Anyone having problem with U-Verse's DVR making a high pitched sound?!

We are on our 2nd dvr box in less than a week and the new one is doing the same thing!. They both started out fine, but after a while they would emit a high pitched sound!. This would happen regardless of if we were recording or not!. also regardless of if it was turned on or not!. I would have to unplug it to make it stop!. Leaving it unplugged for a few hours sometimes helped, but not always!. Did I just get 2 bad DVR's or do all of U-Verse's DVR's do this!?Www@Enter-QA@Com

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