First. Make sure you have definitely set the jumpers correctly. Different drives often have different positions for master and slave. There isn't necessarily a common standard.
You don't mention how old the equipment is you are working with. On older cables, it is possible to connect the cable the wrong way around (no key), so make sure the red tracer, is going to pin one on each of the drives and the red tracer goes to pin one on the motherboard. I am assuming you are putting both drives on one cable!
Finally, if everything noted so far is OK, do you have a different (newer) cable you can try. This problem has been known to revolve around a faulty data cable.