I found the XT keyboard, but I also made an adapter and it worked fine.
It will be with this that I will do all the tests from now on.
I leave here the photos of the adapter, the uC was the PIC12F675.
For now, I can say that it works very well, even through a KVM switch.
Regarding the RAM memory problem, I verified that the address lines goes to the U14 chip through the 74ALS244 - U75 (Octal 3-state Buffer/Line Receiver).
I checked all these address lines and didn't find any problems, they all had activity.
I suspected that one of these lines might have problems, but I didn't find anything suspicious.
Chips MSM3764A and MSM41256:
Pins 2 and 14 Din an Dout (data lines)go to Chip U15 - 9 lines, one for each line
Pin 4 (RAS) go to chip U14 - 4 lines, one for each column
Pin 15 (CAS) go to chip U14 - 4 lines, one for each column
Address lines (A0 to A8) goes to U14 through U75 (74ALS244)
Pin 3 (WE) common to all RAM chips
So far I haven't found anything that could cause that wrong RAM value.
Regarding the chipset, I can't find any information, no datasheet to be able to diagnose the fault.
This motherboard does not have a dip-switch to configure a floppy drive, so i think the Bios have some
control here...but first we have to figure out how to solve this problem and we don´t know for sure which it is...