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rvijay 09-14-2003 09:29 PM

Monitor Screen Shaking a Lot.
Whenever I run Linux, my monitor screen is shaking a lot. There are a lot of lines if one observes closely and also some tiny flashes. I don't have this problem when I run windows. What does this indicate ? Thanks.


maroonbaboon 09-14-2003 09:41 PM

This is in X-windows, right? Your X-window config may be pushing your hardware past its limits. In your /etc/X11/XF86Config-4 file (or same without '-4' if you don't have that) the 'Monitor' Section should have a couple of lines like:

HorizSync 30 - 71 # DDC-probed
VertRefresh 50 - 160 # DDC-probed

You could check that against your monitor specification to see if it is reasonable.

rvijay 09-14-2003 09:59 PM

Yes, this is in X-Windows. They are exactly what you posted above. Do you think it will be safer if I gave something like 40-60 and 50-125 ?



maroonbaboon 09-14-2003 10:19 PM

I'd check against the model of your monitor first. An easier thing to try is to go to a lower resolution (Ctrl-Alt-Keypad+/- switches resolutions). The sequence is determined by what is in the 'Screen' section of the XF86Config file.

If this cures it you can edit out the offending resolution in that Config file, assuming you are OK with the lower resolution.

It may also be that your monitor has a hardware fault, and cannot run at its full spec.

akaBeaVis 09-14-2003 10:20 PM

You may also be observing the opposite, meaning your X refresh rate is low compared to what windows is using, I have found this to be the case on all the distros I use, the X refresh rate could/should be higher, so, if lowering those settings makes it worse, try finding out exactly what the limits of your monitor are, either from the little booklet that came with it, or if you've lost it (like me) go to the manufacturer's website and get the numbers there.

rvijay 09-14-2003 10:38 PM

Here is what I did, I changed it from 30-60 and 50-125. Now it shakes badly only when web pages are loading. Otherwise it is much better.

If my monitor has a hardware fault, how come it works well in Windows ?


maroonbaboon 09-14-2003 11:24 PM

It's possible the fault only occurs in certain frequency ranges, and Windows is just not using those.

It suppose this could also be a video card hardware problem, especially if it depends on what the machine is doing at the time. The drivers for X and MSWin are probably going to treat the hardware in quite different ways. Some video cards are pretty crappy. I had the main chip just fall off one once.

If no-one can suggest any better diagnostics I'd probably look into swapping some hardware around, if any spares are accessible.

rvijay 09-15-2003 07:45 AM

Yes, from what I understand my chip SiS 5597 is a low quality Video Card. How difficult is it to install a new Video Card ? A store locally seems to be selling some old 8MB VGA Cards. There is no software or nothing attached to it. I am afraid that it might interfere with other things. Moreover, if I install the new card, how do I disable my present chip ? This is present on my motherboard and hence can't be physically removed.

By the way, I also tried to load Mandrake it failed very badly. I even tried XFDrake to configure XFFree86Config file. Even settings very close to my system wouldn't work, KDE windows would try to open but shut immediately.

FreeBSD loaded in only high resolution for me. In Vector Linux, I am able to use at higher resolution with lesser flicker/shaking. This is a bit confusing. Please help. Your comments/suggestions will greatly help in resolving this problem.



John55 09-15-2003 08:31 AM

I think you first should google to get the actual specs for your monitor, or use the manual for your monitor if you still have it. The horizontal synch and vertical synch numbers need to be correct.

maroonbaboon 09-15-2003 08:37 AM

That does look a bit suspicious. If you Google for "SiS 5597" with "XFree86" you will see someone else reporting a similar problem.

If you want to try a new card, you may be able to turn off the onboard video in the BIOS, but best check that first. If not you are most likely stuck with what you have. If OK, power down, put in the card, change the BIOS setting, boot into text mode and run whatever XFree86 configuration tool the distribution provides. Or at worst, reinstall.

Have a good look at the cards before you buy one. Note the markings on the main chip carefully and check it against the XFree86 list of supported hardware ( Recognisable brand names on the card are a good sign, as is nice clean construction and soldering. I assume your m/b does not have an AGP slot, so I guess you are looking for a PCI card.

Of course there is no guarantee that this will fix the problem! Also, as suggested above, it would be a good idea to get the monitor settings correct, especially if equipment is more than a couple of years old. And one more thing, if you install a new card and still want to run MSWin, you should also use Google to check that a Windows driver is still available somewhere on the web (most manufacturers now being out of the video card business).

rvijay 09-15-2003 09:33 AM

I know the specifications for my monitor. However, even with the exact specifications I still have the problem. That is why this thread was started seeking further assistance.

If I continue to use this monitor as such will my monitor be damaged ? Thank You.


rvijay 09-15-2003 10:01 AM

Hi everyone:

Everyone here has had some great suggestions and I thank them all in this regard.

I just checked again on the net. Did a search for my monitor AOC and Linux in Several similar problems are reported. I now remember that my monitor was the cheapest in the market at that time. Hence, with a real low end monitor and Videocard no wonder there are problems.

Perhaps, I would be better of running NetBSD ?


Azmeen 09-15-2003 10:06 AM

Perhaps you should not run X... or better still, buy a more suitable monitor and VGA card.

Anyway, even if you install *BSD... guess what? You'll still use X if you need GUI. Cool huh?!

rvijay 09-15-2003 10:40 AM

This is true. But isn't NetBSD supposed to work with old hardware very well ?


frogman 09-15-2003 11:09 AM

I had this problem with an old monitor. It occured when I was viewing large (and even small) areas of white on the screen.

I changed everything (folder backgrounds, text editor backgrounds and default web settings etc) from white to a very light shade of grey and it fixed the problem.


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