This is a picture of a spare factory cable I have for my 810. Note the two pigtails. Yours should have something similat to those. A cable from an 82 would work as long as it has the same connections as the one presently in your car.

Check your fusible links. If the fusible link from your alternator is blown, your alternator will run wide open which can cause other problems.

That's not a factory cable. If you do get one from the junkyard, make sure it has those three pigtails and that they get hooked up to wherever those three are connected. And if it still has an insulator like the one I posted make sure to get that too.