Clean the doors tracks.
Clean and lubricate the spindles (a little white lithium grease) and give the motors a small drop of a suitable oil for sintered bearings.
Add a small drop of f.e. teflon-based oil to the small pulleys under the center panel. 

Martin

Thanks Martin, 

I understand what you are saying. But I don't understand what components you are specifically pointing at. 

The tracks i've cleaned already, 

The spindles; what are these exactly (I don't want to accidentally grease something like the pulley wires) 

I don't see the 'small pulleys under the center panel"; where exactly are these (center panel is removed)? 

Perhaps I am being too hesitant but once you accidentally lubricate tuner scale wires you kinda become slighly anal :-)

Bert

The spindles are the (either shiny chromed or brass colored) rods that are driven by the motors and that drives the strings for the doors.
The spindles each have a fairly large pulley for the belt at one end and are press-fitted into small gaps in the plastic chassis and will need a little greasing to these gap points.

If you follow the strings towards the center of the Beocenter, you will see that they run around small wheels and go back again.
Here is also an arrangement of springs to keep the strings tight.
These wheels will need a little attention too as mentioned above.

Martin   

Hi Martin, 

Ok clear but it did not help sadly. 

I removed the new belts and reinstalled the one old belt I still had. 

Now it is working better but still not good. 

It seems as if it just can't move freely, like it is being held down by something. 

But as far as I can see all of my Beocenters are the same and on the tracks. 

And i've cleaned the hell out of everything with Isopropanol and then greased it (silion grease)

I am a bit stumped here but then again this is B&O. 

I did not do anything with the motor (lubrication) as I don't know where exactly. But the motor seems to work fine. 

It's just as if the motor doesn't have enough power or something like that. 

Strange that this is the same on all 3 machines?

BB

Okay I was able to solve this with:

- An enormous amount of alcohol for cleaning

- roughly 100 cleaning pads (black as night)

- relubricating just about everything. 

- slight touch of Deoxit faderlube on the string (very little)

I also changed the belts for ones that add a bit more tension. 

That last one appears to have a large effect

So now the doors are all sliding nicely again. 

Perseverenace is bliss, sometimes these machines are extremely dirty :-(

Bert