I've got a 286 mobo with missing Bios chips as pictured below. It's a FOREX Turbo 286 20 MHz with Texas Instruments chipset named TACT82411. Unfortunately I can't find anything helpful related to this mainboard and chipset.
Does anyone have something similar and/or can help with a bios image?
I would start with
Re: Bought these (retro) hardware today
Or there is also a TACT8230 at chukaev.
Maybe they are compatible...
*TI (Texas Instruments)
**SN74LS610/2 IBM AT: SN74LS610, SN74LS612 Memory Mappers <84...
**TACT82000 3-Chip 286 [no datasheet] c89...
**TACT82411 Snake Single-Chip AT Controller c90...
**TACT82S411 Snake+ Single-Chip AT Controller [no datasheet] c91...
**TACT83000 AT 'Tiger' Chip Set (386) c89...
**TACT84500 AT Chip Set (486, EISA) [no datasheet, some info] c91
Thank your for your hints. I tried the Bios for the TACT8230x chipset. The board is apparently working and DOS from harddisk can be loaded.
Unfortunately only 512kB of RAM is detected... so the need for the original Bios is still present
Thats good news!
Too lazy to google the ICs...but for me there seems to be only 512K on the photo installed?
Seems it has 8 Samsung KM44C256 installed. Those are 256k x 4 bit DRAMs. So yeah, I think it should have 1 MiB of RAM. But don't BIOS's usually automatically detect the amount of RAM?
https://pdf1.alldatasheet.com/datasheet-pdf/v … +/datasheet.pdf
wrote:Seems it has 8 Samsung KM44C256 installed. Those are 256k x 4 bit DRAMs. So yeah, I think it should have 1 MiB of RAM. But don't BIOS's usually automatically detect the amount of RAM?
https://pdf1.alldatasheet.com/datasheet-pdf/v … +/datasheet.pdf
You are right.In case its a very old BIOS, maybe you have to enter the amount of memory manually?
You can also try testext.exe to see if there is any memory beyong 640 k there. I have linked this nice program here
ISA XMS/EMS Memory Extension / Expansion cards: Now Running without Driver / Documentation :-)
Start with "testext 1500", let it run for 10 minutes and send a screenshot...
wrote:You are right.In case its a very old BIOS, maybe you have to enter the amount of memory manually?
Yeah, I've seen it in some 286 Award BIOSes - you would have to enter it manually and it would verify it during POST memory test. If I entered lower amount - it wouldn't bother to test any further and it would only throw an error message if the memory amount entered was higher than actual amount installed.
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@BastlerMike, any news ?!
I have too the same motherboard (your motherboard’s younger sister) and so far I haven’t managed to find anything about it... I use non-native BIOS but only with this BIOS my motherboard started.
what bios are you using exactly?
BastlerMike wrote on 2020-02-25, 04:45:what bios are you using exactly?
I use non-native BIOS by Winbond (I don’t know what kind of motherboard it is because I bought them in a set of different) but only with this BIOS my motherboard started... and displaying RAM 512 KB only!
