486 processor upgrades

[3pcedev]

The only reason the light would be on is if the drive is toast (i.e. internally faulty due to reversed power connection, age etc) OR if the drive/motor enable pin is stuck high on the FDC side.

Since you have tried a number of drives and cables I would say its a fault with the controller....

If you google the pinout for a FDC you can identify which pin corresponds to drive/motor enable. You can then check the output; however I am not sure if it requires a pullup resistor or not. Someone else on the forums probably knows the answer to this question.

 

[smyke]

I was afraid it might be the controller. Interestingly enough, from within Windows, I was able to fully read and format a disk all while the light stayed on. It would not boot the system from a disk, however. If I were to try a controller card with floppy connection, would I be able to boot from it? Years ago, I had a p166 desktop that had the IDE controller go out and had to use an ISA controller but I don't remember if I was able to boot from a floppy.

 

[3pcedev]

I was afraid it might be the controller. Interestingly enough, from within Windows, I was able to fully read and format a disk all while the light stayed on. It would not boot the system from a disk, however. If I were to try a controller card with floppy connection, would I be able to boot from it? Years ago, I had a p166 desktop that had the IDE controller go out and had to use an ISA controller but I don't remember if I was able to boot from a floppy.

Yes; provided you disable the onboard controller in the bios first.