Clearing cmos question...

[IFMU]

Ok, I dont know if this will make sense... but Ill try!~!

First, I saw this on the front page....
Clear cmos switch
And I could use this with my present mobo here... SO Im thinkin about doing this... but first!~!

I have several questions that I would like to cover...
1st: Will a computer start if the cmos jumper is in the clear position?
2nd: What would happen to a system if you do start the computer with the bios in that position?
3rd: What does happen to a computer if the switch is switched while the computer is running? I already posted in a thread about this the other day, but I would like to be sure......

Now, anyone know or willing to share here?
Thanks
IFMU

 

[Monaco]

hi IFMU,

speaking from experiance of having done it myself,

1. nope.

2.not only will it not start, it might actually permanently fry itself. I killed 2 Abits that way, but my current Soyo is protected against it somehow. Careful!

2. as i understand it, it should probably work! i mean the chip is sitting doing nothing after the first 30seconds your PC is on, right? In practice, after killing 2 diff boards I'm not gonna try it

 

[jbell]

hey man use this and acidental switching will be all but emilinated!!!

 

[David]

1)It will not do anything.

2)It will simply not start. All the jumper does is cut the power flow to the BIOS chip. I once forgot to put the jumper back and started my PC. IT wouldn't do anything, no fans, no beeps, no nothing. Put the jumper back and the PC works fine. I doubt that the board will fry.

3)I imagine the computer would turn off. I am not sure, but I think that is what would happen.

 

[Monaco]

Dave- you got an Abit manual handy? In my BE6-II manual it says in a big box on page 2-11 that clearing the CMOS with power connected will possibly fry your board. And surprise surprise, it did. Of course I had not read the manual, thought I knew it all and I paid the price. One board got a scrambled BIOS
that needed to be flashed again, and one was dead for good.

This may be an Abit-only thing, and may be only with old boards. But- better safe than sorry, right? Check you manual to be sure, or better yet don't risk it.

:edit: i reread your post- starting with the jumper totally off, yah that should be fine. I'm talking about starting the PC with the jumper in the CLR position.

anyway just get a spring-loaded switch that flips back to normal position when you release it, and you'll not need to worry. I think I've seen switches like that at Radio Shack.

 

[David]

Dave- you got an Abit manual handy? In my BE6-II manual it says in a big box on page 2-11 that clearing the CMOS with power connected will possibly fry your board. And surprise surprise, it did. Of course I had not read the manual, thought I knew it all and I paid the price. One board got a scrambled BIOS
that needed to be flashed again, and one was dead for good.

This may be an Abit-only thing, and may be only with old boards. But- better safe than sorry, right? Check you manual to be sure, or better yet don't risk it.

anyway just get a spring-loaded switch that flips back to normal position when you release it, and you'll not need to worry. I think I've seen switches like that at Radio Shack.

I've never had that happen to me - when the BIOS was in the clear position the thing would not start at all. Runs fine now - same board.

 

[stool]

Did it on a Soyo, and the board took power(fans started), but that's all it did. I have read several articles that itwill toast a board. Looks like everyone should clearly mark their switch if they do the mod.

 

[phiber]

if you change CMOS while computer is on...it will shut off and it might have just fryed it self...

 

[crystaldon]

I've seen posts in an unofficial asus site where people have done that because of a typo in the manual. Some damaged the mb and others just lost the setup each time they rebooted.

 

[RoadWarrior]

In my experience.

1) yes or no depending on the motherboard, on some it is a direct jumper between the power pins on the CMOS RAM, on others it enables a clear signal, or just breaks power from the CMOS RAM.

2) Depending on how the jumper is implemented see 1) . . i) nothing, and possible board damage ii)CMOS settings will not save iii)CMOS settings will only be cleared if you power up.

3) Depending on how it is implemented again, if you have case 2i then damage may occur, if you have case ii) or iii) it may either clear the CMOS, or just remove auxiliary battery power fromt he CMOS, if system power is still on CMOS may not be cleared unless system is powered off before the CMOS is repowered. i.e. if you hit it by accident then reset it it's possible nothing will happen. Again this depends on implementation. If it immediately clears the CMOS, then your PC will probably continue to run if the OS is already loaded, but it may crash if the OS is still loading.

Those that have a pair of pads or a single jumper that is off in normal operation are usually the short the power type. Those that have 1-2 2-3 jumper positions are usually a signal type or removal of auxilliary power type.

So in general since theres a 3 in 1 chance your assumption is wrong, read the manual and hope they printed it right!

Road Warrior