The links are great as I may end up getting one. Actually it's my brothers one that is broken but it looks the same as mine which is the one I pictured and has a model RT-MWK08 printed on the box.
I will try exchanging the receivers (modules) today to see if one module can work with the other keyboard. I was hoping to find a module that matches the keyboard if indeed that is what's broken. The keyboard has power.