Starting problem

Hi All, have a problem. I have a MSD distributor(8360 ready to run) with a MSD Blaster 2 coil on a 350 engine(67) The car was running fine but then just quit. I checked to see if I had spark and dont. I pulled out the distributor and coil and brought it to an carbeurator/electrical shop and both tested out fine. With the key to the on on position, I do not get 12 volts on either positive or negative on the coil. Could this be a fuse problem or grounding????

Any ideas would be appreciated. Gary