Seeking informed opinion--

Our very reliable greater than ten year old "Dipose All" just stopped working.

#1) Does anyone know how to fix these things? Can they be fixed?

#2) Does anyone know (and would anyone be willing) to help us learn how to replace it?  We would be willing to pay you for your time, but are hoping to avoid a $$$$ visit from a plumber.

Many thanks.

PS. Does anyone want our scraps for their compost in the meantime?