no spark - 73 Duster Six

Hi I was wondering on a 225 slant six with pointless ignition what would be the more common reasons for a lack of spark. Do I need to remove the distributor and clean the pick-up coil? Do the modules burn out? The car is a 73 Plymouth Duster. Thanks for anybody's help!

A common problem is the ballast resistor mounted on the firewall, these go every so often and won't allow for starting and will need replacing. Also check ground connections where ignition module mounts to body.