Compressor quits from time to time. Found that if I unplug fridge problem re-sets only to occur again within 24-48 hours. Research shows no defrost timer on unit? Any help?:)

Thanks for your help! It worked fine for about a month? Now I have replaced thermostat, re-soldered the relays and it is acting crazy. It goes out on defrost ( I think) then starts clicking on the mother board about every 1.5 seconds and definately has a voltage drop because the lights dim with each click. Sometimes it comes out after an hour or so of clicking but last night it went down for six hours and we lost food. I hate to spend another dime on this unit especially a mother board. Sounds like a contactor trying to pull in but not latching. Any ideas, guesses, suggestions, beer would be appreciated.. Thanks, Bill