View Full Version : Need help identifying 286 mainboard

May 10th, 2004, 09:58 PM
I've scoured the net and especially TH99 in the hopes of finding out the jumper settings for this perticular mobo I scrounged up some time back. While the motherboard appears to work anyways, I'd still like to know what certain jumpers do what.

The only identifying silkscreens I've found on this motherboard are as follows:

4129-1 MB-1212V 904526

There is also a yellow sticker which says:


It has 3 seperate AMI BIOS chips; BIOS plus keyboard, BIOS plus even, and BIOS plus odd. Has 5 VLSI chipsets, Intel 286-12 in recessed socket form, empty slot for 287, total of 48 DIP RAM sockets (2 banks and sockets for pairity), barrel battery.

The BIOS seems to have a 3MB RAM limitation, as well as the usual 512MB HD limitation as usual of the period of manufacture (around 1990).

I will take a picture of this mobo in the morning, once light allows. If you'd like details about this mobo, please specify and I'll fill them in as best as I can.

Thank you.

Terry Yager
May 11th, 2004, 08:08 AM
What kind of DRAM sockets does it have? 16- 18- or 20-pin (or some combination)? (I've got some 1Mb x 1 (18-pin) chips, enough to populate all 48 sockets (6 banks of 1Mb, for a total of 6Mb). Don't know why it would be limited to 3Mb. Are you using 256Kb (16-pin) chips, then? That would give you 1.5Mb. How are you getting 3Mb (am I missing something)?


May 11th, 2004, 09:57 AM
Hehe, yes you are missing something - I was using an extended RAM card to see how much memory I could cram into it, but this (and a similar mobo I have) seems to have a 3MB limit. It just stops there.

As for on the board, I have 1MB installed right now. The first 4 sockets of Bank0 (2 sockets) and Bank1 (2sockets) are 256K 20-pin, as are the last 4 RAM sockets (Bank0, 2 sockets; Bank1, 2 sockets) for the chips if you want pairity RAM. The rest of the RAM sockets are strange looking, each of them staggered seperately for an 18-pin or 16-pin chip. These banks, 4 rows of 9 chips, are all currently filled with 16-pin 256K chips.

On my other board I have the full 3MB installed with DIP chips.

Terry Yager
May 11th, 2004, 10:20 AM
Oh, so it can take the 18-pin chips, then? You could populate those (4?) banks with the 1Mb chips and mebbe see all 4Mb. (Perhaps there's a jumper on board to select how much mem it sees? ...or even something in the CMOS setup?) There is probably a jumper to set which sockets are populated, 16-pin or 18-pin. Another jumper may select between parity or non-parity RAM. The only memory limitation I know of is the 16Mb limit of the '286 processor. Make me an offer (or swap) if ya want these chips I have sittin' round, going to waste.


May 11th, 2004, 12:54 PM
I unfortunately have nothing to swap to offer to you. Being unemployed and near-poor sucks, hehe.

And I don't need the memory, either. All I want is the jumper settings for this motherboard.

Terry Yager
May 11th, 2004, 01:49 PM
You might try going to the FCC page and enter some of those numbers in thier search bar, on the off-chance that one of 'em might be the FCC-ID number.



Tim Wellman
August 19th, 2004, 08:12 AM
sounds like a Biostar mb-1212v