Raptor 90 SE Question

[emoe]

Hi guys. I am just finishing up a Raptor 90 SE Build with 4 Futaba 9252 Servos among other components. My question is I can't get the Collective Pitch Servo to quit buzzing. It doesn't buzz all the time but too often for me. I have NO tight links at all. In fact I almost think my problem is there is so little resistance with the Collective Control Arm Assembly that it could be my problem? With the Collective Pitch Servo Arm unhooked if I lower the nose of the Collective Control Arm and let go it naturally goes back up due to gravity pulling down on the heavier opposite end. Then I hook up the Servo to the Collective Control Arm and I go to full positive pitch or close to that it the servo is silent. But when I go to Zero or Negative Pitch I get buzzing because the Collective Control Arm is slightly pulling on the servo arm while trying to go back to Positive Pitch Position by gravity.
I hope this all makes sense. I think for those of you with a 90 it will.
If it matters I have an Collective Pitch Arm length of 17mm but have tried 10.5 to 20 with no help.
I haven't flown the heli yet I am just finishing up with the assembly and this is my last issue.
Can anyone give me some ideas? Am I missing something?

Thanks for the input.

Eric

[Laurens]

Your collective servo arm should point slightly down. The 90 doesn't really have linear pitch. Also digitals will buz, its normal.

The 9252 will do fine on pitch.