Hi friends, please forgive me if I didn't give you updates anymore about the Avia DSM. I didn't notice the new posts.
I hava a great news about the watches, because two days ago, I've tried to put a new battery into the watches, and after a couple of hours, the first watch (the one I used to wear) started working again. I've tried removing and reinstalling the battery to see if it would take the same amount of time in order to work again, but now it turns on immediately when you put the battery.
Besides that, the little issues that the watch had some months ago (such as segments disappearing randomly and fading if you'd squeeze the caseback) have disappeared. It's strange to see that the watch started working reliably after it apparently died two months ago.
I think it could've been a battery issue (I used an alkalyne AG13 battery before, now I'm using a Renata 357), and maybe I should've kept the battery inside the watch during these months, maybe the watch would've begun to work reliably in a shorter time. I've fixed the crown too.
Here's a picture of my Avia SGT Quartz finally working flawlessly. It keeps good time too! :)
The second one, which wasn't working (my friend was able to fix it but it wasn't very reliable) sprung back to life as well, although it took more time than the first one. Unlike the first watch, the second one works a bit erratically: all the segments but one are visible, and the apparently missing one is so dim that you can barely see it in counterlight. It also lacks a retaining screw which should keep the module firm into the case. However I think that a good cleanup of the module and the contacts would make that second DSM work properly.
At least the story had a good ending: I'm wearing the first watch since three days and it works flawlessly, without any gremlin, just like how it should've been 40 years ago. I love it!