Other than whats mentioned above. There is a mechanics stethoscope you can buy to help with noises. Two cheap alternatives are using a couple feet of heater hose, use one end to find noise and other end up to your ear. Another method would be with a long screwdriver/pry bar and put tip on parts and handle on ear to listen, sometimes a bar or pipe can work too.
Maybe check the belt too and make sure its tight, not glazed or cracked. Sometimes you can spray a lube on the belt to see if noises go away or change, if so the belt is probably loose or bad.