I need to replace this battery, looks still good but it has 25 years at least, but no leakage surprisingly. Bought a holder for CR2023

You will figure out the settings for the ram, at least for the ram you are using. It may take you a few long days of work but think you will get it.
A few years ago I tired to figure out the DIP switches and jumpers to this board: https://theretroweb.com/motherboards/s/dfi-concorde-l
No documentation anywhere but was able to use some other boards docs + trial and error to get 4 - 1Mb simms working proper with bios shadowing. BIOS was very complicated compared to my other 286 board.
Never fully figured out the jumpers so no Math-co yet. Maybe some day will pull it out and try again. Picture I took of the BIOS shadow area, it had to match the ram amount and dip switches or else errors.....

Or, the DIP memory chips are not 256kb each, I'm not sure if I read it correctly (same with Trident TVGA8900D).
4 chips OKI - M514256A-80R
4 chips GoldStar - GM71C4256A-70
I mixed them in 2 banks with 2 each by each bank.

Trident has 8 chips of M5M44256BP. So, it's 1MB or 2MB ?

that's a cool mainboard Horun, I understand that still was more fun that frustration 😀 for me assembling it and fixing stuff is like pleasure or puzzle to be solved, but time consumed can be irritating and nice to have some useful docs 😁
Let's see. It's matter of time to handle it. I'll check the DIP memory chips ... of course, need to learn how to read it properly first

New SIPP memory 4 x 1MB works with the standard settings described in manual (Horun link - pdf). It looks mine 2 x 1MB are not OK (when I've switched them only bips). So, now it's clear

and finally, together with DIP memory is now 5MB (5120KB) with SW1: 1/1, 1/2, 1/3, 1/4 ON. When I enabled again Video BIOS Shadow and Main BIOS Shadow is less: BASE 640KB and Extended 4096KB (=4736 KB)

Awesum !!Good work ! Yes when you enable Shadow's it addresses/converts part of the ram into UMB (the area from 640k to 1Mb) to shadow those bios. Typically it removes 384k which it appears it did 😀
Otherwise it addresses the ram from 0 to 640k then from 1024 to what ever limit ram you have. Now you should test the ram with Ramtest v3 or equal (something that supports a 286)

Hi all ! 😀
After a while I started thinking about BIOS modifications.
On the motherboard I see 3 BIOS chips: CD1, CD2 and CD3. For the first test I've used XGecu T76 to read CD1 using signature: S27C256 (but the CD1 chip is Signetics S27C256-15FA) .

So, in XGPro app for XGecu I've tried few Manufacturers like SGS-THOMSON, ST, TI, ISSI and with option 'Check ID' it couldn't detect properly the chip. Then with unchecked option and now I see under adresses and ASCI some stuff 😀

Does anyone know where I could find a proper BIOS version for AMI 3CD's to have newer version of BIOS like the one which is on 286 / 386 with more advanced config (with colors) instead of black and white version ?

FYI.

1 CD... and 2 CD ... are both 8 bit eproms.
3 CD ... is the keyboard controller microprocessor.

the 1CD... U40 is marked as LO Byte
the 2CD... U30 is marked as HI Byte

both 1CD & 2CD (U40 & U30) contain your mainboards BIOS split into HI & LO byte parts. sometimes referred to as Odd & Even.
If you find a bios image for a 286 which is only one file, you will need to split it into two parts using a program such as romwak https://github.com/freem/romwak/releases
If you want to see the bios which your eproms currently contain, you will need to read both U40 & U30 and re-assemble them using a program such as romwak https://github.com/freem/romwak/releases

Hi weedeewee, let me try to check these soft. Many thanks ! Will be back with update soon

Hi,

The merge was quite straight forward:
romwak_0.3c-bin_windows>romwak_x64.exe /m CD1_TS27C256@DIP28.BIN CD2_TS27C256@DIP28.BIN CD1_CD2.bin
FILE: https://tmpfiles.org/dl/20217003/cd1_cd2.bin

Now I can see text in the merged bin file 👍

Can you share some info what BIOS I could use or where I could find a replacement for motherboard YL-A09S / YL-A09H ?
I started looking here: http://chukaev.ru54.com/bios.htm#z2hlm006 and https://www.minuszerodegrees.net/at_clone_bio … _clone_bios.htm but there are so many.
Do I need to stick to AMI and Headland HT102, Headland GC113, G2 101 chips, number of ISA slots (8/16 bits), etc ?

I see in the current BIOS:
XXXX88886666----0123AAAAMMMMIIII Date:-12/15/89 (C)1985-1989, American Megatrends Inc. All Rights Reserved. 1346 Oakbrook Drive, Suite-120, Norcross, GA-30093, USA.Phone-(404)-263-8181.

Quick update. I did few tests. Copying the old BIOS from my original chips works well ☺️
I tried few downloaded BIOSes, some were similar to mine but mainly were failing (like hanging or showing some strange lines with random chars) further even I could access the BIOS setup.
Surprisingly one AWARD worked quite well 😄 👍

I'll be continuing it. Thought also about finding something like custom AMI (or other) BIOS which could allow us to choose all options which are suitable for our motherboard, but I guess there is nothing like that existing.
Maybe it is possible to upgrade BIOS somehow, need to do some research.

If you have some ideas please share you thoughts