| As with the epee question, more information is needed. By "stopped working", does he mean throwng white lights or grounding. By cold, does he mean genuinely cold (i.e., being brought in after sitting in the trunk on a chilly day)? If it's that, then a possibility is that the cold causes the tip spring to contract a little bit, so that it doesn't connect with the point contact and the tip as securely. The spring expands as it warms to room temperature, making a better connection. Regardless, the difference between 2.5 ohms an zero ohms in not going to make a difference in the functionality of the weapon (the limit for a foil is 2 ohms, btw, and that's an upper, not a lower limit).
One thing people need to be aware of is that you can get a thin (i.e., not visible to the unaided eye) layer of corrosion on the contact surfaces in the point (especially the ends of the spring) that will not be removed by cleaning the point out with alcohol or contact cleaner. You need to lightly sand the ends of the spring with emery paper to clean it up.
-Dave | 
Linear Mode
