@jeecz:
my new power supply is only 7.5 V but works fine.
crappy power supplys tend to drop in voltage when you take "too much" current.
i would recommend buing a better power supply, not just one with a higher voltage rating.
try using a stronger power supply (more mA), since the LED make up most of the LXRs power consumption.
had a similar bug with random freezes in the interface and audio continuing to play when too many LED are on. didn't have that strange characters,…
yeah, proper power supply is pretty important.
with my first power supply the atmega crashed when too many LED were lit.
a better power supply solved the problem