I assumed after 30 years the compressor had gone out. Next morning I wondered why the condenser fan was not running. Used ohm meter and found no power to fan or compressor. Got on internet to find location of defrost timer and thermostat. I had help on line ordering part. My problem was model number had two zeros and not two letters "O".
Part arrived ahead of schedule. I did not understand black lead wire. The package did not come with directions. Checked YOUTUBE and understood it needed to go over one of the four pin on the timer. Old timer had two wire which went to two of the pins. Looked to me the clock on old part was powered from pin marked RED and that new part was internal powered from RED. This left pin #2. Instructions sent on Monday for schematic on Fridge confirmed #2.
Following install the Frig did not start. I accessed the timer thru the access hole and gave a twist to take it out of defrost. Hope this part is good for another 30 years!!