Hey have you heard of our project UH19 ? http://www.win3x.org/uh19/

It's TH99's that we turned into a database that you can browse and that's also editable 😀

You can definitely help us document your board properly if you want.
I think we could use the Peaktron board that's very similar to yours as a base and modify it ^^

Here's an archive containing an SVG conversion of the schema and a .doc file of the "manual"

We also store BIOSes in our database for everyone needing them. Would you like to archive yours ? You don't need a programmer to do that. Just run this from DOS and it'll work 😀 http://cd.textfiles.com/microhaus/mhblackbox3 … MORY/GETROM.ZIP

We can also help for your other motherboard

Deksor wrote on 2021-01-17, 16:51:

Hey have you heard of our project UH19 ? http://www.win3x.org/uh19/ […]
Show full quote

Hey have you heard of our project UH19 ? http://www.win3x.org/uh19/

It's TH99's that we turned into a database that you can browse and that's also editable 😀

You can definitely help us document your board properly if you want.
I think we could use the Peaktron board that's very similar to yours as a base and modify it ^^

Here's an archive containing an SVG conversion of the schema and a .doc file of the "manual"
30307.zip

We also store BIOSes in our database for everyone needing them. Would you like to archive yours ? You don't need a programmer to do that. Just run this from DOS and it'll work 😀 http://cd.textfiles.com/microhaus/mhblackbox3 … MORY/GETROM.ZIP

We can also help for your other motherboard

I can contribute what little I've found - but I've found that the Peaktron PA286-SMT that is already in your database has images of the PA286-SA1 from https://www.clous.cz/pa286-sa1/, so the Peaktron entry needs to be amended as well; they're quite different boards in practice. I'm beginning to suspect that the 'SA1 is a cut-down/budget version of the 'SMT.

The big issue is that we are still guessing what all the memory configurations are.

Yeah I added these here after seeing this thread but I misunderstood. I'll remove them 😀

Something that facinates me about these 286’s is the ability to install ram on a isa card 🤣

Cool build. Following 😀

Got a Headland HT12 board on the way. The same seller who I got the PA286-SA1 board from had a HT12HS board from 'Eurosoft' in stock, so I made an offer (based on the fact I already bought a board from him) and he accepted.

Total Hardware 99 has it listed as a "Unknown G2-12HS HT12" and Deksor's UH19 site lists several variants:

http://www.win3x.org/uh19/motherboard/show/6752 (INFORMTECH INTERNATIONAL)
http://www.win3x.org/uh19/motherboard/show/5187 (UNKNOWN G2-12HS HT12)

Funnily enough, he's posted about some of them already!.... 😁

80286 BIOS image collection
Re: 80286 BIOS image collection

Some differences from 'most' HT12 baby AT boards that I can see:

- 7 ISA slots instead of 6
- Motherboard jumpers (well, the tech info) specifically mention the settings for 20MHz

Sadly this one seems to have SIPP sockets instead of SIMMs (okay, easy enough to solve if I source some SIMM sockets) as well as a soldered on AMD 16MHz cpu (less easy to solve, but have done 2 or 3 of these conversions to PLCC sockets so far without any major cockups).

I also have my eye on that other HT12 board, the one with the full 8 ISA sockets. We'll see if the seller is interested in my offer.

I'm writing up my 286 (re)build journey as well as this developing 286 board shootout on my wiki: https://www.target-earth.net/wiki/doku.php?id … ory_and_repairs

I remember testing a sibling of your peaktron replacement board. It was pretty bad. Not surprised you had problems with it too.
The ht12a one is above average, but that's about it.

If you want your "speed demon", try to obtain HT12P, or especially VLSI 201 based boards.
https://www.petershipkov.com/temp/retro_pc_im … _ht12p-16_a.jpg
https://www.petershipkov.com/temp/retro_pc_im … motherboard.jpg
https://www.petershipkov.com/temp/retro_pc_im … motherboard.jpg
That last one is the fastest 286 motherboard money can buy.

Will watch your progress.
Keep us posted.

pshipkov wrote on 2021-01-18, 06:48:

I remember testing a sibling of your peaktron replacement board. It was pretty bad. Not surprised you had problems with it too. […]
Show full quote

I remember testing a sibling of your peaktron replacement board. It was pretty bad. Not surprised you had problems with it too.
The ht12a one is above average, but that's about it.

If you want your "speed demon", try to obtain HT12P, or especially VLSI 201 based boards.
https://www.petershipkov.com/temp/retro_pc_im … _ht12p-16_a.jpg
https://www.petershipkov.com/temp/retro_pc_im … motherboard.jpg
https://www.petershipkov.com/temp/retro_pc_im … motherboard.jpg
That last one is the fastest 286 motherboard money can buy.

Will watch your progress.
Keep us posted.

Excellent! I'll keep a look out for those board designs.

I have decided I must have a Biostar MB-1220VE.

http://www.win3x.org/uh19/motherboard/show/1132

- 6+2 slots
- VLSI VL83C311L 286/386SX chipset
- 16MB RAM
- 16/20/25MHz options as standard
- Huge BIOS tuning options (according to https://foorum.hinnavaatlus.ee/viewtopic.php?p=10560390)

I must have this board.

Anyone got one?

That's the VLSI SCAMP I mentioned earlier. Good luck sourcing one they are rare and $$$

I must admit, it does look very nicely specified indeed.

One thing I'm not clear on is whether the later VLSI 82C311L is faster than the earlier multi-chip VLSI chipsets? pshipkov mentioned the VLSI 82C201 as being fastest, but I would have naively assumed that the much later one-chip 311L would have been a faster design and withstanding of higher clocks being all on-die.

I have a 386SX motherboard with a VLSI SCAMP chipset and I can say it's pretty quick ! I think it may beat some cacheless 386DX-25. The bios has the same features ^^.

Actually if you can find this motherboard's BIOS I'm sure you can turn any VLSI 311L based motherboard into a speed monster (or maybe you can use the BIOS from mine, it's this one http://www.win3x.org/uh19/motherboard/show/5400 )

Yeah, I think I have my heart set on a VLSI SCAMP based board now. I'm not sure anything else will do!

I can see that the 82C311L has UMB (up to 384KB of it!) via The Last Byte memory manager. Does it also support emulation of EMS memory, as per the Headland chipset? The chipset datasheet certainly mentions EMS 4.0 LIM in the text, but it's unclear if it's referring to traditional ISA-card based EMS, or emulation of EMS using the on-board DRAM.

Also, the same datasheet says 25MHz operation is supported on the hybrid 286/386SX 82C311 (in the correct configuration), but the 286-only 82C311L is rated to 20MHz. I guess it comes down to the luck of the draw and the quality of the supporting components as to whether your particular implementation is stable at that speed.

Looking at the best perf numbers posted on the Estonian forum.
That's about 10-20% slower than what i see here at the same 20MHz frequency.
Figured i should bring it up.

pshipkov wrote on 2021-01-18, 18:04:

Looking at the best perf numbers posted on the Estonian forum.
That's about 10-20% slower than what i see here at the same 20MHz frequency.
Figured i should bring it up.

slower than what, the 200 series VLSI?

and are their numbers from a true 286 or a 386sx?

maxtherabbit wrote on 2021-01-18, 18:17:

pshipkov wrote on 2021-01-18, 18:04:

Looking at the best perf numbers posted on the Estonian forum.
That's about 10-20% slower than what i see here at the same 20MHz frequency.
Figured i should bring it up.

slower than what, the 200 series VLSI?

and are their numbers from a true 286 or a 386sx?

That was done way back in the olden days son...

You had to be there to experience it.

Hey, I'm not averse to picking them BOTH up if I can get my hands on them!

I've never had a need for a 386SX at all -ever.

Skipped the whole 386 class back then and just updated the 286/16 to a 486 and then a Pentium 133. My Dos/win3.1 setup got a lot faster over that time for some funny reason 😀

@maxtherabbit
Looks like my message was ambiguous.
The link megatron-uk provided shows some perf metrics of the Biostar MB-1220VE motherboard running at 20MHz with optimized BIOS settings.
These numbers are about 10-20% lower than a clean 286 system, based on VLSI 201 chipset, running at the same frequency.
Hope this clarifies it.
All best.

@caluser2000
VLSI were kings of the 286 hill.
Not sure what happened to them in 386 land. Some early 386 SX chipset and then gone with the wind.
Maybe Philips's acquisition, etc.

pshipkov wrote on 2021-01-18, 18:40:

@caluser2000 VLSI were kings of the 286 hill. Not sure what happened to them in 386 land. Some early 386 SX chipset and then gon […]
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@caluser2000
VLSI were kings of the 286 hill.
Not sure what happened to them in 386 land. Some early 386 SX chipset and then gone with the wind.
Maybe Intel's acquisition, etc.

Possibly. Good that you are bringing this to the attention of the unwashed mass's 😉. Keep it up mate.