Another MSD problem

Went out to start the Duster this morning to clean it up for a local show. Cranks,no fire. Plenty of fuel, pulled the coil,no spark. When I first put the msd on almost a year ago I had this same problem. I redid the main ground & she fired up & has been running great since then untill this morning. I redid the ground again(moved it to different location)still no fire, tried a different ballast resistor, no change. Tested the msd box for spark according to their instructions & it puts out a healthy spark out of the coil wire but when I hook everything back up no spark out of the coil. I drove her last weekend to the store & back with no problems. I checked the ballast & the switched red with a test light & I have power there but no power to the + coil when cranking the motor. When I first put the msd in I tried to wire it in without the ballast but it wouldn't run with out it. The msd unit is one of Mopar's versions(black housing with MP stickers) that a coworker got for me off e-bay brand new in the box. I'm about to RIP everything out & start over with the old factory conversion kit that was in there