The other large empty socket is probably for a RTC chip. A RTC with internal battery like a "Dallas RTC" could perhaps work even if the board used to use a 3.6V battery.

A RTC only chip, normally of the VIA brand should not be hard to find but I like to mod and repurpose Dallas RTCs when possible.

The manaul for the board in question or at least finding a picture of the board with all chips attached would help.

Edit

I did a quick search and found a picture of a late Forex FX-3000 386 DX 40 motherboard.

This board uses a normal sized RTC without a battery like the one I suppose should go into your large empty socket next to the BIOS socket.

The small empty socket is populated by this on the FX 3000. I'm not sure your board needs exactly the same chip though.

/Edit

someone harvested ICs from this mobo, most likely it's dead

keropi wrote:

someone harvested ICs from this mobo, most likely it's dead

I have freinds who always used to remove for example CPUs and memory from computers they got rid of as they thought those were the valuble parts. A coworker showed me a Pentium 166 CPU he had removed from a 1996 Pentium system he got from a former employer and asked how much it was worth. I answered that it was worth $1.5 as that is the gold value but that the (presumingly) Intel chipset motherboard he had thrown away could have been worth 20 times as much or even more.

Perhaps someone thought that the BIOS chip, RTC and keyboard controller were valuble and removed them before recykling the motherboard. Or perhaps the chips were harvested 15 years ago when the board truly was worthless even if it was working.

Got it from the scrapper/recycler, they always take off every single ic that comes off easily. They keep them in a big pile and i had no intention of searching trough that (wouldn't even know what to look for precisely). I simply assumed it only needed a bios and didn't know what the rest of the sockets was for 😒

A lot of sockets are not populated on old boards (like for cache, co processors and such) so i didn't think it would be a problem....

Last time i got 2 Asus p2b boards there without bios chips. I had a working one at home so i simply hot flashed 2 old bios chips and all three boards work fine now. I thought i needed to do something like that.. 😵

I guess it will be too much of a hassle for me so next time it will be back in the pile. I don't even know if it is in working condition or not. For my own systems i do not go slower as high-end 486 so 386 is not important to me. I just thought it was a shame to leave it as it looked fine and was a later board.

The square socket above the soldered in processor is for a math coprocessor. For example, this 386 board has one installed, it's the chip marked Cyrix FasMath.

That was the only one i knew, but thanx anyway. Before today i didn't even know that a keyboard controller was a chip, i'm way to much used to ''integrated stuff'' 🤣