What Happens When Cmos Jumper Closed?

[cadaveca]

As the title states, what happens when you power up with the cmos jumper closed? I got a system in from a client just now that had had this done...CMOS cleared, and he forgot to remove the jumper when powering back up.

Does it just need a new bios chip, or is the board toast?

[XeroHouR]

Didn't do anything when I've done it on these boards:
DFI lanparty A
Abit nf7-s
Abit AI7
Abit IC7-max3

Soooo I'm not sure exactly if thats what did it, but what else COULD have done it I suppose....

[cadaveca]

The guys is always honest with me with what he has done. Replacing hardware is not an issue for him, thankfully for me.

He said he did two things...clear the cmos after setting memory timings too tight. he also said that when it didn't power up, he reseated all of the cables, and then powered on the system once without the 4-pin 12v connector disconnected, neither of wich should cause any permanent damage, from what i know. But i cannot get this system to boot. I plug in the psu..it automatically starts ups..fans spinning...

Anyway, hotflahsing the chip from this board is very doable..i just have to did out my asus board that is here somewhere...but i just moved a couple of weeks ago, so locating it may not be so easy!




ANy other ideas?

all other components are working by themselves, in two other rigs. been a long day trying to test this one out.

[dolanenwindrift]

I'm really suprised that there is an issue here, I have never seen botting withth CMOS jumper in the CLEAR position cause any problem except not booting. In the few cases I have seen this happen simply setting the jumper back to the normal position should allow the board to boot. Only other thing would be a dead CMOS battery but I would suspect you already checked that.

[cadaveca]

never checked battery no. will try that.

i am surprised as well, but you never know, you know?

i'm not getting any post or anything...will try the battery and everything again after i eat supper.

[dolanenwindrift]

that is the great fun of PCs, always breaking something new... er learning something new, that's it!

[memoryman]

I've killed a few BIOSs powering up with the jumper in the wrong place. It doesn't always kill the BIOS, just sometimes, and on some boards but not all MBs that I've tried in my lab.

[Repo Man]

Nvidia chipset motherboard?

[memoryman]

yep - abit NF7-S rev 2

[Aedan]

The CMOS clear jumper just does that - clears the CMOS memory, which is a bit of static RAM (about 256 bytes from memory). Some boards will refuse to boot (I've come across one or two that will refuse to power up) if the jumper is in the clear position.

That's a little different to flashing the BIOS, which is stored in a completely different chip. nForce 2 boards are a little notorious for trashing their BIOS, as some of the settings are actually written back to the flash chip, rather than to the CMOS memory. Clock speed comes to mind here. No, I don't know why nVidia chose to do that, but that's the solution they went for. I suspect it's to do with the fact that the chipset has to be initialised before the processor can read values from the CMOS memory, and some stuff can only be initalised once.

[memoryman]

Good answer!

[cadaveca]

So how do i fix this board? Hotflash is next, but i don't wanna dig through boxes just yet!

[Aedan]

Normally, just moving the jumper back fixes the problem. Leaving the clear CMOS jumper in it's clear position shouldn't wipe the FLASH, only the CMOS. It sounds like there might have been some other issue - why did the guy think he needed to clear the CMOS?

[cadaveca]

playing with memory timings. when i got the system, the jumper was in the wrong sopt..I of course set it in the right place. no difference.

It's really funny too, as i have spares of almost all the same parts...i am almost tempted to try to duplicate what he did, just so i know, but i cannot afford a dead board right now. All other parts test ok..just the board is problematic. I'd rather not RMA it if i can...just too much hassle, and maybe not a real option. dunno what else it could be beside static damage, but i do not know how to test for that.

[cadaveca]

Hotflash of bios revived the board late last night.

[dolanenwindrift]

Honestly it sounds like a failed bios update. Is it possible that a windows-based BIOS tool was started and then failed? Either that or perhaps a virus attacked the BIOS, seems I had read about such evil things being out there.

[memoryman]

Well, the BIOS working is good news!

[cadaveca]

Originally Posted by dolanenwindrift

Honestly it sounds like a failed bios update. Is it possible that a windows-based BIOS tool was started and then failed? Either that or perhaps a virus attacked the BIOS, seems I had read about such evil things being out there.

I dunno. I think the cmos was corrupted, and this in turn affected the bios, or bootblock, on the first attempt at start-up.

this board is supposed to be able to bring up a utility to flash the bios, regardless of the shape of the bios...even if it is blank...but it would not start. I removed the bios chip, replaced it with a blank one i had ordered, powered up, and low and behold, AWDFLASH greeted me! jumped to my pc at home, downloaded bios, and all was well.

the bad part is that i was too lazy to look before, and just got a new board to put in the clients system, so now i have another board to try to sell. I WILL NOT sell my own stuff in my store(or used parts), so it's gotta be online...ugh...gonna loose some money there....anyone wanta quick A64 upgrade? LoL.

[bradmax57]

Originally Posted by cadaveca

. I WILL NOT sell my own stuff in my store(or used parts), so it's gotta be online...ugh...gonna loose some money there....anyone wanta quick A64 upgrade? LoL.

Why not? Loads off stores in UK sell used, refurbished or returned items offering between a 30 - 90 day warranty or there abouts? ive bought loads of stuff from dabs used selection like recently a nf7-s v2 for £25 everything but the i/o shield was still sealed board looked good as new ans certain runs well, if people are aware that the items are used I dont see any probs

[bhxtyrant]

hey guys i got a small question in reguards to a problem im having with a mobo which seems almost identical to the problem cadaveca is having.Could a dead CMOS battery cause a system not to boot?now before someone says its a stupid questions with an obvious answer let me explain.

I have a EPOX mobo.when i power everything up the board starts and all componets turn on as usual,only thing is nothing gets displayed at all on the monitor it just stays blank.all the hardware has been tested and works perfectly in my MSI mobo.i have tried about 4 different video cards to make sure one wasnt damaged ect.same thing occurs.could this be because of a dead CMOS battery or bad bios chip?

thanks in advance.

EDIT:this may also sound like a newb question but can someone explain,or give me a good link on hotflahing?after reading that cadaveca solved his problem by doing this i am tempted but really dont know where to begin.