it also says "Rev 1.1" at the bottom left part... look at the ISA slots, maybe there is a sticker on the side.
The battery is indeed a rechargeable 3.6v one , most likely in the range of 50~60mAh capacity.

Sadly there is not.
Thx for the info about battery 😀

Did you look through TH99?

If you remove the battery you could power up the board and use a multimeter see what voltage comes out where the battery used to be. I'm not sure what voltage is used to charge those batteries but I'm guessing it would be a float charge so pretty close to 3.6V.

I was also using my old 386dx40 up until 1998 or so. It drove me to do some programming and it gave me a very good understanding of how computers work. I'm not sure GTA would have helped with that 😀

That battery is gone and it began to leak. Clean up the remains well and move the new rechargeable well away from the mainboard. They seem to leak gas as well. My old 386dx25 had some compromised (green but only surface corrosion) IC slots a couple of cm away from the battery. No direct leak to be seen.

Although you don't need any special information to change the battery, for identification purposes, I believe that this is your motherboard:
http://arvutimuuseum.ee/th99/m/A-B/32049.htm

Yeah, a normal rechargeable 3.6v battery is all you need, no need to measure anything...
I just saw that 72pin SIMM socket on the mobo, nice one!

Malvineous wrote:

Did you look through TH99?

I didn't know that site, it's great!

elod wrote:

I was also using my old 386dx40 up until 1998 or so. It drove me to do some programming and it gave me a very good understanding of how computers work. I'm not sure GTA would have helped with that 😀

Same story here 😁

konc wrote:

Although you don't need any special information to change the battery, for identification purposes, I believe that this is your motherboard:
http://arvutimuuseum.ee/th99/m/A-B/32049.htm

It looks exactly like mine. Thank you very much.

keropi wrote:

Yeah, a normal rechargeable 3.6v battery is all you need, no need to measure anything...
I just saw that 72pin SIMM socket on the mobo, nice one!

Ok, I have ordered one.

72 pin SIMM is really useful. I have 80MB of ram now, 4x4 30pin + 64 72pin. It's overkill for sure but why not? 😉 How much can be cached? There is 128kb cache on the board.