You most likely will get alot of impute on this. So heres mine, even though I do not have the 3150, I have changed out a 1200.
I went between repair and replace for many months. I first thought of a house type refg. but decided I was not a good enough carpenter to make it look like it belonged. So I thought about replacement, to get a new one in would have to be through the windshield. That stopped that thought.
I ended up with a new cooling unit from JC Refrigeration and could not be happier. As I am always plugged in I went with the 120v only replacement. Its a very easy DIY project and the folks at JC walk you through everything. I would at least think about it.
https://jc-refrigeration.com/
Good Luck safe travels