What exactly does "clear bios" do?

Discusses BIOS flashers and utilities from Award, AMI and Uniflash
paulus
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I inadvertently set the clear bios jumper on an old Cyrix 233 based PC, which had been working well. Bottom line is that system no longer boots and nothing gets to the video (which used to use system RAM) - so no idea what it is trying to say to me!

Have I cleared the bios PROGRAM (needing a reflash is I can find out what the motherboard is) or have I just cleared the bios SETTINGS, in which case how do I get the video up so that I can enter bios setup and fix?

Any help . . . pleeeeeeeeeeeeeeeeeeeeeeeeeease!

Paulus.
NickS
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If it was the "clear CMOS" jumper it should only have cleared the settings, and if it has on-board video it should have defaulted to sensible settings. Try clearing the CMOS again, with the mains power cable unplugged.
paulus
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Nicks, thanks for the help - done that, but still no boot and (more of a problem) no video. Tried to "blindly" get into setup, then F7 (best performance settings), F10 (exit and save), "y" and "enter. But still no luck! Any ideas on getting my video back so that I can at least see where it's getting stuck?

Regards,
Paulus.
soupy
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Plug in a video card?
Flash your BIOS at your own risk.
NickS
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What does it do? Does it beep ? If not, does it beep if you take the RAM out (power off at wall) and power it on ? If not, there's something seriously wrong.
paulus
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The machine is circa 1998 and uses AMI bios. It doesn't beep but clicks quietly (sounds like the floppy). I am attempting to get my hands on an old video card (not many round any more) - hopefully (if I can get it) then I MAY be able to get something on the screen to tell me what it is looking for. It looks rather terminal, and its age means it's wouldn't stand much of a repair bill - but for the sake of the kids I would love to kick it back into life (especially since I am the fool that move the jumper to clear the bios - HUGE ERROR!!). I guess a bios reload may be the quickest solution, but I CANNOT FIND OUT WHAT THE MOTHERBOARD IS (even though I have the book!!).

Any thoughts or help would be very gratefully received!
Paulus.
Rainbow
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paulus wrote:I CANNOT FIND OUT WHAT THE MOTHERBOARD IS (even though I have the book!!).
Then it should be PC Chips board :lol:
See http://go.to/th2
Patched and tested BIOSes are at http://wims.rainbow-software.org
UniFlash - Flash anything anywhere
ajzchips
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I have a feeling Rainbow's 100% right 8O
paulus
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Thanks guys, however I still need to find some mobo id. The book title is just "Pentium MMX", and its contents just include a list of features/capabilities, diagrams and instructions (including bios) - no manufacturer or type number. I am away from the machine just now, but will try to find some markings on the board itself over the weekend.

Paulus.
Rainbow
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Check around the keyboard connector - if there's version number printed there, it's PC Chips.
Patched and tested BIOSes are at http://wims.rainbow-software.org
UniFlash - Flash anything anywhere
NickS
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paulus wrote:Thanks guys, however I still need to find some mobo id.
If it's PC-Chips, the link Rainbow gave you has a "Start here if you don't know what board you have" feature.
paulus
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Thanks, guys - homing in on this now. After close inspection I believe the board to be a TX ProII board and the version number is 3.2. According to PCChips this could be an M571 - if confirmed I can download the bios and loader and restore the bios. Only problem . . . the machine is not booting, and I still have no video (attepts to procure an old isa card failed).

I guess I need a start-up disk, with autoexec.dat running the flash loader?

BUT my son doesn't have a start-up disk, and the system being dead is not a good time to try to create on. The system on the machine is Win95 - and I have the install CD. Question: can I use a Win98 system and the Win95 CD to create a Win95 start-up disk - ar alternatively can I download such a thing from the internet (obviously using my working Win98 system).

Best regards for all your help,
Paulus.
Rainbow
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Unpack the downloaded BIOS to a blank floppy. Then rename it to AMIBOOT.ROM. Then put it in the drive of non-working computer and power up while holding Ctrl+Home keys. It should read the file and flash automatically.
Patched and tested BIOSes are at http://wims.rainbow-software.org
UniFlash - Flash anything anywhere
paulus
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Rainbow, that seems a heck of a lot simpler - and no need to wonder what the screen may be showing! I assume that the clicking I hear is the bios trying to read the floppy, and that it has its own loader. That being the case I will try this when next to the machine (in a day or two) and let you know. I am trying to confirm that the board is an M571 - which has two roms a 1M and a 2M - not sure which one. Need to confirm but guessing the 1M is probably it.

Thanks, and best regards,
Paulus.
paulus
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Sorry this continues to drag on. Prepared floppy as directed, powered on whilst holding down cntl & home - nothing. The flopy was not read, no beeps nothing. The clicking seemed to come from the CD (select light on). Where from here Raindow?

Q. Will the bios loader read a cd-r (since the cd seems energized)? Would not expect it to. Maybe swapping the ide cables so teh selected device is actually the floppy (boy, am I getting desperate).

It may well be that the bios was set for first boot device to be HDD - hence not attempting floppy read.

A further idea to discount - a friend suggested that clearing the cmos on an old machine may have discharged the cmos battery, and that a flat battery may cuase it not to boot. My only experience of dead cmos batteries is that the clock stops during power off. Can I discount this theory?

What next boss?

Paulus.
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