Burned Out Transistor

Sari,

If the smoke gets out, it is time to replace it.

With no power applied to the circuit.

Set your digital ohm meter to the diode setting. Put the positive lead on the base of the transistor. Put the negative lead on the emitter and then the collector. Note the reading. If greater than .7 all is ok.

Now reverse the positive and negative meter leads. Do the same test. If the readings are greater than .7 all is ok. However, one of these tests pairs should be close to .7. If not then compair to a known good transistor.