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CRT Screen Burn in

AFrost20
04-04-2006, 10:51 PM
Im fairly new to the HDTV scene...but i LOVE it. One quick question....when non-HDTV shows come on my tv ( i have the 30" widescreen Sony Wega HD) i have it set through the cable box to leave the black bars vertically on the sides of the picture so that it doesnt stretch or distort. Will the black bars cause burn in over time? or is that simply a part of the screen not being used? Thanks a lot...if it wil leventually cause burn in, i will live with a stretched image.

godson
04-05-2006, 01:37 AM
I have my CRT for almost a year and have my settings like you do. I have no problems(yet) but I have heard it can cause less of a burn-in,more like the color where the sidebars would are dull compared to center of screen when watching 16x9 programming. I would imagine you would have to watch ALOT of programs with sidebars for tha to happen but I dont know for sure.

mfabien
04-05-2006, 05:25 AM
Recommended viewing with side bars is a limit of 15% with a CRT.

BobY
04-05-2006, 01:37 PM
Some HD CRT's display grey sidebars to try to "age" them at the same rate as the active portion of the screen.

CRT-based projection TV's have a much greater risk of burn-in than direct view as they are driven harder.

Porcupine
04-06-2006, 03:29 PM
If one did have a CRT (or any kind of TV, really) that eventually got a little sidebar burn-in, I wonder if it would be possible to burn it back to normal by purposefully displaying the negative image content of whatever burned it in? :)

In other words, suppose your TV has sidebars slowly burned in due to watching 4:3 material with black sidebars. Maybe if you generated an image of bright white sidebars and left it on for days, the TV would be balanced again. :)

Ratman
04-06-2006, 03:52 PM
Possibly... if you could turn the sidebars white. ;)
Turning the entire 16:9 screen white would serve no purpose...

BobY
04-06-2006, 04:02 PM
If I'm tracking, the black areas of the screen are what is *not* being burned-in. The phosphor is not being excited at all, so it doesn't age as much as the active area of the screen, rendering a difference in brightness over time.

It seems like you should be able to prematurely age the bands by making them bright white, but aging them just the right amount would probably be tricky. Could be an interesting side business for somebody--make a DVD of white sidebars and fix people's burned-in sets!

Although I don't care for the grey bars (so I always watch in the "stretched-sides-only" mode), it's probably the best solution to prevent uneven aging.

maicaw
04-06-2006, 04:21 PM
( i have the 30" widescreen Sony Wega HD) i ... Will the black bars cause burn in over time? or is that simply a part of the screen not being used? .http://www.theperfectvision.com/newsletter/tpv51/sony_kv34xbr910.html30" KV-30XBR910 and the 34" KV-34XBR910. I chose the $2800 KV-34XBR910 for this review.
Why Direct View?
There are good reasons why the analog picture tube is still the preferred choice of display for many consumers. It has the best contrast ratio, with its ability to reproduce a “true” black. As a phosphor-based emissive device, it ties plasma’s wide angle of view. It is capable of accurate color reproduction and is not easily prone to image retention, called “burn in” (only bettered in this respect by flat LCD panels). The CRT, being an analog scanning display, has no set pixel structure, making for a smooth picture. It is also the only multi-scan direct-view technology available, allowing (in this case) native display of both 480p and 1080i sources.

ahof1011
04-06-2006, 04:21 PM
This is a little off subject, but, if watching the a crt television "ages" the screen does that mean that you would eventually have to change the picture settings to acheive an image comparable to a new set?

Ratman
04-06-2006, 04:42 PM
The phosphors age on CRT and plamsa TV's. The longer they produce anything but "black"... they lose the capacity to produce an image.

Over time... they lose the "brilliance" of a new set. There's nothing that can be done (other than increasing brightness/contrast... which can only go so high).

Not to worry... CRT's have made people quite happy for over 50 years.

The only problems that make it more noticible now are sidebars, tickers, bugs, gaming and stupidity. ;)

Porcupine
04-06-2006, 04:56 PM
I think so. I've noticed this phenomena on my Dell 20" Trinitron CRT PC monitor over the last 8 years or so I've had it. I have to turn the brightness settings really high now to get an image I like. But since the change happened so slowly I can't be sure it's not just my eyes degenerating or my preferences changing. :)

I also have an old analog 20" JVC tube (no idea how much it costs, it was inherited) that must be 20 years old, which has an image I really like (perfect screen geometry and convergence, etc) but is just super dark and I can barely see anything through it even with Brightness at maximum. I'm assuming that it was probably good long ago and is simply dead now that is why it is that way. :) But maybe it was always that way, I dunno.

Anyway, the pseudo-death of my 20" JVC is partially what prompted me to recently go out and start looking at HDTVs.

I also think it may be true that even if you increase the Brightness settings on an older set to get it to look the same as when it was new, it still may not look the same. The screen phosphors will be worn out and the electron gun must shoot stronger to compensate. But when the electron gun is forced to operate at high intensities I think there will be more red bleeding, bleeding in general, convergence problems, etc. So I think when a set starts to get kinda dark it is already approaching death. :)

I'm sad. My Dell 20" CRT is so good but after it dies I think it may be irreplaceable because everyone is making LCDs now. :(

maicaw
04-06-2006, 05:41 PM
I also think it may be true that even if you increase the Brightness settings on an older set to get it to look the same as when it was new, it still may not look the same. The screen phosphors will be worn out and the electron gun must shoot stronger to compensate. But when the electron gun is forced to operate at high intensities I think there will be more red bleeding, bleeding in general, convergence problems, etc. So I think when a set starts to get kinda dark it is already approaching death. :):(The cathode (the electron emitter) is probably the problem -there used to be rejuvinators that increased the voltage to the filament to keep the cathode hotter for it's remaining years - but that stuff when out with the B/W tvs - The phosphers can wear out - but more likely it is poor cathode emission or weak flyback transformer ( High Voltage) or atmospheric gasses leaking into the CRT that is the cause of the darkness and red fringes. -
when tubes ruled - "filament activity" testing (lowering the temperature of the cathode about 10% and measuring the loss of emission) was the best way to judge the health of a vacuum tube- same as a CRT now

BobY
04-06-2006, 07:59 PM
Absolutely. In the average lifespan of CRT (certainly in excess of 10 years), you should never get to the point where the image is too dark to see as a result of the phosphor aging (well, maybe if you keep it at maximum brightness and contrast all the time).

It is far more likely you have a power supply problem (which may be repairable) or the tube filament is dieing (not repairable, although tweaking the power supply may improve things until it finally goes for good). Remember it's a BIG vacuum tube and behaves like one.

Porcupine
04-07-2006, 04:13 PM
I see, so you guys are saying that the reason my 20" JVC analog tube has become super dark could be due to other reasons besides phosphor wear. In any case, whatever the reason, my old TV became dark. :) I have no idea how old this TV is. It says AV-2058S on the back now, I just looked. Just did websearch, found some links but nothing to help me figure out when this set was made. I think this TV is pretty damn old though. It must be at least 20 years old I would think, as I inherited it from someone else whom I have no idea how long they used it. It was already fairly dark when I got it, and I think it's become slowly darker since then.

Porcupine
04-07-2006, 04:18 PM
Aha. Found some obscure link that seems to indicate this TV was produced in 1988 or around then. So this TV really is close to 20 years old perhaps. :) So it's totally reasonable for it to be near death from natural aging.

maicaw
04-07-2006, 04:40 PM
Aha. Found some obscure link that seems to indicate this TV was produced in 1988 or around then. So this TV really is close to 20 years old perhaps. :) So it's totally reasonable for it to be near death from natural aging.I have a 1985 25"XBR that is used several hours a day and is still looking as good as new - better than most analog sets in the stores today - when fed high quality NTSC composite (analog cable)- amazing video processing and equipment that no one seemed to appreciate - of course it cost $1000 even then- ˝ a month's pay - those old good CRTs won't die in 20 years!

Porcupine
04-07-2006, 05:43 PM
Maybe something actually went wrong with my set then, I dunno. It's a great TV (perfect geometry, convergence, flatter screen than equivalently-sized curved-screen tubes today) other than the fact that it is dark. Maybe it's worth trying to get fixed, but I'll probably be too lazy. I don't know how long the previous owner used this set either, it could be they left it on all day long for years. :) I also have no idea how much this TV costed, I'm kinda curious.

BobY
04-07-2006, 09:46 PM
I had a Philips 27" IDTV ("Improved Definition TV"--early progressive scan) from 1989 that was still working perfectly and looked outstanding until the power supply blew up in 2004. The tube itself wasn't anything out of the ordinary.

BrianO
04-07-2006, 11:19 PM
I have a 29 year old MGA (Mitsubishi) CRT set that shows no sign of burn-in and still has a bright picture at its "default" brightness, contrast and colour settings. Even its mechanical controls are in reasonable shape. It was only relegated to my computer room in December 2002 and it is on as I type. It has seen daily use since it was purchased. It was manufactured in November 1975 and purchased in early 1976. Of course it has never been abused by playing games on it. :)

AFrost20
04-07-2006, 11:19 PM
I just started using the "stretched" picture setting for my normal digital channels. But, it sucks that some of the local channels that broadcast in "HD" all the time, have the black bars on the side, and there is nothing you can do about it. I assume these are the instances where it is upconverted to HD, as opposed to actually being HD. Oh well.... dont watch them much anyways. Kinda off-topic...this 30" widescreen has been worth EVERY penny of the 719 i spent for it...the HD broadcasts are stunning. Like ive read so many times, i cant STAND to watch normal TV channels now.