trumpeter27

I own a Sony MZ-RH910. It does not work when operating off battery alone. When plugged in to external DC power supply it works fine, but apparently does not charge the battery. I've tried replacing batteries and even charging batteries externally but when I put them in the unit I get no response until the external power is applied. If anyone can give me advice as to what might be causing this, and if there is a relatively easy way to correct it, I would be greatly appreciative. Please CC any responses to trumpeter@aol.com