The phrase "complete teardown" means to fully dismantle or take apart something, down to its smallest pieces, in a very thorough and comprehensive manner. Full definition
The tech experts at iFixit took their time and opened up the tablet only days after completing the teardown of the novel iPhone SE, so here's the deal. (techtimes.com)
If they were in complete teardown, you would have seen a different team post deadline last year, a team that would have not let CK back, not let Hank play after his fall, and trading of other Vets. (sbnation.com)
iFixit has completed a teardown of the Samsung Galaxy S8 / + and notes that the battery voltage, capacity, and design tolerances, and even the manufacturer, are virtually identical to the Note7 which was recalled due to battery issues. (itwire.com)