I am having a problem with my A77. The audio recording used to be normal, but I bought an external microphone and tested it, and found that no sound was recorded, but the was a weird hiss and buzz sound. I removed the external mic and now the internal mic has the same problem! I have tried reseting the camera to default setting, and taking the battery out etc, any ideas?

Video with internal mic on default settings here: http://www.youtube.com/watch?v=_fIXf...ature=youtu.be
Turn your volume to max and you can hear loads of hissing, with a buzzing/beeping sound approximately every two seconds.