Condensation message on GR-DX77 - any solutions?

I have a mini-DV camcorder JVC GR-DX77EK which has performed well since I bought it about 4 years ago, but over the last 12 months it has been coming up with Condensation Message and now this is so bad that I cannot even load a tape. I have tried keeping it on for hours to get rid of any condensation, but this has had very little effect (works for a few minutes, then freezes again). Does anyone have some advice for this camera? I have seen advice on this forum for similar problems with other JVC cameras, but cleaning the sensor and unplugging the connector on the front of the camera doesn't seem to work for me. All advice greatly appreciated.