the board was touched up with power-down.there is no battery backup.these things happened in the field and reported by the service engineers.
to peter & phillip - i can ask my engineers to use proper soldering irons. but my point was wheather the 24cxx can be corrupted by power spikes /static discharges.
as per aka j it can't. so let me thouroughly check.
thanks all and happy Xmas.
uds