Chinese student with translator not working

Question

I have a student from China with a Besta CD 828. Even with the power cord the translator does not work.How can we check the lithium ion battery?Could that need to be replaced?He says his father purchased it in America about 2 years ago, and it worked fine in the US and China. Then when Ming came in November he used it constantly until it no longer functioned. He is a wonderful student and Iwould love to help him get the translator working again, or at least understand what is wrong with it and how we can go about repairing it.thanks so muchhmfoster(sorry my questions are so elementary)