From the information in your post, I would think the hdd just died. This generation of harddrives is really coming to the end now, especially if you are actually using them. There are cheap and easy solutions to your problem. Try to seach for "ide to cf card (or sd card) adapter" . cheers

About the second hdd - 2gb is maximum size for dos.

thanks aui, yes i think the same , the original hdd died , and the second hdd i try to created a small partition there but fdisk not save de changes

Chenko wrote on 2023-03-12, 13:59:

thanks aui, yes i think the same , the original hdd died , and the second hdd i try to created a small partition there but fdisk not save de changes

I'm quite certain that the system bios itself doesn't support a lot bigger HDDs than roughly 500MB. At least that is the case with one of my Compaq 486s. That was very typical for pre-pentium DOS computers, so you need XTIDE or some similar boot rom to take advantage of larger HDDs. As earlier poster said, DOS doesn't support bigger partitions than 2GB.

dose hdd spin-up? will you see hdd on USB connection? you can use EZ-Drive overlay app to partition the hdd,first. I had good success's in this field. Format drive as you can , then install overlay and setup real drive size , re-mount and that's it. I mounted 4.3 GB on Toshiba T3100e 286 , 3x1.5 gb fat 16 partitions , and a full wd4.3 on 486 , that had support in bios for up to 500mb. I had 0 issues. Dos supports 2 TB fat32 , and 2 gb fat16. (windows in other-hand has limited support for drive partitions so for win you need to limit partition).

If your hdd spin-s up , check PCB , clean PCB (wd40 or/+ contact cleaner) and check the resistance of input power , there is schematic somewhere , if had higher resistence than x than it's a burned out component on PCB , you can resolder if you find exact problem.
If no spin-up , than it can be a head crash.... (that's not good).
some info here :
https://stason.org/TULARC/pc/hard-drives-hdd/ … -SL-IDE-AT.html

you also have to search for a schematic.... older hdd are quite robust (not like new stuff) , check different jumper settings also , sometimes using different jumpers makes the drive boot again.