kanecvr wrote:

Hi guys. I've been trying to get my only 386 board that has L2 cache working for the last couple of months. There are two relate […]
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Hi guys. I've been trying to get my only 386 board that has L2 cache working for the last couple of months. There are two related threads on Marvin, but they tackle separate issues, but they have been resolved so I'm opening up a new thread regarding the latest issue I'm having with the board.

I figured out the board originally uses a NEC keyboard controller and I sourced one from a dead motherborard, BUT keyboard still doesn't work correctly. Here are the issues I'm having:

- AT keyboard will usually refuse to work at all - after posting, the machine displays a "Keyboard Error, press F1 to continue". Pressing any key on the keyboard will make the machine beep, but it will not register any actual characters / commands.
- I can use a PS/2 keyboard /w a din to mini-din adapter, and everything seems to work sans the num lock. When pressing "Num Lock" the machine stops accepting input from the KB until I turn it off and on again. Num keys will not work even if I set "Num Lock on at post" from bios. With said setting on, pressing any numpad key will make the machine beep like it won't register a valid keypress. Setting it off will register 8, 2 4 and 6 as arrow keys and the rest as insert, end and such.

I checked the back side of the board and someone seems to have previously replace one of the ICs under the KB controller (S 74F00N I think). Could this have been replaced with the wrong IC? could this be causing the issues?

Said IC is a 2-INPUT POSITIVE-NAND GATE - not electronic-savvy enough to know what it does.

Could you provide a pic of the keyboard controller that you need? Or any other specifics like "model numbers"? (dunno if these even exist for KB controllers tbh)

I don't know the exact model of KB controller - that's one part of the problem... I got the board w/o a kb controller, missing bits, coverd in mud and broken traces... Here are some pics of the board and what I've done so far:

back of the board where the KB controller socket is - you can see someone already messed with one of the ICs

The big-ass wires complete broken traces. They are a temporary solution.

Did you already tried an AMI keyboard bios?

http://i.ebayimg.com/images/g/-HUAAOSwLVZV3~oi/s-l1600.jpg

Mostly they are the same brand.. You need a 386 type one..

... don't have an amikey controller.... 🙁

C'mon guys... any other ideas? Can someone at least point me towards a vogons member who is skilled in this sort of stuff? I really want to finish this machine - it's my fastest 386 by far... 🙁

Robin4 wrote:

Did you already tried an AMI keyboard bios?

http://i.ebayimg.com/images/g/-HUAAOSwLVZV3~oi/s-l1600.jpg

Mostly they are the same brand.. You need a 386 type one..

As an experiment I pulled the KB bios off one of my 486 boards - also a Soyo board with an ETEQ chipset - SY-020C/D - and replaced it with others (it came with an Opti, I tried a NEC and a AMD controller in it) and it worked flawlessly - so it's NOT the KB controller - something else is causing the issue - either a damaged capacitor, a damaged diode or one of the ICs under the KB controller socket...

I really like to know why the previous owner installed that second IC underneath the keyboard controller.. Maybe there wasnt one when it was bought.

... I guess it's a possibility but the SY-020C/D has them too - in the exact same place, also two of them but they are not the same chips as on this board...

I was hoping someone is either knowledgeable about this kind of stuff or has encountered this problem before and knows of a sure-fire way to fix it... if not, I'll have to pull quite a few related parts to test (capacitors for example cannot be tested while in a circuit). The IC's I don't know how to test - I'll just have to replace them with identical parts off other boards and that's quite a bit of work - not to mention removing them off such an old PCB might damage the board...