Hi!

That looks like to be a Soyo motherboard, judging from the ETEQ-labeled chipset. That may not be much but it should be a start.

The most surefire way to be 100% sure would be to get the BIOS POST string...

Interesting ! That chipset was used on a few 486 motherboards like the J-Bond A450C

I have bought ISA ET4000AX vga card. When I receive it I will be able to get BIOS post string.

That looks like a pretty cool 386 board, not often you get sixteen 30-pin SIMM slots like that.

Yeah, you'd think it would stick out and be easy to find from that, but nope, all you get are bigass server boards when you look for 16 SIMM.

IDK if it would be such a dream board though, my suspicious nature would tend to think that they stuck so many SIMMs on because they couldn't support a very large SIMM size... so might top out at 16MB still... or if they were really cruel 4.

16MB from a bunch of 1MB SIMMs isn't so bad. I'm fairly certain it will go higher than 4MB with 16 slots.
Given the 1991 date code on the chipset, I think it's fairly safe to say that it won't limit to 4MB.

funny coincidences....
if it's the same 82C491 as the opti, then max supported memory (for the chipset) is 64MB, 16x 4MB simm

At last I received ISA vga card, but I have no luck. The motherboard gives me 9 short beeps, pause, 9 short beeps and so on.
According to AMI bios beep codes this behaviour indicates on bad bios chip.
What do you recommend now? What should I do? I really would like to save this mobo. Is there a possibility to read the ROM and program another chip - for instance W27C512?

If you have a way to read the chip, please make a backup and send it to us, even if the bios might be corrupted, it may not be corrupted enough to be unidentifiable, and also identify what chipset is that ETEQ (because ETEQ chipsets are rebrands from other chipsets), so you'll be able to find a compatible bios.

Did you make sure that the BIOS ROM chip was inserted correctly? I've met boards where the chip had a crushed or bent over pin that wasn't making good contact with the socket.

Also, I believe this is the appropriate MR BIOS for that board. According to MR BIOS' documentation, this is the ETEQ 'Cougar' Rev. A chipset.

Yes, I have checked BIOS ROM chip pins and also cleaned them - no change, still 9 beeps.

Thank you very much for the attachment. I will try to flash it into another chip and will see what happen.

I managed to buy EEPROM programmer. When I receive it I will be able to attach dumped bios here. Sto stay tuned 😀

Stupid question, but this was not mentioned, so: have you installed memory modules when you tested the board ?
Try installing the SIMMs in other slots.
Are you sure the memory and VGA card are good ? Do they work well in other motherboards ?
Do you have POST card ? I recommend getting one if you don't.
Try removing the tag and cache chips and test again.

Also, some boards will not start without a battery, so it worth trying connecting a battery and retest.

There are empty DIP-panels near the cache. It looks like one is missing 74F244, the other is missing 74F251 and the third I cannot see what (16Kx4 SRAM ?) . Those panels not necessarily need to be filled.

If changing the BIOS doesn't work (either with MR BIOS or with the original, correct AMI BIOS programmed on a fresh EPROM chip), it's possible the BIOS socket is faulty, or maybe that 74ALS573 is faulty. (Have someone with a logic probe and/or scope help with that.)
I've had to replace TTLs (mostly LS245 and F245) recently on old 386/486 boards and even old VLB video cards lately.

Hello guys. I have flashed attached MRBIOS file (V018B301.zip) to the new ROM CHIP and ... it works!!!
The board is alive and I am very happy - I feel like exactly the same when I had my first 386DX PC in 1993.

I have also read original bios from the chip that was installed in motherboard.

I wonder who manufactured this mobo - could you tell me?

30-0400-ZZ1500-00101111-050591-ET/386H

Bios from 1991 - 05 - 05
some googling leads me to think it was made for zz1500 Netcon Co. can't say I ever heard of'm nor if the info is correct, the 1 apparently indicates a taiwanese company.
there is a taiwanese netcom company on the internets, and they make computerhardware, and they have some annoyingly named "486DX" mainboards/SBC/CPUcards... so might well be it.

edit: tried bios image in pcem, and gives same 9 beeps, then repeats.

Netcon Co. does match the "NC-386ET" name imo. So yeah it must be the brand