Station 21 along with the first alarm assignment was sent out to the Walkers Ridge apartments for an audible fire alarm activation. First arriving units confirmed an audible alarm had been activated but no signs of fire were present. The building was evacuated and the fire units checked the structure. The maintenance man at the complex reported to command that there had been a lightning strike close to the building and that had fried the board on the fire panel. The building was checked thoroughly with nothing found and all units were returned to service.