I wish I could diagnose piano technical queries over the internet, but I am not a piano technician. I suspect I couldn\'t even if I was. Do you know a capable competent piano technician? I\'d start with whoever regularly tunes the instrument.
I\'m curious, how does it sound? I\'ve heard of a number of pianos with cracked sound boards. Generally if it doesn\'t sound cracked it\'s OK. If it sounds cracked (and I\'m not sure how that\'s manifested) then it should be repaired or replaced. Sound boards can usually be replaced, the question is whether the instrument is worth it. Good luck.