Replacing CMOS battery without wiping BIOS?

Is it possible to replace the CMOS battery without wiping the BIOS, by keeping the main battery connected, for example?

I have an X61 which works fine but I don't know the supervisor password - if I replace the CMOS battery normally it will wipe the date and time and I'd need the supervisor password to reset them. Otherwise I fear I may not be able to boot at all, or it will nag me every startup...

Any advice, experience most welcome.
Thanks,
T

 

date and time you can update from within OS (i.e. windows).

 

Yes but if the date and time are wiped when I remove the old battery, I won't be able to boot windows without setting them in the bios. This requires the supervisor password, I don't have the supervisor password.
So I shouldn't remove the battery. Sure, but when it dies I'll be in the same pickle.
Hence my desire to forestall the whole thing by somehow adding a fresh battery without wiping anything.

 

well why dont you change it with the computer working then ?

you'd be surprised how much stuff I've done on working machine .. lol.

 

Is replacing the CMOS battery one of these many things?
Sorry, I'm just a bit scared and need reassurance

 

last time I replaced one was on my 486DX-40MHz desktop that I ran on 50MHz

so I dont actually see why you would have to replace yours, but if you want then go ahead. Nothing really that could happen (bad) .. besides you blowing up your building, lol. JK.

bear in mind that those batteries are not generic ones that you can buy from your local grocery store. I could probably upload a picture of mine if you insist, it's yellow

 

I remember reading somewhere that the CMOS batteries were designed to work for at least 7 years...

 

Sorry for my rudeness, if the system clock in my old T40 goes slower than the actual clock by 3 seconds daily, does it mean the CMOS battery is dying?

 

yes .............

 

That's a healthy fear, because that's exactly what's going to happen in your situation if you lose the data in the BIOS.

Keeping the main battery connected works on my T61. In fact, I've been cold-booting with a supervisory password set and the CMOS battery disconnected, and I've received no errors or password prompts at all.

I've had my T61 for three and a half years, and for a good portion of that time I ran it as a desktop without the main battery installed. I almost always unplugged it when I wasn't using it, so my CMOS battery has probably gotten more use than most. It's still working fine. I'm not sure I'd risk replacing yours if you keep a main battery installed all the time like most normal users.

 

Thanks, that's very useful info.