Plug that request into the Forum search engine. Lots of us have had/still have that problem. More prone to happen in humid climates. Real fix involves removing the clock and varnishing the back so moisture can't get at it.
I recommend you post your question over in the technical section. Most of the gurus won't see it over here, and a lot more people frequent over there. Just a few of us greeters hang out over here on a regular basis.