I thought the symptom in this thread was when you press
a button it does not show on the LCD that you pressed
a button and it does not beep. I would look at your RF
if your remote is showing a press and beeping but nothing
is happening. I have not seen a lot of failures on my
900 but every failure I do see is no beep and no LCD change
and consequently no command. I have never had my MX-900
beep with no command issued.