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#1
11-26-2021, 08:09 AM
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Blob or Burn-in???
This roadside find (Samsung 40" CCFL about '07) has some, I think, burns at the lower 1/3 of the screen. The set appears to have high mileage as evidenced by the dust on the inside. Works well otherwise, even has a USB jack (called wiselink) for multimedia-media playback. I thought burn-ins on LCD were impossible due to the way the crystals are energized.
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#2
11-26-2021, 09:59 AM
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Some kind of physical damage.
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#3
11-26-2021, 12:38 PM
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I wonder if that is some kind of heat damage. Like someone had a candelabra infront of the screen.
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Tom C. Zenith: The quality stays in EVEN after the name falls off! What I want. --> http://www.videokarma.org/showpost.p...62&postcount=4
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#4
11-26-2021, 01:06 PM
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I wouldn't go so far as to say burn-ins are impossible on LCD TVs. If this were true, after all, there would be no need for screen savers. My own LCD flat screen TV has a screen saver which starts after the TV has been displaying a stationary image for about a minute or two; the screen saver, of course, replaces the TV picture with a moving image. My computer monitor, which uses LEDs for backlighting rather than a single CCFL, has several different screen savers; one, the one I'm using now, replaces the stationary computer image with small moving dots, almost like snowflakes. My TV also uses LED backlighting.
I have never had problems with image burn-in on any computer monitor or flat-screen TV I've owned; I don't see any reason why I would have such a problem as long as the built-in screen savers work as they should. LCD (later LED) TVs and computer monitors have come a long way since they were introduced some years ago; the technology may and likely will continue to improve as time goes on, including new methods for backlighting. Screen burn-in was a serious problem with early LCD flat-screen TVs and computer monitors, but the problem is probably nowhere nearly as bad as it once was, especially since most flat screens now use LED backlighting rather than CCFLs. That is, image burn-in may still be possible if the monitor is run at very high brightness or backlight level for extended periods of time, but under normal use I don't see this as a problem. I would think LCD/LED TVs and computer monitors which are run full blast (as they often are in store displays, or applications such as bowling-alley scoring screens) would be prone to early burn-in, but, as I said, monitors used with home computers (TVs too) will probably last much longer than monitors used at high brightness 24 hours a day. Even televisions used many hours a day shouldn't have image burn-in as long as the LED brightness (or the normal brightness control) is not set insanely high; this, of course, is a one-way ticket to premature burn-in or even outright failure of the display panel itself, if the display drivers don't fail first from severe overload.
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Jeff, WB8NHV Collecting, restoring and enjoying vintage Zenith radios since 2002 Zenith. Gone, but not forgotten. Last edited by Jeffhs; 11-26-2021 at 01:21 PM.
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#5
11-27-2021, 02:56 AM
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Oh, LCD burn-in is totally possible. It's just that it usually happens to sets that are on the exact same screen for 8+ hours per day, for several years. Commercial environments.
In this case, with the black burn spots, I've seen it before on TVs used for store advertising that were in a window in direct sunlight for years and years. There's a shoe store that has about 4 of them, still in use with similar burn spots. It would be interesting to do an autopsy and see if those spots correspond to, say, resistors on the motherboard. Maybe each spot is an overheated spot. Blunt force trauma usually looks more like cracked glass and the display goes wacky in the area.
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#6
11-27-2021, 09:41 AM
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Wow - never would have suspected sunlight as a problem. Very interesting!
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#7
11-27-2021, 03:19 PM
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Can speak as well for LCD burn-in and heat damage as I repair displays that are running 24/7,365.
An LCD will burn in and as to the photo the black spots are the same as I see on multi-layer displays where the fans fail. The heat of the backlight causes the panel to develop micro cracks and rupture.
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#8
11-27-2021, 06:30 PM
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I have seen these blobs on the outdoor sets at my ballpark. Even covered, the overnight cleaners would high pressure clean near the sets. These blobs were there the next day. Water ingress?
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“Once you eliminate the impossible...whatever remains, no matter how improbable, must be the truth." Sherlock Holmes.
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#9
11-29-2021, 12:51 PM
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I've seen many a kiosk LCD with an "after image" where the large user buttons sit static for hours at a time. Our timeclock kiosk at work are a good example. The large ADP login/out box never goes away.
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#10
12-04-2021, 04:03 AM
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My cell phone has burn it on it. When the screen is on all white I can see the Opera mini taskbar and the icons burnt in at the top and bottom of the screen.
For years it was my only internet access so it's seen a lot of hours. The damage on this TV looks like it was hit by something.
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