I have a Velodyne CT-100 powered subwoofer that has just started making a loud hum.

I've been using this subbie for several years without any problems and there has been no changes to my system recently.  Just suddenly partway through listening to a CD today the unit started to hum loudly.

I know issues with earthing etc can cause hum but this is something that has suddenly occurred without and changes occurring so I suspect there may be a fault in the subwoofer itself.

Does anyone know where I can take it for repair or is there any further checking I can do myself to isolate the cause of the problem?

Thanks,
Chris.