Audio Systems: car audio, output transistors, voice coils

Question
we put a kenwood deck in a pickup(came out of another car) and when we hooked new speakers up the stereo read protect and would function.  what's with this and how do we fix it?

Answer
The protect function can be the result of internal or external troubles.

EXTERNAL:  Miswiring or shorts  in the speaker wires.  Or, shorted voice coils in one of the speakers.

INTERNAL:  Bad power output transistors.  Caused by overdriving or shorted speakers connected.

To check, disconnect speakers at the back of the radio, preferably, and see if protect clears. If so, then you must check for shorted or miswired conditions.  If still in protect mode, do a reset by removing power for 15 minutes and try it again.  If it does not clear it has a failure inside the Kenwood.

Let me know if you need more.


C