Our coach came with the Sharp R-1870 convection/microwave oven, and it started to fail. The microwave would run for 59 seconds, and then stop. I did a search, and found a thread on IRV2 about the problem, how to remove it, and how to repair it. It included the part numbers for the likely culprit, the damper motor and the microswitch. I put it off as long as I could, knowing it might not be easy to remove and put back. And the oven still worked. You just had to reset it a few times. I finally started the project this week.
The thread included photos showing how to remove the oven, open it up, and where the parts were located.
Sharp Microwave Oven R-1874 Circa 2004 removal
Thanks to the thread, it went pretty well. It is pretty much a two person job to take it out and put it back in. So for about $25 in parts and a few hours of time, we have a microwave that works for more than 59 seconds at a time!! And no damage to me or the coach. The same unit is still available for around $500, depending on the color. A nice savings!