i ask myself that question cause my dw-310 has some problems that i couldnt solve out yet.
my guess is the circle flat piece that is glued to the inner side of the backplate of my watch is something like a speaker?
the 2 contacts raising out of the modul , one must touch the metal of the backplate , the other must touch the round thing, right. now the area where the one contact should touch the round thing is scratched, almost scratched away completely, so the watch makes no sound.
then i used one of these round things from a cheap f91w, and just pressed it on the backplate, pressed the plate onto the watch, and voila it made a silent beep, but it worked, so my theory seems right.
but what can i do now, to get the beep back again? i mean i already tried to move the one contact a bot, so it touches another non scratched area of the round thing, but this doesnt do the trick, the contact is already a bit rumbled now, i dont wanna break it. i dont know what to do, but find a cheap backplate of the dw-310, or is there another way?