wondering if the external has cooling or if it was supposed to have a fan that had quit, or... heat is a big problem for hard drives. depending on the external, you might be able to connect the drive while leaving the cover open. you could also use a fan/house fan/desk fan or whatever to move some air over it. big IDE moving 300gb+ would get very warm in the best setup.
the drive jumper should be be set to 'master'.