my 9 yr old refrigerator/freezer suddenly stopped cooling. the fan works and the controls are lit. the compressor will not start and does not make any noise. the coils were dusty so i cleaned the coils. i checked the run cap and its ok. i checked the overload switch and it has continuity. i just replaced the ptcr relay and it did not solve the problem. what do you think i should do next? change the ckt board, temp sensors or something else? i really dont want to attempt to change the compressor... i dont know how to solder the copper tubes and the cost seems too high. i read something about checking the compressor resistance readings and verifying power to the compressor. also, i read that a lot of people have difficulty modifying the replacement ckt board for their particular unit. please advise.