So what do you think is the problem? It looks totally fine for to be operated in normal position. Handle rolled 90 degrees wil not ever work, nothing to do with PID. When it is rolled like that there is no motor taking care of yaw.

Handle tilted back 90 degrees is ok working position, but your gimbal has some flex (every gimbal has) and the PID settings are too high to work on that position. If you need that position, tune the gimbal on that position.

You could also try filters and activating adaptive PID tuning.

What gimbal i that? it has really strange motor configuration, very smal Pitch motor, huge Yaw motor and double that for Roll. Normally it is the Yaw motor needing most power and support.

A bit complicated, but cool idea. I think it is the belt or lens is causing the noise. maybe it flex or is too loose, is it possible to adjust it? Identify the source of the noise, that is what you need to fix.

Your Pitch settings are clearly already low, so it would be good to see what can be done mechanically to improve the Pitch. You could try to lower 'I' for Pitch, but look the mechanics first and also, do you need to use the camera on handle tilted 90 degrees back? if not, do not worry about it, just set the gimbal working well on the handle positions it will be used.

It could be that when the handle is tilted back, the weight shifts so that belt loosens up, or maybe it is the lens.

Different lenses behave much differently, it is not only the weight, but how solid they are. Big loose IS unit inside the lens is bad. also some lenses like Canon 50 1.4 have much free play and are very difficult. also if the lens attachment to the body is not solid causes problems.

Remove anything that can be removed and feels loose, make sure that filters etc. are well installed, loose filters cause problems.

Try also lower power for the Pitch, PID for Pitch need to be retuned after this.

See the updates regarding lens above. I would try to lower the Power even more and retuning the PID, should result higher PID with lower Power.

Also see the filters, http://www.levitezer.com/styled-2/blog-2/files/archive-oct-2014.html

Ps. I am a bit surprised if there is no adjustability for the belt, maybe you could ask from the manufacturer.

There is really bad noise at 0:20 on the video, where does it come from?

It looks like maybe the camera installation is not really solid. With very light lenses I use only camera body installation, with bigger lenses I use camera+ speedbooster installation and in addition flash shoe. It really makes a big difference how well the camera is installed.

Remove the cap (if on place) and hood from the lens, does it affect?

"rings for strap" , I have removed those. Clearly something is shaking badly at that position.

I think you should ask the manufacturer if/how the belt can be adjusted. I think there must be some way.

And it would be good to look in to the filtering, it can really help.

First if yo have not done so already, try auto tuning, holding the gimbal in hand and on position it vibrates worst (on the handle positions you will be using the gimbal). Tune one axis at time. set the stability slider first 1/4 up from good stability. Make sure adaptive tuning is not activated when doing this.

I already tried AUTO PID tune - always from zero at all axes .. i will try with your recommendation, thank you.

in this position vibration is more visible when i use higher D on pitch axe (no visible moving or shaking on belt) must be one of motor and vibration just relay through whole gimbal

these are 42 pole motors, belt drive looks like 1:1 ration, inverted status setted up but i just lower power pro Pitch motor (at manufacturer recommendation), no more changes made on motor setting by me ... i am new in gimbal world

anyway, thanks a lot for your time and advices i wil try your things later today and if there is no change so far i must go to manufacturer to set it up (its very long way) because i need it this weekend