Panasonic ET-RM100 Remote Control "onkyo volume button work" Questions

Onkyo RC-738M remote control mute does not work and volume control is intermittent. How to fix? Mute button is none responsive while volume control sometimes works if one holds down button and waits ...

Onkyo RC-649M remote The volume button works but barely! You have to hit it a bunch of times before it will begin adjust the volume. All the other buttons work fine. It's as if we have over used this ...