Problem solved ! My multi IO VLB and CF-IDE Adapter is reason for instable DX4-run. Reason: I am lazy and i let run CF-IDE adapter without external 5V supply. (CF IDE adapter run on 5v from IDE Port) Abit board and one vlb ide card doesn't like this way. I plug of 5V supply on CF IDE adapter and DX4 run fine.
My Board has rev with four jumper for voltage selection.
Modification-List is only this Rev: 2:1.1
Q4 = LT1085-ADJ or pincompatible type with LowDropout(LD1085V from ST, EZ1084, ...)
TC15 = 10µF capacitor (eletorlytics or Tantal,whatever!)
TC12 = 150µF eletrolytics (recommend by LT1085 datasheet), i use 470µF
JP52, bridged with wire by soldering.
R77 = 270 ohm , 4V CPU voltage , Jumper JP53
R78 = 240 Ohm , 3,6V CPU voltage, Jumper JP54
R79 = 220 Ohm, 3,45V CPU voltage, Jumper JP55
R80 = 200 Ohm, für 3,3V CPU voltage, Jumper JP56
R81 = 127 ohm
R41 and R42 is placed with 10 Ohm (my estimated value ) Location: between VLB slot and CPU socket
All eight capacitor in CPU socket is 100-470nf capacitor.
And the END: JP9 is recommend to setting,
Intel DX4 need this jumper JP9, 1-2 or 2-3, it is not important (recommend (1-2 )). It is possible, it run without jumper stable. I
But AMD DX4 doesn't need him, because this PIN is N.C. It is for 5V tolerance I /O buffer of Intel DX4 and 5v Supply of 486 with 5V
My BIOS doesn't support AMD DX4 and 5x86. it is too old. 😒