fridge/freezer turns itself off

Climate control pad inside fridge shows both fridge and freezer is off. Cannot turn either back on with pad. Power to interior of fridge, have both lights and power to control keypad. No power to either compressor or fan. Following wire diagram, discovered no power from terminal block wire that feeds both compressor and fan motor. Replaced both main circuit board inside rear panel and compressor start capacitor. No change. Still cannot turn on from keypad. Im assuming keypad is "ok", that off status is due to some other issue that is effectively shutting system "off". Any suggestions appreciated.