BIOS halts at initializing keyboard controller, you'd get exact error W/O KB controller, check traces around battery.

Ok, thank you, I will inspect them again.
Do you know the brand of the Mainboard? and is there some info of the Keyboard controller, so I can test the traces to see witch is not OK ?

You may need to desolder the keyboard connector and visually follow each trace and check them for continuity. The biggest issue I see is the power connector being right there and it may obscure your ability to visually follow some of the traces. It's not uncommon for what looks like a trace running straight under a component to be two separate traces, though thankfully power lines are normally larger traces so hopefully the keyboard isn't routed under that.

The chip near the ISA slots labelled mb300-e is probably the keyboard controller

Rudi_K wrote on 2021-03-06, 14:54:

Ok, thank you, I will inspect them again.
Do you know the brand of the Mainboard? and is there some info of the Keyboard controller, so I can test the traces to see witch is not OK ?

That is a Soyo 030F2 motherboard according to the sticker, but there is nothing to be found about it.
I think it is a relabeled other motherboard with OPTI chipset. So your best bet is to check around the keyboard controller and find it's datasheet.

We have the 030E2 on uh19 http://www.win3x.org/uh19/motherboard/show/4650

They look almost identical. Maybe the actual name is 030 and E2/F2 is the revision ?

Thank you for your replays.
I shall Desolder the MB-300E chip and check the traces.
They mainboard looks like the 030E2 so thanks for finding that 😀
If found something I let know here.
Maybe the keyboard controller is broken, I hope I can get a new one if the traces look fine.

These chips are fairly common among motherboards. They're often swappable by any other chip of this kind. Iirc they're intel 8057 clones inside.

Hi All,

The 486 is working again 😀
I removed the keyboard chip, sodler a DIP-40 holder and buy on good luck a LT38C41 Controller.
this one is working perfect 😀
so there are no broken traced and the old keyboard controller was dead.
Thank you all for the help.

Best Regards Rudi.

Deksor wrote on 2021-03-09, 15:37:

These chips are fairly common among motherboards. They're often swappable by any other chip of this kind. Iirc they're intel 8057 clones inside.

They are Intel 8042 clones inside.

That's the "slave processor" variant of the 8048 microcontroller. The 8048 family is the predecessor of the 8051 family, but the keyboard controller kept at the 8048 level, because this is sufficient for the keyboard controller. Later on, especially on laptops, the keyboard controllers got replaced by much more powerful "embedded controllers" that often have completely different architectures. IBM for example used H8/300 processors in their T-series thinkpads for a long time.