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Struggling to identify motherboard. No manual.

seaken

Veteran Member
Joined
Jun 20, 2016
Messages
563
Location
Shokan, New York
I am trying to see if I can resurrect this old 286 motherboard. It had a battery leak and lots of corrosion. I got help from this forum on how to get rid of the corrosion here:

https://forum.vcfed.org/index.php?t...ery-corrosion-completely-neutralized.1239025/

But unfortunately the motherboard will not post when I power it on. All I get is three beeps, continuously, until power down. It is a three-beep (beep, beep, beep) and it continues to three-beep only. No other types of beeps. I have tried to find some information on the motherboard, and using some of the tools available from some forum members here:


But I cannot find this board. I am going to post what I know about it here along with some pictures. Does anyone have a clue on what type of board this is and who made it? Maybe if I knew who made it I cold find a manual or guide?

Next message for info and pics.

Seaken
 
The computer is identified on the front panel as "MicroLab". It is a 80286-16 CPU. No FPU. I found a label on the ISA slot that says March 23, 1990. No other marks to give it a model ID. There is another lable on the 8-bit ISA slot that says "w/No. M932342". On the underside of the boad it has "Made in Taiwan 8947 94V-0"

I found a few articles about MicroLab 286's in PC Magazine in 1989 and a couple of Ads.

PC Magazine says the maker is PAN-UNITED CORP from Edison NJ. Near as I can tell PAN-UNITED did not make the computer they just re-sold under the MicroLab name. It appears to made by one of the Taiwan makers and rebadged.

Some of the chips are:
Chips P82C206
Solutions L1A4736, L1A4438, L1A4436
CPU = AMD N80L286-16/S

Here's some pics:
IMG_20220620_144102655.jpg
IMG_20220620_144111096.jpg

Next message, more pics
 
Thank you! Yes, that does seem to match up pretty good. It at least seems to match the jumpers and ram. My board is slightly different in that there is no 16-bit external memory card and it has Sipps sockets instead of Simms for banks 2 and 3.

I wonder what would happen if I attached a battery to the external battery pins?

And I still don't know how to interpret beeps.

I also noticed there is a mono/color pin. Maybe I should try the color setting with VGA. Or maybe try CGA?

How did you find this? I looked and looked but did not see anything that matched. Then again, I don't really know how to search for motherboards.

Thanks,

Seaken
 
Looks like amibios, so beep codes are pretty consistent.

1 short beepDRAM refresh failure.
2 short beepParity circuit failure.
3 short beepBase 64 K RAM failure.
4 short beepSystem timer failure.
5 short beepProcess failure.
6 short beepKeyboard controller Gate A20 error.
7 short beepVirtual mode exception error.
8 short beepDisplay memory Read/Write test failure.
9 short beepROM BIOS checksum failure.
10 short beepHow to replace the CMOS battery.
11 short beepCache memory error.
1 long, 2 short beeps.Video card memory issue.
1 long, 3 short beeps.Conventional/Extended memory failure.
1 long, 8 short beeps.Display/Retrace test failed.
 
Ahh, so the beeps codes are based on the BIOS. The things you don't know, right?

So, in the future I just need to know what the BIOS is and search for the beep codes? Is that how you got to that link booboo?

Ooops, aparently not. That link is for the motherboard. Is the BIOS type on there?

But I can see the BIOS type on the board.

Learning,

Seaken
 
It looks like the ram chips are all in sockets so I should be able to remove them and move them around.

There are also several pins that affect the ram. Can I put in SIPPS and move the pins to select to use only the SIPPS? I've looked at it several imes but it is confusing to me how to use the pin settings for the ram. I'm assuming the pins are set correctly for the ram that is already in place. But I am not sure how to read it.

Seaken
 
There are also several pins that affect the ram. Can I put in SIPPS and move the pins to select to use only the SIPPS? I've looked at it several imes but it is confusing to me how to use the pin settings for the ram. I'm assuming the pins are set correctly for the ram that is already in place. But I am not sure how to read it.
Look at the manual and you will see the table of allowed memory configurations. Yes, you could use just SIPPs on Bank 2, that's DRAM mode 2. Then set the jumpers based on DRAM mode 2 as documented further into the manual. Personally I would use the existing 256K chips and just depopulate bank 1, and test with bank 0 only initially. You cannot just use bank 1 though.... always bank 0 or bank 2 if there's only 1 bank of RAM.
 
It looks like your board has a different chipset to the boards linked to. I've never heard of those solutions chips. However they did (almost certain) copy a C&T Neat chipset. The part no. for that were however (88C211, 88C212, 88C215, P82C206). This board is different.

Yes beep codes are based on the BIOS.

I think re-seating the RAM chips is a good first move.
 
It looks like your board has a different chipset to the boards linked to. I've never heard of those solutions chips. However they did (almost certain) copy a C&T Neat chipset. The part no. for that were however (88C211, 88C212, 88C215, P82C206). This board is different.
It does have one C&T, the others seem to be OEM versions with the same part numbers, so could be licensed, binned, etc. I do think it's the same board.
 
Ah! I was thown with the Solutions L1A4736, L1A4438, L1A4436 part nos. Yes you do have a Solutions branded NEAT chipset. And it is a great chipset.
 
Ok, I'll start by removing all the ram chips and reseat them, starting with Bank 0 only. Nothing to lose, right? I'm not suire how far I am willing to go with this board. It's interesting to hear that the chipset is a good one. I am not sure exactly what that means yet. Does the chipset interact with the BIOS and is better in some cases than other chipsets?

Sorry, I don't mean to ask stupid questions and I wil research chipsets to learn more about them. But you guys clearly know more about this stuf than I do. Anyway, it does seem that you all have identified the motherboard and I thank you for that.

Seaken
 
@seaken no worries at all... The chipset are all the support 'glue' and functions outside of the RAM, BIOS and CPU. They are responsible for controlling the RAM, and communications between all the subsystems on the board. In later chipsets they also provide things such as floppy and IDE controllers.

Please do remove all RAM but the 2 rows of BANK 0 and see what happens. If you still have that error, swap that RAM for the 18 chip that where in BANK 1. If that works, then you know at least 1 chip is bad. If that doesn't fix it, then chances are that you have a fault elsewhere. Could be traces around that leaking battery, or elsewhere. If you get a LONG beep and 2 SHORT beeps, then that would be success as it would then be indicating you have no video card. At that point you can add a video card, and continue.
 
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