I was happy to come upon this overlooked Vulcain for just a few dollars in a thrift today. I have looked through the Internet and eBay for equivalents and searched thru back threads on these Crickets ( there have been quite a few). But still have some questions. I don't seem to be able to find any that have Subdial seconds. Does that date this piece? Serial on back is S1511A. Also I'm not sure how to open the back. Looks like the back has 2 places for screwing off the back. This does turn but doesn't unscrew. Is it just snap off? Also once I get the back off does one need to be careful how it is put back on? Does it need to be positioned in a particular way? I'm assuming it's one one of those that winds the alarm in one direction and winds the timing in the other direction? The alarm does go off properly but the watch seems to be fully wound but is not running.(Hopefully just needs service). Thanks for any information on this model.