Hi Mike: What do you mean by "possible failure causes"? For example are you trying to determine future reliability, like for a space mission, or . . do you have units that have failed and you want to know why, or . . Have Fun, Brooke Clarke -- w/Java http://www.PRC68.com w/o Java http://www.pacificsites.com/~brooke/PRC68COM.shtml http://www.precisionclock.com -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist