Strange Drive Failure

Hey Guys, got one of the oddest failures I've seen yet here and I'm looking to see if anyone knows why this would occur. Just as a note, power is definately not the issue here.

I run a RAID array in one of my PCs. RAID 5, with 4 120GB drives (two pairs, each pairing is identical, and each identical pair shares a channel/cable). Recently, one of these drives appeared to crap out. No matter what jumper settings (Master, Master w/Slave, Cable Select, or Slave), cable, or channel (the array controller card has four available IDE channels) I put the failed drive on, it won't recognize this failed drive. It doesn't matter whether it has the other match to itself as a master/slave (or vice versa) relationship , or not, it will always see the good drive but not the bad, again, with any jumper setting.

However, this is what seems odd. If I hook the bad drive straight to the mobo, and set as Master or CS, it shows up as the master drive on the primary IDE channel.

I would suspect the controller card, but all the other three drives are recognized regardless of the channel or cable I connect them to it with, and if I add a small spare drive I have laying around to any cable or channel on the controller, it will see it and let me have an option to rebuild the array.