Here is a tech sheet
The compressor fan kicking on and off, The food in frezzer is defrosting. Is my compressor bad or is it the defrost timer?
I would say it is a compressor start problem.
If it was a defrost problem the unit would run continually as it tries to get the temperature down to set point but is unable to do it because the coils are iced up and the fan cannot pull air through the evaporator coils.
Here are a couple good sites with info on how to check the compressor and start components
Refrigerator Repair Guide: How To Fix a Refrigerator - ACME HOW TO.com
Be sure to check the compressor windings before replacing the
start/overload device or it will just blow up when you install it.
Be sure to check the compressor prongs to ground/compressor's case, all should be infinite ohms.
Also check that the compressor/condenser fan is running.