Zoom switch does not work at times

My Sony TRV120 Handycam's sliding zoom switch will be stuck at full zoom (telephoto) at times when I turn the camera on and no matter how many times I try moving the switch it stays stuck in full zoom. This has now happened four times. The first time I shut down the camera and took off the battery and then reinstalled the battery and the camera then worked properly. The last couple of times even this did not work. After shutting the camera off several times and removing the battery it was still stuck at full zoom. About 5 minutes later when I tried the camera again it then worked properly. When the zoom is stuck and I move the zoom switch the little zoom indicator image in the screen stays in the full zoom range and does not move at all. This happens with a fully charge battery and even changing to my other battery which is also fully charged makes no difference. Any ideas? TIA