I noticed my a/c was not cooling today. Went outside and checked condenser unit. The fan was turning slowly and the compressor wasn't running. I heard a loud buzz and immediately shut off the power. I called the installer ( the unit is about 7 years old) and he said the start/run capacitor was probably bad. I replaced this capacitor about 3 years ago and I know how to do it. He told me to go buy one tomorrow along with a hard start kit. Why would I need a hard start kit? How do I check the capacitor with a multimeter that does have an mfd function? Any help would be appreciated.