During my 600L build i did some rather intensive bench testing of my servos and during this found that out of the box the 855 was making chattering noises around mid range. Suspected gear issues.

I also noted that the cyclic servos sounded very different when aileron or elevator inputs where commanded when compared to just pitch inputs.

Both of the issues above were evident when servos were connected to gpro and futaba receiver as well as when directly connected to receiver also (no gpro).

Here are some videos from my testing. (turn volume up to hear servo noise issues)

I sent them all servos back along with the gpro for align to test as part of an RMA through wattsuprc who were very kind prompt and helpful. The parts were then shipped to align via EMS mail (express). I sent the videos to align of my tests also.

approx 2 weeks after sending all back from my end, watttsuprc advise that align have installed my gpro and servos on the same heli and advised everything is working correctly along with a video (see below link).
https://www.dropbox.com/s/9toywvyunldf7dr/1040904EZ05-09A.wmv?dl=0

What concerns me is the way they tested things (Tail servo)
The tail servo i am almost certain has gear issues but their testing was with full fast stick throws without bothering to use small / slow control inputs ???? as per my tests / video recordings. Naturally the gear issue is concealed and not evident.

I wrote back tonight asking them to test the tail servo more thoroughly around mid stick very slowly the way that i had and also to comment on my observations regarding noise of cyclics particularly the elevator servo.

Very concerned with their testing approach. Why would you test the servos on the heli, wouldnt you test on bench, use slight force against horn etc. Also given they have viewed my video, you would e xpect them to try to replicate the issue which doesnt appear to be the case?

Really dont understand their process for testing?

Really worry about how this might end>