I too have a Unitrex quartz LED watch purchased in Ontario Canada in '75/76
http://www.ledwatches.net/photo-pages/unitrex.htm
It looks exactly like that one.
It was a gift to me from a great friend and mentor.
I was involved in manual labour at the time and didn't wear it to work.
Eventually the battery ran out and with the advent of LCD etc which could be used one handed, I removes the batteries and put it away.
Last week I bought new batteries for it but alas no joy. The recommended battery was mallory 10L14 but I was told that a AR13 would do and that is what I tried.
I would quite like to get it going again as it is now a bit of a novelty but more so as a reminder of my now deceased friend.
s