I have never taken an electronic lock apart to see how hard it would be to switch. If anybody has and knows how I would like to know.
I changed the mechanical lock on my son's safe because it wasn't very smooth with a new S&G mechanical lock. I ordered a new lock off ebay and it wasn't too expensive. There are good videos on how to set the combination.
Good video here.
https://www.youtube.com/watch?v=HC7i815Dde8