Qubo fluid >> noises / maintenance ??

[k.quadder]

Good Morning,

starting now into Winter/Indoor "Training season", I observed a strange / annoying noise from my "Quobo-fluid-turbo" unit:

A kind of squeak noise that comes with increase temperature after app. 45min of training at high power.
After cooling done it`s gone, but re-occurs during next session ... ?!

Is this a known issue / can I apply any kind of maintenance (e.g. greasing ..) ?
An "explosion drawing" would help also ...

Many thanks in advance !

Karsten