First, note that you should get two basic outcomes regardless of the technique you use: color change, and taste change. If neither of these occur, then either the technique is wrong or the device is not working correctly. For example, as a first test, without any drawing at all, it should be possible to turn one full load completely brown or even black on a single charged battery. If not, then something is wrong -- check the battery, charger, and that the Box is producing heat. If these tests fail, then it is probably a warranty issue and Magic-Flight will re-issue whatever is necessary to fix it. Otherwise, once you are satisfied your Box passes the basic test, it is a question of technique (or possibly the quality of the loaded materials).