Identify Transistor Pin-outs
Which Pin Is Which on a BJT?
Use this chart to find which pin is the base on a bipolar transistor and at the same time get a good idea of whether the transistor is faulty or good.(Don´t test FETs in this way though - handling FET pins can destroy the transistor!).
Follow tests 1 - 3 then decide from the result which of the four arrows to follow. You may have to go through the test sequence more than once to make your diagnosis.