I'm parked, jacks are down, everything is off. I'm feeling a very slight vibration in the floor of the coach. I'm plugged in to shore power. I originally thought someone close to me was running their generator. But, not the case.
Could it be my converter? It is not a continuous, it does stop occasionally.
It's only bothersome because I don't know what it is.
Any thoughts?
May be the converter fan. Most have a fan that is temperature controlled to keep converter temperature down.
If it is the same location as on the 1993 U240, the OE converter was in the basement compartment passenger's side behind the entrance door/ in compartment in front of the battery bay.
What Brett said. You can only see it from the driver's side in my U225. It's at the far end of the bay next to your generator.