Happy to hear the boards arrived safe and sound! 😀

I've given these boards to Deksor because he's more knowledgeable than me so he has a better chance of fixing them. Prior to sending them I tried to diagnose the boards as best I could and wrote down the faults. So I'll share my observations here:

Board #1: KMA-232F-12S - nice 286 board with integrated FDC HDD I/O and Trident TVGA. I've tried it with a new DALLAS chip and it POSTS, however the BIOS reports the integrated FDC as not working. Also because of the weird form factor, I couldn't fit a regular ISA card in the ISA slot - I guess it needs a riser of some sort.

Board #2: IIRC it's a PTM-1260V. Tried it with the supersoft AT ROM and I got a flashing cursor on the screen. It looks like it has integrated MDA or CGA, and it might need 2x 4464 DRAM modules for the video RAM. However I didn't have any so I gave up.

Board #3: unidentified Headland 286 board. Supersoft ROM said board was ok apart from an error in the "16k region". I couldn't find a matching BIOS. Also IIRC I removed a 32.768khz RTC oscillator from it to try and repair another board.

Board #4: FOREX386 motherboard. Made a thread about it but despite all the help I couldn't make anything out of it.

Board #5: NEAT 386SX board. Came with onboard RAM but wouldn't post at all. It looked like it was too corroded so I decided to salvage the DRAM modules.

Board #6: AMA-1240V1-D Suntac board. I had several of those but this one wouldn't post. I posted about it in the Suntac thread.

Board #7: SUPER 286 8 10 16 20 - looked to corroded for my liking, and the jumper mess hurt my brain so I didn't even start with this one.

Board #8: PTM-1632C NEAT 286-16: wouldn't post with the supersoft ROM.

Board #9: C&T NEAT 286-12 - this one works, says "keyboard error", but despite that the keyboard seems to be working. I assume the keyboard connector and/or some traces are corroded? It might be the easiest one of the bunch to fix. It is similar to the board in my ADDX thread, but in a 12Mhz version.

Board #10: PPPCG4009A - a quick google search says it might be a PS/2 board but it might actually be from a VICTOR PC. Proprietary PSU connector so I didn't do anything with it. I might have salvaged the RTC oscillator from it as well.

Board #11: Another SUNTAC board but with a different RAM layout. IIRC I broke a leg from one of the BIOS chip, in theory it should work with the same Phoenix BIOS as the other SUNTAC board, however I haven't managed to make it POST.

Board #12: BSR-101A 386SX board - POSTs with supersoft ROM but gives "timer & DMA failure" during diagnostics.

Well I hope that's a good starting point and I'll be following this thread closely - hope you can bring some of these boards back to life 😎

Ah so the ROMs on the headland 286 have nothing to do with the board ? That might explain something 😁

I've noticed that +5V has a very low resistance towards gnd (under 50 ohms iirc) so something must be wrong). I've also tested the 386DX with its matching bios and still nothing. There are things I need to check first though that may help me understand the problem. One thing is that the CPU stays totally cold even though it's powered so maybe it doesn't receive signals.

Also, there was a loose ROM chip in the package with specific protection, what is it containing ? Is it a supersoft ROM ?

Anyways thanks for the precisions 😀

I don't know about the ROMs on the headland, I thought maybe they were faulty so I tried with a few other BIOS images found online or on Vogons on some W27C512 chips but none would make it POST.

If you find anything new about the Forex please report your findings in my Forex thread (link in previous post) as there are other members who own a similar board here 😀

The loose ROM chip was given to me by Predator99 when he gave me one of his SUNTAC boards, IIRC he burned a wrong image but I thought I would throw it in the package just in case you need the chip, if you have a UV eraser...

Ah I see, thanks !

Also you didn't remove the 32768khz quartz on the headland, you removed two resistor networks between the 8 bit and the last 16 bit ISA slot (you can see where they're supposed to be on the photo). I'm not sure if they're required to get the mobo working, at least for the upper ISA slots.

i didn't remove them - I guess these resistors were factory removed or whoever had the board before me did it. Maybe the board doesn't need them to work.

Well actually I think I've found something rather interesting about that board ... The solder joint SUCK. They're very bad, I added solder to many of them. Since it's a 286 from 1991 or 1992 it was probably very cheap hence the poor solder joints. Unfortunately it didn't change much.

Also I swapped two SIPP slots for two SIMM slots making the RAM probably less flaky, but I had to remove four of these blue caps ... Oh well it still behaves the same.

I've managed to flash a bios from another board that do something on the POST card, but I still get nothing on the screen. It's an AMI bios which stays for a while at step A1 and then do stuff to end on step 30.

I think if I want to make sure the BIOS is really compatible, I'm going to need a bios from a motherboard having the Headland HT12/A3A0050.

If anyone have a motherboard with this chipset, please send me your bios ^^

Next to the ROMs there is a spot for a jumper header which I added to see if it could change anything (I thought maybe it would let me choose between SIMM/SIPP and chip memory ?), but instead of stopping at step 30 it stops at step 20. Still no luck then.

Also with the original bios, no matter if the ram is populated or not, if I don't plug any video card it stops at step 08 and if I plug a VGA card it go to step 55. But since I don't know what that bios is, I don't know what they mean.

Too bad I have only ONE MDA/CGA/EGA monitor and no room to use it, because it makes my life much harder if I want to run supersoft on any of these boards 🙁

As for the forex 386DX I've checked few things, but still nothing. I'll keep it for later I think.

I've tested other boards rapidly (also some have SIPP slots put so close to one another that I can't fit two SIMM slots there, so I can't test these with my SIMM memory ...), but the headland board is the most alive one so far ^^

Deksor wrote:

(...)

I've tested other boards rapidly (also some have SIPP slots put so close to one another that I can't fit two SIMM slots there, so I can't test these with my SIMM memory ...), but the headland board is the most alive one so far ^^

The C&T Neat 12Mhz is definitely the most alive of the bunch - if you have 18x 41256 or 411000 modules from another board, put them in the board with and you'll see it post. But it's true the layout of the board is cramped and my SIMM holders woulnd't fit in the SIPP slots.

Good news ! The #3 motherboard is working !

I hooked up a speaker and I heared one short beep then eight normal beeps. This means bad video card. The thing is I hooked up a VGA card that I know is working. However when I plugged a MDA video card I got a POST !

Then I went into the CMOS setup and I saved. And then I plugged a VGA video card and I heared the ram being counted instead of the error codes ! (I couldn't hook the video card to a VGA monitor at the moment). So it seems that to use a regular video card I need to initialise the computer with a MDA or CGA video card first.

So what I need to do now is to find a battery for the motherboard and then it should be good.

Switching to another board : board #8.

I tried several things, but I couldn't get it to work properly. So I had to add the KBC and the 32.768KHz oscillator, and then I configured the jumpers for the memory mapping I use, and finally I plugged it.

It seems the DTK bios isn't very "talkative" for the POST card, but there is something going on still because the PC speaker beeps. I've got no video on VGA, but when I plug a MDA card, I get a garbled screen and something seems to blink in the corner. Also after a while, I can interact with the num lock implying that the computer has POSTed somehow.

I also tried this bios 80286 BIOS image collection which is probably exactly the same.
Then I had an idea, maybe I need to enter the BIOS setup, but maybe the board hasn't that in rom ? So I hooked up a io card and some 5"1/4 disk drive just in case. And actually the motherboard does seek A and B drives ! ... but it doesn't try to boot.

Then I tried this bios : 80286 BIOS image collection
This time VGA works, but MDA don't display anything ... And also the bios hangs before the computer counts the RAM ...

Perhaps some of these boards are sensitive to the presence of a battery, so eventually I'm going to need to have a test battery.