Issue with my LCD

Ok, so this is actually my TV, not my monitor. But I figure that since it's LCD, it's similar enough. I'm wondering maybe if it's a capacitor issue?

We got a Sceptre 46" LCD from Costco a couple years ago; it's big and heavy but looks fantastic, and it's been working wonderfully. Until last night.

I went to turn it on, and while its red standby light was on, nothing else happened. Eventually, I tried unplugging it and plugging it back in. The first time, it came on but got stuck on the screen showing which input it was using. The next time, it turned on and worked for a few seconds, then a high pitched beeeeeep came out of the speakers. It was still showing a moving picture but was otherwise frozen. After a couple more instances of unplugging/replugging, it finally powered on and worked fine. Until I tried turning it on today after it was off all night. Went through the same thing again, although this time when it finally turned on it worked fine.

Upshot seems to be that once it's on, it's ok. But completely out of nowhere yesterday it started having these power-on issues. Anyone have any ideas other than capacitor problems? Unfortunately we can't really afford to replace it right now, but if it IS a capacitor, I *might* be able to do something about it...

do you still have the reciept? if so, i'd just take it back and get a new one.

We got it online thru Costco, and it's well outside of their return policy timeframe. Sadly they don't do the unlimited return policy anymore - it's 90 days now. And we bought this back in January of 2009.

crack it open, look for bulging caps? sounds like a power supply issue to me.

Yeah, it's sounding that way. I've noticed too that a couple times it's shut itself off and come back on again within a minute or two of the initial successful powerup. Once it's successfully powered on, it stays that way indefinitely (at least for now). But turning it off and on again it has problems again.

same issue with my 28" HANNS-G that was molested by a drunk guy.


works fine once it gets hot, but it flickers and makes sounds with lots of visual errors when its cold.

Sceptre X46BV-FULLHD User Manual here, Service Manual here.

The User Manual repeatedly stresses that the panel takes at least 10-12 seconds to fully power up. It also has a little troubleshooting info and Sceptre contact information.

You'll probably find that it's a rebranded generic 46" panel made by somebody like LG or Samsung, but there's really no way to know until you open it up and lookup the part numbers. The most common failure point on these sorts of TVs - barring physical damage to the display glass - is corrupted firmware (can be easily fixed/flashed by a tech) or bad power supply (swapping module usually cheaper than detailed troubleshooting and component repair). Sometimes bad caps are just bad caps, cheap junk or poorly rated for the application ... but as often as not they'll be blown because of a more fundamental failure in the PSU design, or (sadly) because of really substandard solder points on high-power connections. You can often replace caps with better ones, same capacitance/farads but higher breakdown voltage, to correct borderline design faults. Large screen TVs are notorious for running hot, their cooling is barely adequate to prevent a fire and parts suffer a lot of strain (die faster) when operating for hours at the upper limits of their thermal ratings; a couple of cheap little 12V fans to suck air out the top of the chassis can do wonders.

Quote:

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Originally Posted by Konrad

Large screen TVs are notorious for running hot, their cooling is barely adequate to prevent a fire and parts suffer a lot of strain (die faster) when operating for hours at the upper limits of their thermal ratings; a couple of cheap little 12V fans to suck air out the top of the chassis can do wonders.

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Also, the new ROHS compliant lead-free solder that's used in absolutely everything now is crap. It fractures under thermal stress, resulting in premature electronics failure (like the "Red Ring Of Death"). Adding in the fans would go a long way to reduce these issues, but also the companies need to look at better electronics design which take into account the lead-free solder problems. The constant march toward thinner models also contributes toward this device failure. It's completely inadequate thermal design.

The constant march towards thinner models does lead into more thermally-efficient display panels. Of course the craze is to always put the new tech into an even bigger screen than ever before, so the heat problem doesn't really go away. But the slightly smaller-screen units (ie: last week's mega screen) tend to run far cooler, while incidentally saving a fair amount on your energy bill.

Do LEDs vs. traditional CFLs make a difference?

LED backlighting is still used in display panels, though I don't think any CFL technologies were ever used. I could be wrong.

The easiest ways to compare CFLs and LEDs would be to plug them through a Kill-A-Watt meter. Or just measure their temperatures after an hour of operation; if you assume they are both rated reasonably close in terms of brightness or candlepower then hotter means more energy wasted in non-visible radiation spectra.

I think it's CCFL, actually....

Missed a sea there.... <_< >_>