Velodyne DLS 3750R strange sound

Hi,

My Velodyne subwoofer makes a strange sound after 20 mins of light use or 5 mins of heavy use, almost like something inside heats up and causes this. ive checked the capacitors and none are bulging, not sure what to check next. I searched all over the internet yesterday trying to find anyone else with the same symptoms but to no avail. the subwoofer was manufactured in 2012. This sound happens even when input is not plugged in. Here is a link to the video I posted on youtube: https://youtu.be/oDRa1HMDX3M

Thanks,

Curtis

Hi, Thanks for the quick response. Here are the photos, if you need a particular spot or a different angle im happy to oblige. Much appreciated.