Well, I got to an insteresting situation with mine.
I haven't used mine for a while. When I tried - I heard a lot of distortions even on low volume levels, and the operating red led got dimmer and dimmer. I understood that the battery is dead, and tried to charge it. The green light at the rear of the unit started blinking. I left the unit in this mode, but battery never got charged - I also confirmed it with USB tested - there was no current when the unit was "charging". So I removed the battery and guess what ... It's dead. Not only discharged but useless - I tried to revive it using Opus 3100 charger - the battery simply can't hold any charger. So I replaced it with another one, this time protected battery. Now when I plug the USB the light lights solid green.
I will try to use the amp and see if it charges the battery or not.
