I recently bought a second hand Canon XM1. It's all fine except for the built in microphone, which outputs a high pitched whistle constantly. If an external microphone is plugged in, the audio is fine.
Is this an unfixable problem with the camera or is there something i can do about it? It doesn't hugely bother me as using an external microphone doesn't cause a problem, but it would be very handy to have the XM1s microphone also.