I have a 486-33 I'm trying to upgrade. I removed the 5 1/4 floppy, changed cmos setup to reflect that, redid the floppy controller so that 3 1/2 is on the end connector after the crossover, and set the cmos for the A floppy.
I'm also trying to install a CD, so have it connected to the HD controller cable. HD works fine.
Thinking the floppy or controller card might be bad, I have switched out both. Same problem results - Seek error or drive not ready (depending upon how the controller cable is plugged into the floppy - at end or in middle).