[G per email 04-11-14]
After using one week my new wristwatch (Pionier 505-6)  it stopped when I put it to the table. I have not broken it, but it stopped itself automatically and then didn't show time at all (hands doesn't move). When I shake it, it starts to run normally again for a while, but after some moments it will stop running again (and it doesn't work any more).