ProGram wrote:

Can you hear that noise when you rock the sub chassis with the platter spindle?

I have tried tapping the main chassis (not the sub chassis) with my finger meanwhile, while the table is turning, with the arm lifted from the record, and that too causes a bit of interference in the audio signal but not the same as you see in the video.

It's a bit difficult to tap the sub-chassis while is it turning or is there a specific way to do this?

The problem that you see in the video is mostly occurring when the arm is in the second half of the record.

I purchased it from a guy in the UK and I trust this device was in top shape when it left his house. He did put it in bubble wrap and in a trolley case for me and I did transport it from London to Brussels myself. The transportation screws were tightened. I don't know if internal wiring is with connectors or all soldered but if it is a connector, might one have come half loose or something during transport?

ProGram wrote:

As I wrote: grab the platter spindle and move the sub chassis (the platter and tonearm are mounted there). But do this while playback. In lifted stage, the sound is muted (or should be). If the noise occurs while shaking or moving the sub platter, I suggest that the audio cable is broken somewhere. Don’t fear to ruin your record, that action is harmless.

Please see 

Is the sound coming from the physical deck or from the speakers?

Martin

Dillen wrote:

Is the sound coming from the physical deck or from the speakers?

Martin

It's coming from the speakers.

As the needle keeps tracking the record and the problem seems to affect both channels simultanously, it can hardly be a bad cartridge.
It must be something common for both channels - like f.e. a signal grounding issue (though that would normally result in hum) or a failing power supply to
the RIAA or to circuits inside the ampilfier.
I suggest you check the ground connections first.

In the video it seems the platter sits very high. Perhaps it's just a trick of the light or the viewing angle.
The platter should be apprx 1-1½mm above the surrounding surface.

Martin