Sorry that I don't have a good picture to explain this. It's hard to put into words...
I'd check the ribbon cable that runs from the wind speed reed switch to the main board.
The cable runs between "levels" in the unit. When you open the unit and fold everything wide out, stress might be put on this cable, possibly causing breaks at the solder joints.
In the last couple of years or so, the way the wind speed reed switch is mounted was changed to avoid this problem. Newer units mount the switch on a little "stand" attached to the main board so the connection between "levels" is no longer there, avoiding the whole stress problem.