and after the fault condition as well. I've run into cases where a bad optocoupler would allow the voltage to slowly rise as the device warmed up, took forever to track down because the symptoms pointed to something else.
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