I'm pretty universally a Japanese watch collector, but came upon a nice example of a Hamilton Electric Pacer (oddly, with a Ventura dial) at too good a price to pass up. I picked up the Rene-recommended battery option, the 387s, and carefully installed it. The watch takes right off, and seems to run strong, but the moment I turn it right-side up, or even on its side at some angles, it stops within a few seconds. I know the watches are very difficult to work on, and I'm somewhere below an amateur tinkerer, so I'm afraid if it's not an easy fix I'll probably just sell it, but am hoping not to. Any tips?
A (lousy phone) pic for goodwill: