Be sure the points are open when you test for voltage. If they are, and you still get no voltage on the (-) side of the coil, you've got an open-circuited primary winding in the coil, or the wire from the coil to the distributor is grounded somewhere.
Take the distributor cap off, rotate the crankshaft until the points open, and test for voltage at the distributor side of the coil. No voltage- - - -take the wire off the side of the distributor and check it for voltage again with the wire connected to nothing. There should be voltage there now. I believe the connector that goes through the distributor housing is grounded, giving the same result as the points being closed all the time. It happens pretty often.
Jerry
