Don, if your Radio Shack meter is like mine, the "Amp" setting is right next
to "volts." One nanosecond of the wrong setting and your fuse is gone. You
can tell when the fuse is blown by putting the meter on ohms (middle
position) and then pressing "select" for the audible signal. If the fuse is
blown, it will make a sound and register "short" when the circuit is
actually open.

By the way, Radio Shack sells these little fuses for almost $3.00 for TWO.
So be careful, and don't just wrap 'em with silver foil, as some of us have
done...