Usually they just lock up. I have had some that make an awful clunking noise for about 3-4 seconds before tripping the breaker. I have also found some that just seem to be worn out, just won't pump like they should.
There are 3 ways to do anything in life; Good, Fast, Slow: You can pick any 2.
I was taging along with a tech at my new job yesturday. He said the scroll had bad valves. Cited high superheat and low head. I put some doubt in his mind but I'm not sure what this type of problem would look like.
He dia. last winter. Commercial app. Thermals were also burnt and he had put on a term. lok kit to get it going.
They had agreed to buy a new unit so it's a moot point.