Originally Posted by donniedu
Call your dealer, get an apointment and have it replaced under warrenty.
Couple of thoughts on this though. If for some reason that the RV was connected to a 240 volt outlet (happens a lot especially with new outlet installations at peoples houses), the microwave is usually toast, so to speak. It's actually the first sign I look for when diagnosing a 240 volt connection.
Has the microwave ever worked since he bought the RV?
What all outlets has he plugged into? Is the RV a 30 amp (3 prongs on power cord) or 50 amp (4 prongs on power cord)?
Has he had a new outlet recently installed at his house/camp (even by an electrician)?
The deal is, if he has plugged into a 240 volt application, it usually fries the converter and microwave right off the bat. It also get's the television many times if it is plugged in.
Now with the converter fried, the 12 volt stuff still operates (the lights, fans, furnace, pumps, etc ) but they are only operating off of the battery. Once the battery depletes, then these aforementioned items will also cease to work. The converter is also the battery recharger, but you may not immediately realize it isn't working until the battery depletes while plugged into 120 volt AC power. So you may think everything is working (as it is but just off the battery as if you were boondocking)
The air-conditioner (if it wasn't turned on while connected to 240 volts) and outlets will still function.
We hope it's as simple as a faulty microwave, but we also need to be prudent and make sure he is not connecting to 240 volts somewhere (which is more commonplace than you know). If that has been the case, he is also going to need a converter replacement in his future.