Lenovo docking station crackling noise issue

Hi
Please can you help.

I am thinking about buying a W530, and I have been reading on the lenovo forum about an issue with a crackling noise from the laptop speakers when it is plugged into the docking station.

From what users were saying it is an issue that is affecting many W530's. There appears to be a motherboard replacement solution. The thread I was reading started in July - people have had this issue since then from what I could gather.

I called up technical support to find out if it was a problem affecting new W530 models and a rep said that he had not heard of the crackling noise problem and I think he implied that if you have the laptop on when plugged into the docking station there would be a crackling noise because it shouldn't be on when plugged into it. He basically said that you should NOT have the laptop on when plugged into the docking station.

However from what I could ascertain, people on the forum have this issue when the laptop is on and plugged into the DS.

Has anyone here been having this DS noise issue?

It seemed a bit strange that he said the laptop should not be on when plugged into the DS, yet people were getting technical help with this issue after having the laptop on and in the DS. What is the correct thing to do regarding the docking station? Is the problem only created because the laptop is plugged in?

Lastly, and excuse my lack of knowledge here, what exactly does the docking station do? Does it come supplied with the W530?

Thank you.