I have been playing my USB stick for years.
Now suddenly I also get the Error 2 in my display.
What is Error 2? it's not in the manual.
Non RF Stereo "Error 2"
Sounds like something has gone wrong with the usb stick's formatting. Have you tried another stick?
This series of errors sounds like it could even be related to a physical connection. I recently found out that usb ports aren't really built for a lot of removal/insertion cycles, so if you're going to be doing that get a small usb extension cable and plug/unplug into the cable port so when it wears out you can just get another cable.
This series of errors sounds like it could even be related to a physical connection. I recently found out that usb ports aren't really built for a lot of removal/insertion cycles, so if you're going to be doing that get a small usb extension cable and plug/unplug into the cable port so when it wears out you can just get another cable.
why is it not in the manual 
Not sure, but probably because it's something they didn't want to expose for whatever reason. Who makes the non-rf unit? Wasn't it also made by rf? I bet whoever made it would know or maybe even have the error documented on one of their other models.