Audio Systems: help!, fuse boxes, how to use a voltmeter

Question
99 mercury sable stereo wont turn on. fuses are fine. replaced battery and lost power to stereo.

Answer
Did you check both fuse boxes?  There are two fuse locations in this car; one under the hood and one inside under the dash near the steering column (which is hard to find, maybe).

Is there any way to check for power at the radio wiring or the connector plugs?  Like do you have and know how to use a voltmeter?  You could look for the 12v connection at three places on the radio; the constant line, the ignition remote turn-on line and the variable lamp brightness line.  And the ground connection must be good;  tight, surface to surface ground connection.

That would be the place to start looking!