8.The E12A only can be turned on when it is connected to a power cable. When take it off the power cable, it can't be turned on.

A: According to your description, we think it is the battery problem. You can send your E12/E12A/E12DIY to us for repair.    
If you want to replace the battery on your own, we can send a E12/E12A/E12DIY's battery and maintain instruction to you, and pls contact us by sending email to support@fiio.net.