The BIOS seems to be already "cleared". You should do the opposite, enter it and correct settings now that you have a new battery. You need another keyboard to do so of course since I don't think your keyboard problem is related to BIOS settings.
btw, which keyboard exactly do you have? Could you post a photo of it? My Acer keyboard (from an older system though) has a switch with 3 positions to set XT/AT/???, could this be the case?

Also testing the keyboard on another pc (a 5-din -> ps/2 adaptor would be the easiest & cheapest way to go) could help locate the problem.

Hi Konc,
Thank you for your quick reply. Here are the pictures of the keyboard. It has a switch but only from 8088 to 286. I am using 286, when I use 8088, only numpad, caps clock and scroll lock work - nothing else.

As for the PS/2 to 5-DIN connector - I am currently awating for delivery from UK, as it turns out in Bulgaria there aren't any.
The thing that bothers me the most is that there isn't any infomration regarding my Mobo.
I will upload images if it turns out that the controller is faulty.
BTW, is there a PS/2 ISA comm card? OR VESA PS/2 comm cards?
I have three VESA ports - my video is also some unknown thingy...

Anyway, thanks for the help.
Will await further instructions.

galinpetkov wrote:

I noticed that the old battery has leaked, so I soldered a new one. There is no damage to the motherboards...

That you can see. Or are you absolutely sure that every trace near the leaked battery is not cut? Did you measure all the keyboard related traces with a multimeter? Sometimes a trace may look in perfect condition, but it has a microscopic hairline crack that is nearly impossible to see with the naked eye. I've also seen traces cut right where they meet a solder pad, but this was only visible when looking at the motherboard through a strong light. Keyboard errors of the kind you describe, even if the LEDs do light up, are usually related to a cut trace.

Ah so it's not an Acer-branded keyboard. Mine with the 3 positions switch is, so obviously this is not a possibility in your case. I'm not aware of any such card, this doesn't mean of course it doesn't exist although I don't think it is probable.
I believe since there is no visible damage to the board you'll be able to investigate better when you have the chance to test the keyboard on a different machine and vice versa (see if any keyboard works with the Acer).
For now you could check with a multimeter what devius said +if all cables from the keyboard's controller reach to pins of the 5-din connector.

Guys,
I found some interuption in the traces - 3 to be exact. The problem is, that there is no chance for me to repair it, since I do not have the schematics of the motherboard.
I tried to remove the connector to shorten the interutped track but failed.
Now, I am not happy. 🙁.
Please see the photos and advise if repair is possible at all.

Thanks for all your help.

Guys, I give up. I am not going to repare this junk.
Can you recommend a good 486 sx with at least one VESA mb?
Thanks

Well, it seems to be repairable. I can see that there are two solder pads missing on the first picture. That will make it more troublesome to repair. What I've done before in these cases is to simply bypass some length of the trace and solder a wire between two good points. Or if that's too difficult solder a wire between the affected component pins. When there is a cut trace like that connecting two components, you only need to make sure that the components are connected again. You don't have to actually repair the trace, although that is preferable for aesthetic reasons.

If that seems like too much trouble, it is. If you have the chance to buy another motherboard for cheap go for it.

Hi Devius,
Thanks for your answer.

I did try to bypass it but I am not sure which pin is the correct one on the connector side. That is why I just gathered everything from the board and will by a new one.
So, do you have a recommendation about a certain board?
Thanks.

Well, usually there aren't many boards for sale that you can choose from, so all I can say is that it depends on what you are looking for. If you want to use more modern hardware with that 486SX getting a PCI motherboard makes sense. If you prefer to go the purist's approach then it will have to be a VLB board. Personally, I have had good experiences with Sis chipsets like the 471 or 496. You could also go for an older all ISA board, but that will limit what you'll be able to do with the system. Some games require a fast video card, and that means either VLB or PCI.

You can read a bit more about motherboards here.

Hi Devius,
Great and useful site.
I will have to get a VESA motherboard as my video card is VESA with 1 MB or RAM.
So, I guess I will look for QDI OPTi 895, as it is the only one from the selected that has 30-pin RAM sockets, as this is the memory I have.
It will be long journey, though, as the MB in ebay are quite expensive and the shipping fees are redicolous.
Thanks,
Galin

My suggestion would be to find an OEM 486. That is the fastest / cheapest solution usually.

I do not have any luck, obviously. Today I bought another one, but again I cannot find the system specs, so I can configure it to run. When I turn it on, it is just on and no beeps or anything. Tried with two diferent RAM card - still the same. See the pictures for more information. All I know is that is some kind of weird model with SIS85C471 chipset and the jumper configuration for the closest model which appear like this one, don't work.
If you could help me, that would be great.

Good luck. This is why I do OEMs only usually: no BS. I have had my share of bad luck with MOBOs. Then again: I like to play games: I do not enjoy troubleshooting / building as much. 😀

I bought it for 5 euro anyway. But how do I know if an OEM mobo from ebay is working one? the most of them are "As is..." which I beleive is "Well, you bought it, no returns you were warned".
I am so agnry right now as I know my way around computers and this is the second mobo that doesn't work...

Thanks, anyway

galinpetkov wrote:

I do not have any luck, obviously. Today I bought another one, but again I cannot find the system specs, so I can configure it t […]
Show full quote

I do not have any luck, obviously. Today I bought another one, but again I cannot find the system specs, so I can configure it to run. When I turn it on, it is just on and no beeps or anything. Tried with two diferent RAM card - still the same. See the pictures for more information. All I know is that is some kind of weird model with SIS85C471 chipset and the jumper configuration for the closest model which appear like this one, don't work.
If you could help me, that would be great.

IMG_1089.JPG

IMG_1088.JPG

It is important that the jumpers are correct. Also can you confirm the CPU and video card are good?

OEM desktops are the way to go. Not OEM MOBOs by themselves. OEM MOBOs typically only fit in the OEM cases.

With hardware from the 1980s and 1990s there is always a big risk something is DOA or dies within days / weeks / months of acquisition. That is just the risk to take. DOSBOX is a good alternative in case you do not like that.

smeezekitty wrote:

galinpetkov wrote:

I do not have any luck, obviously. Today I bought another one, but again I cannot find the system specs, so I can configure it t […]
Show full quote

I do not have any luck, obviously. Today I bought another one, but again I cannot find the system specs, so I can configure it to run. When I turn it on, it is just on and no beeps or anything. Tried with two diferent RAM card - still the same. See the pictures for more information. All I know is that is some kind of weird model with SIS85C471 chipset and the jumper configuration for the closest model which appear like this one, don't work.
If you could help me, that would be great.

IMG_1089.JPG

IMG_1088.JPG

It is important that the jumpers are correct. Also can you confirm the CPU and video card are good?

Hi,
Yes. The CPU is working fine as it worked on the old motherboard. The graphic card is also functioning.
The problem is that I couldn't find a proper schematic for my model. As you see my 72-RAM socket are on the inside of the board. I found models with the same chipset with those socket on the outer side.
Which is odd.

PeterLI wrote:

OEM desktops are the way to go. Not OEM MOBOs by themselves. OEM MOBOs typically only fit in the OEM cases.

With hardware from the 1980s and 1990s there is always a big risk something is DOA or dies within days / weeks / months of acquisition. That is just the risk to take. DOSBOX is a good alternative in case you do not like that.

PeterLi, I am aware of DOSbox but unfortunately, it is not my thins. It is just not the same to emulate a classic like this.
Thanks for the suggestion.
Today, I am awaiting a reply for another whole machine in working condition for 10 euro. I will see how it goes, as currently I do not know the specs.
I will also try again to configure the jumper settings.

Without knowing the jumper settings it will be very difficult. Here's a tip: when looking for old motherboards lookup the manual online before you buy it, or see if you can identify jumper setting instructions printed on the motherboard itself. I have a very similar board, except with the 85c461 chipset and the 72p RAM slots on the top like you mentioned. However that particular board had a jumper that allowed selecting how the RAM was configured. It is possible to select which one is the first bank of memory, either the 30p slots or one of the 72p slots. Without that jumper correctly configured the system would not boot unless I populated the required slots. You also need 72p SIMMs to debug these situations. I have a ton of them, so in the case of the board I mentioned it was relatively easy to figure out what was going on.

About OEM systems, I also agree they are a good bet if they are working. But if something breaks down or is damaged you'll have a hard time replacing or repairing it, unless it's an off-the-shelf component like a HDD or a RAM stick.

The thing about old computers is that they are a pain to setup. They were like that when they were new and they are even worse now. That's why they're so much fun 😁

There is a progress! Kind of.
I managed to find that this is 471 rev. D model. What make - it is not clear. I asumed it is a SiS make model 471 D. I tried with the jumper settings from the manual, but now the board just lights up and then shuts down.
Any ideas?

There must be some kind of marking on the board with a model number. Or a sticker other than the warranty sticker. If you can't find a model number at all just look for the manuals or jumper settings of all the sis 471 based boards you can find. There are quite a lot of them. I wouldn't normally recommend trying random jumper settings from unknown manuals, but if it's not working in any case I guess there's not much lost.

If it lights up and then shuts down it could be an overclocked CPU setting that is making it unstable.