We make a certain network card based F340 and Wiznet 5300. All components are commercial grade components. There is a need to operate this device at -40 Celsius.

1. If this device is operated at -40 degrees Celsius, which components would fail? (There is also a 3 volts button cell for DS1307, discounting the cell, which is sure to fail..) How does the crystal behave in low temperatures?

2. What kind of capacitors work well in low temperatures?

3. If we pot the board, will it help? Will the heat generated sufficient to keep the card above minimum workable temperature? There is a 5v to 3.3 regulator on board. If I pot the device with air column inside, and increase the regulator input to 12 volts or 24 volts, shouldn't it generate sufficient heat to raise the operating temperature to healthier one?

Kindly advice..