Korg Poly800/EX800 Users

I just picked up a poly800II in very good cosmetic condition.  It holds 
patches fine, too.
Sometimes it will just freak out for a moment.  If I pick it up and 
lightly bend it, it makes static noises, or thins the sound out.

Does this sound like bad solder joints?  or did I just buy a lemon?

Any help is appreciated,
James