Roffensian wrote:
It's not magnetised, and shaking it is not going to solve any problems (oh, and NEITHER IS SHOUTING).
If it is fully wound and works in some positions but not in others then there is possibly something quite seriously wrong with it - definitely take it back and I would ask for an exchange. It may simply be dirt in the movement but it could also be something like a broken jewel which is allowing a pinion to shift and affect whether the watch runs. If that's the case then it is likely an indication of a serious impact - like a drop on to a hard surface, so there may be other issues as well.
Thank you very much for the input!