Please Help, Mark Levinson ML 390S making weird noises

My  ML 390S CD player/processor, sitting on the audio rack, in a stand by mode, started making weird noises, almost like a rattling sound. 

I turned it off. Waited a few minutes and turned it on again, but that did not help. 

The manual, is of no help, and there is nothing on any website either. Can anyone here help me solve this, mystery please?