Home |
Search |
Today's Posts |
|
Electronics Repair (sci.electronics.repair) Discussion of repairing electronic equipment. Topics include requests for assistance, where to obtain servicing information and parts, techniques for diagnosis and repair, and annecdotes about success, failures and problems. |
Reply |
|
LinkBack | Thread Tools | Display Modes |
#1
|
|||
|
|||
CRT life
Hi list,
I've read in a DPMS screensaver help file that blankscreen screensavers are not such a good idea, because when the CRT filament is still energized when there's no picture, actually causes the life of the CRT to shorten. Why is this? TIA Halfgaar -- To send me, Halfgaar, email, remove remove from my email address. |
#2
|
|||
|
|||
CRT life
Halfgaar wrote:
I've read in a DPMS screensaver help file that blankscreen screensavers are not such a good idea, because when the CRT filament is still energized when there's no picture, actually causes the life of the CRT to shorten. Why is this? I've got an addition to my question. Does this also mean that DPMS mode suspend is not good for the monitors's life, seeing as how in suspend mode everything is powered down, except the filament. -- To send me, Halfgaar, email, remove remove from my email address. |
#3
|
|||
|
|||
CRT life
Halfgaar wrote:
Halfgaar wrote: I've read in a DPMS screensaver help file that blankscreen screensavers are not such a good idea, because when the CRT filament is still energized when there's no picture, actually causes the life of the CRT to shorten. Why is this? I've got an addition to my question. Does this also mean that DPMS mode suspend is not good for the monitors's life, seeing as how in suspend mode everything is powered down, except the filament. Hmm, it seems that the CRT faq on repairfaq.org disaggrees with this completely: "With modern CRTs, the filaments can be left to minimize the time needed for a picture to appear since this doesn't affect CRT life very much." (found at http://repairfaq.ece.drexel.edu/sam/crtfaq.htm#crtlif). -- To send me, Halfgaar, email, remove remove from my email address. |
#4
|
|||
|
|||
CRT life
This can be a complicated issue.
There is more to the CRT than just the heater. When there is cathode current, the ware is higher. There is a minimum cathold current when there is no brightness on the screen. The tube has to be biased slightly on all the time when working, even though it is in black. When there is some luminocity on the screen, there is a greater amount of cathode wear in the electron-gun. Having a black screen saver will infact save some amount of catholde wear. If you have a small image on the screen that is moving around, this would introduce a bit more cathold current, but it would not be the same amount as having a full screen of white. The best solution is if the screen is not being used for about a 2 to 3 hour period, turn it off, or have the Windows power savings utility turn it off. Cycling the monitor power on and off, can introduce a greater stress on the support components, and the tube, rather than simply leaving it on. This gets in to duty cycle statistics on the wear of the electronics, and tube. This can get very complicated in many cases. The standard CRT should last about 30,000 hours. At this time factor, the brightness output should be about 50% of the nominal. This figure is with the brightness set to normal, and the contrast at about 50 to 70% of its maximum rage. If the monitor is used at about 10 hours per day, it should last about 8 years. In reality these monitors will last about 5 to 6 years. There are many support components that can go wrong before the tube does. Cycling the power off and on will also cause the monitor to fail quicker. After about 6 years of normal use, many of the capacitors start to go bad in monitors and TV sets. Then there are many other types of components that can fail. Since most monitors, unless they are very expensive and high end models, they are designed to not be serviced. In the low to medium end monitors, many of the manufactures don't sell the parts for out of warranty servicing. Enjoy the monitor. The way things are going obsolete these days, in a few years, your monitor will be useless, and may have to be changed anyways. Jerry Greenberg http://www.zoom-one.com -- Halfgaar wrote in message ... Hi list, I've read in a DPMS screensaver help file that blankscreen screensavers are not such a good idea, because when the CRT filament is still energized when there's no picture, actually causes the life of the CRT to shorten. Why is this? TIA Halfgaar |
#6
|
|||
|
|||
CRT life
Jerry Greenberg wrote:
This can be a complicated issue. There is more to the CRT than just the heater. When there is cathode current, the ware is higher. There is a minimum cathold current when there is no brightness on the screen. The tube has to be biased slightly on all the time when working, even though it is in black. When there is some luminocity on the screen, there is a greater amount of cathode wear in the electron-gun. Having a black screen saver will infact save some amount of catholde wear. If you have a small image on the screen that is moving around, this would introduce a bit more cathold current, but it would not be the same amount as having a full screen of white. I can understand this misundertanding... I was talking about that no picture at all is worse than *a* picture. The help file of that screensaver said that displaying a blank image for too long is bad for the filament. But the CRT-faq on repairfaq.org seems to dissagree and somehow I put more fate in the latter. A topic for confusion by the way: I call an image blank when there is no picture. Perhaps the author of that helpfile calls a white image blank... The best solution is if the screen is not being used for about a 2 to 3 hour period, turn it off, or have the Windows power savings utility turn it off. Cycling the monitor power on and off, can introduce a greater stress on the support components, and the tube, rather than simply leaving it on. This gets in to duty cycle statistics on the wear of the electronics, and tube. This can get very complicated in many cases. For most electronics this might be true, but this seems to be a misconception about monitors. You shouldn't power cycle to often of course, but a few times a day is not so bad. A CRT wears down through use very quickly. The disadvantages of leaving it on are greater than the advantages. The standard CRT should last about 30,000 hours. At this time factor, the brightness output should be about 50% of the nominal. This figure is with the brightness set to normal, and the contrast at about 50 to 70% of its maximum rage. If the monitor is used at about 10 hours per day, it should last about 8 years. In reality these monitors will last about 5 to 6 years. There are many support components that can go wrong before the tube does. Cycling the power off and on will also cause the monitor to fail quicker. After about 6 years of normal use, many of the capacitors start to go bad in monitors and TV sets. Then there are many other types of components that can fail. Since most monitors, unless they are very expensive and high end models, they are designed to not be serviced. In the low to medium end monitors, many of the manufactures don't sell the parts for out of warranty servicing. I'm asuming that my Eizo monitor is one of high quality, so I expect to use it for a while. With the color restoration feature, the brightness should even stay constant. BTW, do you know something about that color restoration feature? I may have some troubles with it. Enjoy the monitor. The way things are going obsolete these days, in a few years, your monitor will be useless, and may have to be changed anyways. I hate that aspect of modern economy. Devices are designed to fail after a few years, so the manufacturer will sell more... -- To send me, Halfgaar, email, remove remove from my email address. |
#7
|
|||
|
|||
CRT life
Halfgaar wrote:
I'm asuming that my Eizo monitor is one of high quality, so I expect to use it for a while. With the color restoration feature, the brightness should even stay constant. BTW, do you know something about that color restoration feature? I may have some troubles with it. Most recent Sony monitors have a feature called color restore that appears to apply various preset signlas to the CRT and measures the cathode currents so it can return them to the original factory preset values. It's basically an automatic grayscale adjustment. It works so well that I've been able to swap CRTs and only have to run the color restore to get a perfect grayscale. It take a lot longer to complete the color restore after a CRT swap, but it eventually gets it right. -- Andy Cuffe |
#8
|
|||
|
|||
CRT life
Halfgaar wrote:
Can you tell me this? My monitor, Eizo T766, Sony Triniton tube, displays a grey square for a about a second and then returns to the OSD. I've tested a lot of them, and this is what they do. Except for two exceptions (reasonably new models, newer than mine), which noticibly changes RGB intensity for a while, after displaying the grey square. They do that every time again. So my monitor, and many others, appear to be doing nothing at all. Or, the only thing I can think of, is that by displaying that grey square, it determines that the CRT is still OK and does not have to be adjusted. So in essence, those two models I've seen which do calibrate wouble become the faulty ones, not mine. Any comments on this? Eizo instisted that it should behave like my T766 does. But companies will say anything to protect themselves. Halfgaar -- To send me, Halfgaar, email, remove remove from my email address. I'm not familiar with Eizo monitors, but it you could be right. What happens when you try to run it a second time on the ones that seemed to do a calibration? -- Andy Cuffe |
#9
|
|||
|
|||
CRT life
I'm not familiar with Eizo monitors, but it you could be right. What
happens when you try to run it a second time on the ones that seemed to do a calibration? As I said, they do that every time again (calibrate RGB), but there's something to tell about that. I've borrowed a T965 for a week or so from the repairservicecenter. That one recalibrated red/green/blue time and time again. I also tested one which was on display in a shop. I believe I tried it on that one twice, and both times it calibrated RGB. The odd thing is, when I tried it a week or two later, it did as mine, display only a grey square for about a second. Then the last one: I asked someone I know of an internet-forum who has the same monitor to describe what happens. His monitor also calibrated RGB. But, I didn't ask him to do it a second time. Perhaps I could do that. But is the colorrestoration feature of monitors based on the same tube so different? I mean, it utilizes a feature of the tube, right? What did the Sony tubes display you have experience with? Halfgaar -- To send me, Halfgaar, email, remove remove from my email address. |
Reply |
Thread Tools | Search this Thread |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Forum | |||
Shelf life for glue (revisited) | Woodworking | |||
Titebond III shelf life. Also appreciate an comments from users of this product. | Woodworking | |||
OT-Celebration of George Harrison's Life | Woodworking | |||
Cooker Hood Carbon Filter Life? | UK diy | |||
Life isn't worth living anymore | Electronics Repair |