1986 190E ignition problem.

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