I have purchased Yamaha psr 700 a month ago. Yesterday suddenly the keys stopped responding. Rest all the sound is working, but none of the keys are functioning. Few of the people have given me the option of resetting the keyboard, but that doesnt work as recenting requires to press the right most white key, and it is not being identified. Surprisingly "mic setting" seems to be disabled as it is not getting lightened when I start my keyboard.
Investigate warranty service (repair). A keyboard one month old should be under warranty. Check with your locale's policies. Example for the US: https://usa.yamaha.com/support/warranty/keyboards/index.html
https://www.yamaha.com/paragon/servicerlocator/
Current Yamaha Synthesizers: Montage Classic 7, Motif XF6, S90XS, MO6, EX5R
You may want to make sure settings are correct first, though.
Press [MENU] then [MIDI], make sure "System" tab is selected. Look at "Local Control" and be sure there are green checks for all regions.
Current Yamaha Synthesizers: Montage Classic 7, Motif XF6, S90XS, MO6, EX5R
I think it's possible that your keyboard is broken