Old 486 CMOS Battery Low

[MusicallyInspired]

So I hadn't used my old 486 computer in a while. A short time ago I decided to boot it up and play around with it. Immediately it gave me these warnings that the CMOS battery was low and my only option was to go to the BIOS settings. No matter what I do the message keeps coming up and I can't continue. So obviously the battery is low or probably even dead. The problem is it's not a conventional lithium battery but one of these buggers:



Are these readily available at retail outlets? Are they easy to install? Is there anything I can do short of buying a brand new motherboard?

[Great Hierophant]

All it looks like to me is 3 CR2032s stuck together in a plastic seal.

So I hadn't used my old 486 computer in a while. A short time ago I decided to boot it up and play around with it. Immediately it gave me these warnings that the CMOS battery was low and my only option was to go to the BIOS settings. No matter what I do the message keeps coming up and I can't continue. So obviously the battery is low or probably even dead. The problem is it's not a conventional lithium battery but one of these buggers:



Are these readily available at retail outlets? Are they easy to install? Is there anything I can do short of buying a brand new motherboard?

[Laust]

Batteries like these are often Nickel Metal Hydride rechargeables. They are actively charged by the circuit they're placed in and cannot simply be replaced by normal CR2032 cells.

You can find one example here: http://www.batterymart.com/p-3_6v-60a-3-pin-nimh-battery.html

But of course I don't know if this is the same voltage or capacity as yours. There are no markings on the battery?

[MusicallyInspired]

No markings that I can see. I'll take another look again, though.

Thanks for the replies, everybody.

[gortmertl0]

Sorry to hear about that, MI.

I had a similar problem a year-and-a-half ago with my Pentium 166.  After 13 years with no problems whatsoever, the built-in CMOS battery finally died.    It would start fine in Win98 Safe Mode using the BIOS defaults, but got hung up when loading the Windows drivers in "normal mode".

However, I couldn't find the battery anywhere(!).

After much seraching, I discovered that I had an NVRAM battery, which looks like an IC/microchip.  From a tutorial by Gabriel Torres on "Replacing the Motherboard Battery" at hardwaresecrets.com:

"The NVRAM battery is a little black box that contains the clock circuit and a small lithium battery...

...The NVRAM may be directly soldered to the motherboard instead of being held on to it through a socket. In this case, you will have of de-solder the old circuit and solder the new one. That task is only recommended for people who really have experience de-soldering and soldering electronic components."

Ugh.  That was exactly the case.  I was able to DL the HD, and bought another Pentium computer... This time, one with an easily replaceable CR2032 battery!

[MusicallyInspired]

Managed to get a picture today. Next to the battery is a two-pin connector marked Power Ctrl - JP3. Is that possibly an external battery connector? There's nothing else nearby. Sorry the picture is blurry my camera sucks.

[MusicallyInspired]

Whoops. Just noticed another connector right next to it (I'm blind) called Ext Battery. That must be it, eh? It's a 4-pin connector with only 3 pins.



EDIT: I got it to work! Yey!