Freaky PC problem (graphic failure)

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I have a really strange PC problem: My PC does not change into graphics mode from the bootmanager and when I start a sufficiently advanced OS, the graphical display is strange as if garbage was included into each character description. It works again when the OS (Gentoo Linux) sets its own console font. Exchanging the graphics card did not work, neither did replacing it with a PCI-based one (sufficiently ancient not to have any cooling). While X works as well, it is for me really scary to boot the PC like this. Also I fear hardware failure of some sort. Can you guys and gals help me localizing the problem? Is the BIOS FUBAR? Normally text mode always works, no matter how crappy the state of the computer, but it now seems only to work in the BIOS and in DOS unless explicitly resetted.

try changing the color or see i there is a regestry checker on linux if there is any problem it will fix it. I only know about the regestry checker on windows (I know almost nothing about linux but it's a suggestion)

I don't think Linux has the problematic registry hell of Windows.

I would check to ensure the graphics drivers are up to date and working. General rule is: it's only broken when it's NOT working, ie you can't see anything unless you change the graphics card.

IF you've just replaced the graphics card you may need to install drivers for that to work fully

like i said in my post I know almost nothing about linux other that not many viruses are written for the OS

Does your bios have a "reset to factory defaults" option?
If so it might be worth trying.

L.

I take it this is a desktop, as you're talking in terms of graphics cards.

Althogh I doubt it would help, the BIOS can usually be reset by moving a jumper link, on the motherboard, temporarily, then putting it back where it started. It should be fairly clearly silk-screened onto the mobo, near the battery (the flat disc).

Juggling graphics cards sounds more like your problem. If there is onboard graphics, the BIOS may have an option to disable that, when using a card. Getting a conflict going between onboard graphics and plug-in cards.... not nice.

Another thought - have you let memtest have a quick run, just to check that you don't have any problem there? That can also result in a whole range of "odd" behaviours.

The package "memtest86+" that comes as standard with Ubuntu, etc, installs the following:
/usr/bin/make-memtest86+-boot-floppy

So, I inserted a writeable floppy, typed "make-m<tab><enter><enter>" and away it went. Moved the floppy to other machines (one without a keyboard, even), inserted it and rebooted.

I now have that memtest86+ running on three other machines, all of which seem fine. (It's quite a nice idea to run a serious memory test, once in a while.)

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The BIOS reset - my eyes are no better, I'm sure! I use a magnifying glass to read the mobo. Them generally fumble with the jumper multiple times before I manage to remove/relocate it.

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Hm. The race is on...

My Toshiba T2130CS, Intel 486DX4, Memory 8000K, completed a pass in 11 minutes.

The Compaq Armada 4220T, Pentium-MMX 267.3MHz, L1 16K 171MB/s, Memory 96M 145MB/s, is at 37% after 13 minutes.

The home build Sempron (0.09) 1800MHz, L1 128K 14,755MB/s, L2 128K 1,273 MB/s, Memory 991M 1,278MB/s, Chipset AMD 8000 (ECC:Disabled), RAM:163MHz (DDR327)/CAS:3-3-3-7/DDR-1 (64 bits) is at 77% after 24 minutes.

PS. Memtest86+ full pass timings:

11 minutes for the 8000Kbyte Toshiba.
40 minutes for the 96 Mbyte Compaq.
28 minutes for the 991Mbyte home build.

Make of that what you will. I feel it means that the ancient 486 wasn't that bad a beast.

Id try replacing the power supply (a weakening PSU that doesn't put out quite the wattage it used to can cause strange graphical problems due to low voltage across the buses).

If that doesn't work the only thing left is the motherboard.

The power supply idea is another good suggestion, although a marginal problem with power would be unlikely to manifest in the same way when switching graphics boards.

A thought, there, is to unplug any extra boards that may be present, to see if that alters the symptoms.

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Oh... I took a liberty, and edited not only my messages, but your quote of me, Fraya. I'd left out a "0" in the Toshiba's memory size. (Which I'm pretty sure is clocked at 75MHz). (The Tosh is closer to 12 minutes per pass.)

I suppose the first pair, we have memory x12, speed x3 and test duration x4. That's not wildly unexpected, but seems to hint that the 486 was no worse an architecture that the Pentium.

The second pair, the memory is 10x, the speed 7x, but the test duration has gone down a little. The Sempron is a better architecture than the Pentium?

(The Tosh is closer to 12 minutes per pass.)

Just some waffle. Having run all three memory tests for 7 1/2 hours, with no errors, I may stop them soon.

Sorry I haven't replied until now. I've been offline a lot and forgot to reply. Anyway, this looks like a kernel problem. It only happens with certain kernel versions, certain hardware, and most importantly certain graphic modes.

I had a similar problem with my Asus motherboard and Nvidia Geforce 6?00 desktop for quite long time now. The kernel would hang during boot, and i would get weird colored dots on the screen instead of text. But since one particular kernel upgrade it works fine again. Though, it does not work if you just get the kernel sources and compile. I think you need some distro patches or just the ordinary distro kernel. Myself I'm using (K)ubuntu.

It has only happened to me with the higher resolution graphic modes. In GRUB, try to edit the kernel command line. If there's alreay a vga= option, change it to "vga=normal" or if there is no such option create "vga=normal".

That way, the console font will be too large, and crappy, but hey, it's better than no font at all. Try to mess with the vga option til it looks alright.