MKS 95 uneven response to channel value

[uiron]

one of my MKS95 servos started acting weird. Whenever there's a change in stick movement direction, the horn would start moving very fast, then it would slow down. To test it, I connected it directly via receiver, to rule out FBL behaviour. I can clearly see that while moving stick up and down at even speed, whenever there's a change from "up" to "down" or vice versa, servo horn shoots forward, then decelerates.

The servo used to be on elevator, and as far as I remember had one gear change. In total like 200-300 flights old.

From what I understand, potentiometer went crazy. Tried to open to internals, but doesn't look like there's access to clean it up, it's firmly hot glue'd.

Is the servo busted? Would you replace whole set of cyclics in such case?

[Luvmyhelis]

Originally Posted by uiron

one of my MKS95 servos started acting weird. Whenever there's a change in stick movement direction, the horn would start moving very fast, then it would slow down. To test it, I connected it directly via receiver, to rule out FBL behaviour. I can clearly see that while moving stick up and down at even speed, whenever there's a change from "up" to "down" or vice versa, servo horn shoots forward, then decelerates.

The servo used to be on elevator, and as far as I remember had one gear change. In total like 200-300 flights old.

From what I understand, potentiometer went crazy. Tried to open to internals, but doesn't look like there's access to clean it up, it's firmly hot glue'd.

Is the servo busted? Would you replace whole set of cyclics in such case?

Has this ever been crashed? Or the servo ever taken apart? If so, the potentiometer couple area with the actual gear may have elongated the hole in the gear here? A close inspection is required. And it is easy to get to just by pulling off the forward servo cover.

[uiron]

yeah, it has gone through one output gear change. After another inspection of the slot where output shaft goes in shows that the "D" shape of it is kind-of damaged, I probably pushed output shaft in in mis-aligned. What's strange though, is that it flew like this for well over 100 flights after the gear change.

Anyway, what about another part of my question - would you replace just one servo, or the whole set of cyclics in such case when one servo fails?

[dannylightning]

i would only replace one servo, actually i would send that servo back to mks and see what they could do for me. maybe they could fix it on the cheap.

[Luvmyhelis]

Call Thomas at MKS USA. I have had the honor of spending some serious time chatting with him. Talk about superior customer service! He is the man to talk to here. He returns all his calls personally.

[dannylightning]

Originally Posted by Luvmyhelis

Call Thomas at MKS USA. I have had the honor of spending some serious time chatting with him. Talk about superior customer service! He is the man to talk to here. He returns all his calls personally.

yeah he will talk your ear off haha.. and he will take care of you if your servos are under warranty, i think you get a year warranty..

[uiron]

I don't know, a servo few hundred flights old, had at least one crash with a broken shaft, mis-aligned replacement gear pressed in, damaging potentiometer socket.. hell I would not cover warranty myself. Also, sending it across the Atlantic twice will take too much time and money

I've already got a new servo on the way. does said Thomas have an email? Phonecall is troublesome due to time differences and me being non-native speaker

[Luvmyhelis]

Originally Posted by uiron

I don't know, a servo few hundred flights old, had at least one crash with a broken shaft, mis-aligned replacement gear pressed in, damaging potentiometer socket.. hell I would not cover warranty myself. Also, sending it across the Atlantic twice will take too much time and money

I've already got a new servo on the way. does said Thomas have an email? Phonecall is troublesome due to time differences and me being non-native speaker

Yes. Then again since you are over the pond. Just deal directly with MKS themselves. Their customer service is outstanding! I bought the very first set of MKS 95's directly from them several months before anyone had even heard of these. And did the first write up on them here at HF. To note, the elongated hole issue is cheap to address and the servos are capable of hundreds upon hundreds of flights. I have never seen a motor wear out?

[uiron]

thanks - I'm in the process of trying to get any response, MKS representatives in EU recently changed so it's hard to understand who to talk to.

Anyway, thanks all for help! Tomorrow mailman will hopefully bring the new servo so I can finally test my brand new second hand sk540

[Luvmyhelis]

Originally Posted by uiron

Anyway, thanks all for help! Tomorrow mailman will hopefully bring the new servo so I can finally test my brand new second hand sk540

I spent this afternoon tuning one up on one of my 600s. Great controller! I had one coupled up with my Mks servos on the Warp earlier. Brilliant flying heli. Razor sharp. And the proactive gov is to die for.