First post, by squelch41
Am just getting into the world of 486 building - just for the challenge!
I am trying to change an AMD 486DX2/66 to a AMD 5x86-133ADZ
The motherboard is a Opti 82C895 based VLB board - model V4P895P3/SMT V5.0 with a bios chip marked AMIBIOS 1993 486 ISA BIOS AC0467136
This manual seems to match the board:
I have tried configuring the CPU as both an intel DX4 100 (with volt regulator set to 3.3) and and AMD 3.3v 2x but neither POST. I also tried P24D settings but again no POST
My POST card gets stuck at code 23 with 20 the preceeding code
(I either stuck at D2 D3 on my POST card and it gets through far fewer number swith the p24d )
If I replace the DX2/66, set the jumpers for that (ie 486DX @ 5v) it all POSTs fine and boots happily to DOS
My understanding was that the 5x86 worked with pretty much all boards and it does seem listed as compatible here https://www.elhvb.com/webhq/models/486vlb3/v4p895v5.htm and you set it as an an AMD 486 with x2 multiplyer?
Where am I going wrong?
Help would be appreciated 😀
V4P895P3 VLB Motherboard and AMD 486 133MHz CPU
64mb RAM, CF 4Gb Hard disk,
Realtek 8019 ethernet, ES1869 soundcard, Unknown brand VLB multi-io card with Cirrus Logic GD5428 1mb VGA on it.