I am trying to repair my fridge. It is a Magic Chef model RB21K-4AF. I bought it used about 9 years ago, so I estimate the age to be 15-20 years. The problem is that the compressor gets warm, but will not run. The condenser fan is working. I suspect the PTC relay because when I hook my ohmmeter across it I always get 10 ohms – regardless of whether I hold it over a candle or put it on an ice pack. I measured the compressor resistances – C to R is 3.3 ohms, C to S is 8.9 ohms, R to S is 12 ohms – I think this is correct? Is there a way to check the capacitor? When I hook my multimeter to it, I can see the resistance slowly climb to about 5 megohms and when I switch my leads around, resistance drops and then climbs again.

The problem started yesterday when we lost the neutral coming into our house.

Schematic from back of fridge here: www.avrstmd.com/other/schematic.jpg

Any and all help greatly appreciated!

The resistance of the compressor you posted is fine, does the ptc relay rattle when you shake it?