Nevertheless, I think it IS possible, but not easy nor cheap to determine how a transistor can be zapped and if it will have any impact to the remainder of chip (including the reliability). It might turn out that it can be zapped as well as that it cannot be zapped. But saying: NO it's impossible... Well if one doesn't state the boundary conditions, one can obtain any answer one may wish.

Exactly: "but not easy nor cheap"

If you have an army of scientist spending a vast anmount of time, of course, "testing" can lead to a 99.9% believeable result.

When "testing" raises it's ugly head in a uC forum, it means "see if it works" and referring to THAT as proof of functionality is pure bull.... .

Jan, if you reread the post that started the testing" issue AGAIN you will see that any reader would read what you wrote as "see if it works".

Erik