I think the one I have may help - its for a 1950 but it says WR50M on the strap.
I have no idea how to attach it so email me at [email protected] and i'll send it to you.
probably needs a new battery,cr2016 should be, see videos on youtube on how to replace.What I found was connecting the AC pin to the top of the battery,which is the posive resets the watch after new battery in
Try the battery first. Make sure to do the all reset inside of the watch after changing the battery. If it is not the battery send it to Casio. They may change out the complete module.