I bought a used 80W fiber laser from OMtech and the galvo head has a high pitched sound that I cannot hear- unfortunately I am surrounded by younger people who can hear it. I sent a video of the noise to OMtech and they diagnosed it as the galvo head. They initially said it would be warrantyed but
now say it will not- I am in discussions on that- anyway I had ordered one on ebay [it turns out it was their ebay store] and have the head, so it need to be replaced no matter who is paying for it. There is not much on line about replacing the Galvo head but the little I have seen seem pretty simple. I was trained as an electronics tech 60 years ago- my concern is the re-calibration that might be needed. I will be thankful for any comments you might have, Gene