Another update. Keyboard problem solved. It is a "software" problem, in the BIOS setup option "Turbo switch function" must be disabled. Strange but it solves the problem and the keyboard works normaly. Another interesting thing is that option does not disable turbo switch for real, hardware switch on the motherboard works with no problem via jumper. Also I added FPU unit, now the board looks more complete.

Hi, Is the FPU running at 2/3 or 3/2 ? Afaik, the 2/3 thing was only true for the original 287 from intel (pre-XL).

Edit: Never mind.

Hi, Is the FPU running at 2/3 or 3/2 ? Afaik, the 2/3 thing was only true for the original 287 from intel (pre-XL).

You can choose between onboard 32MHz (16MHz clock) oscillator which in fact is 2/3 of the CPU's 50MHz (25MHz clock).
The other option is custom oscillator via socket on the board for IIT 287-20 I fitted 40MHz.