From memory of my Wind instrument display in the past before I replaced the three displays (wind, speed, and depth), I think there are four small screws at the back under the sealing strip. Remove them and it should open up. I opened my wind instrument after the face got pushed in and it filled with water. I washed it out with fresh water, put it in the airing cupboard for a few days, sealed it all up again, and......it worked!!
Well all that will be in there is wires and bits of stuff and you can then nod knowingly and go "Ah Ha" and "Umm" and "tch tch", so a bit pointless really. But if you really want to get inside and prove it to yourself, try hacksaw and hammer?
Why is everyone so negative? of course open it up.......I have no knowledge of this item but I would certainly find a way into it somewhere. The chances are quite good that you'll spot the fault (perhaps a simple broken wire.................). At the very least you'll know what was inside it and perhaps how to manufacture a better one next time.