how to replace the charger inverter in a four winds

I am just going to leave it alone and replace the circuit breakers. The 20/30 dual breaker. Has always worked just fine until I had to deal with high outside heat. When the heat is not high the A/C works fine. Just not worth the expense to go to 50 amps just for an occasional problem. I also need to figure out if the fan inside the unit is good or bad. I never hear it on.