How can you program a specific button on the PSR-740 keyboard, so you don't have to go through a lengthy process to change, say melody or octave. My grandpa is getting very old and his favourite thing to do is to go around on weddings and play with his Yamaha. Sadly, his eyesight is getting worse and his hand coordination aswell, so it would really help if he had the basics on buttons. Any help is appreciated. :***

The only way to do it is by using Registrations. It is quite simple to do. You can get the directions from the owner's manual.
Thanks for helping Grandpa!
DonM

Yes those registration memories on PSR keyboards are great. You can save your current configuration ( ie. octave etc ) into a registration memory so it can be recalled again with one button press from the front panel.