If i look at the pulse output from the distributor to the ignition module with a scope should I see anything.  The manual says the distributor is supposed to put out an alternating 1oo volts.  I see nothing on my scope.  I am trying to trouble shoot my car because following the manual It says that my ignition module is bad.  I want to be sure because the ignition module is expensive and not returnable.  
Does anyone know of a sure way to tell if an ignition module is bad.  I am getting no spark.
Thank You
for any help.
Don