Sorry to hear that your Soundbridge Radio doesn't seem to power up.
Though according to this
thread, it isn't uncommon that these kind of devices die over time.
Since Roku stopped selling these devices and dropped support as well, you cannot ask them to get it repaired.
Though, some user on this forum might help you.
You can send user Burkhardi
a PM (US), or user g0pkh
It is known that they helped many other here to get their Soundbridge Radio repaired.