On replacing floppy cables with round ones... they can be used, but not without adjustment.
I recently replaced the IDE and floppy cables in my A4000 with round ones. I encountered two problems.
One, the IDE cable had a key pin, so it would not plug onto the motherboard. After researching the pinout, and making absolutely sure that I had the cable in the correct orientation, I decided to gently break the interfering pin off.
Then I realized that the cable had a confusing indicator for pin 1 and I had the cable reversed, and had actually broken off the wrong pin! Fortunately, that pin was just a ground (whew!). So I reversed the cable and broke off the correct pin. Then it plugs on and everything is working fine.
Just a note... after you double check that you have the cable in the correct orientation... tripple check, count pins, think about it, then check it again. :-)
As for the floppy cable, I bought an 18" round single floppy cable (for PC). This didn't work since the cable has pins swapped. So I carefully dismantled the connector on one end of the cable, and put the wires back in the "right" spots so it was a straight-through cable. Then it works fine.
Note that on the PC, to make it so noone would ever have to change a floppy jumper, they have made all PC floppy drives configured as drive 1. Then they put a flip in the cable so it will make the drive ID 0. Notice that the second floppy in a PC has no flip in the cable. I don't know what their plan was if you wanted to use more than 2 floppies. :-) So a round PC floppy cable would work as-is if you use the "second" drive connector.
I prefer the hack-the-cable method. Although it is not easy removing the lock/guard on the crimp-on connector without breaking it, it can be done.
-Jeff
