Looks like a DataExpert EXP4045: https://theretroweb.com/motherboards/s/dataexpert-exp4045

Yes, a DX2-50 would be set up as 25 MHz.

thats its ! thank you !

strange though, I have all the jumpers correct and cant get it to boot. Not having much luck last 24 hours, this is 3rd 486 motherboard that does not boot with few different processors. Tried 4-5 diff ISA and VLB video cards and lots of different RAM chips. Strange as they were all working few weeks ago when I was doing few tests. Suddenly, they just stopped, all three of them.

I'll have to do more torubleshooting later. I guess thats what happens with old hardware.

Omarkoman wrote on 2025-05-17, 03:15:

thats its ! thank you !

strange though, I have all the jumpers correct and cant get it to boot. Not having much luck last 24 hours, this is 3rd 486 motherboard that does not boot with few different processors. Tried 4-5 diff ISA and VLB video cards and lots of different RAM chips. Strange as they were all working few weeks ago when I was doing few tests. Suddenly, they just stopped, all three of them.

I'll have to do more torubleshooting later. I guess thats what happens with old hardware.

Make sure the power supply is good and pins are making good contact. I had an AT one that one of them was iffy- no post until went over the wires one by one and pushed them in a little more

thank you for the tip, the power supply should works ok as I worked on few other boards but lets me try another one as thats one part I did not swap during testing.