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| Thread ID: 49652 | 2004-09-26 10:09:00 | Blurry Desktop | woody99 (6198) | Press F1 |
| Post ID | Timestamp | Content | User | ||
| 275793 | 2004-09-27 00:14:00 | Sorry Darryn That link is correct, but Earnie (AKA E.ric) has taken down the monitor test patterns. Unfortunately he was badly treated by one or two PF1 members and not surprisingly he withdrew his website in protest. I'll look for another site and post that later. Cheers Billy 8-{) :( |
Billy T (70) | ||
| 275794 | 2004-09-27 00:44:00 | Here we go..... sal.neoburn.net sal.neoburn.net |
woody99 (6198) | ||
| 275795 | 2004-09-27 01:30:00 | How old is your monitor? I sell second hand computers, and have had numerous blurry monitors for different reasons. There seem to be three types: 1) The monitor has (one-off) come out of focus. This can be fixed by looking for a focus hole in the back of the monitor, inserting (carefully!) a flat screwdriver and turning while watching the screen to check the clarity of the picture. 2) The monitor is old, and things are starting to change inside it. This will be constantly changing the focus of the monitor, so you will have to do the above every time it becomes blurry. 3) (Your case I'm pretty sure) - The monitor has become damaged in some way internally, and the focus is no longer regulated, but fluctuates with the input to the screen. You may also notice discolouration, also fluctuating with input. The reason this happens is that focus works by the amount of voltage sent into the tube. On your monitor, when there is a bright screen or a dark screen (depending on your particular case), the voltage is changed. Brighter means more voltage, and therefore different focus. This is not easy to fix, so I suggest you try to get it done under warranty. Cheers George |
george12 (7) | ||
| 275796 | 2004-09-27 02:17:00 | There appears to be no difference at all in focus between the 2 images you have put up. | Terry Porritt (14) | ||
| 275797 | 2004-09-27 02:29:00 | Is it just me or does the blurred one look better than the focussed one? | Pete O'Neil (250) | ||
| 275798 | 2004-09-27 03:19:00 | Sorry George, but most of your post is simply incorrect . Only point 1 is true, and then only for relatively old monitors . You will almost never see a modern monitor with an access hole to adjust focus . > 2) The monitor is old, and things are starting to > change inside it . This will be constantly changing > the focus of the monitor, so you will have to do the > above every time it becomes blurry . A broad generalisation that is fundamentally incorrect . Focus performance is pretty much tied to power supply output stability and the regulation characteristics of the horizontal output stage . > 3) (Your case I'm pretty sure) - The monitor has > become damaged in some way internally, and the focus > is no longer regulated, but fluctuates with the input > to the screen . You may also notice > discolouration, also fluctuating with input . Firstly, focus is not directly regulated . Its stability is derived from the power supply and horizontal output stage as mentioned above . Apart from monitors that have been dropped (permanent colour errors) colour patches are usually purity errors (corrected by degaussing) . Colouring variations caused by brightness changes are white-uniformity errors, and they are caused by poor beam registration or warping of the shadowmask or aperture grille due to over contrasting and excessive beam current . > reason this happens is that focus works by the amount > of voltage sent into the tube . On your monitor, when > there is a bright screen or a dark screen (depending > on your particular case), the voltage is changed . > Brighter means more voltage, and therefore different focus . The voltage fed to the CRT (tube) is closely regulated and does not vary significantly with changes in screen brightness . If it did, the image would change size (larger when dark, smaller when bright) which is an effect known as blooming . The focus voltage is tied to the EHT voltage so that won't vary independently either . The most common cause of focus variation with brighness is a weak CRT . The source impedance for the electron beams rise as the CRT ages and the beam current becomes non-linear . When high demands are placed on it for bright screens, the beam will no longer focus properly so it goes blurry . Conversely, turning down the contrast and brightness will allow the image to focus better . The best test for focus problems is to display a cross hatch pattern and look in the corners of the screen, that is where focus problems will first become apparent . If you can't display a crosshatch, open a WP document with the smallest margins you can create and fill it with Arial 20 or 24 point capital H's . They will give nice fine lines out in the corners . I'm not knocking you George, but your information is very inaccurate and that is not really helpful to people looking for answers . I accept that you have established some background experience through your monitor sales, but the reasoning behind that experience is incorrect and it is not helpful to pass on those misconceptions . See FAQ #3 and FAQ #4 for factual information, but remember if you are selling monitors, you cannot open them up to carry out focusing adjustments unless you are appropriately electrically qualified . If you do and something goes wrong electrically the buyer may come back to you and it could be a bit of a nightmare for you . The Electricity Act regulates who may work on or inside electrical and electronic equipment . Cheers Billy 8-{) |
Billy T (70) | ||
| 275799 | 2004-09-27 03:27:00 | Fixed!!! Folks - thanks for all your help. I found a utility embedded on the onscreen menu called "Image Restoration". Tried this and the whole thing went blank and then different shades of grey before restoring itself to near-new clarity. The book says this works but will reduce in effectiveness as the monitor gets older. Worth storing for the next pleb like me you see wandering around PressF1. Thanks again for your troubles.. Darryn |
woody99 (6198) | ||
| 275800 | 2004-09-27 04:15:00 | I'm with you Pete, one looks as good as another to me. | theother1 (3573) | ||
| 275801 | 2004-09-27 06:18:00 | Well Darryn, Image restoration simply resets the brightness and contrast to the original factory settings . Only that and nothing more . It has no effect on focus . Perhaps that is why we couldn't see what was wrong on your screen shot . Maybe you had the contrast turned too low? Either FAQ #3 or FAQ #4 (I forget which) will tell you how to set brightness and contrast correctly if you need to do that manually in future . Cheers Billy 8-{) |
Billy T (70) | ||
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