I removed a 803T from a HD drive and it will not work. It was still in the heatsink and the ribbon cable had not been removed so it had not yet been touched with a soldering iron. I tried to test it before driving it with a DMM on diode test but it justs shows open no matter which leads I connect to... Do these diodes test like a normal diode? Should I be able to read any resisistance between the case or - lead and the + lead or will it be an open? I installed this same diode in a DDL driver circuit limited at 50 to 100ma and it did not work? Unfortunately I tried with another 803T with the same results... What do you think is happening?