The battery is housed inside the ODIN (aka Dallas) real time cock (RTC).
Refer this site for some tips on how to replace the battery: http://pc-restorer.com/replacing-cmos-batteries-in-old-pcs/

It looks like your revision has the headers for a 2032 socket, but takes an RTC module. They can last longer than coin batteries but are a pain to replace when they do die like yours did. Directly to the left of the header, that black box labeled ODiN, is the module which if you're lucky might be socketed however it's usually soldered on board. You can get replacement modules online or mod it to take a coin battery (easy since yours already has the headers on it)

They aren't hard to replace. If you have the equipment, solder wick, solder, and a soldering iron is all you need. Along with the chip of course.

And if you do replace it, SOCKET IT.

thanks all, now i understand this ODIN thing had a battery inside
i spent some time on google and i found schematics and possible fixes,

1. one is removing all the odin and replacing it (i wont do that too much work, time)

2. another one is drilling the odin in the center and replacing the battery (too much of a mess)

3. and the one i might do is take the motherboard out, check on the back of the motherboard to see the 2 pins i need, and soder 2 wires to those pins and then put a coin battery holder connected to those 2 wires

here are the schematics if someone needs them.

Doing that i belive i will get it fixed. (i dont think its a rechargable battery the one in odin so i think i will be fine)

i might do something like this, to preserv the look of the motherboard

I think the problem with your solution #3 is that pins 16 and 20 in the Odin RTC do not actually connect to the motherboard. They are actually bent upwards and go inside the block. That's why you need to drill the thing in order to gain access to those pins and solder the coin battery leads.

I would definitely try to desolder the Odin block, put a socket in its place and then either do the CR2032 mod on the chip or just buy a new one (in your case it would be a DS12C887A I think). In my opinion doing the mod with the chip still soldered to the board is much riskier than desoldering, especially if you don't have a steady hand.

Cga.8086 wrote:

3. and the one i might do is take the motherboard out, check on the back of the motherboard to see the 2 pins i need, and soder 2 wires to those pins and then put a coin battery holder connected to those 2 wires

Good one 🤣

TheMobRules wrote:

I think the problem with your solution #3 is that pins 16 and 20 in the Odin RTC do not actually connect to the motherboard. They are actually bent upwards and go inside the block. That's why you need to drill the thing in order to gain access to those pins and solder the coin battery leads.

I would definitely try to desolder the Odin block, put a socket in its place and then either do the CR2032 mod on the chip or just buy a new one (in your case it would be a DS12C887A I think). In my opinion doing the mod with the chip still soldered to the board is much riskier than desoldering, especially if you don't have a steady hand.

Listen to these words of wisdom, remember, haste makes waste.

Had exact same issue and i managed to decap RTC completely. The whole process was far easier than i expected, used just a hairdryer(!) to heat up epoxy and with small pliers squeezed epoxy chunk by chunk untill RTC IC with battery socket and quartz were exposed, managed to replace old battery as battery holder was not damaged in the process and because RTC is socketed, i can now use it in any motherboard with a battery-dead RTC 😀