Diagnosing a compressor on an old sub-zero

I have a sub-zero freezer (model 201fd ser#525509) from 1985 that’s stopped working recently. Here’s the story.

A few days ago I noticed that the unit was clicking on, then clicking back off just a few seconds later, and of course the freezer was getting warm. So I went to check the relay and overload on the compressor, and they actually crumbled into pieces as I was very gently removing them. So, I tried hooking up a 3 n’ 1, and it seemed to start for a second, and then stopped altogether. I tested for resistance in the compressor, and it looks alright. I also tested for a ground fault, and found none. Nevertheless, when I fire up the freezer and test for amps, I get absolutely nothing–no amps, no noise, no heat, nothing.

Is it possible that the 3 n 1 is defective, or is this compressor just shot? I’m not exactly excited about replacing the compressor, but I’m also not going to pay $10k for a new Sub-zero in a house I’d like to sell soon.