ECU Failures

Just looking for a little help here. I have a factory electronic ignition system on my 74 Dart Sport. It has an OEM 4 prong ballast resistor and an MSD Blaster 2 coil. I had an Orange Box go bad but figured it was just crappy quality and it was about 3 years old. I replaced it with a new Jegs brand ECU and after 3 weeks that one has now stopped working. Not sure what could be causing these issues and looking for some guidance on what to check.

Thanks