Its a standard ROM, HI/LO in one file. Works in an EMU. Your ROM is OK 😉 Remove the battery please 😉

Battery is perfect - has 3.25V after 6 hours. Мore than enough. The board is dead so far without battery leakage.

The battery wil destroy your board earlier or later - remove it.

You should not give up that fast. Try the supersoft-ROM.

As long as a new NiMH battery costs more than this board in present condition I don't care about the battery so far. It has several years more until it leaks well enough eventually. BTW there are some brands of NiMH accus that amaze me after 30 years -- they haven't leaked and/or still hold charge. I will switch on the scope tomorrow. At least we saved the BIOS which otherwise I would have been lazy enough to dump.

keropi wrote on 2013-09-13, 17:40:

^ good thinking, will back it up , I do have a willem programmer , thanks for the tip because once it's dead the mobo will be useless...

Hello keropi. sorry for for reviving this old thread, but I got the very same mainboard SNB-M008 or GSH286, whatever the right name is. It had some damage because of a leaking battery, so I had to fix some traces, but now it works somehow. I replaced the SIPP memory slots by SIMM slots, because I didn't have any SIPP memory modules. However, the mainboard starts with only 640KB of memory. I already tried to remove the DIMM memory and used SIMM only with 4x1MB modules, but with the same result. Only 640K RAM is detected. Do have an idea? I tried the jumpers all to 1-2 and all to 2-3 position, but this doesn't seem to change anything. What does this 4MB vs 5MB written on the PCB mean anyway? What do I have to setup, if I want to have, let's say, 1MB in DIMM and 1MB in SIMM? Any ideas?

I also couldn't find the ROM, did you upload it somewhere? May be I could try yours? Who knows...

Hey scorp
I am so sorry I don't have the motherboard anymore, AFAIR I gave it in 2014? I remember nothing of it or what happened to the BIOS dump...
maybe give a shot at georgel's dump here: Re: Need some info on a 286/16 SNB-M008 mobo

@keropi sorry man, I didn't answer. I just realized today, that I get no notifications from vogons somehow 😀 I thought, why nobody answers? An didn't even bother to look into the thread. Stupid me 😀 Just changed the settings to send the notifications again.

keropi wrote on 2020-01-06, 23:29:

Hey scorp
I am so sorry I don't have the motherboard anymore, AFAIR I gave it in 2014? I remember nothing of it or what happened to the BIOS dump...
maybe give a shot at georgel's dump here: Re: Need some info on a 286/16 SNB-M008 mobo

Thank you keropi, I tried that and the mainboard starts actually, but with the same result, only 640K of RAM, despite, that I have 1-4MB installed. Hm..... I still have a strange feeling, that the BIOS is not the correct one on my mainboard. I can see the sticker on the chip was at least peeled off once. I found this mainboard in a pile of garbage. Some traces were scratched off the surface and the battery slightly damaged the traces. I repaired all that stuff and the mainboard started eventually. Just to show me this odd memory problem. I even can boot into DOS and do things, but only with 640K of RAM 😀

Sounds to me like the extra memory just needs to be configured.

Anonymous Coward wrote on 2020-02-02, 02:58:

Sounds to me like the extra memory just needs to be configured.

I'd think that too, but you can't configure much here. There are several jumpers in a row, which you can set either to 4 or to 5MB at once, that's it. And I tried already both variants. The mainboard just uses 640KB. Meanwhile I am pretty sure, that the BIOS, which was on the mainboard is not the original one. I peeled the sticker from it and it is an EEPROM from year 1991, but on the sticker I can read 1986. It is quite suspicious that the sticker is 5 years older, then the chip underneath, isn't it? Furthermore, the sticker looks like it was already peeled off back in the days, as I mentioned before. And the next thing is, that the flash chip is an EEPROM, which is absolutely not usual for that time. As far as I know, usually EPROMS were used in the end of the 80's.

I also think it just needs to be configured in the CMOS. Is there an option available to enter the ext. memory size?

I would also suggest to try the program testext (testx.exe). It will show you the RAM that is installed behind 1 MB and ignores what the BIOS reports.

In the BIOS you can't setup much, at least I can't see any memory settings options. I'll give testx.exe a try, didn't know about that, thank you. However, if anyone has original BIOS for this mainboard, I would be glad to have a copy.

Ok, some very strange thing happened. I booted into DOS without HIMEM.SYS or anything else except pure command.com. Then I started the testext.exe as suggested. It showed also no extended memory on the top, but during the run the program aborted with a "memory protection error" and some registers information, leaving the system hanging hard. After a reset the mainboard instantly counted above 640K up to full 5M, without any action from my side. Now I can insert/remove/change memory modules, all between 256K and 1M each without a glitch. I left the mainboard disconnected from power for a night and still, everything is detected properly. I have no clue, what happened there and I don't believe in magic, especially, when talking about computers. Any ideas?

By the way , georgel's dump: Re: Need some info on a 286/16 SNB-M008 mobo works also with this mainboard. I saw some minor differences in the BIOS, but no "real" change. So they seem to be compatible.

I really like testext but its new to me its able to fix a broken PC...
What happens if you start it now? All 5MB RAM detected and Ok?

Predator99 wrote on 2020-02-03, 13:41:

I really like testext but its new to me its able to fix a broken PC...
What happens if you start it now? All 5MB RAM detected and Ok?

Sorry for late answer, I just wanted to test it over some days. It is kind of magic to me, but yes, it works now as it should. All 5MB RAM are detected if I set the Jumpers to 5MB. If I set them to 4MB, DIP memory chips are not detected and I get 4MB RAM. I even tried other combinations 1MB DIP + 1MB SIMM (4x256KB) works also. In case someone is interested, the 4MB/5MB jumpers actually seem to mean "SIMM/DIP only" or "Both". I got now all kinds of configurations through 1MB, 2MB, 3MB, 4MB and 5MB. The odds are when both type of memory is used DIP and SIMM together, the evens are SIMM only. Except 1MB, this can be either one of them at a time. Sizes bellow or between of full MBs seem not to work, so no 512KB or 1,5MB possible.

Does anyone have a jumper manual for this SNB-M008 mainboard? 🤔

RiP wrote on 2020-05-13, 21:03:

Does anyone have a jumper manual for this SNB-M008 mainboard? 🤔

Look similar to what I have, which settings are you actually interested in? May be we can figure this out? There are barely jumpers there, so....?

scorp wrote on 2020-05-13, 22:08:

RiP wrote on 2020-05-13, 21:03:

Does anyone have a jumper manual for this SNB-M008 mainboard? 🤔

Look similar to what I have, which settings are you actually interested in? May be we can figure this out? There are barely jumpers there, so....?

I need to know the jumpers and also the empty place of oscillator.
Is it for FPU? I would like to install 287XL FPU.

Sorry for the late answer, I had to search for the mainboard in my stock. I finally found it, but yours is missing an IC 74F74 in the socket near the jumper 3. My board looks like this: http://www.amoretro.de/2013/11/jet-electronic … ld-chipset.html. There are actually barely jumpers on it, one row to select DIMM and SIMM mixed usage, one to set color/mono display, one to select internal or external battery and it is mostly it. The place for additional oscillator is also free and one jumper near it is hardwired. Why don't you just put an FPU into the socket and see if it just works? In the worst case it will be overclocked, but you can measure it on the pin and try to figure out, what to do on demand.

And you should really remove the battery ASAP. It already leaked heavily and it currently eats the traces. If you don't remove the battery and clean the mainboard now you will soon not need any jumpers settings anymore.

scorp wrote on 2020-05-19, 15:59:

Sorry for the late answer, I had to search for the mainboard in my stock. I finally found it, but yours is missing an IC 74F74 in the socket near the jumper 3. My board looks like this: http://www.amoretro.de/2013/11/jet-electronic … ld-chipset.html. There are actually barely jumpers on it, one row to select DIMM and SIMM mixed usage, one to set color/mono display, one to select internal or external battery and it is mostly it. The place for additional oscillator is also free and one jumper near it is hardwired. Why don't you just put an FPU into the socket and see if it just works? In the worst case it will be overclocked, but you can measure it on the pin and try to figure out, what to do on demand.

And you should really remove the battery ASAP. It already leaked heavily and it currently eats the traces. If you don't remove the battery and clean the mainboard now you will soon not need any jumpers settings anymore.

What is IC 74F74 for? and would you specify those jumpers?

The board has been restored successfully. I'll take a shot later 😀