Repaired Armstrong myself, so I have to brag!
Mine did that once. A single screw had dropped out of the main relay.
It was a 15 minute fix, after taking the interior facade off, and then the underlying cover for the electrical components, the screw dropped onto the floor giving me the hint I needed to find the problem.
Don't assume the compressor yet, there are other things that can be suspect.
The fact that I am opinionated does not presuppose that I am wrong......