So I was preparing a Pentium 75 for sale when I decided I wanted to make a boot disk for it so whomever buys it gets easy access to the 640K games. The only thing I did to it was the RTC battery mod - it was long dead and would not boot from the hard disk without it.

Insert diskette to format - Write protect error. OK, check tab, not write protected. Try a few more diskettes - write protect error.

Check manual, CMOS has a write protect feature for floppies. It's disabled.

Change the drive itself. Twice. Write protect error.

Change the ribbon cable - Write protect error.

Swap A: B: in BIOS - Write protect error.

Go to look at all the jumpers (there's like 5, 3 for CPU stuff, one for Diagnostics mode - tried that, floppy farted at me for a long time, then lots of POST beeps, and one was for CMOS clear).

Hmmm.... why is the CMOS clear jumped? Remove jumper, Formatting diskette (yay!) - how though? I wonder if this was the reason the computer was abandoned decades ago? A non-writable floppy in the 90s makes a pretty useless computer.

That jumper seemed to have affected only the writing to the diskette (and not actually clearing the CMOS at all - it kept all the info for a whole 24 hrs). I formatted the hard disk, Fdisked it, loaded 95, CDROM works, NIC, sound, everything. Just not the ability to write to the diskette (and that included deleting files). So if anyone is working on a 27 year old Digital 575 or derivative, see if someone left the CLEAR CMOS jumper on. 😁